ft* 
 
GLASGOW 
 PUBLIC LIBRARIES 
 
PUBLIC LIBRARIES 
 
 THE 
 
 RAY SOCIETY. 
 
 INSTITUTED MDCCCXEIV 
 
 ^.^^^_^ 
 
 ^i^-^^^^ 
 
 LONDON; 
 
 MDUCCLXII. 
 
GLASGOW 
 ON THE ''UBLIC Li3RAR!E! 
 
 GERMINATION, DEVELOPMENT, AND 
 FRUCTIFICATION 
 
 HIGHER CRYPTOGAMIA, 
 
 AND 
 
 ON THE FßUCTIFICATION OF THE 
 
 CONIFERS. 
 
 BY 
 
 Dr. WILHELM HOFMEISTER. 
 
 TRANSLATED BY 
 
 FREDERICK CURREY, M.A., F.R.S., Sec. L.S. 
 
 LONDON: 
 
 PUBLISHED FOR THE RAY SOCIETY, BY 
 
 ROBERT HARDWICKE, 192, PICCADILLY. 
 
 MDCCCLXII. 
 
^ 
 
 /^f/O' 
 
 ■<r/^ 
 
 I, 
 
 i 
 
 f6nb 
 
 PRINTED BY J. E, ADI.ARD, BARTHOLOMEW CLOSE. 
 
TRANSLATOR'S PREFACE. 
 
 The work of which the following pages contain a trans- 
 lation has not yet been published in Germany, and a few 
 words are necessary to explain its nature and origin. It 
 is founded mainly upon the author's well-known treatise on 
 the higher Cryptogamia, which appeared at Leipzig in 
 1851. Since that period Dr. Hofmeister has continued 
 his valuable researches, and the results of his observations 
 have been published in the 4th and 5th volumes of the 
 'Transactions of the Royal Academy of Saxony,' in the 
 Reports of the same Academy for the year 1854, and in 
 the 'Regensburg Flora' for the same year. In addition 
 to the matter relating to the Cryptogamia, the original 
 treatise also contained some remarks on the fructification 
 of the Coniferae, and on the analogies between the sexual 
 phenomena in mosses and vascular cryptogams on the one 
 side, and the conifers on the other. Dr. Hofmeister 
 has since published further observations upon this latter 
 subject in the ' Regensburg Flora' for 1854, and in the 
 first volume of ' Pringsheim's Jahrbücher für wissen- 
 schaftliche Botanik.' 
 
 At the request of the Conncil of the Ray Society", and 
 
VI TRANSLATORS PREFACE. 
 
 for the purposes of the present translation, Dr. Hofmeister 
 undertook to combine all the above publications into one 
 uniform whole, revising the text throughout, and adding 
 a quantity of matter existing in manuscript, being the 
 results of his subsequent researches. Dr. Hofmeister's 
 object has been to render his work a complete record of all 
 thatjs at present known of the subjects to which it relates, 
 and the translator feels confident that this object has been 
 fully attained. 
 
TABLE OF CONTENTS. 
 
 CHAPTER I. 
 
 PAGE 
 ANTHOCEKOS L^VIS AND PIJNCTATTJS ... 1 
 
 Vegetation of Anthoceros, 1 — 7 ; cell-multiplication in the stem of Antho- 
 ceros, 3 — 7 ; chlorophyll bodies, 5 — 7 ; organs of fructification of 
 Anthoceros, 7 — 18; formation of antheridia in Anthoceros, 7 — 9; 
 escape of the antherozoids, 9 ; formation of the archegonia in Antho- 
 ceros, 9 ; their impregnation, 9 ; their development into the fruit, 
 10, 11; cell-development in tlie young fruit, 11 — 14; the so-called 
 calyptra, 13; the columella, 13, 14; formation of the spore-mother- 
 cells, 14 — 17; spores, 17, 18; reproduction of Anthoceros by buds, 
 18; observations of Mohl, Nageli, and Schacht on the development 
 of the spores of Anthoceros, 18, 19; reference to figures of Antho- 
 ceros, 19 ; observations of Nees von Esenbeck, Bischoff, and Schacht 
 on the fr\ictification of Anthoceros, 19. 
 
 CHAPTER II. 
 
 LEAFLESS JTTNGERMANNIiE . . . .21 
 
 {Pellia epiphi/lla, Aneura pingids and multißda, Metzgeria f areata.) 
 
 Structure of the spores of Pellla epiphi/Ua., 21 ; their germination, 21, 22 ; 
 vegetation of Pellia epiphi/lla, and cell-multiplication in the stem and 
 shoots, 22 — 29; production of roots, 23, 24; formation of hairs, 24; 
 production of shoots, 26 — 28 ; production gf antheridia, 29, 30, and 
 spermatozoids, 30, 31 ; production of archegonia, 31 — 34 ; perianth, 
 33 ; impregnation, 34 ; development of the fruit, 34 — 39 ; formation 
 of elaters and spore-mother-cells, 38; production of spores, 39 — 41; 
 vegetation of Metzgeria furcata, 41 — 43 ; cell-multiplication in its 
 stem, 41 ; development ot shoots in Metzgeria fiircata, 41, 42 ; small 
 size of its cliloropliyll-granules, 42 ; develo[)ment of adventitious 
 shoots, 42; production of fructiferous leaves or lateral axes, 43; 
 antiieridia and archegonia, 43 ; devf-lopnient of si em and shoots in 
 Aneura, 43, 44; production of archegonia, 44, 45; development of 
 the fruit, 45 ; development of antheridia, 45, 46; production of buds 
 by Aneura nmltifida, 46. 
 
Vlll TABLK or CONTENTS. 
 
 CHAPTER III. 
 
 PAGE 
 LEAFY JUXGEIOIANNI.E . . . .47 
 
 Gradual trausition from leafless to leafy Juugermannia;, 47; Blasia pusilla, 
 a remarkable transition form, 47; its stem, shoots, and leaves, 47, 48; 
 its reproductive buds, 48 ; cell-multiplication in the terminal bud of 
 Blasia pusilla, 49; its reproductive buds and bud-receptacles, 50, 51 ; 
 spores of FruUania dilatata, 51 ; their germination, 51, 52 ; spores of 
 Juugermannia bicuspidata,^^; their germination, 52 — 54; germination 
 of Jungermannia divaricata, Alicularia scalaris, Sarcoscyphus Funkii, 
 and Jungermannia crenulata, 54; germination of Lophocolea hetero- 
 phylla., 54, 55; spores of Radula coniplanala, 55; their germination, 
 55, 56; cell-multiplication in the end of the stem of leafy Juuger- 
 mannise, FruUania dilatata, Lophocolea bidentata, Trichocolea tomen- 
 tella, Kadi Jungermannia bicuspidata, 56, 57; m Jungermannia connivens 
 and divaricata, 57; the forms of the leaves of Juugermannise, 57, 58; 
 origin of the leaf of Fossombronia pusilla, 58; appendages of 
 the leaves of Lophocolea, 58, 59 ; growth of the teeth of leaves 
 of Lophocolea heterophylla, 59 ; leaf-development in Jungermannia 
 bicuspidata, connivens and divaricata, 59, 60 ; in Ptilidium ciliarey 
 60; development of the leaf of FruUania dilatata, 61 — 63; of 
 Radula complanata, 63 ; leaves of Jungermannia curia and crenulala, 
 and Alicularia scalaris, 63 ; general observations on leaf-develop- 
 ment in Jungermannia;, 63, 64 ; mode of ramification of the Juuger- 
 mauniae, 64, 65 ; half-subterraneous shoots of Haplomitrium Hookeri, 
 regarded by Gottsche as its roots, 64, 65 ; development of antlieridia 
 of Liverworts, 65 — 67 ; cell-division in antheridia of Madotheca 
 plat 1/ phi/ IIa, Fossombronia pusilla^ and Lophocolea heterophylla, 65 ; 
 formation of spermatozoa in Liverworts, 66 ; peculiar formation of 
 antheridium of Madotheca platgphylla, 67 ; sizes of spermatozoa in 
 leafy Jungermaimia;, 67 ; development of archegonia of leafy Liver- 
 worts, 67 — 72; calyx or perianth of Liverworts, 68 — 71; in Radula 
 complanata, 68 ; in Jungermannia bicuspidata and divaricata, and 
 FruUania dilatata, 69; in Alicularia scalaris, 69, 70; abnormal 
 perianth of Calypogeia Trichomanes, 70, 71 ; development of the 
 germinal vesicle in Fossombronia pusilla, 71, li; proportion of fruit 
 to archegonia and antheridia, 72, 73 ; development of fruit in Jun- 
 germanuiae, 73 — 83 ; cell-development in the fruit of Jungermanniae, 
 74, 75 ; cell-development in that of /. divaricata, 75, 76 -, elaters of 
 /. divaricata, 75, 76; cell-multiplication and production of elaters in 
 Jungermannia biscuspidata and trichophylla, Radula complanata, 
 Lophocolea heterophylla, Alicularia scalaris, and Calypogeia Tricho- 
 tnanes, 77, 78 ; development of fruit of FruUania dilatata, 78, 79 ; 
 formation of the calyptra in Liverworts, 79, 83 ; individualisa- 
 tion of the elaters and spore-mother cells, 81—83; Hedwig's in- 
 vestigations of the germination of spores of Jungermannice, 83 ; 
 jS'ees von Esenbeck on the same subject, S3 ; Bischofl' on the germina- 
 tion oi Pellia, S3 ; Gottsclie's observations on the spores oiPeUia, and 
 on the ^cxmn\Ki\o\\oi Blasia pnsUla, 83; Gottsche on the germination 
 of Jungermannia crenulata, 84 ; Grönland's investigations on the 
 germination of leafy Jungermannise, 84; Nägeli's observations on 
 cell-multiplication in the stems of Jungermannise, 84, 85; Nees von 
 Esenbeck and Gottsche on the ramification of Jungermanniae, and 
 Gottsclie's statements regarding the development of the leaf iu 
 
TABLE OF CONTENTS. IX 
 
 PAGE 
 
 Haplomitrium Hookeri, 85 ; Hedwig's determination of the structure 
 of the archegonia of Jungernianniae, 85, 86 ; fruit of Jungermannise 
 observed by Gottsche, Schniidel, and Hedwig, 86 ; development of 
 their spores observed by H. von Mohl, 86 ; membrane of the elater 
 seen by Schmidel in Aneura multifida, 86 ; Gottsche's observa- 
 tions on the ehiters and perianth of Jungermanniae, 87 ; Schmidel's 
 discovery of self-motile bodies in the antheridia of Fossombronia 
 pusilla, 87; figures and descriptions of antheridia and spermatozoids 
 of Jungermannia; given by various authors, 87 ; Gottsche's observa- 
 tions on the antheridia of Haplomitrium Hookeri, 88. 
 
 . CHAPTER I\^. 
 
 KICCIA AND EIELLA 
 
 The germ-plant oiRiccia glauca and the arrangement and multiplication of 
 its cells, 89 ; vegetation of Riccia glauca, 90 — 93 ; its leaves, 92 ; de- 
 velopment of its organs of fructification, 93 — 97; antheridia, 94; 
 archegonia, 96 — 96 ; development and maturation of the fruit, 96 ; 
 production of gemmae in Riccia glauca, 97; Lindenberg's observa- 
 tions on Riccia, 97; Riella, 97; peculiar habit of Riella {Duriena) heli- 
 coplylla, 98 ; germ-plants of Riella Reuteri, 98 ; vegetation of Riella 
 Reuteri, 98, 99; development of its leaves, 99 ; succession of its 
 shoots, 99 ; development of antheridia and archegonia in Riella 
 Reuteri^ 99, 100 ; impregnation and development of its fruit and 
 spores, 100, 101. 
 
 CHAPTER V. 
 
 MARCHANTIE^ AND TARGIONIE^ .... 102 
 
 {Marchantia polymorpha, Fegatella conica, Rebouillia hemispherica, 
 Lnnulariu vulgaris, Targionia hypophylla!) 
 
 Vegetation of the above plants, 102 — 112; formation of each new shoot 
 by the amalgamation of three shoots, 102 ; development of rudiments 
 of spring shoots of Fegatella conica in the preceding October, 102, 
 note ; mode of growth of the shoots of Marchantiece and Targioniece, 
 103 — 104 ; their ramification, 104 ; formation of buds or bulbils in 
 Lunularia and Marchantia, ]04 — 107; vegetation of the buds, 107, 
 108 ; second mode of production of shoots in Ltmularia, Mar- 
 chantia, Targionia, Rebouillia, and Fegatella, 108, 109 ; structure 
 and development of the leaves of Marchantiese, 109, 110; stomata 
 and air-cavities of Marcliantiese, 110, 111 ; inflorescence of Mar- 
 chantiese, 111 — 114; development of the fructiferous shoot, 112 ; in 
 Rebouillia hemispherica, 112, 113 ; receptacles, 113; those of Rebou- 
 illia hemispherica producing usually only four archegonia, 113 ; produc- 
 tion of archegonia in Marchantiere, 113 ; condition of the tissues of 
 the receptacle in the neighbourhood of impregnated archegonia, .113, 
 114; growth of the young fruit of Rebouillia, 114: ; archegonia of 
 Fegatella conica, 114, 115 ; archegonia of Marchantia polymorpha, 
 115, 116; air-cavities of the receptacle of Marchantia polymorpha, 
 
TABLE or CONTENTS. 
 
 PAGE 
 
 117,118; development of archegonia in Targionia hypophylla^W^, 
 119 ; fruit of Targionia, 119; spore-motber-cells and elaters of Tar- 
 gionia, 120; development of autlieridia in Marchantia polj/morpha, 
 120 — 122; spermatozoids of Marc/iauiia, \22 ; antlieridia of i^eioM- 
 iUia hemispherica, 122; Ristorical resume: — Bischoff's woric on tiie 
 Marcliantiese, 122 ; Nees von Esenbeck on Marchautiege, 122 ; 
 Gottsclie, on Marchantieae, 123 ; observations on fructification of 
 Marchantia, by Micheli, Dillcnius, liupp, and Linnaeus, 123 ; 
 Sclimidel's observations onMarchantieBe,123; Hedwigen theantlieridia 
 and fruit, 123 ; Mirbel's work on Marchantia polt/morpha, 123 — 126; 
 von Mohl on the cells of the stoniata of Marchantia, 124 ; Nägeli on 
 gemmae of Marchantia, 124; ramification of Marchantia, described by 
 Nees von Esenbeck as dicliotomous, 125 ; Bisclioff on the impregna- 
 tion of Lunuluria, and on the germ-plants of Marchantieae, 126, 
 127 ; Gottsche and Grönland on the germination of Preissia commu- 
 iata, 127; Grönland on the germination of Lumdaria and Marchantia, 
 127; Henfrey on the development of spores and elaters in Mar- 
 chantia polymorpha, 127; observations on the spermatozoids of 
 Marchantia, by Unger and Meyer, 127i 128; Thuret's figures of 
 spermatozoids of Marchantieae, 128. 
 
 CHAPTER VI. 
 
 MOSSES 129 
 
 Mode of growth of the stems of mosses, 129 ; cell-multiplication in the 
 stem of Sphagnum, 129 — 135 ; Nägeli's observations on this subject, 
 130, 131, note ; pitted cells in Sphagnum, 131; phyllotaxis in Sphag- 
 num, 135 — 137; observations of Braun and Schimper on this subject, 
 136, note; lateral shoots oi Sphagnum, 137 — 139; Schimper's views 
 on the ramification of the branches of Sphagnum, 138, ]39; develop- 
 ment of the stem and branches in Oithotrichum affine, 139 ; develop- 
 ment of the leaves in Sphagnum, 139 — 112 ; Nägeli's observations on 
 cell-development in the leaves ofSphagnum, 110, 111, note; annular and 
 si)iral threads in cells of the leaf of Sphagnum, 112 ; development of 
 the leaves of Phascum, Bryum, Ilypnum, and Polytrichum in agree- 
 ment with that in Sphagnum, 112, 113 ; formation of the pocket at the 
 base of the leaf, 143, 144 ; development of the leaf of Fissidens, 143 — 
 146; chlorophyll bodies in the leaves of i^m/f/c/M and Phascum cus- 
 pidatum, 146, 117 ; Niigeli's views on chlorophyll bodies discussed, 
 146; those of Von Mohl, Artiiur Gris, and Sachs, 146, 147; views 
 of Nageli and Schleiden on the development of the leaves of mosses, 
 147 ; fruit-bearing branches of mosses, 148 ; development of the arche- 
 gonia of mosses, 14S — 152 ; development of the antheridia of mosses, 
 152, 153 ; their bursting, and escape of the spermatozoids, 153 ; burst- 
 ing of the antheridium of Funaria hygrometrica, 153, 154; motion of 
 the spermatozoids of i^w/ff/w awd Polytrichum formosum, 154; develop- 
 ment of antheridia of Sphagnum, 154, 155 ; spermatozoids of Sphagnum, 
 155 ; Schleiden's erroneous views of the structure of the antheridium 
 in Sphagnum, 155 ; impregnation of mosses, 155, 156 ; development of 
 the fruit of mosses, 156 — 168 ; fruit of Funaria hygrometrica and 
 Gymnostomum pyriforme, 157, 158; production of the vaginula, 159; 
 production of spore-mother-cells, 160 — 164; production of the spores 
 of mosses, 164, 165; fruit of Gymnostomum pyri/orme, 165 , spore- 
 
TABLE OF CONTENTS. XI 
 
 PAGE 
 
 mother-cells of Funaria hygrometrica, 167 ; formation of spores of 
 Funaria, 167, 168; fructification oi Archidium phascoides, ]68 — 17Ü; 
 its deviations from the ordinary type in mosses, 168, 169 ; its anthe- • 
 ridia and spermatozoids and archegonia, 169 ; development of its 
 fruit, 169, 170; Schimper's explanation of the nature of the ripe fruit, 
 169, note ; germination of the spores of mosses, 170 — 175 ; production 
 of the pro-embryo, 171 — 17*4; Schimper's observations on the ger- 
 mination of spores of Sphagnum in water ; distinction of the pro-em- 
 brjos of mosses from the prothallia of ferns, 174, 175. Historical 
 resume: — Hedwig's observations on the sexual reproduction of 
 mosses, 175, 176; development of the leafy axis from the pro-embryo 
 explained by Kageli, 176; Nägeli's results extended by Schimper, 176 ; 
 Unger the discoverer of spermatozoids in mosses, 176, 177 ; indica- 
 tion of spermatozoids in the observations of Bischoif, Schmidel, and 
 Nees von Esenbeck, 176, ?^o;'(?; Schleiden's erroneous statement re- 
 garding the structure of the antheridia refuted by Schimper, 177; 
 Schimper's observations on the archegonia of mosses, 177 ; Valen- 
 tine's description of the rudimentary cell of the moss-fruit, 177 — 179 ; 
 development of the moss-capsule first accurately described by Von 
 Mohl, 179 ; observations on the development of the fruit and spores 
 of mosses, by Bischoif, Von Mohl, and Lantzius-Beninga, 179, 180; 
 Bruch's observations, 180; abnormal fruits observed by Gumbel, 180, 
 181; possibility of hybridization suggested by Bayrhoffer, 181. 
 
 CHAPTER VIL 
 
 182 
 
 Their germination, 182 — 185; the first rootlet, 1S3; formation of the 
 prothallium, 183 — 185 ; the turning away of the prothallium from the 
 light, 183 ; formation of antheridia, 185, 186 ; differences in prothallia 
 and antheridia of certain Polypodiacese, 186, 187; Wigand on the 
 occurrence of spermatozoids and their mother-cells in vegetative cells 
 of the prothallium, 187, note ; cell-development in the antheridia, 188 ; 
 production of spermatozoids, 188, 189; observations of authors on 
 the spermatozoids of ferns, \^2,note; production of the archegonia, 
 189 — 197; number and position of the archegonia, 192, 193; pro- 
 duction of the germinal vesicle, 193 ; abortive nature of most of the 
 archegonia on a prothallium, 195, 196 ; growth of sterile prothallia of 
 ferns, 196, 197 ; production of shoots byabortive prothallia, 197 ; great 
 number of antheridia produced by shoots of prothallia, 197 ; pecu- 
 liarities of old abortive prothallia of Gymnogramma chrysophylla, 197, 
 198 ; impregnation of the archegonia, 198, 199 ; development of the 
 archegonia after impregnation, 198 — 201 ; production of the embryo, 
 200, 201; development of the embryo, 201—207; formation of 
 the first frond, 202, 203 ; the first root of the young fern, 203—205 ; 
 adhesion of the embryo to the prothallium, 205, 206; influence of the 
 growth of the embryo upon cell-multiplication in the prothallium, 206, 
 207 ; Von Mercklin's supposed observation of dark striped vessels in 
 the prothallium, 207, note; development of the second frond, 207; 
 Pteris aquilina and Aspndiumfilix-mas examples of two extreme types of 
 growth, 208; vegetation oi Pteris aquilina, 208 — 226; growth of the 
 
XU TABLE OF CONTKNTS. 
 
 PAGE 
 
 frond, 208—210 ; formatiou of the pinnae, 209, 210 ; growth of the 
 first root, 210, 211; growth of the primary axis, 211; growth 
 of the stem-bud and I'ronds, 211 — 214; structure of the stem 
 and formation of tlie vascular bundles, 213 — 222 ; formation 
 of new fronds, 221 — 223 ; development of roots, 223, 224 ; 
 ramification of roots, 224; increase of the tendency to furca- 
 tion in terminal bud with the age of the shoot, 224; unbranched, 
 frondless, terminal shoots, 224, 225 ; position of buds from which 
 new shoots are produced, 225, 226 ; vegetation of Aspidhim filix-mas, 
 226 — 245 ; production of first frond, 226 ; second and following 
 fronds, 227 ; rapid increase in thickness of the stem beyond the 
 fifth or sixth frond, 227 ; cell-multiplication in the terminal bud, 
 227, 228 ; arrangement of the fronds, 228 ; production of first 
 vascular bundles, 228, 229; growth of Aspidium filix-mas in the 
 second year, 229 ; production of roots in the mature plant from 
 vascular bundles of the stipes, 229, 230 ; production of vascular 
 bundles in the stem, 230 — 232 ; form and development of the apical- 
 cell, 232 — 239; table of measurements of apical cells in Aspidium filix' 
 masi Aspidium spinulosum, and Aspleniurn filix-femina, 233 ; relations 
 of base and sides of apical cell in various states of Aspidium filix-mas, 
 234 — 236 ; irregularly shaped apical-cells of Aspidium filix-mas and 
 aspidium spinulosum, 236 ; explanation of the facts connected with 
 the apical cell, 236 — 239 ; coincidence of two-edged form of apical cell 
 and bilinear arrangement of fronds in various ferns, 239; cell-succession 
 in apex of leaf-buds of flowering plants, 239, 240 ; table of measure- 
 ments of apical cells,240; cell-succession in the terminal bud oiAspidium 
 filix-mas and aspidium spinulosum, 241; mucilage surrounding the bud, 
 242 ; development of scales on the terminal bud, 242,243 ; Kunze on 
 the bodies at the base of the stipes in Ilcmitelia capensis, 243, note ; 
 development of frond in Aspidium filix-mas, 243 ; formation of roots, 
 243, 244 ; rarity of furcation of the terminal bud in Aspidituu filix-mas, 
 244; adventitious buds m. Aspidium filix-mas mid Aspidium spinulosum, 
 245; Schleiden'ssupposed axillary buds,245,«oi'e; vegetation ol'^i;/3/(?««>^;?j 
 ülix-femina, Aspleniurn Bellangeri, Slndhiopteris Germanica, Nephrolepis 
 undulata and N. splendens, 245 — 248 ; peculiarities in the growth of 
 Aspleniurn filix-femina, 246 ; development of adventitious buds and 
 furcation of the stem in that fern, 247 ; adventitious shoots of Slru- 
 thiopteris Germanica, 247 ; production of adventitious buds on the 
 frond of Aspleniurn Bellangeri, 247 ; development of runners iu 
 Nephrolepis, 247, 248 ; vegetation of Bolypodium and Niphobolus, 
 248 — 251 ; two-edged form of apical cell and bilinear arrangement of 
 fronds in Niphobolus and Pohjpodium, 248 ; not occurring in Poly- 
 podium vulgare, 248 ; growth of P. vulgare and Bryopteris, 248 — 
 249 ; formation of the stipes and develo|)ment of scales in the above 
 ferns, 249 ; development of the fronds, 249 — 251 ; scales at the base 
 of the fronds, 251; vascular bundles and roots, 251; vegetation of 
 Platycerium alcicorne, 251 — 254; development of the fronds, 251 — 
 253 ; structure of the stem and roots, 253 ; form of the apical cell, 
 253; vegetation of Maratlia cicutafolia, 25 4 — 256; statements of 
 De Vriese and Hartig on the devolojjnient of the MarattiaceJB, 
 254, note; form of the apical cell, 254; growth of the fronds, 254, 
 255; development of the Perula, 255 ; development of scales and 
 roots, 255 ; development of new plants from fragments of Maratlia 
 cicutafolia, 255, 256 ; development of the fruit and spores of ferns, 
 256, 257. Historical review : — 257 — 266; reproduction of ferns by 
 
TABLE OF CONTENTS. Xlll 
 
 PAGE 
 
 spores first indicated by Morison, 257 ; Eluhart's observation of tlie 
 two-lobed leaf preceding the perfect fern, 257; germination of spores 
 of ferns, first accurately observed by Kaulfuss, 257 ; sexual organs of 
 prothallium, discovered by Bischoff, 257, 258 ; antheridia and sper- 
 matozoids, discovered by Nägeli, 258 ; Nägeii's observation of the 
 arcliegonia, 258 ; real nature of the archegonia first ascertained by 
 Suminski, 258, 259; Wigand on the sexual organs of ferns, 259; 
 observations of Hofmeister confirmatory [of Suminski's results, 260; 
 Schacht on the archegonia and impregnation of ferns, 200, 261 ; 
 Von Mercklin on the same subject, and his observation of the 
 entrance of the spermatozoid into the archegonia, 261 ; Mettenius' 
 observations, 261; Henfry on the sexual reproduction of ferns, 261 ; 
 further statements by Hofmeister and Wigaud on the same subject, 
 261,262; anatomy of fern-stem, first clearly explained by Von 
 Mohl, 262 ; Brogniart on the ramification of ferns, 262 ; his views, 
 supported by Hofmeister and Steuzel, 262 ; opposed by Karsten and 
 Mettenius, 263 ; views of Pringsheira and Irmisch adopted by Hof- 
 meister, 263—266. 
 
 CHAPTER VIII. 
 
 EaUISETACE^ 267 
 
 {Equisetum arvense, pratense, varieffatum, hyemale, palustre, and limosum.) 
 
 Growth of the stem of Equisetum, 267 — 269 ; Cramer on cell-succession 
 in the end of the stem, 267, note ; production of the leaf, 269, 270; 
 production of the teeth of the edge of the leaf, 270, 271 ; relation of 
 the cells of the pith to those of the outer layers of the stem, 271 — 
 273 ; formation of the epidermis, 273 ; difi'erentiatiou of the vascular 
 bundles, 273 — 275; separation of the cells of the pith, 275 ; ramifica- 
 tion caused entirely by adventitious buds and their mode of growth, 
 275 — 278; formation of adventitious roots in Equiseta growing in 
 damp situations, 278 — 280; fructification of Equisetacese, 280 — 288; 
 development of spore-mother-cells, 281 — 286; elaters, 287 — 289; 
 spores, 288 — 290; Sanio's observations on abnormal formation of 
 elaters, 291 ; evolution of the spores, 291, 292 ; formation of the pro- 
 thallium, 292, 293 ; male and female prothallia, 293 ; formation of 
 antheridia, 293, 294; spermatozoids, 294 — 296; obstacles to the 
 germination of Equisetacese, 296, 297; female prothallia, 297; Bis- 
 choff's observation of antheridia and archegonia on the same prothal- 
 lium of a. sylvaticum, 297, note; observations on the production of 
 male and female prothallia, 297, 298 ; formation of archegonia, 298 — 
 300 ; impregnation, 300 ; development of the impregnated arche- 
 gonium, 300, 301 ; development of the embryo, 301 — 303; formation 
 of the stem, 303 ; development of adventitious buds, 303, 304. His- 
 torical Review : — Observations of Vaucher and Agardh on the germina- 
 tion of the spores of Equisetaceae, 304, 305 ; Bischoff's observations 
 on the same subject, 305, 306 ; first account of the antheridia given 
 by Thuret, 306 ; archegonia discovered by Bischoff, 306 ; observations 
 of Milde and Hofmeister on the sexual organs of Equisetaceae, 306. 
 
XIV TABLE OF CONTENTS. 
 
 CHAPTER IX. 
 
 PAGK 
 OPHIOGLOSSE.E 307 
 
 Germinatiou and development of Botrychium Lunaria, Sw. : — Underground 
 germination of this plant, 307 ; structure of the prothallia, 307, 308 ; 
 production of antheridia and archegonia, 308 ; development of the 
 embryo, 308, 309 ; Roper's notion of the growth of Botrychium, 309, 
 310; modified by Presl, Mettenius, and subsequently by Roper, 310 ; 
 Braun on the growth of Oplnoglossum, 310; Schacht's assertion that 
 Botrychium is reproduced only by adventitious buds, 310 ; production 
 of fronds in Botrychium, 311, 312; Roper's observations on ramifica- 
 tions of stems oi Botrychium in loose, sandy ground, 312, note ; vege- 
 tation of Ophioglossum vulgatum, 312 — 315 ; development and arrange- 
 ment of the fronds, 313, 314; form of the apical cell, 314; develop- 
 ment of vascular bundles and roots, 314, 315 ; relation of fertile and 
 sterile fronds, 315 ; observations of Mettenius on the germination of 
 Ophioglossum pedu)iculosum, 315 — 317; its prothallia, 315, 316; pro- 
 duction of antheridia and archegonia, 31G ; development of the em- 
 bryo, 316, 317. 
 
 CHAPTER X. 
 
 PILULARIA GLOBULIFEKA AND MINUTA ; MARSILEA PTJBESCENS . 318 
 
 Truit of Pilularia, 318 — 321; development of spore-mother-cells, 319; 
 formation of the macrospores, 319, 320 ; formation of the micro- 
 spores, 320; dispersion of the spores, 321 ; germination of the macro- 
 spores, 321, 322 ; development of the prothallium and pro-embryo, 
 and formation of the archegonia, 322; production of spermatozoids 
 from the microspores, 322, 323 ; development of the embryo, 323 — 
 325 ; structure and germination of the large spore of Marsilea pubes- 
 cens, 325, 326 ; formation of the prothallium and archegonium, 
 326, 327: failure of experiments with the small spores, 327. 
 
 CHAPTER XI. 
 
 SALVINIA NATANS 328 
 
 Structure of the large ripe spores, 328 ; production of the prothallium, 
 328, 329 ; formation of the archegonia, 329, 330 ; development of 
 the microspores and production of spermatozoids from them, 330 — 
 332 ; development of the impregnated archegonium and formation of 
 the embryo, 332 — 334 ; production of vascular bundles, 334 ; infertility 
 of prothallia kept from microsporangia, 334. Historical review: — 
 Confusion produced in regard to the germination of Rhizocarpeaj by 
 Schleiden's 'Grundzüge,' 335; observations of Nägeli, Mettenius, 
 and Hofmeister on this subject, 335. 
 
TABLE OF CONTENTS. XV 
 
 CHAPTER XII. 
 
 PAGE 
 ISOETES LACUSTBIS ... . 336 
 
 Importance of the study of tlie development of the IsoeteEc in botanical 
 morphology, 336 ; peculiar phenomena in the growth of these plants 
 indicated by Von Mohl, 336, 337 ; observations on the arrangement 
 of the fronds of young plants, by A. Braun, 337; structure of the 
 spore described by Mettenius, 337 ; Karl Müller's account of the 
 germination of Iso'etes lacustris, and observations of Mettenius on the 
 same subject, 337 ; form and structure of the microspores of Isoetes 
 
 1 lacustris, 338, 339 ; Roper and Schleiden on the supposed presence 
 of carbonate of lime in the exosporium, 338 ; evolution of the spores, 
 339 ; formation of the prothallium, 339, 340 ; production of arche- 
 gonia, 340, 341 ; microspores of Isoiiies lacustris, 341 ; production of 
 spermatozoids by them, 341—343; observation of Mettenius on the 
 slow motion of the spermatozoids, 342, note ; development of the 
 embryo, 843—345 ; production of the first leaf, 345, 346; develop- 
 ment of the scale, 347 ; formation of the sheath, 347 ; growth of the 
 primary axis, 347 ; formation of the first root, 348, 349 ; develop- 
 ment of subsequent roots, 350—355 ; experiments on the germina- 
 tion of spores, 351 ; arrangement of the leaves, 354 ; structure of the 
 stem in the germ-plant, 356; formation and development of cam- 
 bium, 356, 357; growth of bark, 357—358; formation of roots of 
 the second year, 358—360; ramification of the roots, 360; sub- 
 sequent growth of the plant, 360, 361; effect of the annual 
 renovahon of the cambial layer, 361, 362 ; scalariform arrangement 
 of cells in the leaves, 362 ; periodicity in the production of sterile 
 and fertile leaves in IsoHtes, 362—363; origin of the scales of the 
 leaves, 363, 364; production of the sporangia of Isoetes lacustris, 
 364—367 ; spore-mother-cells, 365, 366 ; furrows of the underside 
 of the stems in Isoetes, 367; differences of growth connected with 
 the presence of one furrow or more under the stem, 367—370 ; re- 
 semblance of Isoetes in its mode of reproduction to the Conifer«, 370 ; 
 spores of Isoetes favorable to the observation of the peculiar mode 
 of reproduction by macro- and microspores, 370, 371 ; distinction of 
 germination of Isoiites from that of vascular cryptogams with green 
 prothallia, 371 ; agreement of Isoetes with Lycopods, both in vegeta- 
 tion and fructification, 371, 372 ; annually renewed cambium-layer, 
 peculiar to Isoetes among vascular cryptogams, 372 ; general observa- 
 tions on the stem and roots of Isoetes, 372. 
 
 CHAPTER XIV. 
 
 SELAGINELLA 373 
 
 Growth of the end of the stem in species of Selaginella, with 2i 
 arrangement of leaves, 373—376 ; formation of the leaves, 376— 
 380; production of a flat cellular body (stipule) from the upper 
 side of the base of the leaf, observed by R. MiUIer, 378 ; structure 
 of the stipule, 378, 379 ; production of papilte at the margins of 
 the leaves, 378, 379 ; furcation of the apex of the stem, 380—382 • 
 
Xvi TABLE OF CONTENTS. 
 
 PAGE 
 
 unequal development of the forks of the stem in some species, 381 ; 
 their equal development in others, 381, 382 ; structure of the stem, 
 
 382, 383; production of adventitious roots from the forks of the stem, 
 
 383, 384 ; production of new plants from fragments of the stem of 
 Selaginella, 384 ; fructiferous shoots of Selaginella, 384, 385 ; produc- 
 tion of tiie sporangia, 385—392 ; views of Bischoffand Von Mold on the 
 nature of the sporangia of Selaginella, 387 ; differentiation of the 
 macrosporangia and microsporangia, 387 ; development of the macro- 
 sporangia, 387 — 389 ; production of the macrospores, 388 — 390 ; 
 differences in certain species, 389, 390 ; development of the micro- 
 spores ; formation of rudiments of prothallia from macrospores before 
 the bursting of the macrosporangia, 391, 392; Mettenius on the de- 
 velopment of the cells of the prothallium, 392, ?wte ; uncertainty as to 
 tlie first stages of development of the prothallium, 392, 393 ; dormancy 
 of the macrospores of Selaginella hortensis and S. Helvetica, 393 ; 
 germination of macrospores, 393 ; formation of archegonia, 393, 394 ; 
 production of spermatozoids from the microspores, 394, 395 ; cause 
 of want of success in experiments on sowing spores of Selaginellcr, 
 295 ; only one archegonium usually impregnated on the prothallium, 
 395 ; development of the pro-embryo, 395, 396 ; development of 
 the embryo, 396, 397 ; greater resemblance of Li/copoditim in its mode 
 of growth to Polypodiacese than to Selaginella, 398 ; growth of Psilo- 
 tum triquetrum, 398 ; remarks on the reproduction of Lycopodiacese 
 with spores of only one kind, 398, 399 ; De Bary's observations on 
 the spores of lycopodium inundatum, 399. Historical review : — 399. 
 
 CHAPTER XV. 
 
 C0XIFE11.K 400 
 
 Structure of the ovules of Coniferse, 400, 401 ; development of the pollen 
 of the Coniferje, 401 — 406 ; peculiar cell-multi|)licatiou in the free 
 pollen-cells of Coniferse, 404, 405 ; structure of the pollen of the 
 Abietinese explained by Fritzsche and Schacht, 405, note ; passage of 
 the pollen through the micropyle of the ovule to the nucleus and 
 formation of pollen-tubes, 406 ; resemblance of the pollen of Ephedra 
 to that of Larix, 406, note; development of the endosperm, 406 — 
 409 ; development of the endosperm in Taxus, 409, 410 ; production 
 of the corpusculum in Coniferse, 410 — 414; statements of Mirbel and 
 Spach as to the contents of the corpuscula, 414 ; development of the 
 endosperm of Coniferse not always dependent on the contact of pollen 
 of the same species, 414, 415 ; second penetration of the pollen-tube 
 towards the embryo-sac, 415 — 421 ; development of free spherical cells 
 in the ends of the pollen-tubes which reach or enter the corpusculum, 
 416; penetration of the pollen-tube into the corpusculum in Pinus 
 sylvestris, 417, 418 ; in Pinus Abies, L. {Abies excdsa), 418, 419 ; in 
 Pinus Larix, 419, 420 ; relation of the pollen-tube to the corpuscu- 
 lum, 421 ; development of the embryo, 421 — 432 ; evolution of the 
 impregnated germinal vesicle, 421, 422 ; Schacht on this subject, and 
 Geleznoff on the formation of the embryo in Larix, 422, note ; rela- 
 tion of the pollen-tube to the endosperm in Taxus baccata, 422 ; de- 
 velopment of impregnated germinal vesicle in that species, 423 ; im- 
 
TABLE OF CONTENTS. XVU 
 
 PAGE 
 
 pregnation of Thuja orientalis, Juniperus communis, and /. Sahina, 
 424 — 426 ; evolution of the impregnated germinal-vesicle in Coniferse 
 generally, 426, 427; production and growth of the pro-embryo, 427 
 — 430; non-ramification of pollen-tubes in Abietinese, 430; several cor- 
 puscula impregnated in Taxus by the expanded end of one pollen-tube, 
 430 ; development of the pro-embryo in Taxus, 430 ; Hartig's obser- 
 vations on this subject, 430, ?iote ; production of the pro-embrvo in 
 Juniperus and Thuja, 431, 432 ; development of the embryo of Coni- 
 ferge, 432. Historical review : — 432. 
 
 CHAPTER XVI. 
 
 REVIEW 434 
 
 Comparison of the development of mosses and liverworts with that of 
 ferns, Equisetaceee, Rhizocarpese, and Lycopodiacese, 434 — 438; 
 alternation of generations in mosses and ferns, 434, 435 ; homologies 
 of ferns and mosses, 435; comparison with liverworts, 435; condi- 
 tions of life in mosses, compared with vascular cryptogams, 435, 436 ; 
 occurrence of thickenings of the cell-walls of spoiiferous generations 
 of mosses and ferns, 436 ; want of natural foundation for the separa- 
 tion of mosses and liverworts into only two groups, 436, 437 ; their 
 division into four groups, 437 ; formation of the embryo of Coniferse 
 intermediate between that of the Phsenogams and higher Cryptogams, 
 438, 439 ; general considerations, 439 — 441. 
 
 Note on the cell-multiplication of the apex of the stem of the leafy 
 
 Jungermannise 442 
 
 Explanation of the figures 443 
 
 Index 493 
 
0\ TUE 
 
 GERMINATION, 
 DEVELOPMENT, AND FRUCTIFICATION 
 
 OF THE 
 
 HIGHEli CRYPTOGAMIA. 
 
 CHAPTER I. 
 
 ANTHOCEROS LEVIS AND PUNCTATUS. 
 
 The young germ-plants as well as the adventitious 
 shoots of Anthoceros form linear flat masses of cellular 
 tissue, the breadth of which continually increases from 
 back to front (PI. I, fig. 1). In the middle of the fore 
 edge a shoot is formed, on both sides of which, in the 
 angles between it and the adjoining parts of the fore edge, 
 new masses of cells are rapidly protruded. These con- 
 stitute, in the first instance, a vigorous median shoot, 
 on the right and left of which, shoots of a more delicate 
 nature are formed almost contemporaneously, which latter 
 in the progress of growth unite on either side with 
 the median shoot (PI. I, fig. 7). The new shoots formed 
 by the amalgamation of these actively growing cellular 
 masses unite themselves on either side to the primary 
 shoot, which now constitutes the middle lobe of the fore 
 edge. By the rapid elongation of the new shoots, the 
 primary one increases in breadth, and its original semicir- 
 cular outline (PI. I, fig. 7) assumes that of the segment 
 of a circle (2 '). In the two indentations of the fore 
 edge of each of the new shoots the same process is re- 
 peated, and henceforth the regular ramification of the 
 plant goes on in like manner. At the bottom of the 
 
 1 
 
2 HOFMEISTER, ON 
 
 two indentations exhibited by the fore edge of each 
 shoot (which indentations arise from the amalgamation 
 of three growing masses of cells, viz., a median shoot 
 and two side shoots) three cellular protuberances origi- 
 nate, first a median one, and then two side ones. They 
 grow into one another nearly up to their fore edge, and 
 unite on either side with the median lobe of the fore 
 edge of the next older shoot. By further elongation 
 they Ijecome new shoots, producing an increase in the 
 bi-eadth of the median lobe. The ramification of the 
 plant is therefore irregularly dichotomous, depending 
 upon the continual formation of side shoots on cither 
 side of a median shoot, which latter is limited in its 
 longitudinal growth — a mode of ramification which, in 
 the case of phacnogamous plants, has Ijeen called by 
 Schimper " Dichassium." As the new shoots, lying in 
 one plane, diverge from one another at angles exceeding 
 90°, a succession of three generations of shoots suffices 
 to render the outline of the entire plant circular. The 
 habit of the plant depends, for the most part, upon the 
 extent to which the three component parts of each new 
 shoot amalgamate longitudinally inter se and Avith the 
 median lobe of the fore edge of the next older shoot. 
 Where the elongation of the lower part of the new shoots 
 begins at a late period^ there the extent of the amalga- 
 mated growth is very considerable. This is the case 
 with specimens of Anthoceros IcBvis grooving in sunny 
 open fields. Here, in consequence of the perishing of 
 the oldest shoots, those namely which originate directly 
 from the spore, the plant usually has the appearance of 
 an exactly circular or slightly lobed expansion of dark 
 green, succulent cellular tissue. The extent of amalga- 
 mation of the shoots is nuich smaller in Anihoceros 
 punctatuSj and still less in plants of Anthoceros lavis 
 which have grown in moist shady places or in higlier 
 temperature (as, for instance, in pots AAdiich have been 
 long under glass), 'ilie ramification of Anthoceros is 
 similar to that of the Riccieae, the Marchantiea^, and 
 several leafless Jungermanniae, as, for instance, Pellia. 
 In Anthoceros, however, the regiüarity of the ramification 
 
THE HIGHER CRYPTOGAMIA. 3 
 
 is much interrupted by the fact that individual marginal 
 cells, and in Antltoceros pimctatus even the surface cells, 
 become transformed into adventitious shoots. The circum- 
 stances under which the plant grows have a decided in- 
 fluence upon the number of the adventitious shoots which 
 come to perfection ; and these circumstances also determine 
 whether the growth of such shoots shall terminate at an 
 early period, or whether, hke the mother-shoots, they shall 
 continue to ramify and develope themselves. The latter is 
 always the rule in Anthoceros pimctatus. It contributes 
 much more to the crisped, distorted aspect of the plants of 
 this species, than the perishing of the upper coverings of 
 the air-cavities which are enclosed in their tissue. In 
 Anthoceros lavis, ramification only takes place when the 
 plant grows in a very moist atmosphere and in deep shade. 
 Then A. Icevis ramifies to as great an extent as -the other 
 species, from Avhich, however, it is decidedly distinguishable 
 by the entire absence of air-cavities in its tissue. 
 
 The flat stem of Anthoceros groAvs and elongates itself 
 by continual division of the cells of its fore edge. These 
 cells have the form of a three-sided prism, with one side 
 (that, viz., which forms the fore edge) convex. These cells 
 divide repeatedly by septa, which are inclined at angles of 
 about 45° alternately towards the upper and under surfaces 
 of the flat stem. In the cell constituting the fore edge 
 (viz., the cell of the first degree), the division is repeated 
 until the full number of cells belonging to the segment 
 (which segment is limited in its longitudinal growth) is 
 reached. This cell-multiplication terminates at a later 
 period in the median line of the segment than it does at 
 the sides. Hence it follows, that the shape assumed by 
 each of the three lobes of the fore edge of a shoot is that 
 of the segment of a circle. The cells of the second degree, 
 which are distinct from the three-sided prismatic cells of 
 the fore edge, have the form of procumbent prisms with 
 a rhombic base. Each newly formed cell of the second 
 degree divides immediately by a septum parallel to the free 
 outer surface. This division is followed by that of the 
 inner and outer daughter-cells, which takes place by means 
 of a septum parallel to the neighbouring cell, and at right 
 
4 HüFMElSTE«, ON 
 
 angles to the free outer surfocc of the stem (PI. I, figs. 3, 
 4). The outer one of the cells thus formed continues to 
 divide hy septa parallel to the free outer surface, until the 
 cells have reached the number of ^yhich the shoot is des- 
 tined to consist in the direction of its thickness. This 
 nuniher (al)out thirteen) is greatest in the median line 
 of the shoot, and diminishes to one at the sides. The 
 arrangement of the cells of a section of the end of a 
 growing shoot, taken through the median line at right 
 angles to the surface, is what is called scalariform; 
 the cells of each longitudinal moiety of the shoot are ar- 
 ranged in roAvs parallel to one another bearing upAvards 
 from the longitudinal axis. Each of the cell-masses which 
 unite to form a shoot consists in its earliest stage of a single 
 cell, situated normally at the bottom of the indentation of 
 the fore edge of an older shoot (PL I, fig. 7), but, when des- 
 tined to form an adventitious shoot, placed at the edge or on 
 the surface of such older shoot. The primary division of 
 this cell, which takes place by a septum inchned to the 
 horizon, is followed immediately by the division of the 
 cells of the first and second degree, by means of a longitu- 
 dinal septum perpendicular to the surface of the stem. As 
 the young shoot increases in length, the number of its cells, 
 reckoned in the direction of its breadth, increases largely 
 and continually, the cells of its fore edge dividing in like 
 manner by longitudinal septa. Thus it happens that, as 
 long as the shoot grows, its fore edge becomes continually 
 Avidcr. The arrangement of the cells seen from the sur- 
 face is fiabelliform, in rows Avhich radiate from the base of 
 the shoot to the arcuate fore edge. In each of the cells 
 Avhich constitute the permanent upper and under surface of 
 the shoot, four cells are produced by duplicate cell-divi- 
 sions, Avhich four cells lie in one plane. It follows that, in 
 full-groAvn shoots, these superficial shells are four times 
 smaller than the internal cells. A suppression of the final 
 septum not unfrequently occurs in individual cells of the 
 inner parenchyma. Some of the latter are often found 
 which arc twice the size of the adjoining cells. 
 
 The growing cells of the fore edge of young shoots con- 
 tain a thick coating of a mucilaginous fluid rendered tur- 
 
TIIK HIGHER CRYPTOGAMIA. 5 
 
 bid by numerous granules, and in this fluid is a spherical 
 or slightly flattened nucleus formed of a less highly 
 refractive substance (PL I, fig. 3). Appearances are not 
 wanting which point to a uniformity in the process of tlie 
 cell-multiplication with that which usually obtains in tlie 
 more highly organized plants. The nuclei of the cells of 
 the first and second degree appear sometimes to be under- 
 going a manifest process of dissolution. Individual cells of 
 the first or second degree are sometimes devoid of nuclei 
 (PI. I, fig. 3 *). Not unfrequently two nuclei, not separated 
 by any septum, occur in one and the same cell. The wall 
 between the cell of the first degree and the youngest cell of 
 the second degree is always of the greatest delicacy, so as 
 to leave no doubt that it has only just been produced. 
 Prom these facts it necessarily follows that the vegetative 
 cell-multiplication in Anthoceros (as in nucleate cells gene- 
 rally) commences by the dissolution of the primary nucleus 
 of the cell, which is quickly followed by the formation of 
 two secondary nuclei. Between the two new nuclei a 
 septum is then formed, which extends through the entire 
 cavity of the cell. 
 
 In the youngest cell of the second degree, sometimes even 
 in a cell of the first degree, there is produced near the surface 
 of the nucleus a colouring matter consisting of numerous, 
 immeasurably small, colom'ed particles. The particles ai'e 
 of a pale bluish-green colour in the youngest cells ; in the 
 next older cells they tinge the immediate neighbourhood of 
 the nucleus (that is to say, the mass of protoplasm which 
 surrounds it, and from which filaments radiate through the 
 cell-cavity, PI. I, fig. 3) with a bluish verdigris colour. In 
 rather older cells the colouring matter suddenly seems to be 
 enclosed in a well-defined vesicular body surrounding the 
 luicleus (PI. I, fig. 6) ; the somewhat thick, membranous 
 peripheral layer of this body is of an intense emerald green. 
 The less highly refractive substance of the interior of this 
 body is of a much paler colour. At a later period nume- 
 rous very small starch-granules are usually formed in tlic 
 interior of the chlorophyll-bodies, and, for the most part, 
 inside the nucleus which they surround. No other changes 
 
 * See the lower cell adjoining tlic apical cell; a cell of the fourlli degree. 
 
6 HOFMEISTER, ON 
 
 of importance occur in the chlorophyll-bodies dimng the 
 life of the cell. Anthoceros alone, therefore, amongst all 
 known plants, exhibits the phenomenon of a single very 
 large chlorophyll-body in each cell.* The form of it in 
 Anthoceros lavis is (in most of the cells) globular or elhp- 
 soidal; in the very elongated cells of older shoots it is 
 flattened and spindle-shaped, and then often much dra^vn 
 out at the points ; in the epidermal cells it is much flat- 
 tened, and, when seen from above, often irregularly stellate. 
 The normal form of the chlorophyll-bodies in Anthoceros 
 punctatus is similar. The chlorophyll-bodies of both species 
 are ahvays parietal in the older cells, closely attached to the 
 mucilaginous layer clothing the inner sm-face of the cell, 
 i. e., the primordial utricle. By treatment with a weak 
 alkaline solution, the primordial utricle shrivels up. Tt 
 then appears in the form of a delicate sac, to the inner wall 
 of which the chlorophyll-body is attached (PI. I, fig. 10). 
 In cells which already possess a fully developed chlorophyll - 
 body, the duplication of the latter precedes the division 
 wiiich takes place by the formation of a septum. In cells 
 on the under or upper surface, in which division is about to 
 take place, two separate chlorophyll-bodies are often found, 
 each of which encloses a (secondary) nucleus (PI. I, fig. 6). 
 In the chlorophyll-bodies of cells which are about to divide, 
 and which bodies occupy about two thirds of the cavity of 
 the cell, the included primary nucleus of the cell always 
 becomes less distinct, and eventually disappears altogether. 
 In the chlorophyll-bodies of other neighljouring cells may 
 be seen two indisputably newly formed nuclei. The chlo- 
 rophyll-bodies of other cells again exhibit a dark line in the 
 ecpiator of the ellipsoidal chlorophyll-body (PI. I, fig. 14 *), 
 the dai'k line being the side view of the dense assemblage 
 of immeasurably small coloured particles lying in the equa- 
 torial plane. No intermediate stages between this condition 
 and the perfect division of the chlorophyll-body into two 
 parts has been observed ; the one seems to follow^ imine- 
 
 * In the ' Vergleichende Unters uclmngen,' p. 3, I called this body a 
 c1iloropliyll-?T«V/e — a name whicli H. v. Mohl lias rightly objected to as inaccu- 
 rate, inasmuch as, wiicu the chlorophyll-body has swollen and become partly 
 dissolved by the absorption of water, uo trace of a surrounding nienibranc is 
 visible.— 'jöo^. Zeitung,' 1855, p. 107. 
 
THE HIGHER CRYPTOGAMIA. 7 
 
 diately upon the other. These processes can be seen m the 
 cells of the wall of the lower part of the young fruit Avhose 
 cell-multiplication is in progress, and still more clearly in 
 the epidermal cells of young shoots. It is true that in the 
 cells of the fruit the chlorophyll-bodies are manifestly smaller 
 than in those of the epidermis. Por this reason, however, 
 during the process of cell -multiplication which is con- 
 stantly going on from above downwards, no doubt can exist 
 as to the mode of succession and the signification of the 
 different states observed. The cells of the upper part of the 
 young fruit contain, without exception, tivo chlorophyll- 
 bodies. It would seem that here an ultimate division of 
 the cells commences, but is not perfected. In the inner 
 tissue of the stem the appearance of two chlorophyll-bodies 
 in one cell is unusual. I once saw between two such chlo- 
 rophyll-bodies a free nucleus ; it was united to both the 
 chlorophyll-bodies by a thread-like filament of granular 
 mucilage (PI. I, fig. 9). 
 
 The position of the organs of fructification of Anthoceros 
 is not confined to any definite points of the fiat stem. 
 Both in Anthoceros lavis and in A. pimctatus, groups of 
 archegonia and antheridia are scattered about, apparently 
 without regidarity ; in some instances occurring in great 
 numbers upon one shoot, in others being very sparingly 
 distributed. The first appearance of antheridia consists in 
 the separation from the underlying tissue of a circiüar 
 group of about sixteen cells of the upper layer of a very 
 young shoot. Hence arises a small lenticular cavity in the 
 cellular tissue, which is filled with a watery fluid, and only 
 covered by a single layer of cells* (PL III, fig. 16). Its 
 basal cells divide by vertical, longitudinal, and transverse 
 septa. Certain of the smaller cells which thus originate 
 (six in number at the utmost in A. lavis, but amounting to 
 twenty in A. pimctatus) grow into short papillce, which pro- 
 trude into the intercellular cavity (PI. Ill, fig. 16). The 
 dome-shaped portion, which protrudes considerably into the 
 air- cavity, becomes separated by a septum from the primary 
 
 ® Tlie large cavities in tlie interior of the cellular tissue of A. jmndatus arc 
 also formed by the separation of cells originally in close cohesion. These 
 usually die-shaped cavities contain at first a watery fluid, and afterwards air. 
 
8 HOFMEISTER, ON 
 
 cell-cavity. In the licmispherical cell which is thus pro- 
 tUiced there coinmences, either immediately (Plate III, 
 figs. 10, 17) or after the occurrence of one or two divisions 
 of the same cell by means of horizontal septa, a series of 
 repeated divisions of the apical cell, by means of septa in- 
 clined in opposite directions. The cells of the second 
 order which are thus formed are bisected by the growth of 
 radial longitudinal septa (PI. Ill, fig. 18). There is thus 
 produced a short clavate mass of cellular tissue, composed 
 of four parallel longitudinal rows of cells. One of the cells 
 of the double pair of cells adjoining its apex divides by a 
 septum which, lying parallel to the longitudinal axis of the 
 organ, forms with the side walls of the mother-cell an 
 angle of 45°. Thus arises an inner cell which is sur- 
 rounded on all sides by a simple cellular layer. The inner 
 cell expands at the expense of the surrounding cells, the 
 latter becoming tabular and flattened. These cells hence- 
 forth multiply only by divisions produced by septa perpen- 
 dicular to the free outer walls. It is probable that the 
 munljer of the cells of the cortical tissue of the antheridia 
 increases, but such tissue always consists of a single layer 
 of cells, l^he inner cell, on the contrary, becomes converted, 
 by means of a series of continued bisections, into a multi- 
 cellular body, the cells of which become smaller in pro- 
 portion as their number increases (PI. Ill, figs. 19, 20). 
 In its latest stage of development, this cellular body is a 
 spheroidal mass of very small, almost tabular cells (PI. Ill, 
 fig. 21). Each of them contains a lenticular vesicle which 
 almost fills the cell. The walls of the cells decay as the 
 antheridia approach maturity. In the mean'^time, in each 
 of the vesicles, a delicate helicoid filament of from two to 
 three and a half turns, and composed of a substance Avhich 
 is coloured yellowish by iodine (PI. Ill, fig. 22), forms 
 itself into an antherozoid. At this period the cellular layer 
 which covers the cavities in the cellular tissue of the frond, 
 and wliich cavities are almost filled with antheridia, bursts 
 irregularly. It often happens that in the mean time the 
 chlorophyll-bodies have assumed a reddish-yellow colour. 
 The same colour appears regularly and with increased in- 
 tensity, at the approach of maturity, in the colouring par- 
 
Ij , kSTABLISHED \ 
 
 THE HIGHER CRYPTOGAMTA. ^1*^ iÄi )* 
 
 tides of the cells of tlic covering layer of the antherioiTi^^- ' 
 which several, to the amount of eight, are here found in 
 one cell. The antheridia, when fully ripe, open at the 
 apex, the cells of the covering layer parting asunder. The 
 contents, that is to say the lenticular vesicles before men- 
 tioned, emerge under water by degrees, and become 
 distributed in the surrounding fluid. The vesicles begin 
 to rotate slowly, during which the enclosed antherozoid 
 becomes free, apparently by the gradual dissolution of the 
 wall of the vesicle. It moves about slowly in the water, 
 rotating slowly round the axis of its spiral. 
 
 The formation of the archegonia of Anthoceros differs 
 essentially from that of all other Hepatiae. A single string 
 of cells, situated on the upper side of a young shoot, and 
 directed obliquely backwards and inwards, becomes filled 
 with granular mucilage. The cells of this row are arranged 
 in a straight line one above another, and form part of a 
 group of cells produced by the multiplication of an upper 
 cell of the second degree. There is no formation of chloro- 
 phyll-bodies in these cells (PI. I, fig. 4). The low^est of 
 the cells of this row swells up during the time that the 
 cells of the stem are increasing in number in the direction 
 of its thickness, and, consequently, before the number of the 
 cells lying between such lowest cell and the upper surface 
 of the stem has reached its limit (PI. I, fig. 4, a). In 
 the basal cell a free daughter-cell is formed, which, in- 
 creasing rapidly in size, soon fills up the greater part of 
 the mother-cell (PI. 1, fig. 16). The transverse septa 
 Avhich divide the rest of the cells of the row from one 
 another are then absorbed. Thus there originates a narrow 
 open passage, filled with mucilaginous fluid, which leads 
 into the interior of the tissue of the stem, and into the 
 basal cell of the archegonium, which is now open above 
 (PL I, fig. 17). Seen from above, this passage is a hexagonal 
 opening, bounded by six cells of the epidermis, and becoming 
 narrowed inwardly to a cylindrical canal (PI. I, fig. IS'')« 
 By this means the spermatozoa, after their escape from the 
 antheridium, are enabled to reach the immediate neigh- 
 bourhood of the oval daughter-cell of the basal cell of the 
 archegonium. 
 
10 HOFMEISTER, ON 
 
 So far all the archegonia comport themselves alike. In 
 many, however, the further development noAv ceases. The 
 daughter-cell which originated in the basal cell disappears. 
 Frequently the walls of the passage leading from the basal 
 cell outwards assume a brown colour. In other arche- 
 gonia, Avhich in all probability have been impregnated by 
 the entrance of the spermatozoa, the daughter-cell, as well 
 as its nucleus, increases manifestly in size ; numerous large 
 granules appear in the fluid in its interior (PI. I, fig. 17). 
 The oval cell soon divides by an oblique septum (PI. I, 
 fig. IS), upon which another septum, inclined in a contrary 
 direction, is shortly afterwards seen (PI. I, fig. 20). In 
 the same manner, the terminal cell divides two or three 
 times by septa inclined in contrary directions (PI. I, fig. 19). 
 Tlie body, which at this period consists of a few large 
 cells, can now be easily isolated. After some time a division 
 of the apical cell takes place by means of a septum inclined 
 to the ideal longitudinal axis of the organ at the same angle 
 as the previously formed' septa, but diverging from them at 
 an angle of 90°, and cutting the under edges of the apical 
 cell. The next septum which is formed stands opposite to 
 this, is inclined in a contrary direction, and forms also a 
 right angle with the two older septa of the cell. The ter- 
 minal cell of the obtusely conical body, which now plainly 
 constitutes the fruit-rudiment, increases by the production 
 of a series of septa wliich collectively have the same incli- 
 nation to the longitudinal axis of the young fruit, b\it Avhich 
 point in four different directions, and not in two only, as 
 heretofore. The divisions succeed one another in such a 
 manner that the development of a septum turned towards 
 the south is followed by that of another turned towards the 
 north ; a septum towards the east is folloAved by one 
 towards the west, and so on.* The form of the cell of the 
 first degree resembles that of a three-sided prism with one 
 of its lono; sides turned doAvnwards. The cells of the second 
 degree have partly the form of a parallelopipcd, in so far as 
 they originate from the division of the apical cell hy 
 
 * In tlie 'Vergleichende Untersuchungen,' an erroneous statement has crept 
 in hy a slip of the pen. The series of ecU-divisions is erroneously stated to run 
 round the circumference of the apical cell in the course of aright-handed spinal. 
 
THE HIGHER CRYPTOGAMIA. 11 
 
 a septum cutting one of its sides, and parallel to one of 
 its other sides ; and partly the form of a three-sided prism, 
 so far as they originate from the division of the apical cell 
 by a septum parallel to one of its short side-walls. Seen 
 from above, the apical cell has an oblong form (PI. I, tig. 25); 
 in a longitudinal section, it is triangular if the section is per- 
 pendicular to the long side-walls (PL I, figs. 21 "' "' 23 *), 
 quadrangular, on the other hand, if the section is at right 
 angles to the shorter side-walls (PI. I, figs. 21 ''■ 23 "). 
 Each cell of the second degree divides, soon after its pro- 
 duction, into an inner and an outer cell, by means of a 
 septum parallel to the chord of the arc of the free outer 
 surface. Each of the latter cells is divided l^y a longitu- 
 dinal septum radiating from the longitudinal axis of the 
 fruit ; those cells adjoining to the side faces of the apical 
 ceU being divided at an earlier period, and more repeatedly, 
 than those adjoining the terminal faces (PI. 1, fig. 23). 
 These divisions take place in such a manner that the cell 
 is divided into two portions of imequal size, of which the 
 larger portion immediately divides again by a septum 
 parallel to the septum last formed. Eurther longitudinal 
 divisions take place (especially in the side cells of the 
 mass of cells wdiich is formed by the multiplication of a 
 single cell of the second degree), in such a manner that, 
 measured in a tangential direction, their number appears 
 to be represented by the odd numbers, 3, 5, 7, &c. 
 (PI. I, fig. 25). The division of those cells of the outer 
 surface of the fruit Avhich immediately adjoin the apical 
 cell (which division takes place by a radial longitudinal 
 septum) is shortly folloAved by the formation of a trans- 
 verse septunij also perpendicular to the free outer surface, 
 but at right angles to the septum just mentioned. In 
 the cells which originate from the smaller cells of the 
 second degeee, the formation of the transverse septum 
 often precedes that of the longitudinal one (PI. I, fig. 25). 
 
 In the rudimentary fruit of Anthoceros, as in other 
 growing organs, one step in the regular series of cell- 
 divisions is often anticipated. It sometimes happens that 
 a division takes place before the occurrence of another divi- 
 sion which usually follows it, and yet the final arrangement 
 
12 HOFMEISTER, ON 
 
 of the entire mass of cells is not thereby materially affected. 
 The enlargement which takes place in a direction radial 
 to the axis of the fruit, and the cell-multiplication in the 
 direction of the sides of the paraboloid which constitutes 
 the apex of the rudimentary fruit, are somewhat more 
 extensive in the cells derived from tlie wider cells of the 
 second degree than in those derived from the narrower 
 ones. The outline, as seen from above, of the mass of 
 cells produced by the multiplication of each rectangular 
 combination of four cells of the second degree, which out- 
 line is at first elliptical, becomes consequently soon trans- 
 formed into a circle. 
 
 The innermost of the cells into whicli each cell of the 
 second degree divides is separated by longitudinal se})ta 
 into two halves. Immediately under the apex, the fruit- 
 rudiment consists of four axial longitudinal rows of cells, 
 which are covered by an almost entirely simple layer of 
 peripheral cells (PL I, fig. 24). The fruit-rudiment in- 
 creases in thickness and circumference by the growth of 
 tangential longitudinal septa in the peripheral cells, which 
 growth is always repeated in the outermost of the new cells, 
 and alternates with the formation in the same cells of radial 
 longitudinal septa. The cells of the base of the very young 
 fruit-rudiment expand considerably in breadth, imd thus 
 lay tlie foundation of the flattened spheroidal enlargement 
 by means of which the fruit is buried in the cellular tissue 
 of the stem (PI. I, figs. 21 '"' 22). At the period of the 
 middle age of the fruit, the cells of this swelling not only 
 attach themselves very firmly to the neighbouring cells of 
 the stem, but force themselves inwards between the latter 
 cells to some depth, becoming transformed into cylindrical, 
 crooked papillae, comporting themselves like short radicular 
 hairs (PI. II, fig. 5). 
 
 The cells of the stem which adjoin the archegonium 
 multiply actively in all three directions of space during the 
 development of the fruit-rudiment. By this means the 
 surrounding tissue keeps pace, for a considerable time, Avith 
 the increase in size of the fruit-rudiment (PI. I, fig. 19 ; 1^1. 
 II, fig. 1) ; afterwards it usually so far outgrows the latter, 
 that a wide hollow space, filled with tough gelatinous 
 
THE IIICIIKU CllYrTOGAÄIIA. 13 
 
 iiintter, is formed above the young fruit, into which indi- 
 vi(hial cells of the adjoining tissue protiiuhi in the form of 
 jointed hairs (PL II, fig. 2). A wart-like elevation of the 
 upper side of the flat stem denotes the spot at wdiich a 
 fruit-rudiment lies concealed within. Owing apparently to 
 the position of the archegonium {i. e., the young fruit), tliis 
 excrescence is always oblique to the fore edge of the shoot. 
 Eventually the growth of the fruit exceeds that of its 
 covering. One of the causes of this growth is an increase 
 in number (commencing at an early period, and continuing 
 until the bursting of the fruit) of those cells of its lower 
 portion which lie immediately underneath the basal enlarge- 
 ment ; or, in other words, a continually repeated division 
 of all the cells of one of the lower zones of cells. Another 
 cause of the growth of the fruit is an expansion of its cells 
 commencing at the apex of the fruit at the period when 
 the apical cell ceases to multiply, and extending slowly to 
 the base (PL 11, fig. 5). The fruit breaks through the 
 arcuate lid of the surrounding cavity, and carries the 
 decaying tissue of the lid upwards, attached to the gelati- 
 nous mass which is accumulated above the apex of the 
 fruit, and which is traversed by the jointed hairs now 
 broken up into their individual cells ; it (the fruit) then 
 a})pears above the surface of the stem, apparently sur- 
 rounded by a sheath. The dome-shaped mass of gelatine, 
 covered with a brownish layer of cells, is the so-called 
 Calyptra of the earlier observers (PL 11, figs. 4, 5*). The 
 differentiation of the parts of the internal tissue of the 
 fruit begins shortly before the latter breaks through its 
 covering, and proceeds from above downwards. Certain 
 cells, forming an axile cylindrical string of from twelve to 
 sixteen rows of cells, one above another (each now showing 
 four cells in transverse section), cease to form horizontal 
 septa, whilst in all the other cells at least one more such 
 division takes place (PL II, fig. 5). This string of cells 
 is the future colmnella. The layer of cells immediately 
 surrounding it is that out of which the spores and elaters 
 are developed, which extend from the columella to the 
 wall of the fruit. In this layer the multiplication of the 
 cells by division by horizontal septa is twice as active as 
 
14- HOFxMEISTER, ON 
 
 in other parts of the fruit. Measured vertically, one cell 
 of the columella, or two of the wall of the fruit, are equal 
 to at least four of the cells of the latter layer (PI. Ill, flp:. 1). 
 The wall of the fruit is thinnest in its upper part. It con- 
 sists there of only four layers of cells, whilst towards the 
 base there are five such layers (PI. Ill, fig. 1), being the 
 result of the division of the cells of the second layer (reckon- 
 ing from without inwards) by longitudinal septa parallel 
 to the longitudinal axis of the fruit. 
 
 Those cells of the layer surrounding the columella which 
 are destined to be the mother-cells of spores become 
 detached from the neighboiu-ing cells, and assume a spheri- 
 cal form. Their contents consist of finely granular })roto- 
 plasm, and a large central transparent nucleus with a large 
 nucleolus (PI. Ill, figs. 1, 3). Those destined to form 
 elaters remain less developed. Their nucleus disappears ; 
 in its place are seen two new nuclei, between wdiicli a 
 septum is produced, dividing' the cell into two daughter- 
 cells (PI. Ill, fig. 1 *). The same process recurs in one, 
 sometimes in both, of the newly formed cells ; so that the 
 fully grown elater consists of a row of three or four cells. 
 
 The j)erfecting of the spore-mother-cells proceeds slowly 
 from the upper to the lower part of the fruit. A \vell- 
 made longitudinal section of a half-ripe fruit exhibits a 
 graduated series of all the different states, from the fii-st 
 separation from the neighbouring cells up to the formation 
 of the spores. The spore-mother-cell increases rapidly in 
 size after becoming detached from the neighboming tissue. 
 The protoplasm in its interior divides into strings, radiating 
 from the nucleus, and into a thin parietal layer (PI. Ill, 
 fig. 4). Shortly afterwards an accumulation of mucilagi- 
 nous plasma is formed close to the primary nucleus which 
 occupies the middle point of the cell. This plasma, in 
 Anilioceros lavis, is usually coloured green by the particles 
 dispersed in it ; in A. p/inctatus it is colourless. 'J'his 
 accumulation divides itself into two halves, each of which 
 clothes one of the poles of the globular nucleus (PL III, figs. 
 5, 5 *). In slightly older cells, two newly formed second- 
 ary nuclei are found near the primary nucleus, surrounded 
 by a halo of finely granular protoplasm, fi'om which strings 
 
THE HIGHER CRYPTOGAMIA. 15 
 
 of protoplasm radiate to the inner Avail of the cell (PI. Ill, 
 fig. 6). The new nuclei, in Anthoccros lavis, usually con- 
 sist of a greenish substance ; in A. pundatus, of a colourless 
 substance, containing coarser particles. They doubtless 
 orio-inatc from the fact, that each of the accumulations of 
 protoplasm which clothe either pole of the primary nucleus, 
 has become rolled into a balb and distinctly defined. The 
 layer of protoplasm which surrounds each of the newly 
 formed nuclei, often contains so many granules, that the 
 outlines of the latter are at first completely concealed, and 
 only become visible long after their first production. The 
 contrary, however, is frequently the case in both species. 
 The secondary nuclei are often without any solid substances 
 in their interior. Sometimes they contain a single large 
 nucleolus ; sometimes a larger number of granules, which, 
 becoming blue with iodine, indicate the existence of starch. 
 Late in the autumn, after the occmTence of the first frosts, 
 each of the secondary nuclei is found, in many of the fruits, 
 surrounded by a thin-walled, rather larger cell (PL III, 
 fig. 15). Fruits of this kind decay without further de- 
 velopment : their state is one of disease. 
 
 In more fully developed mother-cells lying nearer to the 
 apex of the fruit, the outlines of the secondary nuclei are hazy 
 and less defined. Ultimately two masses of granular proto- 
 plasm are found occupying their place, the limits of which 
 are confluent Avith the surrounding layer of protoplasm 
 (PI. Ill, figs. 7, 8). In the mother-cells immediately above, 
 each of these masses is divided into two sharply defined 
 globular balls, i. e., into two tertiary nuclei. Their position 
 at first is ordinarily decussate (PI. Ill, fig. 9) ; at a later 
 period, they usually group themselves in a manner answer- 
 ing to the four corners of a tetrahedron. They are bound 
 together by thick strings of protoplasm ; thinner strings 
 of more finely granular, almost transparent protoplasm 
 proceed in greater or less numbers from each nucleus to 
 the inner wall of the cells (PI. Ill, fig. 10). Up to this 
 point the primary nucleus of the cell has become continually 
 more transparent and paler; now, it and its nucleolus 
 have disappeared. Immediately thereupon the mother-cell 
 divides into four daughter-cells ; the special-mother- cells, 
 
16 HOFMEISTER, ON 
 
 by means of six triangular septa, passing between each two 
 miclei, and cutting each other in the middle point of the 
 cell. The wall of the mother-cell increases manifestly in 
 thickness from the time of the appearance of the secondary 
 nuclei until the formation of the septa. In Anthuceros heels, 
 it remains smooth ; in JnlJioccros punctatus it is furnished 
 witli numerous dots {Tüpfeln); (PL III, fig. 23). The 
 inner layers of the thickened wall are very sensitive to the 
 action of w^ater, especially in AntJioceros Iccvis ; they swell 
 up rapidly, and to a great extent, contracting the cavity of 
 the cell, and compressing its contents into a small space, 
 causing great difficulties to the observer. The affinity of 
 the swelling layers for Avater is so remarkable, that the 
 swelling takes place even in saturated saline solutions. 
 Alcohol is the only medium in which it fails to occur ; it 
 is Aery much diminished in diluted alcohol. If spore- 
 mother-cells, in which the four tertiary nuclei are fully 
 formed, are placed in diluted alcohol, the cell-contents first 
 contract ; a slight swelling of the membrane of the cell 
 then beghis, which increases in proportion as the alcohol 
 escapes l)y evaporation from the fluid. It is now plainly 
 aeen that it is one of the middle layers in particular of the 
 cell-wall M'hich increases in size by absorption of water 
 (PI. Ill, fig. 11). The outermost layer of the membrane 
 passively follows the increase in size of the middle one, and 
 becomes ex])anded. If pure alcohol is added, water is 
 withdrawn from the swollen membranous layer ; the latter 
 diminishes in size ; the outer layer of the cell- wall there- 
 upon becomes wrinkled, inasmuch as its volume does not 
 diriiinish in the same proportion as that of the middle 
 layer, and its elasticity does not equal its power of ex- 
 pansion. H. V. Mold has shown that the formation of 
 the septa of the mother-cells progresses gradually from the 
 j)eriphery to the centre ; and he has figured a condition in 
 A\hich this growth has taken place to so small an extent 
 that the yet imperfect septa have not interfered with the 
 strings of protoplasm uniting the four tertiary nuclei.* The 
 ]-apid swelling up of the waUs of the mother-cells prevented 
 me for a long time from repeating this observation, which 
 
 * 'Linntea,' 1836; "Vermischte Schriften," tab. iv, fig. 23. 
 
THE HIGHER CHYI'TOGAMIA. 17 
 
 is certainly of great importance with reference to cell-nuilti- 
 plication. However, since I made the experiment of using 
 alcohol in the observation, I found in every fruit which was 
 submitted to dissection spore-mother-cells (situated between 
 spore-mother-cells which were yet undivided and others 
 which were already completely divided into four daughter- 
 cells) the inner walls of which were traversed by the rudi- 
 ments of the future septa, in the form of ridges protruding 
 inwards (PI. II, fig. 12). By adding water to such a 
 preparation, the imperfect septa are seen to be direct con- 
 tinuations of the innermost layer of the cell-wall, which 
 layer swells up but little in water (PL III, fig. 13), The 
 swelling up of the inner layers of the membrane of the 
 mother-cells has a peculiar appearance in those mother-cells 
 in which very numerous strings of protoplasm pass from 
 the tertiary nuclei to the cell-wall. The enlarging sub- 
 stance of the membrane does not force these strings in- 
 wards, but shapes them to itself and clings to them (PL 
 III, fig. 15). The swollen substance of the membrane is 
 manifestly less firm than that of the strings of protoplasm.''' 
 Nevertheless, the swollen layer of the wall exhibits sharp 
 broken edges when the cell is ruptm'ed by pressure with 
 the covering-glass. It is only after prolonged soaking in 
 water that the substance of the swollen layers becomes dis- 
 integrated ; the middle layers first dissolve, and then the in- 
 nermost ones ; the outermost layer remains behind to the last. 
 After the walls of the special iiiothcr-cells have attained 
 a moderate thickness, there is formed in each one of them 
 a single spore, which, from the first moment of its membrane 
 becoming visible, occupies the entire cavity of the mother- 
 cell. In Aiit/ioceros jjtr?ictcäus, the prominences attached to 
 the outer membrane of the spore exactly fill up the dots of 
 the wall of the mother-cell. Irregularities of spore forma- 
 tion occur in both species : occasionally two special-mother- 
 
 * It was probably the observation of similar cases which led Kiitziug to the 
 erroneous notion that the prolongations of the exosporium were hardened, 
 thread-like prolongations of the protoplasm surrounding each of the nuclei. 
 ('Philos. Bot.,' Leipz., 1S51, p. SGI.) The error of this view is at once mani- 
 fest, from the fact that the exosporium of Anthoceros presents, at its first 
 appearance, an entirely smooth outer surface. Its protuberances originate at a 
 later period. 
 
 2 
 
18 HOFMEISTER, ON 
 
 cells and two spores only are formed in some of tlie mother- 
 cells, in wliicli case the two spores are donblc the usual 
 size ; this is similar to what occasionally takes place in the 
 formation of the pollen of many phaenogams. When the 
 upper four-üfth parts of the long cylindrical fruit have be- 
 come tilled with ripe spores, the wall, which assumes a dark 
 brown colour as soon as it contains ripe spores, splits lon- 
 gitudinally into two halves, and the spores which have be- 
 come free by the absorption of the walls of the mother-cells 
 are dispersed. These spores are of a brownish-yellow 
 colour in Anfhoceros Icevis, and somewhat darker in Aiiiho- 
 ceros punctatits. 
 
 Both species are also reproduced by 1)uds. These are 
 formed in the interior of the tissue of the stem in the follow- 
 ing manner : — The contents of individual cells of that tissue, 
 after a slight contraction of the entire ujiper smface, become 
 clothed with a new membrane (PL 1, tig. 11), and the 
 new cell thus formed becomes transformed into a cellulai' 
 body by a series of divisions following the course of 
 those which occur in the cell-nndtiplication of young shoots 
 (PI. I, figs. 1:2, 17). This cellular body sometimes com- 
 mences its own independent development by the protrusion 
 of radicular hairs, even Avhilst fully enclosed in the cellular 
 tissue (PI. I, fig. 13). The contents of the cells of very 
 young buds consist of colourless protoplasm ; the cells of 
 older buds are filled with numberless small starch- gramdes, 
 between which is seen a dark bluish-green colouring 
 matter, composed of extremely minute particles. The buds 
 are usually set free by the disintegration of the tissue sur- 
 rounding them, which takes place as the stem slowly 
 decays from back to front. If they remain very long en- 
 closed in the tissue of the stem, a discoloration of th.; 
 parenchyma connnences in their middle, which is followed 
 by the breaking up of the bud into its component cells, and 
 this latter process advancing gradually to the periphery 
 ultimately destroys the bud. The development of the 
 spores of Anthoceros is a process which has been the subject 
 of very many observations (j\Iohl. sup. 'Nägeli Zeitschr. 
 f. Botanik,' H. 2; Schacht, 'Berk Bot. Zeit.,'' 1850, 24— 
 26). The observers just cited agree with me as to the 
 
THE HIGHER CRYPTOGAMIA. 19 
 
 facts observed in all essential points ; but there is a dif- 
 ference of opinion as to the interpretation of these facts. 
 Mold assnmes that the duplication of the secondary nuclei 
 takes place by gradual constriction ;'"^" Nägeli, that it occurs 
 by the growth of a septum bisecting the internal cavity of 
 the secondary nucleus of the first order, and by the subse- 
 quent differentiation of the two halves ; Schacht's notion 
 of the process approximates to that of Mold, from which niy 
 own explanation only differs in the mode of expression. 
 
 Figures of Anthoceros are to be found in Dillenius 
 (' Historia Muscorum,^ tom. Ixviii, figs. 1, 2), in Schmidel 
 ('Icones pi.,' t. xix, A. Icevis ; t. xlvii, A. pu?ictatus), and 
 also in Hedwig [A. Imvis, theoria generat., ed. ii, t. xxix, 
 xxx). According to these figures, the characters of the 
 floAvers appear to be principally grounded upon a " radi- 
 ating mode of growth, progressing in all directions from a 
 central point of attachment." The history of the develop- 
 ment of the fruit Avliich is given by the above observers 
 does not extend further back than the appearance of the 
 fruit above the edge of its veil or covering. Nees v. Esen- 
 beck (' Naturgeschichte der Europ. Lebermoose,' B. iv, 
 s. 334, 1838) describes the rudiments of the fruit, whilst 
 enclosed in the substance of the stem, as archegonia {Stem- 
 pel). BischofF, on the other hand, had already (1835) 
 rightly described the relation of the young fruit to the 
 tissue of the stem which covers and encloses it (' Nova 
 Acta Acad. C. Carol. Leop.', T. xvii, p. 2, s. 934), and has 
 figured it. (' Handb. der Botan. Terminol,' B. ii, t. Ixvi, 
 fig. 2783.) He does not mention the archegonia. Schacht 
 has lately (' Berliner Bot. Zeit. Jahrg,' viii, 1850, N. 24 — 
 26) pubhshed a contributiori to the history of the develop- 
 ment of the fruit and spore of Anthoceros. My own obser- 
 vations, in the 'Vergleichende Untersuchungen/ were com- 
 pleted before the appearance of Schacht's paper. Schacht has 
 only once observed an archegonium (1. c. 459), unfortunately 
 an imperfect one, of which the essential parts were already 
 decayed. The arrangement of the cells of the stem adjoining 
 the base of the archegonium appeared to him to bear a great 
 
 * See Waguer's ' Handwöiterbiich der Physiologie,' Bd. iv, s. 215. 
 
20 HOFMEISTER, ON THE HIGHER CRYPTOGAMIA. 
 
 resemblance to that occurring at tlic base of the ruclinicn- 
 tary fi'iiit. Tliis led him to the erroneous conclusion, that 
 the fruit Avas the product '' of ccriaiii cells lijing at the bot- 
 tom of a nmall, narrow, deep catial of the leaf'' The above 
 remarks show the inaccuracy of this view. The following 
 observations will exhibit the essential agreement in fruit - 
 formation existing between Anthoceros and the liverworts 
 and mosses generally. 
 
PUBLIC LIBRARIES 
 
 CHAPTER II. 
 
 LEAFLESS JUNGERMANNI^E. 
 
 PeJ/ia cpipliylla, Aneura j)wgim and muJtIßda, Mcf^gcria 
 
 fiircata.) 
 
 Amoivgst all the liverworts indigenous to Germany, 
 Pel/ia cpipliylla has the largest spores. They are oval, 
 Surrounded by a delicate, linely granular outer mem- 
 brane ; in the ripe state, as they escape from the opening 
 fruit, they are multicellular. They usually consist of four 
 cells, arranged in a single row, two of which are disc- 
 shaped and two hemispherical (PL IV, fig. 1). Sometimes 
 one of the former is divided by a longitudinal septum, so 
 that the spore is 5-cellular (PL IV, fig. 2). The internal 
 cavity of the cell contains much chlorophyll ; the green of 
 which, appearing through the thin, pale-yellowish wall of 
 the capsule, imparts to the unopened fruit its dark colour. 
 The cell which constitutes one of the ends of the spore 
 contains a far smaller quantity of chlorophyll-granules than 
 the other cells. Prom it springs the first of the long root- 
 like papillae by Avhicli the plant is attached to its place of 
 support. The cell next to this divides by a longitudinal 
 septum a few hours after the spores have been sown 
 on moist earth, even if such division has not taken place 
 earlier ; the same process then follows in the neighbouring- 
 cell, and frequently also in the cell opposite to the radicular 
 cell. Each pair of cells of the middle region of the germi- 
 nating spore is doubled by longitudinal division, taking 
 place principally in the direction of one of the transverse 
 diameters (of the spore). Some varieties occur throughout 
 the whole extent of the ccll-multiphcation caused l)y this 
 longitudinal division, which, however, have little influence 
 upon the ultimate form of the })lant. The division begins in 
 the cells next to the rooting cell (PL IV, fig. 3), sometimes 
 
 5^% 3 
 
22 IlOrMEISTER, ON 
 
 only in one of these cells (PI. IV, figs. 4, 5, 9), sometimes in 
 the cells next but one to the rooting cell (PI. 4, figs. 6, 7), 
 or even in one only of such cells. The germ-})lant con- 
 sists now of the basal cell, which is protruding the first 
 radicular papilla ; of two sets of cells above the basal cell, 
 each consisting of from two to four cells adjoining one 
 another ; and of the apical cell, which is already not unfre- 
 quently divided by a longitudinal septum (PL IV, figs. 9, 10), 
 
 The activity of cell-multiplication in the direction of the 
 breadth of the plant increases continually towards the apex. 
 Although it never occiu's more than once in the cells next 
 to the basal cell, it is a rare occurrence when it only takes 
 place in one of the next higher cells, and it is a nüe almost 
 without exception that it happens repeatedly in the fourth 
 pair of cells reckoned from the basal cell upwards (PI. IV, 
 figs. 12, 14). Hence the plant assumes the form (more 
 and more distinctly marked as it advances in growth) of a 
 plate widening continually towards the fore edge. In its 
 earliest youth the base, notwithstanding the smaller number 
 of its cells, is as wide or wider than the apex. The expan- 
 sion of the lower cells, which occurs at an early period, 
 keeps pace up to a certain point with the increase in 
 breadth of the upper cells. But, when a month old, the 
 outline of the young plant has already assumed the shape 
 ofaspatiüa (PL IV, fig. 14). 
 
 The expansion of the ceUs adjoining the base of the 
 plant begins at the time of the protrusion by the basal cell 
 of the first rootlet ; this takes place contemporaneously 
 Avitli the commencement of the nmltiplication of the cells 
 in the dii'cction of the longitudinal axis, Avliich latter 
 results only from the continual division of the apical cell, 
 or (as is more often the case) of the two adjoining apical 
 cells. Both cells divide contemporaneously by a very 
 oblique* longitudinal septum, upon which a similar septum, 
 inclined more obliquely, but in the opposite direction, 
 is soon imposed (PL IV, figs. 7, 8, 13). This division of 
 the terminal cells by septa alternately inclined in different 
 directions to the surfaces of the plant, is repeated con- 
 tiimally, and with tolerable rapidity ; for instance, twice in 
 
 * The longitudinal axis of the spore being considered to be vertical. 
 
THE HIGHER CRYPTOGAMIA. 23 
 
 three clays in a plant kept moist upon the stage of the 
 microscope. If the number of the apical cells of the plant 
 increases in a lateral direction by the division of the exist- 
 ing cells, the like process immediately follo^vs in all the 
 ncAvly formed cells : in the entire row of apical cells 
 division takes place continually by septa inclined either to 
 the upper or the under surface of the plant. The newly 
 formed cells of the second order divide, very shortly after- 
 wai'ds, by septa almost parallel to the surfaces of the plant 
 (PI. IV, fig. 13). By this means the number of layers of 
 cells increases, and Avith it the thickness of the plant. This 
 increase is only slight at first ; it does not seem that the 
 process is repeated whilst the plant is quite young, or 
 that either longitudinal or transverse sections exhibit more 
 than four layers of cells. Very frequently those cells only 
 (hvide which are turned towards one (? the lower) surface ; 
 the plant then consists, in the direction of its thickness, 
 of three layers of cells (PI. IV, fig. 16). By this time 
 certain of the superficial cells of the plant are divided once 
 or twice by a septum perpendicular to the surface, which 
 cells consequently appear twice or three times as small 
 as those in the interior of the tissue (PI. IV, fig. 13). This 
 is afterwards the normal condition. By the penetration 
 of the first rootlets into the ground, the young plant 
 is set erect. It retains this position only a short time. 
 The expansion which immediately commences in the 
 the cells of its lower portion is not uniform ; the cells of one 
 surface expand far less in a longitudinal direction than 
 those of the other (PI. IV, fig. 13) : hence it follows, that 
 the apex of the plant becomes more and more inclined to- 
 wards the less expanded side of the basal cell, i. e., the 
 future under surface of the plant ; so that the direction of 
 the growth of the young Pellia is parallel to the surface of 
 the soil beneath it. Individual cells of the under side, 
 especially those lying in the median line, grow out into 
 long rootlets, which penetrate deeply into the ground. 
 The rootlets originate in the following manner -. at a certain 
 point, iTsnally, exactly in the middle of the onter surface of 
 one of these cells, the membrane grows out into a strongly 
 developed point, which shortly leads to the formation of ^ 
 
24 HOFMEISTER, ON 
 
 long tube attached to the cell The mode of origin of the 
 first main root docs not differ essentially from that just 
 described ; the conical cell Avhich emits the rootlet usually 
 (not always, see PI. IV, fig. 12) becomes transformed by 
 degrees into the main root. 
 
 In consequence of the commencement of the expansion 
 of the basal cell of the germ-plant, the outer membrane of 
 the spore (which, although it has become considerably ex- 
 panded and more delicate, has, nevertheless, up to this i)oint, 
 still enclosed the germinating spore) is ruptured (PI. IV, 
 fig. 10). The cUhris of this membrane may be found, for 
 some time afterwards, attached to the apex of the young 
 plant (PI. IV, fig. 13). 
 
 Ity this time, the cells nearest to the fore edge of the 
 young Pellia have begun to protrude short club-shaped 
 hairs (PL IV, figs. 18, 14), which appear in increased 
 numbers as the growth of the plant progresses (PI. IV, 
 figs. 24, 27). 
 
 From six to eight weeks after the sowing of the spores, 
 the germ-plant has, partly by the multiplication and partly 
 by the expansion of its cells, attained a length of from \"' 
 to § '". It is now attached to the ground by a larger num- 
 ber of rootlets ; the fore edge, from repeated division of its 
 marginal cells, has become wider than the older parts. At 
 every repetition of a longitudinal division of the marginal 
 cells, the septa, which continue to be perpendicular to the 
 surfaces of the plant, appear to diverge laterally more and 
 more in the fore part of the plant. Tlie consequence is, that 
 the arrangement of the ceUs (PL IV, fig. 15) is flabelhform. 
 The sides of the fore edge grow more rapidly than its middle, 
 partly on account of a more frequent division of the cells by 
 moans of sc))ta inclined alternately in different directions, 
 but princi})ally on account of a more vigorous expansion of 
 the cells. The apex of the young plant appears indented, 
 at first slightly, afterAvards more deeply (PL IV, fig. 15). 
 Tlie cell which occupies the bottom of the indentation 
 begins all of a sudden to multiply itself actively. It divides 
 twice by a transverse septum jx'rpendicular to the surfaces 
 of the plant. The foremost of the new cells divides by a 
 longitudinal septum into two, each of which is again divided 
 
THE IlIGlIEll CRYPTOGAMIA. 35 
 
 by a transverse septum. The body thus formed, of which 
 the ground plan exhibits five cells, now protrudes into the 
 indentation of the fore edge (PL IV, fig. 17). The further 
 multiplication of its cells in the superficial direction takes 
 ])lace, in the following manner: a membrane, directed 
 obliquely outwards, is mounted upon each of the last-formed 
 transverse septa ; thereupon each of the inner ones of the 
 four newly formed cells of the fore edge divides by a trans- 
 verse septum at right angles to the longitudinal axis of the 
 shoot. In each of the outer cells there is formed, at the 
 same time, a longitudinal septum parallel to the last-formed 
 oblique septum. By this means the ground is laid for the 
 fan-shaped arrangement of the cells of the middle shoot. 
 
 All that is now" necessary for the development of the cell- 
 arrangement of the half-developed (PL IV, fig. 23) as well 
 as of the perfect middle shoot, is the repetition of the 
 division by transverse septa of the two middle cells of the 
 fore edge — the repeated transverse division of the cells late- 
 rally adjoining the latter — the commencement of a longitu- 
 dinal division in these cells after a repetition once or twice of 
 the transverse division, and lastly, — the frequent reciu'rencc 
 of the same series of divisions in the lateral cells for the 
 time being of the fore edge of the shoot. 
 
 The gro^vth of the middle shoot of the germ-plant is 
 limited, as is the case with all the divisions of the stem in 
 Pellia. The multiplication of its lateral cells is slight at the 
 base, increases to the middle, and increases rapidly from 
 thence to the apex. The form of the shoot is therefore 
 either that of a short spatula, or semi-oval. 
 
 The cells which are situated in the axil formed by the 
 middle shoot and the lateral whig of the germ-plant begin 
 to multiply vigorously, according to a similar rule, as soon as 
 that shoot has attained to about a fifth part of its develo])- 
 inent. The cell, which, when seen in profile or from above or 
 below, is oblong or trapezoid, appears, when viewed in the 
 direction of the surface of the plant, divided in the first in- 
 stance, by means of a transverse septum, into two cells, of 
 which the hinder cell is square, and the front cell trapezoid. 
 The latter divides by a longitudinal septum ; each of the 
 newly formed ones again by a transverse septum ; the outer 
 
26 HOFMEISTER, ON 
 
 cells thus formed divide by laterally inclined longitudintd 
 septa, and so on, as in the case of the origin of the middle 
 shoot. The Hke process is repeated in the angles at both 
 sides of the new sjioot, soon after the connnencemcnt of its 
 formation. A shoot originates in each angle, which unites 
 in growth with the median shoot, on the side which is 
 tiu'iied towards the latter. By this means a new shoot is 
 formed on each side of the rai(ldle segment of the fore edge 
 of the young plant (PL IV, fig. 19), which new shoot, in 
 consecpience of its being comjjoscd of tlirec united slioots, 
 is tripartite at its fore edge. Tlie flat cellular masses which 
 thus originate unite in giowth firudy and intimately with 
 the middle shoot, bv the edf»c which is turned towards the 
 latter. The new shoots, composed of these amalgamated 
 cellular bodies, protrude from the indentations of the 
 fore edge of the young plant, in consequence of the 
 connnencemcnt of longitudinal expansion in its basal 
 cells ; by their expansion, the middle lamellae wdiich are 
 imited to them are drawn out laterally. Their form is 
 now a complete repetition of that of the germ-plant in 
 its earliest stage : the fore edge exhibits a short, spatula- 
 shaped median segment, and two lateral wing-shaped ones. 
 The subsequent ramification takes place in Hke manner. 
 There is one invariable rule for the entire development of 
 the i)lant, connncncing from the formation of the middle 
 shoot of the germ-plant : the rule is, that each shoot has its 
 origin in the amalgamation of three shoots, which are formed 
 almost contemporaneously in one of the indentations of the 
 fore edge of an older shoot. Each new shoot, therefore, 
 exhibits at its first appearance two indentations of the fore 
 edge. According to the ordinary rule, new^ shoots are 
 formed only in those indcmtations wdiicli point out the 
 boundaries of the three amalgamated shoots. Hence arises 
 the furcate ramification of the ])lant (PI. lY, figs. 19—22). 
 The growth of each shoot is limited.* 
 
 * BIschnfT considers that (lie first slioof of the cfci-m-plant of Tcllia is a protlinl- 
 liiini, disliuct from the snl)sequciit slioots. ('Handb. d. Terminoloffie,' ii, 733 ; 
 'Botaii. Zeituiif,',' 1853, 115.) As, however, tiie first shoot is not distinguish- 
 able iu^any essential parlieulars from th.c later ones, I agree witli (Joitsche 
 CBot. Zeitnng,' 1858, Aniian?, IG) in thinking that there is no ground for tliis 
 distinction. 
 
THE HIGHER CRYPTOGAM I A. 27 
 
 The multiplication of the cells of each shoot in the 
 direction of its longitudinal axis takes place exclusively in 
 the cells of the fore edge. In the young germ-plant they 
 divide, as has l)een shown above, by septa inclined to the 
 horizon alternately in different directions. The form of 
 the cell-multiplication in the fore edge of the growing 
 shoots of older plants is essentially different. Here the 
 marginal cells divide by septa which are parallel to one 
 another, slightly convex on the inner side, and perpendi- 
 cular to the surfaces of the plant. This form of division 
 often occurs in young germ-plants of two months old 
 (PI. IV, fig. 24). The phenomenon which occurs so fre- 
 quently, — viz., the fact that in the earliest stages of develop- 
 ment the division by horizontal septa parallel to one an- 
 other"* precedes that which in all subsequent stages is the 
 normal mode of cell-multiplication, viz., division of the 
 terminal cell by septa alternately incHned in different direc- 
 tions, — makes it probable that the latter form of cell divi- 
 sion is to be looked upon as a more perfect, higher form of 
 growth than the former. Still more remarkable is the 
 fact (which as yet stands alone), that in Pellia the simple, 
 apparently lower form of cell-multiplication follows, in 
 point of time, the more complex form which occurs in the 
 later periods of the life of the plant. 
 
 This phenomenon appears most distinctly in the first 
 spring-shoots of fruiting specimens. Here the cells of the 
 fore edge of the first, second, and third order exhibit, 
 during the growth of the shoot, large and manifest nuclei, 
 from which mucilaginous threads often pass to the walls of 
 the cells; they contain, besides, a shghtly gramüar, yellowish 
 slime. In the older cells lying behind the fore edge, 
 numerous small chlocophy 11- granules make their appear- 
 ance ; the nuclei of these cells are less easily seen (PI. IV, 
 fig. 25). The cell of the first order — the terminal cell — has 
 the form of a slice taken from the middle of a double convex 
 lens by two sections parallel to the small axis ; the cell of 
 the second order, at its first appearance, is shaped like a 
 
 * This occurs ill the proihalliiun of mosses, in the suspcusor of Selaginella, 
 iu the greater number of phsenogans, and in the rudiments of tlie fruit of 
 many mosses. 
 
28 HOFMEISTER, ON 
 
 similar slice from a Areniscus. Through the division of tliese 
 cells by means of septa parallel to the surfaces of the plant, 
 the shoot increases in thickness. The first of these septa does 
 not coincide with the ideal axis of the shoot ; the two parts 
 into which it divides the cell are very Tuiequal (PI. IV, fig. 
 25). The two newly formed cells divide again several times 
 by horizontal septa ; the thickness of the plant, however, 
 never seems to go beyond eight layers of cells. From some of 
 the cells near the fore edge, hairs, shaped like a club, and 
 bent forwards, take their origin. The latter become bicellu- 
 lar, soon after their appearance, by the gro\vth of a transverse 
 se})tum. The basal cell, when fully groAvn, usually con- 
 tains starch-granules ; the terminal one, a thin fluid muci- 
 lage. A mend)ranous layer of tougli gelatine encloses 
 the growing fore edge of these hairs. The cells which form 
 the permanent upper and mider surface of Pellia ultimately 
 divide by a vertical, longitudinal, and transverse septum ; 
 so that each cell of the outer layer is four times as small as 
 one of the neighbouring inner cells. This division occurs 
 sometimes in the fourth youngest, sometimes even in the 
 seventh youngest group of cells produced by a cell of the 
 second order. As the growth of a shoot progresses, the 
 activity of the cell-multiplication in the direction of its 
 thickness diminishes continually from the base to the fore 
 edge, more slowly, however, in the median line than at the 
 sides. The free margin of each shoot of which the deve- 
 lopment is completed, is formed of a single layer of cells ; at 
 the base of the indentations of this margin are found pro- 
 tuberances of cellular tissue projecting downwards : these 
 are the voung new shoots. 
 
 TIk! shoots of barren plants growing in flowing water 
 exliibit conditions in the position and shape of their cells, 
 which can only be cxplahied by looking upon them as foinis 
 transitional l)etAveen the first and the second form of cell- 
 multij)lication (PI. IV, figs. 26, 27). 
 
 It is a remarkable circumstance that, in the earliest 
 spring-shoots of Pellia, the two sides, owing to the moi-e 
 vigorous expansion of the cells of one of them, are always 
 unequally develo})ed. One of the shoots which protrude 
 themselves from the indentations of the fore edge pushes 
 
THE HIGHER CRYPTOGAMIA. 29 
 
 II]) n])parently to the apex of the parent shoot through the 
 distortion of the outUne of the Latter, whilst the other 
 appears at some depth below, closely pressed to the side 
 (Fl. IV, fin-s. 20, 21). The former is always developed 
 more rapidly than the latter (PL IV, fig. 22), which often 
 fails altogether, often remains quiescent for months and 
 then suddenly begins to grow. Most of the distm'bances of 
 the regular furcate ramification have their origin in the 
 circumstances just mentioned. 
 
 It is only in barren plants (where it often occurs) that 
 shoots are found on the upper side also of the flat stem. 
 In individual cells of the surface there conunences a pro- 
 cess of cell-multiplication differing, so far as regards its 
 regular mode of progression, in no material respects from 
 that which obtains in the germination of spores (PL IV, 
 fig. 28). A number of shoots of the above nature, similar 
 to germ-plants, only more fleshy, are often situated close 
 together: — in old joints of the stem I have counted as many 
 as thirty upon a single joint. The tufted mode of growth 
 of barren Pelliae in flowing water uiay, perhaps, be OAving 
 to these shoots. 
 
 On the upper side of the earliest spring-shoots of fertile 
 Pellise, club-shaped cellular masses are protruded, consist- 
 ing of a short central string, usuall}' of only two cells^ sur- 
 rounded by a single layer of four cells, each lying at the 
 same elevation (PL IV, fig. 29) : these are the first rudi- 
 ments of the antheridia. The arrangement of the cells leads 
 to the conclusion that they have originated in the division 
 by means of septa inclined alternately in different directions, 
 of one of the cells of the upper surface. Each cell of the 
 second order is divided by a longitudinal septum ; two of 
 the cells thus formed, v.hich are placed one above another, 
 and have almost the form of the quadrant of a cylinder, are 
 divided by a septum cutting the side-walls at an angle of 
 45°, into an inner three-sided and an outer four-sided 
 cell, of which the latter has an arched outer surface. This 
 determines the structure of the first rudiments of the 
 antheridium. By continual multiplication of the five cells 
 of its clavate end, the inner one of Avhich divides in all 
 three directions, the four outer ones only in the direction 
 
30 HOFMEISTER, ON 
 
 of the tangent, the antheridiimi assumes the form of a 
 mass of cellular tissue, supported upon a very short stalk, 
 consisting of four cells. Contcniporaneously with the 
 first appearance of the young antheritliuni above the surface 
 of the joint of the stem, an annular wall of cellular tissue 
 is raised round the antheridium by means of repeated 
 division of the adjoining cells of the upper surface of the 
 frond (PI. IV, fig. 29), which wall, keeping pace in its 
 growth with that of the antheridium, surrounds it when 
 ripe, enclosing an open space above its apex. 
 
 The cells, sixteen to twenty-five in number, of the outer 
 cellular layer of the ripening antheridium arc flattened and 
 tabular (PL IV, fig. 30). Their Avails are covered with 
 rather large chloi'ophyll-bodies (starch-grains surrounded 
 by a very thin green layer), which, when the organ is fully 
 ripe, assume a dull yellow colour. The inner cells continue 
 to divide for a long period by alternate longitudinal and 
 transverse septa ; so that the antheridium, when nearly ]-ipe, 
 consists of a glol)ular mass of very small, four-sided, tabular 
 cells, surrounded by a single layer of large, flat cells, con- 
 taining chloro})hyll. Each of the small tessellated cells con- 
 tains a lenticular vesicle, in which a spiral thread is formed, 
 consisting of transparent mucilaginous matter (PI. IV, figs. 
 30 — 32), When the antheridium is fully ripe, the cells of 
 the covering layer separate from one another at the apex ; 
 the small cells, whose primary intimate adhesion has been 
 destroyed by the softening and swelling up of the cell-mem- 
 branes, escape through the crevices, mixed with nnicilaginous 
 granules, in the form of a thick pultaceous mass ; when 
 brought under water, they disperse themselves in the fluid. 
 The spiral thread enclosed within them (the spermatozoid) 
 soon exhibits an active whirling motion, in consequence of 
 which it resembles a closely Avound watch-spring (PI. IV, 
 fig. 32 "'''■); it is still surrounded by the lenticular vesicle, 
 which, however, diu-ing the motion, can with difficidty be 
 seen. When the wall of the vesicle which envelope's the 
 spermatozoid bursts (which usually occurs after the vesicle 
 has been in the water for half an hour), the spermatozoid im- 
 mediately escapes through the fissure. It then forces its way 
 through the gelatinous,'softened substance of the wall of the 
 
TUE HIGHER CRYPTOGAMIA. 31 
 
 (originally tabular) mother-cell. The turns of the spiralarc 
 drawn out from one another, so that it assumes the form of 
 a screw. The spermatozoid moves abont with some rapidity 
 in the water, keeping up a continual revolution round its 
 own axis, and often dragging behind it the ruptured vesicle. 
 The hinder end of the spermatozoid is draAvn out into a very 
 long, fine point ; the opposite end is thickened, but hardly 
 perceptibly so. At this end I saw very clearly, in sperma- 
 tozoids whose motion had been arrested by a solution of 
 iodide of potash, two long, thin, lateral cilia, exactly like 
 those which Tlmret discovered in the spermatozoa of Chara. 
 The observation of these cilia, which I could not succeed in 
 finding in any other liverwort, is a matter of some difficulty 
 even in Pellia Avitli our present magnifying powers. The cilia, 
 and the thread-shaped ends of the spermatozoa, which some- 
 times adhere to other bodies, exhibit an active motion which 
 is winding and helicoid rather than pendulous. One end of 
 a spermatozoid will often remain attached to the mucila- 
 ginous mass which escapes with it from the ripe anthe- 
 ridium. The movements of the spermatozoa last only a 
 short time ; ten minutes after theii- escape they relax sen- 
 sibly ; in all the cases Avhich I have observed, they have 
 ceased entirely after two hours and a half.* 
 
 The number of the antheridia is very large; it often 
 amounts to fifty on the same shoot. They first open at the 
 beginning of May ; but even at the end of June a good 
 number of ripe ones may still be found. Upon Pelli» 
 growing in running water, which, as a rule, are barren, iso- 
 lated antheridia are not unfrequently found; but arche- 
 gonia are hardly ever met with. 
 
 Upon the shoots situated in the indentations of the fore edge 
 of those spring-shoots which bear antheridia, oval, closely 
 packed cellular bodies are protruded, varying in number from 
 four to twelve; these are the first rudiments of the archegonia. 
 Immediately after their appearance, the young shoot makes a 
 further growth underneath them, but without attaining to 
 
 * Thuret has shown that spermatozoa of a like structure exist in all the 
 Muscinese. (' Ann. Sc. Xat.,' 3rd ser., vol. xvi). He has given very good 
 fig\ircs of those of Pellia (1. c, pi. x). Schacht's figures ('Die Pfianzenzdle,' 
 Berlin, 1S52, pi. v) do not exhibit correctly the relation of the cilia to the 
 body of the spermatozoid. 
 
33 HOFMEISTER, ON 
 
 the same thickness as before. The archegoiiia, consequently, 
 ap])ear to be seated upon the scarp ])rodiiced on the upj)er 
 surface by tlie sudden diminution in thickness of the joint 
 of the stem (PL V, fig. 1). The deveh)pment and struc- 
 ture of their first rudiments correspond exactly to those of 
 the very young antheridia. A cell of the upper surface of 
 the yet very young shoot becomes slightly arched outwards ; 
 it divides l)y a septum inclined to the surface of the stem, 
 and the uj)])er one of the newly formed cells divides by a 
 septum inclined in an opposite direction to the latter sei)tum. 
 Whilst the division is repeated in the ucav terminal cell by a 
 septum perpendicular to the last and parallel to the last but 
 one, the last formed joint-cell divides by a vertical septum 
 into two cells whose basal outline is a quadrant. The 
 same })roccss recurs in each second-youngest cell, whilst 
 the terminal cell divides anew by a septum inclined in a 
 direction opposite to that of the last. The archegonium 
 would have the appearance of a column consisting of 
 four roAvs of cells, but for the fact that in all the cells 
 of one of the four rows, inunediately after the division 
 of the cell of the second order by a radial longitudinal 
 septum, a partition-wall appears which divides the cell into 
 an inner three-sided cell, surrounded by other cells, and an 
 outer cell, of which one of the foiQ- Avails is free (PL V, 
 figs. 3, 4). The young archegonium thus presents the ap- 
 pearance of a cylinder of cellular tissue, rounded above, con- 
 sisting of a central string of cells (as many as thirty in 
 number), Avhicli is siuTounded by a single layer of four 
 cells. The central cellular string does not extend quite to 
 the base of the young archegonium, Avhich base consists of 
 a short stalk, of the height of one or tAvo cells, and com- 
 ])osed of four cells lying in the same plane (PL V, figs. 5, 
 6, &'). The cells of the central string become filled, soon 
 after their formation, Avith a granidar nuicilage, in Avliich 
 the nucleus lies imbedded in the form of a transparent 
 vesicle (PL V, fig. 4). The undermost of those cells saa'cIIs 
 considerably ; its nucleus also increases in size (PL V, 
 fig. 5). The adjoining cells divide by longitudinal se])ta 
 as soon as the longitudinal groAvth of the archcgonimn is 
 finished (PL V, figs. 5, 6, 7). The same division proceeds 
 
THE HIGHER CRYPTOGAMIA. 33 
 
 to some extent (to the height of five cells), towraxls the 
 apex of the archegonium, the lower part of which thus 
 becomes enlarged. In the mean time, the horizontal 
 septa which divide the cells of the central string of 
 the archegonium from one another become dissolved 
 (PL V, fig. 5). A canal, filled with mucilnge, and closed 
 above, thus originates in the longitudinal axis of the archego- 
 nium. The cells which form the arch over its upper end sud- 
 denly part from one another, bending themselves somewhat 
 backwards ; an open passage, not obstructed by any cell- 
 wall, now leads from the outside through the entire length 
 of the archegonium down to the large cell in its swollen 
 lower part (PL V, figs. 6, 7). In the mean time there is 
 formed in the large cell a free spherical cell, enclosing 
 a central nucleus, and which, w^hen fully grown, almost 
 fills the cavity of its mother-cell (PL V, figs. 6, 7). 
 
 During the development of the first archegonia a thin 
 lamella of cellular tissue grows out of the upper surface of 
 the flat stem, from the point of insertion of the archegonia 
 backwards. It follow^s the longitudinal growth of the 
 archegonia, inasmuch as the cells of its fore edge con- 
 tinually divide by transverse septa, and its side edges unite 
 with the thin prolongation of the shoot which extends 
 itself underneath (in front of) the archegonium (PL V, 
 fig. 2). A pouch-shaped covering thus originates, which 
 is open in the fore part, and encloses the archegonium. It 
 entirely corresponds in its Avhole development with the 
 perianth of the leafy Jungermannise, especiall}^ in the fact 
 that it appears at a later period than the first rudiments of 
 the archegonia. Pellia must not be classed with the 
 Gyromitrise. 
 
 The above condition is attained by all those archegonia 
 whose longitudinal growth is terminated before the time 
 when the rudiments of the fruit begin to appear in one of 
 the archegonia enclosed in the same perianth with them- 
 selves. The time of the development of the archegonia 
 is very uncertain : the earliest open at the beginning of 
 May ; the latest in the middle of Jidy. Even then, those 
 flowers which contain no rudiments of fruit exhibit abortive 
 archegonia, in which the walls of the canal of the neck and 
 the wall and contents of the large cell in the expanded 
 
 3 
 
34 HOFMEISTER, ON 
 
 loAvcr portion arc of a deep-brown colour. Of these 
 abortive arclicgonia some have only just burst at the apex, 
 some are still closed, and others again are in the earliest 
 stages of development. 
 
 I consider those archegonia whose apices have just 
 opened, and the cell-walls of whose necks have not yet 
 become brown, as in a state ready for impregnation ; and I 
 believe that, in order to effect such impregnation, it is 
 requisite that some, perhaps one only, of the motile threads 
 formed in the antheridia should reach the funnel-shaped 
 opening of the archegonium. I have not, indeed, seen the 
 spermatozoa of Pellia in that position, even if such be the 
 case with other liverworts, about which I shall speak here- 
 after. I have frequently found, however, that in those 
 flowers of Pellia to which I had applied a drop of water 
 containing ripe, opened antheridia, several (from three to 
 seven) archegonia have produced the rudiments of fruit 
 (PI. V, fig. 9"). The circumstance, that the ripening of 
 the antheridia and the bursting of the archegonia begin and 
 end precisely at the same time, affords as good ground for 
 the above view as the more exact knowledge which we 
 possess with regard to mosses — a view, moreover, 
 which in all essential points has been entertained for an 
 equal length of time with regard to both liverworts and 
 mosses. 
 
 The outer cells of the expanded portion of the im- 
 pregnated archegonium divide rapidly several times one 
 after another, by radial septa, by longitudinal septa 
 parallel to the free outer walls, and by transverse septa ; 
 this cell-multiplication is most vigorous at the base of the 
 archegonium. All the ncAvly formed cells become filled 
 with chlorophyll. Thus, very soon after the beginning of 
 th(^ development of the rudiments of the fruit, the ex- 
 panded portion of the sm-rounding archegonium assumes 
 the form of a somewhat large, dark -green, cellular mass. 
 The neck of the archegonium remains unaltered. 
 
 The fruit is developed from the free spherical cell which 
 is enclosed in the central cell of the expanded por- 
 tion of the archegonium. That cell first divides by a 
 transverse septum into a lower and an upper cell, of which 
 
THE IIlfillER CRYPTOGAMIA. 35 
 
 the former is much the hirger of the two, and the latter 
 has the shape of a segment of a sphere. Tlie hitter 
 divides by a longitudinal septum shewn in PI. V, fig. 8, which 
 represents the rudimentary fruit extracted entire. Each of 
 the two cells W'hich have a semicircular basal outline is 
 divided after previous expansion in length, by a longitu- 
 dinal septum at right angles to the previous one, and 
 each of the four cells thus formed is divided anew by a 
 transverse septum. The young rudimentary fruit now^ 
 exhibits four apical cells (cells of the first order). Its 
 growth is carried on by continually repeated division of 
 these cells by means of horizontal septa. 
 
 In the first four interstitial cells thus formed, cell-multipli- 
 cation commences in the direction of their breadth and thick- 
 ness. Each of these cells (whose form is that of the quadrant 
 of a cylinder) divides by a longitudinal sejrtum parallel to 
 the axis of the rudimentary fruit, cutting both the side 
 walls at an angle of 45°; and each of the four new outer 
 cells thereupon divides by a radial longitudinal septum. 
 In the next higher double pair of cells, the cell-multiplica- 
 tion does not proceed any further. Erora thence (going 
 upAvards) the division is repeated in the eight outer cells by 
 a longitudinal septum turned towards the free outer surface, 
 and the following division takes place by a radial longi- 
 tudinal septum. By this time the rudimentary fruit has 
 the form of a short club (PI. V, fig. 9). Its upper end, how- 
 ever, soon increases considerably in thickness by divisions 
 which take place in the cells of the apical surface by means 
 of septa inclined outwards from the longitudinal axis of the 
 organ, w'hich divisions alternate wdth the longitudinal and 
 transverse divisions of these cells. The cells of the apex of 
 the rudimentary fruit exhibit, in consequence, when cut 
 longitudinally, a regular radiate arrangement, which arrange- 
 ment changes, in the lower part of the fruit, into one con- 
 sisting of parallel rows of cells (PL V, fig. 10). 
 
 About two months after impregnation, the apical cells of the 
 young fruit cease to divide. An active cell-multiplication be- 
 gins instead in almost all its already formed constituent parts. 
 The cells of the upper clavate end, excepting the irmermost 
 
86 HOFMEISTER, ON 
 
 of them, divide by septa parallel to a tangent to tlie nearest 
 portion of the outer arcuate surface, which latter septa alter- 
 nate with others at right angles to them, and with radial 
 septa. The cellular mass, Avhich thus increases in size, is 
 the future capsule. In the middle of the rudimentary fruit 
 the cells which eventually form its stalk divide, frequently 
 several times over, by means of horizontal septa exclusively. 
 There is thus formed a cylindrical column of about sixty 
 (12 measured diametrically) vei-tical rows of small tabu- 
 lar cells. The lower third part of the rudimentary fruit 
 ultimately exhibits a rapid increase in the number of its 
 cells, both in length and thickness — an increase which 
 diminishes gradually downwards. This end of the rudi- 
 mentary fruit assumes in consequence the form of a turnip; 
 its thickness very soon considerably surpasses that of the 
 cylindrical middle portion (PL V, fig. 11). At this period 
 an active midtiplication commences in the cells of the cir- 
 cumference of the short upper protuberance of the swollen 
 base of the young fruit. These cells, which form a girdle 
 of about four cells in height, divide first by horizontal septa 
 (PI. V, fig. 11), and afterw^ards by septa parallel to a tan- 
 gent to the circumference. By this means there arises out 
 of the upper portion of the turnip-shaped enlargement of 
 the fruit-stalk a hollow cylinder, enclosing its columnar 
 portion. This sheath increases in length by continually re- 
 peated division of the cells of the free upper edge by means 
 of alternately inclined septa. Its cells of the second order 
 are soon divided anew by membranes at right angles to the 
 latter septa, the older lower cells being divided more fre- 
 quently than the upper younger ones. The free upper edge 
 of the hollow cylinder consists, in all its stages of develop- 
 ment, of a single layer of cells ; towards the base the number 
 of the cells continually increases. In the com'se of further 
 development, four (in exceptional cases three) triangular flaps, 
 enclosing the fruit-stalk upAvards for a considerable distance, 
 are formed from the edge of the sheath, by means of a 
 locally increased intensity in the cell- multiplication in a 
 longitudinal direction. During the formation of the sheath, 
 the end of the fruit-stalk beneath it continues to increase in 
 thickness ; this increase terminates, as does also the multi- 
 
THE HIGHER CRYPTOGAM lA. 37 
 
 plication of the cells of the sheath in a longitudinal direc- 
 tion, when the sheath has attained a length equal to a 
 fourth or a third part of the stalk of the young fruit which 
 is still enclosed in its calyptra (PL V, fig. 13). At an early 
 period, even before the expiration of the third month from 
 the commencement of the rudiments of the fruit, a diffe- 
 rentiation of the tissue appears in its upper swollen end, 
 i. e. the future capsule. The cells of the outer surface 
 divide by septa perpendicular to this surface, and then 
 again by partitions also perpendicular to the arched outer 
 surface, cutting the last-formed septa at an angle of 90°. 
 The inner cells take no part in this division ; they appear, 
 therefore, eight times larger than the others ; in longitu- 
 dinal and also in transverse sections, the boundary of each 
 pair of cells of the outermost layer coincides with that of 
 one of the adjoining inner cells (PI. V, fig. 11). At the 
 same time the walls of the inner cells of the young capsule 
 begin to thicken. The substance of the thickened walls 
 swells up very rapidly and extensively in Avater ; to such an 
 extent that, in cutting through a young fruit placed in water 
 upon the stage of the microscope, the cells of the interior 
 of the capsule immediately protrude laterally beyond the 
 wall of the capsule. The swollen gelatine is dispersed in 
 the water ; the primordial utricles of the cells become free, 
 and assume a spherical shape (PI. V, fig. 12). In order 
 to get an insight into the structure of the interior of the 
 young capsule, it is indispensable that it should be examined 
 in rectified spirit of wine. With tincture of iodine the 
 entire mass of its cell-walls becomes coloured a vinous red 
 or violet. Even after the differentiation of the wall from 
 the inner tissue of the young capsule, the cells of both in- 
 crease considerably. The cells of the lower part of the wall 
 divide by septa parallel to the outer surface ; consequently, 
 at the spot where the wall of the capsule adjoins the fruit- 
 stalk, that wall consists of two layers of cells. On the other 
 hand, the cells of the wall of the upper part and of the 
 apex of the young capsule divide exclusively by septa per- 
 pendicular to the outer surface (compare fig. 11 of PI. V 
 with fig. 13). At the same time the cells of the interior, 
 especially those at the boundary of the wall of the capsule, 
 
38 HOFMEISTER, ON 
 
 increase in all three directions ; most actively in the neigh- 
 bourhood of the apex. By the coincidence of both methods 
 of multiplication of its cells, the hemispherical form of the 
 YOung capsule is changed, within a month, into a long oval 
 fornr(Pl. V, fig. 13)/ 
 
 By the end of August the walls of the cells of the inte- 
 rior are entirely broken up and undistinguishable. The 
 free primordial utricles begin now to clothe themselves with 
 new and firmer cell-walls. They then exhibit a very dif- 
 ferent deportment. One portion of the cells becomes elon- 
 gated and spindle-shaped — the future elaters. A whole 
 string of cells lying in the longitudinal axis of the young 
 fruit assumes this spindle form ; around this string the 
 rest of the cells destined to form elaters are arranged, radi- 
 ating upwards (PI. V, fig. 37). Another portion of the 
 cells of the interior assumes a spherical form : these are 
 the mother- cells of the spores. In their fluid contents, very 
 numerous small chlorophyll - granules now make their 
 appearance. 
 
 The mother-cells retain the spherical form only for a 
 short time. By the first week of September their walls ex- 
 hibit four protuberances, each of which, sitviated at a 
 distance of 120° from the neighbouring one, constitutes an 
 arched surface, the basal outline of Avhich is an equilateral 
 spherical triangle. These bulgings of the cell-wall become 
 rapidly more and more arched; by the middle of Sep- 
 tember each mother-cell appears to be composed of four 
 oval sacs open at one end, which unite at an angle of 120° 
 with the open, more pointed ends, so as to form a quadrangu- 
 lar median space (PI. V, figs. 14, 15). Each of these bulgings 
 of the mother-cell contains a nucleus ; the mode of its origin, 
 as well as that of the primary central nucleus of the mother- 
 cell, (which latter nucleus has now disappeared,) is difficult 
 to make out, on account of the opaque cell-contents, which 
 consist of a thick mass of chlorophyll-granules. It is even 
 somewhat difficult to feel assured of what is an undoubted 
 fact, viz., the presence of a secondary nucleus in each of 
 the bulgings of the mother-cell. 
 
 At the boundaries of the four protuberances of the mother- 
 cell, the inner wall of the latter becomes nuich more thick- 
 
THE HIGHER CRYPTOGAMIA. 39 
 
 ened than in its other parts. Six bands are formed, 
 which are attached to the inner wall, and protrude inwards. 
 At their first appearance, in the middle of September, they 
 are tolerably flat, but increase slowly in height until the 
 beginning of December (PI. V, fig. 17). The median space 
 by which the four protuberances of the mother-cell are in 
 continuous communication * is thereby narrowed ; rather 
 narrow circular cavities lead from it to the four protuber- 
 ances. It is now filled exclusively with transparent fluid 
 matter as clear as water ; chlorophyll-granules and granules 
 of mucilage are as yet found only in the protuberances. 
 Suddenly each of the latter appears separated from the 
 quadrangular median space of the mother-cell, by a wall 
 convex towards the interior (PI. V, fig. 17). This dehcate 
 membrane is probably not mounted upon the edge of the 
 broad ledge which protrudes into the median space, but 
 clings to its surface, and encloses the entire contents of 
 the protuberance, which, consequently, now represents a 
 very delicate-walled oval cell, /. e. the young spore. By 
 the dissolution of that portion of the wall of the latter 
 cell which belongs to the protuberance of the mother-cell, 
 the space very soon becomes free ; I l^ave reason to sup- 
 pose that this occurs within forty-eight hours after the 
 spore has become individualised. The six thickened bands, 
 on the other hand, which consist of glass-like cellulose, 
 and which unite to form the skeleton of an uneven-sur- 
 faced quadrangular figure, last for several days ; they are 
 to be found in large numbers amongst the escaped spores, 
 and are most elegant microscopical objects (PI. V, fig. 20). 
 The spores of Pellia exhibit in the course of their develop- 
 ment several peculiarities, which are of importance in the 
 study of cell-formation. That the walls of the special 
 mother-cells grow gradually inwards from the inner wall of 
 the mother- cell is placed beyond a doubt, as well by the 
 slow growth of the bands above mentioned, as also by the 
 fact that, in Pellia, the walls in question are normally only 
 
 * This appears perfectly clearly when one of the protuberances of a mother- 
 cell which has been h'm^ in water bursts, and a portion of the contents escapes 
 through tlie fissure (a very frequent occurrence). The fluid contents of the 
 uninjured protuberances of the mother-cell then flow slowly, mixed with chloro- 
 phyll-granules, into the one which has been ruptured. 
 
40 HOFMEISTER, ON 
 
 developed to the extent of two third parts, and never com- 
 bine to form partition-walls. If there were any need of ad- 
 ditional evidence in opposition to the theory again brought 
 forward by Karsten, viz., that vesicles too small to be seen 
 with the microscope gradually grow into daughter- cells and 
 occupy the entire space of the mother-cell, it would be 
 afforded by the existence for three months before, as well 
 as during and after the hidividualization of the spore, 
 of a secondary nucleus in each of the protuberances of the 
 mother-cell, which protuberances for a long period freely 
 communicate with one another. The circumstance that 
 the four protuberances of the mother-cell of PeUia, which 
 eventually become the spores, leave a space between them 
 filled only with Avater, is a convincing proof of the inde- 
 pendent nature of the halves of the primordial utricle. 
 
 The young spore divides by a transverse septum very 
 shortly after it has become clothed with a proper membrane ; 
 usually whilst it remains attached to its three sister-spores 
 by the remnants of the mother-cell (PL V, figs. 18, 19). 
 Upon the commencement of this process the central nucleus 
 of the spore, disappears ; two new nuclei, of a flattened ellip- 
 soidal form, appear (PI. V, fig. 18). The numerous small 
 chlorophyll-granules through which the nucleus is faintly 
 seen, thereupon appear separated into two groups, each 
 filling one half of the spore, so that in its equator thei-e is 
 formed a narrow zone of transparent mucilaginous fluid, 
 free from grannies and chlorophyll -bodies. This light space 
 appears suddenly traversed by a very delicate but sharply 
 defined line, which is the side view of a septum passing 
 through the spore (PL V, fig. 21). The same process is 
 shortly afterwards repeated in each of the two semi-el] ip- 
 soidal cells which arc thus formed (PL V, figs. 19, 22, 21). 
 At this time (the beginning of December) one of the four 
 middle cells sometimes divides by a longitudinal septum 
 also (PL V, fig. 23). Henceforth the number of the cells 
 of the spore does not increase until its dispersion in the 
 spring of the next following year. The spore, however, 
 secretes over its whole extent a brownish, slightly trans- 
 parent outer membrane, covered on its external surface with 
 numerous very small asperities, which, when the spore is 
 
THE HIGHER CRYPTOGAMIA. 41 
 
 ripe, renders the boundary lines of the four or five eells of 
 which the spore is composed very indistinct. 
 
 Under cuhivation, irregularities in the development of 
 the spores of Pellia are rather frequent. The primary 
 halves of young spores sometimes divide by longitudinal 
 septa instead of by transverse ones (PI. V, fig. 25). Not 
 unfrequently all the mother-cells of a fruit become abortive 
 shortly before the period of the independent existence of 
 the spores, excepting a few of the mother-cells, which in 
 such a case attain almost double the usual size. 
 
 The vegetative development of the rest of the species 
 mentioned in the title of this chapter differs materially from 
 that of Pellia. The growth of Metzger la fur cat a in length 
 and breadth is discussed by Nägeli, in his essay on the 
 study of cell-multiplication, " Wachsthumsgeschichte der 
 Laub, und Lebermoose" ('Zeitschrift f. Botanik/ Heft 2). 
 My view of the process, as the following remarks will show, 
 differs in some subordinate points from that of Nägeli. 
 
 The longitudinal growth of the strap-shaped stem, which 
 is slightly rounded at the apex, results from the conti- 
 nually repeated formation of septa, spreading right and left, 
 and perpendicular to the surface of the stem (PI. V, figs. 
 26, 27, 28). The cells of the second order thus produced, 
 whose basal outline is a rather lono; five-sided fio-ure, 
 divide first by a septum at right angles to the side walls and 
 perpendicular to the surface of the stem. In the outer- 
 most one of the newly formed cells the same process is 
 repeated again : a septum appears parallel to the one last 
 formed, or else this cell, as well as its inner sister-cell, 
 divides by a longitudinal septum parallel to its side walls. 
 In the former case the shoot grows in breadth ; in the latter 
 in length. Li both cases the division is repeated several 
 times, always in the outermost cells, by septa at right angles 
 to the side walls. The development of each shoot begins 
 with the second form of cell-nmltiplication of the cells of 
 the second order ; as the longitudinal growth draws to 
 a close, the shoot is prepared for fm'cate ramification 
 (PI. V, fig. 28), and thus the first form of cell-multiplica- 
 tion steps in. Li each of the masses of cells which are 
 formed by the division of a cell of the second order, septa 
 
42 HOFMEISTER, ON 
 
 parallel to the surface of the stem are only found in the one 
 innermost cell adjoining the longitudinal axis of the shoot. 
 After the first division of this kind, the formation of a 
 horizontal sci)tum is repeated twice in each of the under 
 cells. The middle hne of the stem consequently consists 
 of two parallel rows of four tabular cells one above another ; 
 the remaining part of the stem is a single superficies of 
 cells. Both the inner pairs of cells of the mid-rib which 
 protrudes from the lower side, divide by longitudinal septa 
 at right an des to the surface of the stem ; thev are, there- 
 fore, about half the size of the adjoining cells of the upper 
 and under sides (PL V, fig. 29). Sometimes the cells of the 
 underside of the mid rib follow in this division. The under 
 side of the fore edge of the mid-rib sends out numerous bicel- 
 lular hairs with a swollen terminal cell, and Avhich, bending 
 themselves upwards, enclose to a certain extent the growing 
 end of the stem. The entire under surface of the stem 
 sends out rootlets, which are especially numerous on the 
 mid-rib and the side edges. The young cells exhibit a 
 nucleus with transparent fluid contents, which is freely 
 suspended in the slightly granular cell-sap. The nucleus 
 lasts for a long time, and, by means of the chlorophyll ad- 
 herent to its exterior, it is perceptible even in older cells, 
 where its contents refract the transmitted light much in 
 the same manner as the fluid contents of the cell. The 
 chloi'ophyll-grauules of iMetzgeria are amongst the smallest 
 in the vegetable kingdom. 
 
 Adventitious shoots are often developed from individual 
 cells of the edge or of the under side of the mid-rib 
 of plants growing in dry situations. The cell-multiplica- 
 tion in such shoots, which is very easy to observe, takes place 
 in precisely the same manner as it does in growing primary 
 shoots (PI. V, fig. 26). Vigorous adventitious shoots, 
 whilst still very young, form a mid-rib in the same manner 
 as the growing primary shoot, which mid-rib, by the divi- 
 sion of the cells lying between the first cell of the adventi- 
 tious shoot and the mid-rib of the primary shoot, is not 
 unfretjuently prolonged backwards to the mid-rib of the 
 primary shoot. Sometimes, in unhealthy specimens, the 
 formation of cells of the third order is entirely suppressed ; 
 
THE HIGHER CRYP'l'OGAMIA. 43 
 
 the shoot then consists simply of a double row of cells 
 (PI. V, fig. 25). 
 
 A third mode of origin of lateral axes takes place at the 
 approach of fructification. On the under side of the mid- 
 rib, attached not exactly in the middle, but laterally either 
 to the right or left, there is formed, at some little distance 
 underneath the end of the stem, a cucullate leaf, in the 
 axil of which a branch is developed, but only to such an 
 extent as to form a flat cushion-shaped process. On its 
 upper surface are produced either archegonia or antheridia. 
 The antheridia, in structure and development, are exactly 
 like those of most of the leafy Jungermanniae, e. g. Rachila 
 complanata. The archegonia, which are short and thick, and 
 only six cells in height, are situated, like the antheridia, 
 usually from four to seven in number, in the axil of a leaf. 
 Their regiüar mode of cell-development resembles that of 
 Pellia; in Metzgeria, also, the large size of the cells of 
 the archegonium facilitates observation (PI. V, fig. 80). I 
 have not had an opportunity of investigating the develop- 
 ment of the fruit of Metzgeria. In spite of the countless 
 multitudes of apparently healthy archegonia and antheridia 
 produced by the thick patches of Metzgeria furcata, 
 which in our hilly districts clothe the masses of rock 
 in shady, moderately damp localities, the fruit is very 
 rarely met with. Probably, the cause of this remarkable 
 fact is to be found in the drought which prevails in the 
 habitats of the plants at the period of the ripening of the 
 antheridia, viz., the middle of Jime. 
 
 The species of Aneura {A. pin^uis and mulUfida), not- 
 withstanding the great difference of their habit from that 
 of JMetzgeria, exhibit the same kind of development at the 
 ends of the stem (PI. VI, figs. 2, II). There is, however, one 
 essential difference, viz., that the cells of the second order, 
 even before their division by the septa perpendicular to the 
 surface of the stem, divide by septa /jo'r«//6'/ to that surface. 
 This division is repeated rapidly and frequently, after 
 the manner of the growth (in thickness) of Pellia (PI. VI, 
 figs. 3, 12), so that the shoot increases very rapidly in 
 thickness ; longitudinal sections through its growing end 
 have a parabolic form. 
 
44 HOFMEISTER, ON 
 
 The ramification of the stem takes place in the same 
 manner as in Metzgeria furcata. In Ancura, however, the 
 growth of one of the young shoots in a forward direction 
 exceeds that of the other, which hitter, at a very early 
 period, appears in consequence to be pushed on one side. 
 This more vigorous development takes place alternately 
 and regularly on each occasion of the division of the end 
 of the stem, occurring at one division in the shoot pro- 
 duced on the ric/lit side of the apical cell, and at the next 
 division in the shoot produced on the left side. In conse- 
 cjuence of this, Aneura exhibits a median principal axis, 
 and lateral axes with normally limited growth. In the side 
 shoots of Aneura multifida, whose longitudinal growth is 
 arrested, the parts adjoining the terminal bud on the right 
 and on the left often outgrow the former, so that the fore 
 edge of the branch appears deeply indented, resembling at 
 first sight the Marchantiese (PI. VI, fig. I). 
 
 The ramification of Aneura and Metzgeria is therefore 
 truly furcate, like that of the stem of Selaginella ; that of 
 Pellia is not truly so, but resembles the ramification of 
 Viscum, the cause of w^hich lies in the fact that the develop- 
 ment of each terminal shoot in Pellia is limited. 
 
 The archcgonia of Anem-a originate at the apex of very 
 short side-shoots of the second or third order. In their 
 origin and nature they resemble those of Metzgeria. Under- 
 neath their point of attachment there is produced, contempo- 
 raneously with the conmiencement of their formation, a 
 circle of small leaves, from four to six cells in height, con- 
 sisting at the base of from three to four cells, and at the 
 apex of a single cell. 
 
 When the large cell in the interior of the flask-shaped 
 portion of the archcgonium of Aneura multifida * first 
 begins to be transformed into the rudiments of the fruit, a 
 series of very active divisions, which last for a long time, 
 commences in the cells of the archegoniiun, excepting those 
 of its neck. The lower part of the archegonium thus be- 
 comes a clavate, fleshy mass, which attains the size of a 
 millet-seed, even when the rudimentary fruit consists of 
 
 * I have not had the opportunity of examining the formation of the fruit in 
 A. piiiguis. 
 
THE IIIGHEll CRYPTOGAMIA. 45 
 
 only eleven cells. The cells of the branch bearing the 
 archegonia, which adjoin the place of attachment of the im- 
 pregnated archegoniiini, also take part in this division. In 
 conseqnence of this, uninipregnated archegonia are often 
 carried up on to the oval cellnlar mass (the calyptra) formed 
 by the amalgamation of the flask-shaped portion of the im- 
 pregnated archegonium with the adjoining parenchyma of 
 the stem. By this means the growing calyptra, which in- 
 creases vastly in size, is bent npw\ards, so that its longitu- 
 dinal axis is at right angles to the sm-face of the stem (PI. 
 VI, fig. 8). 
 
 The multiplication is very active in the cells of the calyp- 
 tra immediately under its apex, with the exception of the 
 epidermal cells, which continue of rather a large size, (PI. 
 VI, fig. 8), and grow out into long cylindrical papillae 
 (Fl. VI, fig. 4), upon whose outer w^all a network of pro- 
 jecting bands is formed. The neck of the impregnated ar- 
 chegonium is usually thrust off at an early period (PI. VI, 
 fig. 8). 
 
 The development of the fruit itself corresponds entirely 
 in essentials with that of PeUia (PL VI, figs. 5 — 8), but it 
 is altogether of a more slender construction. The fruit- 
 stalk consists of only tw^o concentrical layers of cells ; the 
 enlargement at its lower end is much less developed ; the 
 cells destined to form the elaters and the rows of spore- 
 mother-cells are already differentiated (as in Prullania) at 
 the time when the entire contents of the young capsule 
 consist of a single horizontal layer of cells. Each indivi- 
 dual elater, however, divides by a transverse septum ; each 
 pair reaches from the base of the capsule to its upper arched 
 roof. 
 
 The autheridia of Aneura pinguis originate in precisely 
 the same manner as those of Pellia. A hemispherical or 
 shortly cyhndrical cellular body, consisting of four short 
 longitudinal rows of cells, is formed by the multiplication of 
 one of the cells of the upper side of the stem (PL VI, figs. 
 14, 15); by the division of one of its middle cells into an 
 inner and an outer one, the ground is laid for the diffe- 
 rentiation of an outer layer, and an inner cellular mass 
 destined to produce spermatozoa (PL VI, fig. 12). A wall 
 
46 HOFMEISTER, ON THE HIGHER CRYPTOGAMIA. 
 
 of cellular tissue is raised romid the antheridiura In' the 
 multiplication of one of its adjoining epidermal cells. 
 Aneura muHißda produces Ijuds, often in very large num- 
 bers, near the ends of its shoots. Some of the cells of the 
 upper surface, not unfrcqucntly whole groups of twenty or 
 more, protrude outwards in the form of an arch, become 
 quite filled with chlorophyll-granules, and divide by a sep- 
 tum passing transversely through the cell perpendicular to 
 the surface of the shoot ; the same thins; occurs, but less 
 frequently, in the cells at the edge (PI. VI, fig. 9). The 
 bicellular bud becomes free by the swelling up of the middle 
 layers of the wall of its mother-cell into a gelatinous sub- 
 stance Avhicli expands largely in water, in consequence of 
 which the outer lamella of the wall bursts, and the buds 
 escape. Their form is that of a somewhat elongated ellip- 
 soid, strongly constricted at its equator; its outline brings 
 to mind that of many of the Desmidieae (PL VI, fig. 10). 
 The development of the buds into a new plant begins with 
 the repeated division of one of their cells by alternately in- 
 clined septa. 
 
CHAPTER III. 
 
 LEAFY JÜNGERMANNLE. 
 
 The transition from the leafless to the Icafv Juniper- 
 maimise is a very grackial one ; it passes through an un- 
 broken series of gentle intermediate stages. One genus 
 (Diplolsena) which apparently coincides with Aneura in all 
 its vegetative phenomena, except that it has inferior leaves, 
 is followed by the peculiarly formed genus Blasia, whose 
 stem when young exhibits, in transverse section, the form 
 of an ellipse, and when more advanced, is drawn out in 
 breadth so as to become foliaceous — a genus w^hose superior 
 and inferior leaves differ in shape, the former having en- 
 tire, the latter denticulate, margins. Allied to these is the 
 genus Fossombronia, which has a stem only slightly ex- 
 panded, but nevertheless always much flattened on the 
 upper side, and bearing only superior leaves : this genus 
 differs very little in the relative size of its stem and leaves 
 from many of the leafy Jungermanniae taken in the most 
 limited sense. 
 
 The most remarkable member of this series of tran- 
 sitional forms is, beyond all question, Blasia pusilla. In 
 perfect shoots, that is to say, shoots bearing bud-recep- 
 tacles, the stem is so much widened that its edges seem 
 to amalgamate wdth the horizontally-arranged superior 
 leaves ; these leaves have been somewhat generally con- 
 sidered to be, and have been described as, " segments of 
 the flat stem." On the shoots just mentioned it is only 
 the inferior leaves which look really like leaves ; they are 
 denticulate scales on the right and left of the longitudinal rib 
 which protrudes from the under side, and which throws out 
 roots (PL VI, fig. 16). At the upper end of the stem is found 
 
48 HOFMEISTER, ON 
 
 the terminal bud, which is surrounded by closely crowded 
 su})erior and inferior leaves, and which is usually very 
 diiiicult to make out, on account of the buds situated near 
 it and upon it ; this terminal bud is a mass of cellular 
 tissue, which, in shoots capable of further development, has 
 a much-flattened conical form, whilst in shoots whose 
 longitudinal growth has terminated it is flat and cmnrginate 
 at the apex ; it bears on its under side amphigastria, and 
 on the other side scale-like, lubricated superior leaves. 
 Numerous hairs, similar to those on the very young parts of 
 Pellia and Aneura, are scattered amongst the most newly 
 formed leaves (PL VI, figs. 17, 18). 
 
 It is well known that muuerous reproductive buds are 
 formed on the under side of the stem of Blasia. Their 
 mode of development is very like that of the similar organs 
 in Anthoceros. The contents of one of the inner cells of 
 the tissue of the stem (which cells are only separated from 
 the under side by a single cellular layer) become transformed 
 into a cell occupying the whole cavity of the motlier-cell. 
 This daughter-cell changes into a roundish body, composed 
 of small cubical cells, which contain numerous very small 
 chlorophyll-bodies of a dark bluish-green colour. The 
 cellular layer of the under surface of the stem which covers 
 the reproductive buds becomes swollen to a hemispherical 
 sha])e by the increase in size of the latter. 
 
 1 have not seen these reproductive buds develope into 
 young plants. Corda figures their germination in Sturm's 
 Deutschl. Flora, II abth., taf. 32. Bischoft" treats this 
 figure as a ])roduct of the author's imagination. I do not 
 agree with Bisclioft"s opinion. It is true that the branched 
 rootlets which Corda represents are not found in any liver- 
 wort. This portion of the figure is, at all events, erroneous. 
 I consider it, however, beyond dispute that the organs in 
 question are really reproductive buds, judging from the 
 analogy which they bear to the undoubted buds of Antho- 
 ceros which originate in like manner. If old buds of 
 Blasia are opened under water, their cells separate from 
 one another in the surrounding fluid. The like phenomenon 
 occurs in the undoubted buds of Anthoceros and Riccia, 
 if the surrounding tissue continues to retain its vitality 
 
THE IlIüHEll CllYPTOGAMlA. 49 
 
 for a very long time. It depends, certainly, only upon the 
 decay and internal disintegration of tlie buds. 
 
 Blasia differs from all other leafy liverworts in the fact of 
 its producing these reproductive organs, but still more in the 
 fact that the well-known flask- shaped bud-cups are formed 
 upon its upper side. 
 
 The cell-multiplication of the terminal bud of Blasia very 
 much resembles that of Anthoceros, or of the young plants 
 of Pellia. The apical cell continues to divide repeatedly by 
 septa inclined alternately upwards and downwards (PI. VI, 
 figs. 19, 20). The cells of the second order divide by a 
 septum coinciding with the longitudinal direction of the 
 stem, and perpendicular to its surface. The frequent repe- 
 tition of the formation of these parallel septa in the two 
 halves of the stem causes the stem to increase rapidly in 
 width (PI. VI, figs. 17, 18). By the division of the cehs of 
 the second order (and their daughter-cells) by septa parallel 
 to the surface of the stem, the stem increases in thickness 
 (PI. VI, figs. 19, 20). At the spot where a bud-receptacle 
 is about to be formed, this latter cell-multiplication ceases 
 at a very early period, even as early as in the cells of the 
 second order, whilst it continues in the neighboiu-ing cells. 
 A circular depression is thus formed on the upper side of 
 the stem, close to its growing end, and quite covered by the 
 youngest superior leaves (PI. VI, fig. 20). Individual cells 
 of the base and sides of each depression send forth clavate 
 papillae, which are soon separated from the original cavity of 
 the mother-cell by a transverse septum (PL VI, fig. 20). After 
 the apical cell of these short, hair-like papillae has divided 
 two or three times by transverse septa, the hemispherical 
 terminal cell divides by a longitudinal septum. In this 
 way a process of cell- formation originates, which soon leads 
 to the production of a globular (or polyhedral) cellular 
 mass, viz., a reproductive bud, which is attached to the 
 above-mentioned depression in the upper surface of the 
 stem, by means of a hyaline stalk, consisting of one or two 
 narrow cylindrical cells, with clear fluid watery contents. 
 The arrangement of the cells of the reproductive buds cor- 
 responds with that of the terminal bud of the stem (PL VI, 
 fig. 21). 
 
 4 
 
50 HOFxMEISTER, ON 
 
 Soon after the commencement of the development of tlie 
 first reproductive buds, the margins of the depression in 
 Avhich they originate become elevated like walls — the eleva- 
 tion conunencing with the hinder margin (PL VI, fig. 20). 
 A cylindrical tube, open above, is formed over the depres- 
 sion in which the buds are generated (PL VI, fig. 21). 
 The cells of the bud-receptacle itself, and those of the 
 lower part of its growing margin, take part in the longi- 
 tudinal elongation which now^ commences in the tissue of 
 the stem. The cells of the upper part of the above tube 
 extend themselves upw^ards only ; those of its free margin 
 continue to divide by transverse septa. By this means the 
 lower part of the bud-receptacle becomes elongato-lageni- 
 form ; the open tube appears inserted in its upper end. 
 
 Reproductive buds now make their appearance on the 
 inner-side also of the upper arched surface of the bud- 
 receptacle. The inner cavity of the receptacle is filled, like 
 those of the Marchantiese, with dense transparent slime, in 
 which numerous short greenish threads, too narrow to 
 admit of being measm^ed, are imbedded (PL VI, fig. 22). 
 (Are they the rudiments of fungi?) A very striking 
 peculiarity is exhibited by the rudimentary reproductive 
 buds in these cells, which are destined for a process of 
 active multiplication. Their contents are as clear as water. 
 No nucleus of any kind is to be seen. It is only on rare 
 occasions that solid bodies are found in the cell -sap, in the 
 form of from one to three sharply defined, angular, very 
 small bodies with exceedingly active molecular motion 
 (PL VI, fig. 22*). Concentrated tincture of iodine precipi- 
 tates a scarcely perceptible quantity of a yellowish-brown 
 substance upon the inner wall of the cell, even when the 
 tincture is considerably heated. When the bud (omitting 
 the stalk) has become 4-5 cellular, a nucleus is for the first 
 time perceptible in each of the cells, contemporaneously 
 with the appearance of the first small chlorophyll bodies, 
 which are of a beautiful emerald green. The number of 
 these increases considerably towards the period of the 
 perfecting of the bud. At this time numerous drops of a 
 clear, yellow, fatty oü make their appearance in the cells of 
 the buds. The chlorophyll changes colour. Ultimately the 
 
THE HIGHER CRYPTOGAMIA. 51 
 
 stalk of the ripe bud detaches itself from the wall of tlie 
 receptacle ; the bud is ejected through the narrow tube of 
 the lagei!iform receptacle, and becomes free. The escape of 
 the buds is doubtless caused by the pressure which the 
 numerous, rapidly-growing young buds, necessarily exert 
 upon the mucilaginous contents of their re(;cptacle, wdiich 
 contents are thereby in constant motion towards the opening 
 in its neck. 
 
 It is stated in some books that the bud-receptacles of 
 Blasia are closed when young, and open at the top at a 
 later period (see Nees v. Esenbeck, Naturgesch. d. Europ. 
 Lebermoose, B. 3, s. 395). An incorrect figure of Hed- 
 wig's has probably given rise to this erroneous notion (see 
 * Theoria generationis,' ed. 2, t. xxx, fig. 9). 
 
 The germination of the German liverworts, irrespective 
 of the very special wonderful development of the spores of 
 Blasia (see the beautiful observations of Gottsche, N. A. A. 
 C. L., vol. XX, p. 1 ; and the supplementary ones of 
 Grönland, 'Ann. Sc. Nat.' ser. iv, t. i, pi. 3) ; exhibits at 
 least three essentially different methods of development. 
 
 Frnllania dUatata has the largest spores. They are longish 
 and tetrahedral, with rounded edges and angles ; more 
 rarely spherical. The inner membrane is as clear as glass, 
 and not very delicate ; the outer one is thin, membranous, 
 and of a yellowish-brow n colour, beset at regular distances 
 with circular groups of brown protuberances (PI. XI, fig. 
 27). The contents consist of a yellowish, viscous fluid, in 
 which numerous granules are suspended. In the middle 
 point of the spore a roundish ball of opaque matter (a 
 nucleus surrounded by granules) is indistinctly seen. The 
 germination of the spores commences as early as the fifth 
 day after sowing. Numerous very small chlorophyll bodies 
 are formed in the fluid contents. The primary central nucleus 
 disappears, and in its place are found two new ellipsoidal 
 nuclei. Erom eight to tw^elve days after sowing, these 
 nuclei appear separated by a delicate line, wdiich is the side- 
 view of a septiun, dividing the spore into tw'O cells (PI. XI, 
 figs. 20, 29). One of these cells divides rapidly and con- 
 tinually by alternately inclined septa (PI. XI, figs. 30 — 34) ; 
 the daughter- cells thus formed divide by radial septa. The 
 
5.2 HOFMEISTER, ON 
 
 cells of the third order divide by septa parallel to the longi- 
 tudinal axis of the germinating spore, and cutting the side 
 walls at an angle of 45°. In the outermost new cells of 
 the fourth order, vertical and radial septa are formed, and 
 then horizontal septa. In this way the spore, in the course 
 of a month, is transformed into an oval cellular mass, whose 
 longitudinal diameter is from three to five times the length 
 of that of the ripe spore. The outer membrane of the 
 spore, which expands considerably, surrounds the continually- 
 increasing cellular body for some time, until eventually 
 it bursts (PI. XI, figs. 32, 33) ; the remnants of it often 
 remain for a long time adherent to the base of the cellular 
 body (PL XI, fig. 37). 
 
 One of the basal cells of the germ-plant now grows into 
 a root with a thick wall and a narrow cavity, precisely simi- 
 lar to those which are developed by the perfect plant (PL 
 XI, fig. 35). All the cells of the upper surface of the germ- 
 plant, excepting those of the apex, protrude outwards in the 
 form of arched papillae. Ten days later the first leaves 
 sprout forth close under the apex of the germ-plant, placed 
 opposite one another on the stem at equal distances (PL 
 XI, fig. 37). The arrangement of their cells shows that 
 their growth results from the repeated division of a cell of 
 the surface of the stem, b}* means of alternately inclined 
 septa at right angles to the surface of the leaf. The second 
 pair of leaves stands exactly over the first ; the two other 
 rows of leaves of the older plants first appear at a later 
 period. The form of these earliest leaves (ovato-acurninate) 
 is moreover very different from the tvvo-lobed closely-folded 
 later leaves. The terminal bud of the stem is situated 
 between the leaves, in the form of a blunt, conical protu- 
 berance (PL XI, fig. 38). In this bud also the growth 
 manifestly results from the division of an apical cell, by 
 means of alternately inclined septa. 
 
 The small globular spores of Jungermannia hicuspidala 
 have a brittle, finely granular, brownish outer membrane ; 
 they contain a mucilaginous opaque fluid (PL IX, fig. 1). 
 The cushion-like masses of Palmellea3 which are usually 
 found under the patches of this liverwort afford a peculiarly 
 suitable substratum for the germination of the spores. As 
 
THE HIGHER CRYPTOGAMIA. 53 
 
 early as the eighth day after the spores have been scattered 
 over the moist, sKmy mass, the expanding inner membrane 
 ruptures the outer membrane, and protrudes in a vesicular 
 form through the fissure (PL IX, fig. 2). It contains numer- 
 ous very beautiful, small, emerald-green chlorophyll bodies. 
 The protruding portion of the inner membrane is soon 
 divided from the remainder of it by a transverse septum. 
 By continual division of the fore-cell (that one, namely, 
 which is furthest from the remnants of the exosporium) by 
 means of transverse septa, — which septa are always preceded 
 (as in higher plants) by the appearance of two new nuclei in 
 the mother-cell (PL IX, figs. 3 — 7) — the germinating spore 
 is converted, within a month after it has been sown, into a 
 simple row of cells, seven or eight in number. 
 
 In the apical cell, and often also in the interstitial cells, 
 with the exception of the one or two lowest, division by 
 longitudinal septa now commences contemporaneously with 
 an active longitudinal growth of the germ-plant, which latter 
 growth results from the division of the apical cell by means of 
 alternately inclined septa. In this way there originates a 
 small band, formed of a single layer of cells, lying side by 
 side in pairs (PL IX, fig. 8), near the lower end of which 
 a slight thickening of the cellular tissue is often found, 
 originating from the division by more than one longitu- 
 dinal septum, of some of the interstitial cells of the cellular 
 thread produced by the germinating spore. The ribbon- 
 shape of the fore end of the germ-plant is soon changed to 
 that of a cylinder through the division by radial longitu- 
 dinal septa of the cells of the second order, produced by 
 the division of the terminal cell by inclined septa (PL IX, 
 figs. 10*' 11"'*'''). Prom some of these cells short cellular 
 branches sprout out always close under the septum dividing 
 the particular cell from the next higher one. These 
 branches are soon separated from the inner cavity of their 
 mother-cell by a transverse septum. They are arranged in 
 two vertical rows, the lower being placed (with respect to 
 their attitude) irregularly upon the germ- plant, the upper 
 ones being very regularly alternate (PL IX, fig. 9). The 
 lower ones do not undergo any change, but in the third or 
 fifth, reckoned from below, division occurs by a transverse 
 
54 HOFMEISTER, ON 
 
 septum ; in tlie higher ones this division is repeated in 
 the terniiniil cell, so that they present the appearance of 
 3-cellular rows of cells. Those which originate at a later 
 period exhibit longitudinal septa in their basal cells, and a 
 furcate ramification at the apex ; they resemble now, even 
 in tlieir outline, the leaves of the plant (PL IX, fig. 9). 
 Higher up, in more advanced germ-plants, perfect leaves 
 appear in the place of the above rows of cells. Individual 
 points of the wall of many of the cells of the underside of the 
 germ-pliuit often develope, even at an early period, into root- 
 lets, and penetrate into the substratum (PI. IX, fig. 10). 
 In isolated cases the longitudinal growth of the first shoot 
 of the germinating plant is suppressed ; a new shoot then 
 arises near to, and underneath, the apex, whose cells exhibit, 
 at a little distance above the place of origin of the shoot, 
 the same arrangement as that wdiich is found at the apices 
 of germ-plants in a more advanced state of development, 
 and which arc commencing to form leaves (PL IX, tig. 12, 
 12*).* 
 
 Jungermannia divaricata, Engl. Bot., and Alicularia 
 scalaris (PL VII, fig. II), of both of which I have found 
 spores just germinating and half developed germ-plants, 
 appear to germinate in the same manner, in fill respects, as 
 Junc/ermannia hicuspidata. The same is the case, according 
 to Grönland (1. c. PL I), in Sarcoscypliiis Fimkii and Junger- 
 mannia crenulata. The germination of LopUocolea Jtetero- 
 phijUa coincides generally with that of /. divaricata. Here, 
 however, the delicate brownish outer spore- membrane is 
 not ruptured by the expanding inner membrane, but is only 
 gradually stretched, until finally it disappears in the further 
 progress of the germination. The small globular spores scat- 
 tered over decaying bark, swell to three times their original 
 size within a few days. Numerous chlorophyll bodies are 
 produced at the same time in their fluid contents ; a 
 nucleus becomes clearly visible in the centre of the cell, and 
 may even be seen, although with diificulty, whilst the spore 
 is still enclosed in the capsule. This nucleus vanishes, and 
 
 * Grönland has observed that, the germ-plant whilst exhibiting only a sinn;le 
 row of cells, not uufrequenlly ramifies; a fact which 1 have not ODserved. (See 
 'Ann. Sc. Nat.' iv ser. 1, p." 15.) 
 
THE HIGHER CRYPTOGAMIA. 55 
 
 two new nuclei make their aj^pearance. The germinathig 
 spore divides into two halves by a transverse septum 
 originating between the two nuclei. The same process is 
 repeated in one of the newly-produced cells ; in this way a 
 short, simple row of cells is formed (PL IX, figs. 17 — 25). 
 The terminal cell of the row swells to the shape of a head, 
 and divides by a longitudinal septum. From the continual 
 division of the terminal cells a small band of cellular tissue 
 is produced, similar to the second stage of development of 
 the germ-plant of /. bicuspidata (PI. IX, fig. 26), and 
 which, as in that plant, produces lateral regularly-placed 
 hairs, hair-like roots on the underside, and finally, after 
 further development, perfect leaves at its apex (PI. IX, 
 fig. 26). At the time of the first appearance of the latter 
 I always found the oldest hinder part of the plant entirely 
 dead. 
 
 The spores of Radula comjüanafa are tolerably large, 
 globular, and clothed with a brownish-yellow exosporium. 
 In the fluid contents, which enclose numerous very small 
 chlorophyll bodies, a very well - defined large nucleus 
 is suspended (PI. XI, fig. 16). T"\venty-four hours only 
 after sowing the spores upon moist bark the greater 
 number of them begin to germinate ; some lie quiescent 
 for weeks, and then germinate suddenly. Two nuclei, 
 which are very prominent as light circular spaces in the 
 opaque cell-sap, appear in the place of the primary central 
 nucleus. Between them a septum is formed, dividing the 
 spore into two halves (PI. XI, fig. 17). The division is 
 repeated in the newly-formed cells, but by septa at right 
 angles to the first septum (PI. XI, fig. 18) ; fom' cells 
 having the form of quadrants of a sphere have now been 
 formed in the spore. Each of these divides, in the first 
 instance, by a septum either parallel to the first-formed 
 septum or perpendicular to it (PL XI, figs. 19, 20) ; the 
 four four- sided ones of the newly-formed cells divide by septa 
 cutting the last-formed septa at an angle of 90° (PL XI, 
 fig. 20 *'*"). The body which has been formed by the 
 division of the spore-cell, and which now consists of tw^clve 
 cells, four central and eight peripheral ones, has now a 
 well-defined cake-like shape. Henceforth, the multiplica- 
 
5G HOFMEISTER, ON 
 
 tion of the cells takes place exclusively in the direction of 
 one surface, with the exception of a single division of all 
 the cells Avhich takes place by septa parallel to the sm-face, 
 sometimes at this period (PI. XI, fig. 21), and sometimes 
 rather later. The underside of the flat expansion sends out 
 rootlets with very narrow cavities, exactly similar to those 
 produced from the lower leaf-lobes of fully developed plants. 
 The cells of the margin, as well as those of the middle, 
 multiply continually by division caused by septa perpendi- 
 cular to the surfaces of the plate-shaped body (PI. XI, 
 figs. 23, 24). Ultimately, five months after sowing, a 
 small protuberance of cellular tissue is seen at the margin 
 of the flat germ-plant, which is soon recognised as the 
 first commencement of the leafy stem by the fact of its 
 producing rudimentary leaves under its apex (PI. XI, figs. 
 25, 26). The arrangement of the cells of the terminal 
 bud of the voung stem shows clearlv that its longitudinal 
 growth is the result of the continual division of an apical 
 cell by alternately-inclined septa (PI. XI, fig. 26). 
 
 The normal mode of cell-multiplication in the growing 
 end of the stem of developed plants of the leafy Jumger- 
 mannias, is most diflficult to ascertain. The terminal bud 
 protrudes very slightly above the place of origin of the 
 youngest leaf; the older leaves embrace the bud more 
 closely than in any other plants I know. Numerous hairs 
 which are developed upon and between the youngest leaves 
 interfere with the observation ; the contents of the youngest 
 cells (viz. a thick nuicilage in which numerous, often closely- 
 packed chlorophyll bodies are imbedded) are almost opaque ; 
 all which matters present almost insuperable obstacles to 
 the observer. With the exception of the instances brought 
 forward in treating of the germination, there have been but 
 few cases in Avhich I have arrived at clear results, viz., 
 in Frullania dilatata (PI. XI, fig. 9, 10), Lophocolea hiden- 
 faia (PI. IX, fig. 13), Trichocolea tomcntella (PI. VIII, 
 fig, 4), and Jan(/ermannia hiciispidata (PI. VIII, 12, "*) ; the 
 shoots here examined were the few-leaved shoots which 
 break out between the leaves, and which originate from 
 adventitious buds. They all agree in essentials with one 
 another, as also with the modes of development of the rudi- 
 
THE HIGHER CRYPTOGAMIA. 57 
 
 meiitary stem observed in the germination of different 
 species. One apical cell divides continually by septa alter- 
 nately inclined in different directions. In Jungermannia 
 bicuspidata, and Frullania dilatata, these septa are directed 
 alternately right and left ; the apical cell has the form 
 of, a segment of a sphere. The cells of the second order 
 are divided by radial longitudinal septa. In each of 
 the three-sided daughter-cells a septum is formed, cutting 
 the side walls at an angle of 45°, and dividing the cell into 
 an inner and an outer one. The latter is divided by a 
 radial longitudinal septum into two halves ; the growth of 
 the circumference, even in leafy shoots, terminates at this 
 point in J. bicuspidata and many nearly allied species, such 
 as J. connivens, and divaricafa. In these species both layers 
 of cells, but more frequently only the outer one, continue 
 to divide by horizontal septa ; the four inner cells again 
 divide by longitudinal septa, parallel to the axis ; and after- 
 wards at least two, often four of the newly- formed narrow 
 cells of the interior of the stem, divide by radial septa. 
 The axis of the stem consists, consequently, of somewhat 
 elongated cells, which are much narrower than those of the 
 single cortical cellular layer. Hence, also, there arises the 
 indication of a vascular bundle, traversing the longitudinal 
 axis of the stem. At a similar stage of the development of 
 the stem in thickness — the lowest which occurs in the 
 vegetable kingdom, from the leafy mosses u[)wards — the 
 germ-plants of all observed species make a stand ; ultimately 
 and by degrees thicker shoots are formed, which produce 
 the rudiments of fruit. 
 
 The great variety of forms in the leaves of Jungermannia 
 is only partly accounted for by the rules of development of 
 their cells. Many of the most striking varieties of form in 
 perfect leaves are produced by an anomalous expansion of 
 small groups of cells, and a multiplication, commencing at 
 a late period, in individual cells of the margin of the leaf. 
 The same difficulties which interfere with a clear ascertain- 
 ment of the structure of the terminal bud, hinder to a still 
 greater extent the observation of the first stages of develop- 
 ment of the leaves. 1 have only been able in a few cases 
 to observe directly that the leaf originates in the continual 
 
58 HOFMEISTER, ON 
 
 division of a single cell of the upper surface of the stem, 
 which protrudes in an arched form, at an early period, above 
 the bounding surface of the stem. One of these cases is 
 Fossomhronla pmilla. Here the leaf, at its first appearance, 
 is exactly like a sliort hair; the papilteforin protruding cell 
 of the n|)per surface of the stem is soon separated from tlie 
 original cavity of the cell by a transverse septum, and after- 
 wards divided by a septum parallel to the latter, into a 
 lower cylindi'ical, and an upper clavate cell. The fluid con- 
 tents of the latter are tolerably transparent, those of the 
 former exhibit numerous chloro])hyll-granules (PI. IV, 
 fig. 25). The lower cell only, divides in rapid succession; 
 first by a transverse septum, and then the lower one 
 or both of the newly-formed cells, by a septum at right 
 angles to the last, and to the surface of the young leaf 
 (PL VI, fig. 27). The upper pair of cells of the third 
 order divide by transverse septa ; longitudinal septa appear 
 in the lower one, followed by transverse septa again in the 
 outer cells (PL VI, fig. 26). The like succession of divisions 
 takes place in the lower of the two pairs of cells, which 
 originated in the transverse division of the two cells of the 
 third order adjoining the apical cell, and is repeated, (with 
 the recurrence of the transverse division of the upper of 
 these pairs of cells,) continually in the two newly-formed 
 cells lying nearer to the base of the leaf on the right and 
 left of the median line. In the mean time, by frequent 
 longitudinal division of the marginal cells of the lower part, 
 the leaf increases considerably in breadth (PL VI, fig. 28) ; 
 the one longitudinal half is always more vigorous than the 
 other. This multiplication lasts much longer at the base 
 of the leaf, where it keeps pace with and ultimately exceeds 
 the growth of the stem, than it does at the upper margin, 
 towards which it gradually diminishes. Individual cells of 
 the margin continue to multiply for a longer period than 
 their neighbours, repeating in miniature, in the mode of 
 their multiplication, the formation of the leaf; in conse- 
 quence of tliis the leaf assumes its multi-angular shape. 
 
 The rudimentary appendages of the leaves of the Lopho- 
 coleae are, as has been already observed, short rows of cells ; 
 the first rudiments of the leaves themselves are nothing 
 
THE HIGHER CRYPTOGAMIA. 59 
 
 more than simple cells, produced by the cutting off 
 of short papillae by a transverse septum. This renders 
 it in the highest degree probable that a single cell of the 
 bounding surface of the stem is the mother-cell of the leaf. 
 However at the period when the young leaf first appears 
 above the sm*face of the stem, it consists, when viewed from 
 above, of four cells arranged side by side, embracing more 
 than a fourth part of the stem (PI. IX, fig. 14). The two 
 middle ones are considerably larger than the side ones. 
 The foundation for the two-pointed form of the leaf is 
 laid immediately upon the division of the nikldle cells by 
 septa, both at right angles to the median line of the leaf, 
 and diverging from it to the right and left. Each of the 
 two middle cells of the 4-cellular fore-edge of the leaf 
 developes a papillseform prolongation, directed forwards 
 and at the same time obliquely outwards ; the outline of 
 each is parabolical, and each of them divides repeatedly by 
 transverse septa (PI. IX, fig. 15). The wide and low 
 interstitial cells thus produced are divided from once to 
 as many as eight times by septa parallel to the longitudinal 
 axes of the teeth of the leaves. The activity of this cell- 
 multiplication diminishes from below upwards ; the tips of 
 the teeth of full-grown leaves consist of short simple rows 
 of cells. During the formation of the teeth, the number 
 of the cells of the lower part of the leaf continues to increase 
 considerably by longitudinal and transverse divisions. The 
 septa there formed are not always at right angles, or parallel 
 to the longitudinal axis of the leaf, but are often laterally 
 inclined to a considerable extent (PI. IX, fig. 16). Frequent 
 irregularities in the arrangement of the cells are produced 
 thereby, especially in Lophocolea heterophi/Ua. 
 
 In the latter plant the growth of the teeth on those leaves 
 which are intermediate betw^een the two-pointed lower leaves, 
 and the entire upper leaves, is caused by division of the 
 terminal cells by alternately-inclined septa, not by septa 
 parallel to one another. 
 
 Jungermcmnia bicuspidafa, and the closely allied /. conni- 
 vens and /. divaricafa, comport themselves, in the matter 
 of leaf-development, similarly to the Lophocolcse. In these 
 latter, however, the regularity of the arrangement of the 
 cells is mucli greater ; the cell-multiplication in the lower 
 
60 HOFMEISTER, ON 
 
 undivided half of the leaf is very limited, often almost sup- 
 pressed in /. divaricafa. The first rudiments of the two 
 points of the leaf in /. bicuspidafa are of a very plump 
 form (PI. VIII, figs. 8 — 10). In Ptilidu/m ciliare an active 
 multiplication of the cells of the superior leaves commences 
 at a late period, and is more clearly defined than even in 
 Lophocolea and /. bicuspidafa. With it the formation of 
 the leaf commences by the protrusion outwards in the form 
 of an arch, of one of the stem-cells of the second order, 
 close underneath its apex; the protruding cell assumes 
 the form of a swollen seam, embracing nearly half the cir- 
 cumference of the stem (PI. VII, fig. 9, a). The cell divides 
 by a longitudinal septum radial to the axis of the stem ; 
 both halves of the seam are separated from the original 
 cavity of the cell by septa parallel to the outer surfaces of 
 the stem. Each of the two cells of the young leaf there- 
 upon developes itself independently in length. Each arches 
 itself outwards to some extent, so that the fore-edge of the 
 leaf exhibits two very blunt points ; thereupon each of the 
 cells divides by a transverse septum, which separates the 
 protruding portion from the original cell-cavity (PL VIII, 
 fig. 9, b, where only half of the leaf is shown). This division 
 is repeated continually in each of the two apical cells. Each 
 interstitial cell (cells of the second order) is bisected by 
 a longitudinal septum. The cells of the third order divide 
 by septa, either parallel to the latter septum or converging 
 to it (PI. VII, fig. 51, c) ; thereupon the cells of the edge 
 of the leaf grow out into the long cilia which give the 
 specific name to the plant, extending themselves in the 
 form of papillae, and then repeatedly dividing in their apical 
 cell by transverse septa (PI. VII, figs. 7, 8). Ultimately, 
 longitudinal septa are formed in the lowest of the cells of 
 the second order of these excrescences of the edge of the 
 leaf. In highly developed leaves new cilia spring from the 
 marginal cells of these pointed appendages of the edge of the 
 leaf, originating in precisely the same manner as the parts 
 upon which they are borne. The leaf now consists of 
 two synunetrical halves, which have only a single row of 
 cells for their connnon basis, and are connected together 
 at the bottom only to the extent of a single cell (PI. VII, 
 fig. 8). It is this transverse row of cells which, by repeated 
 
THE HIGHER CRYPTOGAMIA. 61 
 
 bisection, commencing at a late period, forms the cellular 
 surface, often ^'" in length, which carries the two-pointed 
 heads of the leaf. 
 
 In Frullania dilatala, which is furnished with such wide 
 leaves, the leaf, at its first appearance above the surface of 
 the stem (the periphery of which at this period exhibits only 
 four cells) consists of a single wide-stretched cell (PI. XI, 
 fig. 9). It divides at first, once or twice, by a transverse 
 septum ; the newly-formed cells then divide by longitudinal 
 septa (PL VIII, fig. 3). Each cell of the lower pair is now 
 divided by a septum coinciding with the longitudinal axis 
 of the leaf, and parallel to the first septum (PI. XI, fig. 
 8 "' *). The two apical cells of the rudiment of the leaf then 
 divide by septa almost at right angles to its longitudinal 
 axis, thus forming three-sided superior cells of the first 
 degree of the second order, and four-sided inferior trans- 
 versely extended cells of the second degree. The latter are 
 divided immediately after their formation into inner and 
 outer cells by means of a septum parallel to the longitudi- 
 nal axis of the leaf (PI. XI, fig. 8 '). The like processes 
 are repeated several times in the two apical cells of the 
 young leaf, so that the latter soon assumes the form of an oval 
 cellular sm'face, consisting of two inner rows of cells bounded 
 right and left by a row of marginal cells. The leaf soon 
 begins to increase in breadth by repeated division of the 
 marginal cells by means of septa parallel to the margin of 
 the leaf. At the same time the mode of multiplication of 
 the apical cells changes ; the division by means of a septum 
 almost at right angles to the longitudinal axis of the leaf, 
 is followed by a division by means of a septum, mounted 
 upon the latter septum, and only slightly diverging from 
 the median line of the leaf. The now four-sided elongated 
 apical cells continue to divide by alternate longitudinal and 
 transverse septa (PL XI, fig. 14). In the later stages of 
 development of the leaf, the cells produced by the division 
 of the two apical cells, both the marginal cells and the double 
 row of inner cells adjoining the median line of the leaf, are 
 divided soon after their formation by septa at right angles 
 to the longitudinal axis of the leaf (PL XI, fig. 13). This 
 division is followed by a division by means of septa inter- 
 
62 HOFMEISTER, ON 
 
 secting tlie last-fomied septa, and parallel to those lateral 
 cell-surfaces which are turned towards the median line of 
 the leaf. In the cells of the interior of the leaf this latter 
 division occuis once only ; in those of the margin it is 
 repeated sometimes as many as eight times in the outer- 
 most cells. The lower part of the leaf thus increases 
 considerably in breadth, in proportion to the increase in 
 circumference of the stem. As the longitudinal groAvth 
 of the leaf draws to a close, the two apical ci^lls do not 
 keep pace with one another in their multiplication ; one 
 of them is usually a generation in advance of the other 
 (PI. XI, fig. 14). 
 
 By the time that the leaf is of the height of four 
 cells, one of the marginal cells of its base begins to 
 protrude laterally in the form of an arch. The protu- 
 berance is soon separated from the original cell- cavity 
 by a transverse septum. By repeated transverse divi- 
 sion of the apical cell the latter is transformed into 
 a row of flattened cells, into a ribbon-shaped appendage 
 of the young leaf, embracing the stem (PL XI, fig. S ') ; 
 this is the first rudiment of the lower lobe (which 
 presses against the upper one) of the 'superior leaves. 
 It increases in breadth by the division of its cells by 
 means of septa parallel to the longitudinal axis. This 
 cell-division is repeated much oftenef in the marginal 
 cells of that side of the lower leaf-lobe which is turned 
 away from the upper lobe, than in those of the opposite ' 
 side. It frequently does not continue in the cells nearest 
 to the apical cell. This latter cell grows regularly into 
 a club-shaj)ed hair (PI. XI, fig. 2). 
 
 After the form of the leaf is thus prepared the cells 
 of its base divide by frequently alternating longitudinal 
 and transverse septa. The outline of the leaf is not 
 thereby changed, but the number of its cells is veiy 
 nmch increased, and the space over which the upper 
 leave-lobe coheres to the lower is considerably extended. 
 
 The first stages of development of the inferior leaves 
 of TriiUunia cUlatala entirely resemble those of the bi- 
 dentate superior leaves of Lojjhocolca Udp.niuia, two teeth 
 being formed on the fore-edge in the same maimer as 
 
THE HIGHER CRYPTOGAMIA. 63 
 
 in the latter plant. Soon, however, a new process of 
 cell-formation appears at the sicle-edgcs of the leaf, under- 
 neath the place of origin of these teeth ; commencing by 
 a lateral expansion of one of the marginal cells, followed 
 by a cutting off, by means of a transverse septum, of the 
 protuberance thus formed, and by repeated transverse divi- 
 sion of the newly-formed cells. By this means the hitherto 
 double-pointed leaf becomes four-pointed. 
 
 The leaves of Badala camplanata are developed in all 
 their parts in a manner precisely similar to that of the 
 superior leaves of Frullania dilatata (PI. XI, fig. 15). 
 In this species, also, the apical cell of the lower lobe 
 after its last division usually grows out into a clavate 
 hair (PL XI, fig. 1). The multiplication of the cells of 
 the base of the leaf lasts for a considerable time after 
 the termination of the division of the apical cells. 
 
 The arrangement of the cells in the leaves of the 
 round-leaved common Jungermannise (/. curta, crenidata, 
 Alicularia Scolaris) very much resembles the later condi- 
 tion of the upper lobe of the superior leaves of rriilla- 
 nia ; it answers exactly to the arrangement of the cehs 
 in the direction of the sm-face, of young shoots of Pellia 
 (PI. VII, fig. 21). 
 
 The leaves of the Jungermanniae usually exhibit a very 
 decided inclination to development in breadth. I know 
 of no species in which a single apical cell divides by means 
 of septa spreading alternately right and left, and in which 
 the division lasts until the termination of the growth 
 of the leaf. The development of the leaves of all Jun- 
 germannias agrees in this, that the leaf originates in the 
 extension outwards of one or more cells of the bounding 
 surface of the stem close underneath its growing apex, 
 and the subsequent separation by septa of the protuber- 
 ances thus formed from the original cell-cavity. This 
 first rudiment of the leaf grows at first exclusively by 
 division of the cells of its apex and edge. After a 
 series of such divisions, sometimes after very few (in ex- 
 treme cases, as in Fossombronia, and in Haplomitrium 
 according to Gottsche, after one single division) then^ en- 
 
Gil HOFMEISTER, ON 
 
 sues a most active and long- continuing multiplication of 
 the cells of the base of the leaf, which gives the leaf its 
 final shape. 
 
 The leaf-development of the different Jungermanniae, which 
 I have endeavoured to describe in the preceding pages, may 
 be looked at from one and the same point of view^ How- 
 ever different at first sight the individual processes may 
 appear, tlun' may be looked upon collectively as a tendency 
 in the longitudinal halves of the young leaf-rudiments to 
 develope themselves independently, and often unequally. 
 The upper and lower lobe of the leaves of Scapania, Frulla- 
 nia, Radula, &c., answer to the two tips of the leaves of 
 Lophocole?e, J//?/r/. dicusjjidafa, Ptilidium, and others. 
 
 The mode of ramification of the Jungermannias is very 
 difficult to unravel, on account of the natiu-e of the terminal 
 buds. I have not arrived at an enth'ely clear idea of it in 
 any species. ]\Iany observations pohit to the conclusion 
 that the normal ramification of the axis results from a 
 genuine furcate division of the naked apex of the terminal 
 bud above the place of origin of the youngest leaf {e.j/., PI. 
 YIl, fig. I, Ptilidium ciliare), and there is nothing opposed 
 to this view. The cases which appear to contradict it (such 
 as the development of new shoots out of the axils of the 
 leaves of fruit-bearing, or even older branches of terrestrial 
 Jungermannia?), may be looked upon as the development 
 of adventitious buds. 
 
 These shoots in /. hicuspidaia often attain the length of 
 several millimetres without producing leaves. They are, 
 therefore, just the objects in Avhicli the nature and method 
 of cell-multiplication in the apex of the stemof Jungermanniae 
 may be most conveniently investigated (PI. VIII, fig. 12"'*). 
 The half-subterraneous shoots of IlapIomiiriumHookcri often 
 remain in like manner leafless for a considerable extent. 
 These are the processes wdiich Gottsche is inclined to con- 
 sider as being true roots of this liverwort, which is entirely 
 unprovided with rootlets ('Nova Acta Acad. C. Leop.,' vol. 
 XX, 1, 275). I had the opportunity of convincing myself 
 that the structure of the growing end of these shoots en- 
 tirely coincides with that of the end of the stem (PI. VII, 
 
THE HIGHER CRYPTOGAIMIA. 65 
 
 fig. 1). They grow by continually repeated division of a 
 single apical cell by means of septa alternately inclined in 
 different directions. These shoots are also remarkable from 
 the fact that in the older portion of them each epidermal 
 cell grows out into a short papilla (PL VII, fig. 2), an en- 
 largement of the upper surface, which may serve as a 
 compensation for the absent rootlets. 
 
 The antheridia of the liverworts are mostly axile, some- 
 times solitary (Jungermannia, Lophocolea, Radula, JMa- 
 dotheca), sometimes gregarious (Alicularia, Frullania), in 
 the axil of the same leaf. They are only occasionally free, 
 i. e., not protected by covering leaves on the upper surface 
 of the stem (Fossombronia, Haplomitrium) . The formation 
 of the antheridium commences by the protrusion outwards 
 in the form of an arch, and to a considerable extent, of 
 one of the cells of the upper surface of the stem, before 
 the latter has ceased to grow in thickness, and by the sepa- 
 ration, by means of a transverse septum, of the protu- 
 berance thus formed from the original cell cavity. In the 
 cell thus formed, which protrudes above the surface of the 
 stem, there sometimes commences a series of repeated 
 divisions of the apical cell by septa alternately inclined in 
 two directions {Madotheca jjlatyphyUa, Fossombronia pii- 
 silla). This series of divisions, however, is not of frequent 
 occurrence. More frequently the primary cell of the 
 antheridium is divided several times successively by septa 
 parallel to one another. By this means it is transformed 
 into a row of cylindrical cells, which is sometimes of con- 
 siderable length, as in Lophocolea heteropltylla. The ter- 
 minal cell of this cellular thread swells in a clavate manner 
 (PL XI, fig. 39). It divides by a septum diverging from 
 its longitudinal axis ; the upper one of the newly formed 
 cells then divides by a septum inclined in the opposite 
 direction. The cells of the second degree are divided by 
 radial longitudinal septa; one of the cells of that upper 
 pair of cells of the third degree which is nearer the apex of 
 the antheridium, divides by a septum parallel to the longi- 
 tudinal axis, and cutting the side walls of the mother-cell 
 at an angle of 45°. The young antheridium now consists 
 of a spherical group of cells — a central cell surrounded by 
 
 5 
 
G6 HOFMEISTÜR, ON 
 
 five cells — wliicli is borne by an elongated cylindrical 
 stem consisting of a single row of cells (PI. XI, fig. 1, 40). 
 
 The cells of the latter continue to divide frequently by 
 septa parallel to those already present. The central cell 
 of the spherical head which it supports multiplies actively 
 in all three directions by repeated bisections (PL IX, fig. 
 31 ; PI. XI, figs. 2, 41), whilst the cells of its outer layer 
 divide only by septa at right angles to the outer surface, and 
 much less frequently than the central cell. The anthe- 
 ridium is now a spherical mass of small cells filled with 
 mucilage, surrounded by a single layer of tabular cells con- 
 taining chlorophyll (PI. XI, fig. 3). In each of those 
 smaller cells a spermatozoon is formed inside an ellipsoidal 
 or spherical vesicle (PI. VII, fig. 6 ; PI. XI, fig. 42). 
 When the antheridium is ripe, the cells of its outer layer* 
 separate from one another (PI. VI, fig. 37 ; PI. XI, fig. 42) ; 
 the vesicles containing the spermatozoa, which have become 
 free by the dissolution of the walls of the cellules containing 
 them, escape in the form of a mucdaginous mass. They 
 disperse themselves under water, and commence a rotating 
 motion. The wall of the vesicle bursts, the enclosed 
 spermatozoon escapes either wholly or partially (PI. XI, 
 fig. 42), and moves about in the water, keeping up a per- 
 petual rotation round the axis of the spiral which it pre- 
 sents (PI. VII, fig. 12; PL VIII, fig. 3). 
 
 In the antheridia of those species in which division by 
 alternately inclined septa commences even in the earliest 
 primary cell of the antheridium, the essential parts, i. e., the 
 mother-cells of the first degree of the spermatozoa and 
 their covering layer, are developed in a precisely similar 
 manner. A long series of cells of the second degree fail to 
 nudtiply, so that a cylindrical double row of cells (long in 
 ]\Iadotheca, short in Possombronia) represents the second 
 stage of develo})ment of the antheridium. The free end of 
 this cylinder swehs up to a clavate shape ; and in the two 
 youngest cells the divisions now ensue which lead to the 
 formation of the central cell and its covering layer. 
 
 * In some species (e. ff., Fosssombronia pusilla) llie granules of eliloropliyll in 
 lliese cells have by this time become yellow, as is the case iu Authoccros, and 
 iu the mosses. 
 
THE HIGHER CRYPTOGAMIA. 67 
 
 Madotlieca platyphylla exhibits a remarkable peculiarity. 
 The cells of the covering layer not only divide very fre- 
 quently by septa perpendicular to the outer siu'face, so that 
 they appear proportionally small and very numerous in 
 the perfect antheridium ; but the lateral cells and those 
 underneath the central cell divide also by septa parallel 
 to the outer surface of the young antheridium ; the 
 upper ones once, the lower ones several times over. 
 By this means the antheridium acquires a consider- 
 able size ; the oval group of cells in which the sperm- 
 atozoa are produced occupies only a small portion of its 
 upper half. The covering of this group of cells consists 
 also always of a single layer of cells (PL VII, fig. 5). The 
 walls of the cells of the covering-layer are coloured a bluish- 
 red by iodine. 
 
 The spermatozoa in the leafy Jungermanniae are con- 
 siderably smaller than those of Pellia. Fossomhronia 
 pusilla has the largest of all those which I have examined ; 
 the diameter of the vesicles in which they originate is 
 yjo'" ; those of the diminutive Jurigermannia divaricata 
 are a httle smaller (PI. YII, fig, 21) ; those of FndJania 
 dilatata and Madotheca plaii/pIiijUa K\:Q\QYy small (PI. VII, 
 fig. 6; PL XI, fig. 42). 
 
 The development of the archegonia of the leafy liver- 
 worts corresponds exactly with that of the like organs in 
 Pellia, the Marchantiae, and the mosses. In Fossombronia 
 and Haplomitrium these organs are produced in the axils of 
 leaves ; in the other genera treated of in this cha[)ter they 
 are found only on short lateral branchlets. In growing 
 archegonia, however, the peculiar condition which occurs 
 in Pelha and the mosses is seldom seen. In Pellia and 
 the mosses it often happens that the formation of the cells 
 of the axile string does not extend as far as the cells im- 
 mediately adjoining the apical cell, a fact which is doubt- 
 less to be attributed to the slow, and consequently relatively 
 limited development of the neck of the organ. The arche- 
 gonia of the true Jungermanniae, and of Radula complanafa, 
 are proportionatelv short and uniformly thick (PL VII, 
 figs. 14, 15 ; PL VIII, figs. 1, 2 ; PL X, fig. 1 ; PL XI, 
 fig. 1) ; those of Possombronia (PL VI, figs. 29—33) 
 
68 HOFMEISTER, ON 
 
 and of Frullailia are remarkably distended at the place 
 where the large cell at the base of the neck is enclosed ; 
 those of Frnllania have a longer neck than any moss or 
 liverwort, without exception, with which I am acquainted 
 (PI. XII, figs. 1, 3). 
 
 "With a few exceptions peculiar to the Jungermanniae 
 proper (PI. VII, fig. 15; PI. VllI, fig. 2 ; PL X, fig. 1), 
 the archegonia of the leafy liverworts agree in the fact that 
 until the formation of the rudiments of the fruit, the mother- 
 cell of the large cell at the apex of the distended portion, 
 is enclosed only by a single layer of cells ; and they also 
 agree in the fact that the distended portion is only of 
 moderate height, and that before impregnation only two or 
 three, or at the most four cells, are to be counted between 
 the low^er arched surface of the above-mentioned large cell 
 and the base of the archegonium. 
 
 The archegonia of the greater number of leafy liverworts 
 are furnished with a pecidiar cup or pitcher-shaped organ 
 of later growth than the archegonium itself — the calyx or 
 perianthium of authors. In all cases Mdiich have been 
 observed, the first appearance of this organ is in the form 
 of a closed ring, consisting of a single layer of cells. 
 
 This is the case in the very different perianths of 
 PruUania and Radula, and of Jungermannia bicuspidata 
 and divaricata. The first rudiment of tlie perianth is 
 formed by a contemporaneous protrusion, outwards and 
 upwards, of a belt of cells belonging to the apex of the 
 stem, surrounding the archegonia ; and by the separation of 
 the protruding portion of the cells, from the portion lying 
 within the body of the stem, by means of a transverse 
 septum. The like form of division is repeated several 
 times in the coronet of apical cells of the young organ. In 
 Radtda complanata it lasts until the perianth has completed 
 the full number of its cells in the direction of its length. 
 Here and there cells belonging to the margin are also at 
 the same time divided by vertical septa, and thus the 
 nmnber of cells of the circumference is increased above 
 (PI. XI, fig. 1). The form of the perfect perianth of 
 Radula is consequently that of a horn continually 
 widening upwards, and closely compressed laterally ; doubt- 
 
THE HIGHER CRYPTOGAM I A. 69 
 
 less the result of the resistance of the almost contiguous 
 fore and hind lobes of the enveloping leaves, between which 
 the organ must develope itself. 
 
 A very different state of things is presented in Jmu/er- 
 mannia bicuspidata and divaricata, and in Fridlania dilatafa. 
 In these plants, and in the latter of them at a very early 
 period, the multiplication of the cells of the free upper 
 edge of the perianth ceases altogether. On the other hand 
 there ensues an active multiplication of the basal cells by 
 rapid and often repeated divisions, in Jiingermanma divari- 
 cata and cuspidafa chiefly by horizontal septa, in Frullania 
 almost as vigorously by vertical septa (PL VII, fio-. 14 ; 
 PL VIII, figs. 1, 2 ; PL XII, fig. 2). The cells of the free 
 edge of the perianth of Jungermannia bicuspidata grow at an 
 early period into Ions; teeth, with transparent contents and 
 thick cell-walls (PL VIII, figs. 1, 2). The form of the organ 
 passes from that of an open basket into a cylindrical, and 
 thence into a clavate shape ; the converging teeth close the 
 opening over the half-ripe fruit. In Frullania dilatata the 
 perianth during development becomes more and more 
 distended (PL XII, figs. 1, 2). The mouth, a narrow 
 ring, is lifted up higher and higher, reaches the height of 
 the apex of the archegonium shortly after the completion of 
 impregnation (PL XII, fig. 3), and by the time of the 
 termination of the longitudinal growth of the perianth, is 
 carried about five times higher, by the continuous multi- 
 plication, and ultimately extensive expansion of the cells of 
 the base. At the time of the ripening of the fruit the 
 number of the cells of the free edge of the narrow mouth 
 of the perianth is not greater by one than at the first 
 appearance of the perianth out of the surface of the stem 
 beneath the archegonia, when it amounts to from sixteen to 
 twenty. In Alicularia scalaris the intercalary cell-multi- 
 plication extends from the basal cells of the perianth, 
 up to the tissue of the end of the stem which bears the 
 archegonia. At the time when the rudiments of the 
 perianth appear in the form of an annular border enclosing 
 the young archegonia, the end of the stem is slightly 
 convex.* During the growth of the perianth there ensues 
 
 * See Gottsche, 1. c, p. 325. 
 
70 HOFMEISTER, ON 
 
 an active multiplication in the direction of their growth 
 (outwards and at the same time obliquely upwards) of the 
 peripheral layers of cellular tissue of the apex of the stem. 
 This nudtiplication extends downwards from the rudiments 
 of the perianth to the second or third pair of leaves. By 
 this process the end of the stem which bears the archegonia 
 becomes depressed below the level of an annular wall- 
 shaped enlargement of the cortex of the stem, which 
 enlargement bears upon its upper margin the young 
 perianth, and upon its outer surface the uppermost pair of 
 stem-leaves. An expansion of the cells of the above 
 enlargement, in a direction parallel to the longitudinal 
 axis of the stem, ultimately raises the points of insertion of 
 the upper leaves above the apex of the calyptra. 
 
 Trom an exaggeration of the same condition is produced 
 the peculiar formation of the (abnormal) perianth of Calypo- 
 geia TricJiomancs. Gottsche has shown* that the short 
 few-leaved branch which springs laterally from the median 
 line of an inferior leaf, bears upon its apex the archegonia 
 which are immediately surrounded by the last leaves ; the 
 apex of this branch inclines upwards, and becomes a round 
 fleshy knob.f Successful longitudinal sections perpendicular 
 to the plane in which the surfaces of the leaves of the prin- 
 cipal axis lie, and passing through this axis, and also through 
 the young fruit-branch which lies laterally in the axil of one 
 of its inferior leaves, proved to me that the latter branch, 
 which at first is directed obliquely downwards, curves itself 
 upwards, so that at the period of impregnation the arche- 
 gonia are erect (PL X, fig. 1). The central c(;ll before 
 impregnation is exceedingly small. The completion of the 
 impregnation is first recognisable by an unusually active 
 multiplication of the cells of the central portion of the 
 archcgonium during its conversion into the calyptra; a 
 multiplication which forthwith commences in the tissue of 
 the fruit-branch inuuediately adjoining the base of the 
 archegonium (PI. X, fig. 1). The small-celled tissue thus 
 formed, which bears the impregnated and the abortive 
 archegonia, becomes developed into the fruit-sac. The 
 
 * «Nova Acta Ac. C. L,,' xxi, p. 427. 
 t L.c, p. 4S8. 
 
TIIK HIGH KR TRYPTOGAMIA. 71 
 
 larger wide-celled moiety of the fruit-stalk above the former 
 takes no part in this new formation. An active cell- 
 multiplication continues to take place in the former tissue 
 for a long time. In the cells imdergoing division, transverse 
 septa perpendicular to the convex outer surface of the fruit 
 branch often make their appearance. The annular zone of 
 new cells thus formed, which lies at the greatest distance 
 from the archegonia, undergoes, immediately after its forma- 
 tion, a considerable longitudinal elongation, at right angles 
 to the partition-walls by the fonnation of which the cells 
 were individualised. This is the mode in which the end of 
 the fruit-branch, which is originally cushion-shaped, becomes 
 transformed into a pitcher-shaped organ (PI. X, fig. 6).* 
 The cells of the inner surface of its cavity are from four to 
 eight times narrower than those adjoining them. Tliis 
 arises from a division of the cells of the inner surface, by 
 means of longitudinal and transverse septa perpendicular to 
 the free surface, which takes place after the last division of 
 the cells adjoining them. These narrower cells expand into 
 long papilloe directed rectangularly inwards, which almost 
 entirely fill the cavity of the fruit-sac (PI. X, figs. 6, 8).t 
 
 Shortly before the commencement of the dissolution of 
 the transverse septa of the string of cells which occupies 
 the longitudinal axis of the neck of the archegonium of 
 Fossomhronia pusilla, a small free cell becomes visible in 
 the middle cell of the ventral portion of the archegonium, 
 occupying about an eighth part of the cavity of the latter 
 cell, and near its very distinct primary central nucleus. 
 The contents of this small free cell are transparent, and it 
 has a finely granular nucleus with no nucleolus. There 
 can be no doubt that this cell originates in free-cell forma- 
 tion round a secondary nucleus. In archegonia a little 
 more developed, this cell, which has considerably increased 
 in size, quite fills the lower third-part of its mother- cell. The 
 
 * It is essentially the same process which makes the cavity of the ovary of 
 epigynous Phaneiogamia inferior, and by v^hich the nucleus of many anatropal 
 ovules which have massive outer integuments, becomes sunk within the integu- 
 ments, except that in these cases, and especially in the latter, cell-formation 
 and cell-expansiun are not so clearly distinguishable from one another as in 
 Calypogeia. 
 
 f Gottsche has given an elegant figure of a longitudinal section of a later 
 condition of the fruit-sac, 1, c, T. xxxi, f. 15. 
 
72 HOFMEISTKH. ON 
 
 primary nucleus of this latter cell has become indistinct, in 
 fact hardly discernible ; it is manifestly undergoing dissola- 
 tion (PI. Vl, fig. 32). As soon as the canal which trans- 
 verses the neck of the archegonium is completely formed 
 by the dissolution of the transverse septa of the axile row 
 of cells, no trace of the primaiy nucleus of the central cell 
 is any longer perceptible. The free daughter-cell, the 
 germinal vesicle, noAv occupies about two third parts of the 
 central cell (PL VI, fig. 33).* 
 
 In those forms where the central cell of the archegonium 
 is smaller, the germinal vesicle at the time of the opening of 
 the apex of the archegonium, almost entirelv fills the mother- 
 cell (PI. VII, figs. 15, 16; PL VIII, fig. 2; PL XII, fig. 1). 
 
 ]\Iost archegonia are not developed beyond this stage. 
 The cell-walls, which adjoin the longitudinal canal of the 
 neck, assume a chestnut-brown colour, as also the inner Avail 
 of the large central cell of the ventral portion. The spheri- 
 cal cell, which has originated in the latter, becomes trans- 
 formed into a dark brown mass. In individual archegonia, 
 however, seldom in more than one in the same inflorescence, 
 a fruit is produced by continuous division of the spherical 
 cell which has been formed within the central cell of the ven- 
 tral portion. It is more than probable that the action 
 upon the archegonium of the spermatozoa, emitted from 
 the antheridia of the same species, is necessary in order to 
 bring about the development of the rudiments of fruit. 
 Where antheridium-bearing plants are found in the 
 neighbourhood of those bearing archegonia, much fruit is 
 met with ; when the contrary is the case there is no fruit. 
 The connnon Lophocolea hidentata is a remarkable instance ; 
 this plant usually has abundance of archegonia, but very 
 seldom bears antheridia, and the fruit is proportionately 
 rare. 
 
 Those species fructify the most abundantly which bear 
 
 * The nucleus of the germinal vesicle very much resembles the defunct 
 primary nucleus of the central cell. This circumstance, and the rapidity with 
 wliieii the ahove-mcntionod process of development is gone through, led me on 
 a former occasion (' Vergleichende Untersuchungen,' pp. -37, 47, <i7,) to look 
 upon the nucleus of the germinal vesicle as identical with that of the central 
 cell, and to assume that the formation of the germinal vesicle took place by 
 means of free cell-formation round the primary nucleus of the central cell. 
 
THK HIGHER CRVPTOGaMIA. 73 
 
 antheridia in the axils of the leaves of the shoot which has 
 archegonia at its apex. This is the case with Lophocolea 
 heterophylla and Radula complanata, and frequently, but 
 not always, with Jungermannia divaricata, all of which are 
 nearly allied to Lojjiiocolea hidentata. Fndlania dilatufa, 
 a very free-fruiting species, certainly does not very often 
 produce antheridia. Here, however, the mode of growth 
 of the plant, is such as greatly to facilitate the passage of 
 the contents of the antheridia to the archegonia. The 
 patches of Erullania, which are in a dry situation, and at 
 some height from the bottom of the tree on which they 
 grow, are those which especially produce antheridia. When- 
 ever rain falls, or there is a heavy dew, a considerable 
 quantity of water trickles down from the patches which 
 bear the antheridia, to those beneath them in which the 
 archegonia occur. Moreover, the quantity of fruit in Frul- 
 lania, however abundant it may be, is not at all proportion- 
 ate to the enormous number of archegonial branches which 
 the plant produces. The greater number of the flowers 
 (which only contain two or three archegonia) are abortive, 
 and produce no fruit. 
 
 The structure of the perianth of the Jungermanniae is no 
 obstacle to the impregnation. In Radula, in Frullania, even 
 in the Lejeuniae, the development of the rudiments of the 
 fruit commences before the margin of the perianth is raised 
 above the apex of the archegonia. In Jungermannia bicus- 
 pidata also the development of the fruit often begins very 
 early, when the perianth has still the form of a wide open 
 basket (PL VIII, fig. 3), but often also (as is the case too 
 with /. divaricata) at a considerably later period, wdien the 
 perianth has assumed the form of a hollow cylinder, when 
 its margin begins to become folded and to bend inwards. 
 These instances, however, are just those which afford un- 
 doubted proof that even under unfavorable circumstances 
 the spermatozoa can reach the antheridia. In perianths of 
 both species which I have cut open longitudinally and 
 placed quickly in w^ater, I have several times most clearly 
 seen spermatozoa in rapid motion, Avhirling actively around 
 the archegonia (PI. VIII, fig. 12). In the Jungermanniae 
 there is found at the aperture of all archegonia which have 
 
74 HOFMEISTER, ON 
 
 recently opened, small globular drops, often in large quan- 
 tities, consisting of a hyaline transparent slimy substance. 
 They api)oar to be formed from the escaped contents of the 
 canal which traverses the neck of the archegonium. In 
 recently-opened archegonia of /. hicuspidata and /. divari- 
 cata, as well as of /. hicreimta and Alicidaria scalaris 
 (which archegonia by the commencement of the swelling of 
 their ventral poi'tion exhibited the first indication of the 
 fruit-formation), I saw between these drops, delicate, more 
 or less twisted, colourless filaments, in appearance and size 
 exactly similar to the spermatozoa of those species, but 
 motionless (PI. VII, figs. 12, 17 ; PL VIII, fig. 3). 
 
 The first division of the mother-cell of the rudiment of 
 a fruit takes place by a transverse septum, at right angles 
 to the longitudinal axis of the archegonium, and to that of the 
 future fruit (PI. VII, figs. 12, 17; PI. VIII, fig. 3; Pl.X, fig. 1; 
 Pl.XII, fig. 3). In FrvUania dilatata and Calypofjeia Triclio- 
 mancs the youngest, bicellular condition of the fruit is 
 shortly oval ; in Jun(^. divaricata it is somewdiat more elon- 
 gated, and in /. bicuspidala it is drawn out to a great 
 length. The lower of the newly-formed cells continues 
 (with rare exceptions) during the whole life of the fruit 
 without division ; the upper one divides either immediately 
 by a longitudinal septum (as is almost always the case in 
 Frullania dilatata, Lophocolea Ueteropliylla, Ihidula compla- 
 nata, and Alicidaria scalar is), or else it divides once or 
 several times by horizontal transverse septa (as in /. bicus- 
 pidata, PI. VIII, figs. 4, 5, /. divaricata, PI. VII, fig. 8) ; 
 the division by a longitudinal septum first occiu's in the 
 apical cell of the very young rudimentary fruit which con- 
 sists of a single row of from three to five cells. 
 
 A horizontal transverse septum is noAV formed in both the 
 newly formed apical cells; each divides into an upper cell, hav- 
 ing the form of a quadrant of a sphere, and a lower cylindrical 
 one. A longitudinal septum bisecting the cell and radial to 
 the axis of the young fruit is then formed in each of the apical 
 cells, so that the rudimentary fruit now exhibits foin- ai)ical 
 cells. In Prulkmia this division commences normally in the 
 ])air of cells nearest to the basal cell (PI. XII, figs. G, 7). 
 In Calypogeia the same phenomenon is frequent (PI. X, 
 
TIIK HIGHEE nUTTOnAMIA. 75 
 
 figs, 2, 4) but not normal (PI. X, fig; 3). Henceforth, the 
 number of the cells of the rudimentary fruit, in the direc- 
 tion of the longitudinal axis, is increased ; at first exclu- 
 sively by repeated contemporaneous division of its four apical 
 cells by means of horizontal transverse septa at right 
 angles to the axis of the fruit. 
 
 This kind of cell-multiplication shows itself in the 
 most simple form in the few-celled rudimentary fruit 
 of J, divaricata. Its apical cells contain colourless muci- 
 lage, rendered turbid by numerous large and small gra- 
 nules ; the interstitial cells are coloured deep grey-green 
 by numerous small chlorophyll-granules (PI. VII, figs. 
 13, 19). After the transverse division of the four apical 
 cells has been repeated eight or ten times, the longi- 
 tudinal growth of the fruit is completed (PI. VII, fig. 20). 
 The double pair of cells which now forms the apex of the 
 clavate rudimentary fruit, then remains for the first time 
 unaltered ; the three next, on the other hand, divide into 
 inner and outer ones by means of septa parallel to the lon- 
 gitudinal axis of the fruit, and cutting the side walls at 
 an angle of 45° (PL VII, fig. 20). The outer cells become 
 the wall of the capsule ; further divisions take place in 
 each of them by means of longitudinal and transverse septa 
 perpendicular to the free outer surface. The wall of the 
 capsule shortly before it bursts usually has twenty-four cells 
 in its circumference, and eight cells in its height ; the cells 
 being of an oblong tabular shape. By a series of divisions, 
 occurring principally in radial and tangential directions, 
 the inner cells become transformed, partly into rows of 
 mother-cells, and partly into elaters. The claters in 
 J. divaricata, as in all true Jungermannise and also in 
 Radula, extend horizontally from the inner wall of the 
 capsule to the longitudinal axis. In all these the inner 
 tissue of the capsule, from which the spores and elaters 
 are formed, consists, from the moment of the differentia- 
 tion of the capsule-wall from its contents, of a short slightly 
 distended columella, formed of a douljle pair of cells, with 
 a quadrantal basal outline (PL XI, fig. 6). The first divi- 
 sions of the latter cehs take place by septa ])er))endicular 
 to the longitudinal axis of the fruit alternating with others 
 
70 nOFMEISTUR, OS 
 
 radial to it. In the cells destined to form elaters no 
 transverse septa are formed, -whilst their sister-cells by 
 repeated division parallel to the axis of the fruit form rows 
 of cubical cells — the spore-mother-cells. These are, there- 
 fore, arranged in rows, whicli radiate horizontally from 
 the longitudinal axis of the capsule, each three of which are 
 succeeded by an elater, and of which fom- (sometimes by 
 displacement, as many as eight), are contiguous to each elater 
 (PI. YIII, fig. 7 ; PI. IX, fig. 23). 
 
 Contemporaneously with the commencement of the dif- 
 ferentiation of the capsule-wall of /. divarkata from its 
 contents, (which takes place by division into outer and 
 inner ones of three double pairs of cells of the upper 
 clavate portion of the rudimentary fruit,) septa parallel to 
 the axis of the fruit are also formed in the first and second 
 double pairs of cells above the base of the young fruit ; 
 the outer ones of the new cells thus formed divide by 
 radial longitudinal septa. As they expand considerably in 
 breadth, and protrude arcuately outwards, they form the 
 knobby protuberance by which the fruit is attached to 
 the tissue of the stem which bears it (PI. Vll, fig. 20). 
 The basal-cell and the pair of cells above it remain un- 
 changed. On the other hand, the cells of that portion of 
 the rudimentary fruit which lies between the basal en- 
 largement and the bottom of the capsule, — i. e., the fruit- 
 stalk, — divide all together by horizontal septa. They thus 
 represent quadrants of cylinders of very small height ; the 
 transverse diameter is from six to eight times greater than 
 the altitude. A sudden longitudinal prolongation of these 
 cells, to an extent manifestly far exceeding fifty times 
 the original longitudinal diameter of the cells, lifts the 
 capsule up (wheu the fruit is ripe), through the fissure of 
 the ruptured calyptra, high above the perianth. 1 have 
 found no trace of a flow of sap into the cells of the fruit- 
 stalk in this species, although it is certainly the one best 
 suited for such an observation. 
 
 The development of the fruit of the greater number 
 of the Jungermannise agrees very ch)sely with that of 
 /. divaricafa, and differs only by the more frequent repeti- 
 tion of certain cell-divisions, and by more vigorous develop- 
 
THE HIGHER CUYPTOGAMIA. 17 
 
 raent in length and thickness. In /. biciispidaia (PI. VIII, 
 figs. 5, 7), and /. tricopki/ila, in Badula coniplanata (PI. XI, 
 figs. 4, 5), Lophocoica heterophylla, Alicularia scalaris, and 
 CaJypogeia TricJiomaues (PI. X, figs. 2-8), the four apical 
 cells of the rudimentary fruit often divide repeatedly by 
 horizontal transverse septa ; the three-sided cells of the 
 second degree thus formed divide, however, all together, 
 by septa parallel to the tangent of the curved outer-wall, 
 and cutting the side- walls at an angle of 45°. In /. bicus- 
 pidata (PI. VIII, fig. 7), this division takes place once, in 
 Lophocolea lieterojdliylla, and Radula comjjlcmata twice (PI. 
 XI, figs. 4, 5) ; in the latter by a repetition of the division 
 in the outer cells, after a previous formation of radial 
 longitudinal septa therein. After the cesser of multiplica- 
 tion in the apical cells, the capsiüe-wall is produced by the 
 continuous division of the outer layer (in Lophocolea, Kadula, 
 and Alicularia, of the two outer layers) of cells of the 
 rudimentary fruit ; by the multiplication of the elongated 
 axile group of cells, formed out of four longitudinal rows of 
 three-sided cells, are produced the elaters, which radiate 
 from the longitudinal axis of the fruit to the capsule-wall, 
 as well as the rows of spore-mother-cells, which are inserted 
 between these in horizontal rows. The cells of the middle 
 part of the rudimentary fruit assume a depressed tabular 
 shape by repeated transverse divisions ; collectively they 
 form the fruit-stalk. In Jungermannia hicuspidata and 
 tricopJu/Ua, the fruit-stalk normally consists of twelve longi- 
 tudinal rows of cells, of four strings of three- sided cells 
 traversing the interior of the stalk, and a layer of eight 
 cells surrounding these standing at an equal elevation. In 
 the cells of the outer layer transverse division ensues to a 
 greater extent than in those of tlie central string ; the latter 
 are double the height of the former (PI. VIII, fig. 7 ; PI. 
 IX, fig. 23) .The fruit-stalk of Lophocolea, Radula, Alicu- 
 laria, and Calypogeia (PI. X, fig. 7), which, after the dif- 
 ferentiation of the capsule-wall from its contents, consists 
 of three concentrical layers of cells, continues to grow in 
 thickness up to this period ; in Radula the growth takes 
 place by a single division ; in Lophocolea and Aliciüaria 
 by repeated divisions of the cells of its circumference. 
 
78 HOFMEISTER, ON 
 
 By cell-multiplication extending on all sides, and dimi- 
 nishinpr downwards, the base of the riidiuientary fruit be- 
 comes transformed into a turnip-sliaped enlargement, sunk 
 into the tissue of the fruit-bearing shoot. This enlargement 
 is most vigorously and peculiarly developed (as is known 
 from Gottscheds beautiful observations, ' N. A. A. C. L.' 
 vol. xxi, p. 2) in the Geocalycea3, w^here its upper margin 
 grows into the sheath surrounding the fruit-stalk ; and in 
 Calypogeia, where it grows into a highly delicate membrane. 
 A similar appearance is presented in Alicularia Scolaris, 
 which, in the formation of its perianth, in some respects 
 resembles the Geocalyceae : here foin* triangular fleshy lobes 
 which surround the base of the fruit-stalk, are developed out 
 of the enlargement of the lower end of the rudimentary fruit 
 (Pl.VII, flg. 10). These are less conspicuous in the true Jun- 
 germannise, and in Lophocolea. Fndlania dilatata exhibits 
 hardly any indication of them (PI. XII, fig. 9) ; lastly, in 
 Badida complanaia there is only a very moderate enlarge- 
 ment of the lower end of the fruit-stalk, produced by a 
 transverse stretching and papillate expansion of the cells of 
 its outer surface (PL XI, flg. 7). 
 
 The development of the fruit of FruUania dilatata (and 
 doubtless also that of the nearly-alUecl Lejeunise) differs in 
 its middle stages not immaterially from that of the proper 
 Jungermanniae. In Fndlania the four apical cells of the 
 rudimentary fruit divide, even at an early period, by means 
 of longitudinal septa, which form an angle of 45° with the 
 side-walls, but diverge at a sharp angle from the longitu- 
 dinal axis of the fruit. The division of the apical cells 
 afterwards proceeds in the same manner as in Pellia and 
 Aneura. In the mean time the lower part of the rudi- 
 mentary fruit increases considerably in thickness ; the cells 
 of its circumference divide repeatedly by longitudinal septa 
 parallel to the axis, alternating with radial septa. The 
 form of the rudimentary fruit is far less slender, its apex is 
 proportionately far wader, than in /. hicuspidata or Radtda 
 complanata (PI. XII, fig. 8), The elaters and the spore- 
 mother-cells are produced by the multiplication of a hori- 
 zontal sti-atum of cells, which is separated by a double 
 layer above it from the cells of the apex of the rudimentary 
 
THE HIGHER CllYPTOÜAMIA. 79 
 
 fruit. Tliis production takes place after the multiplication 
 of the apical cells of the young fruit in a longitudinal 
 direction has terminated (Fl. XII, fig. 8). The two 
 covering layers of cells form the capsule-wall, having first 
 nudtiphed considerably by often repeated longitudinal and 
 transverse divisions wdiich take place by septa perpendicular 
 to the outer surface. The capsule-wall, in consequence of 
 the rapid increase of the number of its cells, eventually 
 becomes hemispherical (PI. XII, fig. 9). Most of the 
 somewhat elongated cells of the horizontal cellular surface, 
 enclosed by the capsule-w^all, follow the progress of the 
 latter as its arched surface becomes elevated, dividing 
 repeatedly by transverse septa; some, however, expand 
 only in a longitudinal direction until they eventually assume 
 the form of narrow cylindrical tubes, parallel to the longi- 
 tudinal axis of the fruit. These tubes are attached at the 
 base to the upper end of the fruit-stalk, and at their apices 
 touch the hmer arch of the capsule-wall (PL XII, fig. 9). 
 The latter are the elaters ; the tessellated cells produced 
 by the division of the elongated cells, become the spore- 
 mother-cells. 
 
 Contemporaneously with the earliest period of the de- 
 velopment of the rudimentary fruit of liverworts, there 
 commences a very active multiplication of the peripheral 
 cells of the ventral portion of the archegonium, w Inch thus 
 becomes the calyptra. The cell-division, which occurs 
 repeatedly and in rapid succession, often extends far down- 
 wards into the tissue of the branch which bears the im- 
 pregnated archegonium. Whilst the lower part of the 
 archegonium becomes transformed into the upper half of 
 the calypt]-a, its distended form becomes companmüate 
 (/. hicuspidata, PL VIII, fig. 6 ; Badida complanata, 
 PL XI, fig. 4). The lower portion of the calyptra is 
 formed out of the upward- growing tissue of the tip of the 
 shoot npon the apex of which the archegonia stand. The 
 abortive archegonia often appear pushed up high on the 
 side-walls of the calyptra, which has originated from the 
 impregnated archegonia (PL XI, fig. 4, Badida com- 
 planata^. 
 
 No distinction can be traced between the base of the 
 
80 HOFiMEISTER, ON 
 
 calyptra in many liverworts (which is produced by the 
 miihi[)hcation of the cells of the apex of the stem), and the 
 vaginula of the mosses. In Itndida complanata, for in- 
 stance, the base of the calyptra is not less remarkably 
 conical and fleshy than in Phascum. This multiplication 
 of the cells underneath the impregnated archegonium in 
 the direction of tlieir thickness, is very active in Radula 
 complanata, less so in Lophocolca and the true Junger- 
 manniae ; lastlv, in Fridlania dilatata it is entirely 
 wanting ; here the midtiplication of the cells is limited 
 exclusively to the ventral portion of the impregnated arche- 
 gonium, towards the base of which it diminishes con- 
 siderably. The form of the calyptra in this species is 
 flask-shaped in all stages of its growth ; it is narrowly " 
 constricted at the base (PI. XII, figs. 3, 5). 
 
 The lower, reduced end of the rudimentary fruit, extends 
 downwards to the same distance as the cell-multiplication 
 beneath the impregnated archegonium extends upwards 
 into the tissue of the stem (PI. VlII, fig. 6 ; PI. XI, fig. 4). 
 The arch of the basal cell of the end of the stem often 
 exhibits a marked thickening of its wall (PI. VIII, figs. 
 4, 5) ; perhaps it is by means of this that it acquires 
 sufficient firumess to penetrate the cells of the yielding 
 tissue which lies in its way. In Fridlania dUatata the 
 cavity of the calyptra, which encloses the young rudi- 
 mentary fruit enlarges soon after impregnation by a mul- 
 tiplication of the cells of its walls, often so rapid aiid con- 
 siderable, that the growth of the rudimentary fruit cannot 
 keep pace with the increase in circumference and height of 
 the cavity, which is filled with mucilage ; at this period 
 the young fruit often lies quite free in the interior (PI. XII, 
 fig. 4). 
 
 Gottsche observes a similar phenomenon in Cali/pot/eia 
 Trichomanes.^ I have convinced myself by an observation 
 made in 1853, that in Calypogeia, also, the development of 
 the impregnated germinal vesicle normally follows step by 
 step the great enlargement of the central cell of the arche- 
 gonium, which is produced by the multiplication of its 
 neighbouring cells. Both developments are slow, that of the 
 * L. c, T. XXX, f. 8, 11. 
 
THE HIGHER CRYPTOGAMIA. 81 
 
 germinal vesicle into the fruit the slowest. After the 
 completion of the rudiments of the fruit-sac, the calyptra 
 has only increased moderately in size, and the impregnated 
 germinal vesicle is still undivided, although doubled in 
 length. In the fruit-sac, when from 1 to 3 mm. long, the 
 rudimentary fruit is only 4-8 cellular (PL X, fig. 8^. At 
 all stages of development it entirely fills the cavity of the 
 calyptra. The condition figured by Gottsche is certainly a 
 diseased one ; the rudimentary fruit, developing itself feebly, 
 could not follow the growth of the walls of the archegonium. 
 
 In certain Muscinese {Pellia epiphylla, Jung, divaricata, 
 Phascmn cuspidatum), and also in some vascular cryptogams 
 {Pteris aquilina, Aspidium Filix-mas, and Salvinia natans)^ 
 where several archegonia of one and the same group have 
 been impregnated, the less developed of these archegonia 
 have aflbrded me similar cases decisive of the point that 
 the increase in size, and the form of the growing base of 
 the archegonium, is not produced by the contact of the 
 rudimentary fruit or of the embryo. In all these cases, 
 moreover, two archegonia of the same prothallium had been 
 impregnated ; the arrest of development of the embryo had 
 occurred in the less-perfect archegonium, which had 
 manifestly been the latest impregnated and insufläciently 
 nourished. 
 
 In the leafy as well as in the leafless Jungermanniae the 
 individualization of the elaters and spore-mother-cells is 
 preceded by a considerable thickening of their walls, and 
 the conversion of the substance of these walls into a mate- 
 rial which swells up extensively in water. The mass of the 
 thickened cell-walls often swells up in water more rapidly 
 and to a greater extent than even in Pellia ; in /. bicuspidata, 
 Radula complanata, and Frullania dilatata, the determina- 
 tion of the arrangement of the cells of the interior of the 
 young capsule is thereby rendered extremely difficult. In 
 all the species which I have examined the substance of the 
 walls, when moistened with tincture of iodine, became 
 quite blue. In the mother-cells of the large-spored Frulla- 
 nia dilatata four protnisions of the wall (quite similar 
 to those of Pellia, before mentioned,) and the gradual 
 increase in size of the inner wall of the superimposed. 
 
 6 
 
82 HOFMEISTER, ON 
 
 ridges, which by their ultimate confluence become the 
 septa of the special mother-cells, are clearly perceptible 
 (PL XII, fig. 10). These special-mother-cells in Frullania 
 dilatata exhibit delicate pits (Tüpfel) similar to those of 
 Anthoceros pundatiis. 
 
 The wall of the half-ripe capsule of most Jungermann iae 
 consists of a double layer of cells (./. bicuspidata, tricho- 
 phi/lla, Frullania dilatata, Radula complanata). As the fruit 
 approaches maturity the inner of these cellular layers is 
 usually dissolved, and displaced by the growing spores. 
 
 The individualization of the cells of the interior of the cap- 
 sule depends, as in all similar cases, upon a highly advanced 
 state of this change in the properties of the substance of the 
 wall of the outer layer of the affected cell-membrane. There 
 exists, however, a striking diiference between what occurs in 
 Jungermanniae, and the analogous processes in the develop- 
 ment of the spores of other mosses and vascular crypto- 
 gams, and of the pollen-cells of Phanerogamia. In 
 Jungermannise a thick layer, constituting almost the 
 entire mass of the cell - membrane, undergoes trans- 
 formation into a substance w^hich becomes distended 
 in w^ater into a gelatinous mass, and disperses itself 
 through the fluid; whilst in other cases this modifica- 
 tion of the cell-membrane is limited to an immeasurably 
 thin external layer. In many cases, even in Jungermannise, 
 the condition of the different layers of the mother-cell- 
 membrane during the distension varies. In Fossombronia 
 pusilla the inner layer of the wall of those cells which are 
 exclusively developed into elaters is so vastly distended by 
 water w^hen in a young state, that it bursts the outer layer 
 of the cell-membrane (PI. VI, fig. 36). The same state of 
 circumstances, somewhat modified, occurs in the mother- 
 cells of the same plant, where, however, the less-distendible 
 outer layer is so tliick that it does not burst ; the expansion 
 of the inner layer takes place at the expense of the volume 
 of the ccfl- contents, which are compressed into a smaller 
 space (PI. VI, fig. 35). In Blasia pusilla also the mem- 
 brane of the cell, from the division of which two spore- 
 mother-cells have arisen, and which is very often present 
 after the formation of the tertiary nucleus, resists the action 
 
THE HIGHER CRYPTOGAMIA. 83 
 
 of water more than the membrane of the spore-mother- 
 cells themselves (PL VI, fig. 23). The mother-cells of the 
 spores of all the true Jungermanniac which I have examined, 
 those of Radula and Frullania, are rich in chlorophyll-gra- 
 nules. In Blast a pusilla the presence of chlorophyll is 
 limited to the tertiary nuclei destined for spore-forma- 
 tion, the substance of which seems usually to be coloured 
 green throughout (PI. V, fig. 24). 
 
 The first investigations into the germination of the spores 
 of Jungermanniae, are those of Hedwig.* They extend no 
 fiu*ther than the protrusion of the first rootlet. The observa- 
 tions published by Nees von Esenbeck,f do not advance 
 the knowledge of this subject to any further point. Bis- 
 choff", eighteen years later, | directed attention to the 
 geimination of Pellia, up to the formation of the first shoot. ^ 
 Bischoff' s observations agree entirely with those of later 
 observers, even in the unimportant circumstance that he 
 represents the base of the germ-plant (the hinder part of 
 the multicellular spore) as a globular enlargement of too 
 great thickness. I have already spoken of the incorrectness 
 of the expression (Vorkeim) applied by Gottsche to the 
 first shoot of the germ-plant. Gottsche noticed, || although 
 not very clearly, the multicellular natiu-e of the spores of 
 Pellia, and followed their germination, cell by cell, until the 
 perfect development of the first shoot, stating more intel- 
 ligibly the relation of the exosporium to the germ-plant. 
 Gottsche at the same time published an account of the 
 remarkable germination of Blasia pusilla ; he showed that 
 when the spore (after being sown) has become indistinctly 
 multicellular, a long, cylindrical, tubular cell shoots forth, the 
 end of which is developed into a cellular body, from which 
 at a later period the stem of the germ-plant is produced. 
 Lastly, Gottsche gave the first account of the germination 
 
 * 'Tlieoria geiierationis,' Leipz., 1798, 17. 
 
 t 'Nova Acta,' A. C. L. N. C, xiii, 1 (1824), 165. 
 
 + 'Handb. bot Terminologie,' Bd. ii, Nurnb., 1842, 733, t. Ivii, 2795-96. 
 These observations appear to have been made as early as 1828. See 'Bot. 
 Zeit.,' 1853, 14. 
 
 § Biscliotf completed this work at a subsequent period by the publication of 
 further figures. See ' Bot. Zeit.,' 1853, t. ii, f. 14—21. 
 
 II ' Nova Acta,' A. C. L., vol. xx, pars 1, 382. 
 
81 HOFMEISTER, ON 
 
 of the spores of a leafy Jimgermannia, /. crcnulata* 
 That accoiiiit does not extend beyond the formation of a 
 short filament from the mncr spore-cell. After Gottsche's 
 observations no notices of the germination of Jnngerman- 
 niai ap])eared imtil my own, mentioned above. At a later 
 period Grönland! published his investigations of the germi- 
 nation of the leafy Jungermannia3. He showed that the 
 formation of the long, cylindrical tube discovered by 
 Gottsche in the germination of Blasia was suppressed in 
 cases where the spores were very thinly sown ; that under 
 these circumstances the spore immediately assumes the form 
 of a cellular body, similar to that which, when the spores 
 are sown thickly, originates in the end of each tube.j He 
 pointed out, moreover, the occasional ramification of the pro- 
 thallium of leafy Jungermannia3,§ and extended the obser- 
 vation to some species hitherto not investigated or only 
 imperfectly so — Sarcoscyphus Ftmkii, J. cremdata, and 
 Alicularia scalaris, the development of which in other 
 respects exhibits nothing peculiar. 
 
 The first important observations as to the mode of growth 
 and cell-multiplication of the ends of the stems of Junger- 
 manniae are those of Nägeli. 1| He pointed out the mode 
 in which the terminal cell of the leafy axis of Metzgeria fiir- 
 caia divides by alternating septa, directed obliquely right 
 and left perpendicular to the surface of the stem, and the 
 way in which the cells of the second degree thus formed 
 produce, by continued bisection, the entire mass of cellidar 
 tissue of the flat stem. He shoAved fm'ther that the growth 
 of the stem which^ is developed from the gemmae of J. ecc- 
 secta, and that of the end of the stem of J. irichophi/Ua,^* 
 was produced by continual division of a single apical cell, 
 by means of oblique septa, of the same or a like inclination, 
 but differing in position. I have not obtained from my 
 own observations of the leafy Jmigermanniae any ground of 
 
 * /. c, pp. 387, 391.^ 
 
 !' Ami. d. Sc.,' iv ser., t. i, p. 1. 
 /. c, p. 20. 
 I. c, p. 16. 
 11 'Zeitschrift f. wiss. Bot.'H. 2 Zurich, 18i3, 138. 
 ^ /. c, p. 166. 
 *♦ /. c, p. 172. 
 
THE HIGHER CRYPTOGAMIA. 85 
 
 support for Nägeli's assumption that these septa arc turned, 
 not in two opposite directions only, but in several direc- 
 tions. 
 
 With respect to the ramification of the Jungermannia?, 
 the books afford but little information. I find no mention 
 by any earlier observer of the difference, to which I have 
 called attention, between the true dichotomy of Metzgeria 
 and Aneura and the pseudo-dichotomy of Pellia. The re- 
 marks made by C. G. Nees v. Esenbeck, with respect to 
 the ramification of the Jungermannise, have reference only 
 to the fully developed condition.* His statement that the 
 place of insertion of a branch in the principal axis is fre- 
 quently not determined by the position of the angle of the 
 leaf, in other words, that it is not found above the 
 median line of the next lower leaf, afford as much sup- 
 port to my conjecture that the normal ramification of the 
 leafy Jungermanniae is a true dichotomy, as does the 
 figure which Gottsche gives of a leafless subterraneous 
 shoot of Ilcqjlomitrium Hookeri divided into two branches 
 beneath the apex.f 
 
 With respect to the development of the leaves of Junger- 
 mannia3, Gottsche's important statement must be remem- 
 bered, that in Haplomitrium Hookeri the leaf, when quite 
 young and consisting of only a few cells, bears at its apex 
 (or when multi-angular at each of its angles) a clavate, bent, 
 retort-shaped cell, which, in a fully developed leaf consisting 
 of a great number of cells, is still found in the corresponding 
 position. I This observation, once made, afforded proof 
 that the cell-multiplication in the leaf of Jungermannia is 
 not the result of a continued, multiplication of one apical 
 cell. 
 
 The knowledge of the structure of the archegonia of the 
 Jungermanniae was, like that of the similar organs in the 
 mosses, first established by Hedwig.^ He figures the arche- 
 gonia as organs closed before impregnation, as open at the 
 
 * ' Naturgeschichte Europ. Lebermoose,' i (Breslau, 1833), 17. 
 
 f ' Nova Acta,' A. C L., xx, pars i, t, xiii, f. 1. 
 
 + I. c, pp. 275, 276. 
 
 § ' Theoria generationis,' Leipz., 1798, 164. 
 
86 HOFMEISTER, ON 
 
 top at the time of impregnation, and then traversed in the 
 longitudinal axis by a canal ; as organs out of which at a later 
 period the calyptra, crowned Avith the neck of the archego- 
 nium, is developed. Oui' knowledge of the stnicture of 
 these organs had made no progress since the time of 
 Hedwig until my own observations were published.* 
 
 Prior to my own observations, the very young condition of 
 the fruit had only been seen by Gottsche twice in Calypo- 
 geia TricJiomancs, in the form of a two- or three-celled body at 
 the base of a wide cavity of the calyptra, and wdiich Gottsche 
 considered to have sprung from the base of such cavity. f 
 At a somew^hat later stage of development of the young 
 fruit, Gottsche saw indications of the formation of the same 
 out of four rows of cells trending dowaiward to the one 
 basal cell, but he could not make out the matter clearly. 
 Schmidel had already obsen^ed the well-defined limits 
 between the low^er end of the fruit-stalk and the tissue of 
 the stem into w^hich that end is smik ;| as also had Hedwig,'^ 
 who had obsen^ed the many toothed sheath around the 
 base of the fruit-stalk in Pellia epiphylla. 
 
 With respect to the development of the spores of the Jun- 
 germannia3, H. von Mohl established the fact that they are 
 formed in fours, in round mother-cells, and that the elaters, 
 as long as the spores are lying unformed in the mother-cell, 
 have the shape of spindle-hke, delicate-walled cells, standing 
 in no organic connection wdth the spore-mother-cell. Von 
 ]\Iohl also observed that the young oval spores of Pellia 
 ejApliylluy whilst still hanging together in fours, are only 
 in contact with one another by a small portion of their upper 
 surface. 1| 
 
 The membrane of the perfect elater had been noticed by 
 Von Schmidel in Aneura multifida^ Nevertheless, the 
 notion of ''naked elaters'' was prevalent until a recent 
 
 • Compare C. G. Nees v. Eseubeck, 1. c, p. 60; Gottsche, 1. c., p. 315. 
 t ' Nova Acta,' Ac. C. L., xxi, pars ii, 445, 447. 
 X 'Icoiics plantarum,' iii. Erlangen, 1797, Tf. 57, f. 14, J. exsccia. 
 § ' Tlieoria gcueratiouis,' t. xvii, f. 10; /. ncmorosa, t. xxiv, f. 4; xxv, f. 2, 
 Pellia epiphylla. 
 
 II ' riora,'' 1833. ' Vermischte Schriften,' p. 68. 
 ^[ ' Icon, plant.,' t. Iv, f. 13. 
 
THE HIGHER CRYPTOGAMIA. 87 
 
 period ; Gottsclie first put a final end to it* by showing 
 the destructibility of tliis membrane by sidpbm-ic acid, the 
 action of which was resisted by the substance of the spiral 
 thread. Gottsche showed also that the coloured thicken- 
 ings of the cell- membranes of the capsule-walls comport 
 themselves in this respect like the spiral thread of the 
 elaters, and by this discovery was in a position to give the 
 most satisfactory representations of the course of these 
 thickenings of the walls of the elater-cells and of the cells 
 of the capsule-wall. t 
 
 We are indebted to the same author for an explanation 
 of the development of the perianth of the Jungermanniae . He 
 showed I that the perianth in the Jungermannige is formed 
 in the same way as in Marchantia jpolymorpha, where it had 
 been observed by Hedwig § and Mirbel, [] and where it 
 takes place at a late period, after the commencement of the 
 formation of the fruit ; he described the development of the 
 perianth of the principal types, and showed that the involucre 
 of Trichocolea is nothing more than the very fully developed 
 calyptra, similar to that of Aneura. 
 
 Schmidel's discovery of the self-motile bodies in the 
 antheridia of a cryptogamic plant was made in a Junger- 
 mannia, in Fossombronia pusilla.% The attachment of the 
 antheridium to a stalk is first well figured by Hedwig in 
 the same plant.** The first figure of the spermatozoa of 
 a Jungermannia — Aneura jjinffuis — was given by Meyen.ft 
 The existence and natm^e of these bodies had in the mean 
 time been discovered in Sphagnum by Unger, and the 
 cilia by Thuret in Chara. Gottsche afterwards figured 
 those of Haplomitrium HooJceri, Alicularia scalaris, and 
 Fosso7nbronia pusilla ;X\ lately Thuret has given those of 
 Fellia ejpiphylla and Fossombronia pusilla.^ ^ 
 
 * 'Nova Acta,' A. C. L., xx, pars i, 360. 
 
 f I. c, t. xvii, f. a — d. 
 
 X I. c, p. 544. 
 
 § ' Theoria generatiouis,' p. 177, t. xxvi, f. 6, 7. 
 
 II 'Mem. Acad, des Sc. lust, de France,' xiii (1835), 3S0. 
 
 ^ 'Icon, plant.,' p. 85. 
 ** 'Theoria generatiouis,' t. xx, {. a, a, 
 
 W ' Neues system der Pflanzenphysiologie,' Bd. iii (1839), t. xii, f. 39, 40. 
 XX ' Nova Acta,' A. C. L., xx, pars i, t. xvi. 
 §§ ' Ann. d. Sc.,' iii s6*., t. xvi, 10, 11. 
 
88 HOFMEISTER, ON THE HIGHER CRYPTOGAMIA. 
 
 Gottsche is of opinion that the antheridia of the liver- 
 worts in general have a wall consisting of a double layer of 
 cells — an inner layer, the cells of which become detached 
 when ripe and contain colouring matter, and an outer layer 
 of hyaline, tubular cells, of small height, with transparent 
 fluid contents. Gottscheds opinion is founded mainly upon 
 investigations of Haplomitrium Hookeri. He attributes a 
 similar structure to the antheridia of Fossombronia.* He 
 is decidedly in error in both cases ; the covering layer 
 is certainly a single layer of cells, which, when the 
 organ is fully ripe, give way at the apex, and separate 
 from one another. This cannot be a matter of doubt 
 to any one who witnesses the spontaneous opening of 
 an antheridium under the microscope. But the structure 
 of the covering layers, even in antheridia, which are still 
 closed, can be fully made out with a good microscope. 
 Gottsche's view may have originated in the circumstance 
 that in Fossombronia, as well as in Anthoceros, the coloured 
 bodies often lie close to the inner side of the wall of the 
 cells of the covering layer, so that the somewhat swollen 
 protuberance of the free outer wall appears to be filled 
 merely with a clear, watery fluid. 
 
 With regard to the outer of the two cellular layers of the 
 covering of the antheridia of Haplomitrium, a preparation 
 of which has been figured by Gottsche (1. c, t. xvi, f. 8), 
 I find that the antheridia of this plant are similar to 
 those of Sphaginum ; that a thin glassy cuticle encloses 
 the simple covering layer of the antheridia. In Haplo- 
 mitrium the boundaries of the cells appear upon this 
 cuticle in the form of prominent ridges, but this is not 
 the case in Sphofjnum {cymhifoliwni). The cells of this 
 covering layer isolate themselves at the time of the ripen- 
 ing of the antheridia of Sphagnum, precisely after the 
 manner of the cells of Haplomitrium ; a median lamella of 
 the wall of the ecus swells up into a gelatinous substance. 
 By this means the vermifonn cells become detached from 
 one another, and separated from the cuticle. 
 
 * /. c, vol. XX, p. 291. 
 
CHAPTER IV. 
 
 RICCIA AND RIELLA. 
 
 The germ-plant of Biccia glauca is a simple, short, 
 ribbon-shaped, or three- sided shoot, consisting of homo- 
 geneous cellular tissue (PL XIII, fig. 1).* The arrange- 
 ment of the cells of the germ-plant in the direction of the 
 surface corresponds exactly with that in Pellia ejnpli^Ua. 
 Individual cells of the side edges are transformed into 
 elongated papillae which are bent forwards ; a few cells 
 of the mider surface grow out into long, radicular hairs. 
 At an early period there is formed in the middle of the 
 fore edge a deep, narrow indentation, produced by the fact 
 that the growth of the lateral portions of the fore edge ex- 
 ceeds that of the middle (PI. XIII, fig. 1). In this inden- 
 tation a new shoot originates. It grows rapidly in length, 
 its fore edge becoming continually wider (PL XIII, fig. 2) ; 
 the wing-shaped lateral portions of the fore edge of the germ- 
 plant are thereby stretched far apart from one another. At 
 the same time the lateral margins of the under part of the 
 new formation amalgamate with that portion of the two 
 wings of the fore edge which is directed inwards. Shortly 
 afterwards new shoots are formed in the angles of both, 
 at the spot where ,the amalgamation ceases. An almost 
 hemispherical mass of cellular tissue originates at the 
 bottom of the narrow cleft. The arrangement of its few 
 cells repeats in miniature that of the germ-plant (PL XIII, 
 fig. 4). On its right and left new shoots are soon produced, 
 clearly originating from the nuiltiplication of a single 
 cell. They amalgamate with the median shoot as soon 
 as their increase in breadth causes their lateral margins to 
 
 * I liave not, beeu able to procure, under cultivation, the first stashes of 
 development of the spores of Riccia or of Antheceros; in both genera I have 
 been limited to germ-plants which I have found in their native habitats. It is 
 strange that two of the most widely spread and comniou plants should germi- 
 nate with so much difficulty. 
 
90 HOFMEISTER, ON 
 
 touch it. The longitudinal growth of the lateral shoots 
 soon surpasses that of the middle shoot, and shortly after- 
 ^Yards the growth of the former in breadth and thickness 
 also exceeds that of the latter. The result is that the 
 median shoot, closely surrounded above and below by the 
 more rapidly growing lateral ones, is pushed to the bottom 
 of one of the narrow crevices formed by the lateral shoots, 
 which shoots are more vigorous in their longitudinal growth. 
 By the multiplication of its cells in the longitudinal 
 direction the median shoot is blended Avith the two lateral 
 ones, which surround it almost entirely, and far exceed it 
 in size. The shoot formed by the junction of three masses 
 of cells in a state of active longitudinal growth amal- 
 gamates at its sides with the advanced portions of the fore 
 edge of the germ-plant by which it is enclosed. On the 
 one side it amalgamates with one of the wing-shaped 
 lateral portions, on the other with the one half of the 
 median shoot, which in the mean time expanding more and 
 more in breadth, has assumed an entirely emarginate 
 shape. By further longitudinal growth the shoots of the 
 second order make their appearance out of the two narrow 
 crevices which the fore edge of the germ-plant exhibits, and 
 which answer to the limits of the median lobe of the fore 
 edge and its lateral portions. The apex of the young Riccia is 
 furcate. The apical point of the bifurcation is the middle 
 of the fore edge of the median shoot. Each point of the 
 fork exhibits in the middle of its fore edge a deep, narrow 
 incision, formed by the two lateral component parts of the 
 shoot of the second order, which almost touch one another. 
 At the base of this incision is the median shoot, of which 
 the apex alone is free, and not united in growth with the 
 lateral ones, and at the sides of which ncAV shoots, being 
 the median ones of the third order, are in process of 
 formation. An active multiplication and expansion of the 
 cells of the median portion of the shoots of the second 
 order now commences ; this median portion, by its longi- 
 tudinal groAvth and the continually increasing width of its 
 fore edge, ])ushes asunder the lateral portions of the same 
 shoot which have hitherto confined it in a narrow crevice. 
 New shoots originate in like manner out of its angles. 
 The subsequent ramification of Riccia follows the same 
 
THE HIGHER CRYPTOGAMIA. 91 
 
 rules ; eacli shoot originates from the blending together of 
 three sub-shoots, and has only a hraited growth. New 
 shoots are only formed in the two incisions which the fore 
 edge of each fully developed wedge-shaped shoot exhibits. 
 All shoots, with the exception of the first, which proceeds 
 directly from the spore, undergo complete distortion, caused 
 by the peculiar growth of their median portion and by the 
 expansion of the next younger shoots of a new order, 
 which originate in the incisions of the fore edge of each, 
 and which amalgamate with the median portion ; their 
 form passes from a pointed semi-oval, through that of a 
 wedge, to a furcate shape. The repeated furcate ramifi- 
 cation of young plants soon renders their entire outline 
 circidar. 
 
 The multiplication in a longitudinal direction of the 
 cells of each of the three parts of which a shoot is com- 
 posed takes place through the division of the cells of the 
 fore edge by means of transverse septa inclined to the 
 horizon (PI. XIII, figs. 7*, 14). The multiplication is much 
 more active in the median line of the young shoot than at 
 its sides. The cells of the second degree divide by septa 
 almost parallel to the upper and under surface of the shoot, 
 and this division is repeated in the outer of the newly 
 formed cells, by which means the shoot increases in thick- 
 ness. Immediately after the appearance of the first of the 
 above septa each of the two cells which have originated 
 from the division of each upper cell of the second degree 
 is usually divided into two by the formation of a transverse 
 septum, perpendicidar to the outer surface, and cutting the 
 longitudinal axis of the shoot at an angle of 90° (PI. XIII, 
 fig. 7^). The cells of the upper half of the flat stem are 
 consequently, even in their earliest stage, usually one half 
 shorter than those of the under half. It is only in those 
 shoots in which the longitudinal growth is especially active 
 that the transverse division of the cells of the under half of 
 the stem lags behind that of those cells of the upper 
 surface which are situated further back from the fore edge 
 (PI. XIII, figs. 11, 14). Such shoots arc usually those 
 which bear the archegonia. The growth in thickness, the 
 division by septa parallel to the surfaces of the shoot, is far 
 more active in those cells which are })roduced by the 
 
93 HOFMEISTER, ON 
 
 niiiltiplication of the cells of the second degree belong- 
 ing to the upper surface, than in those which are pro- 
 duced by the multiplication of the like cells of the under 
 surface. The increase in the number of cells, in the direc- 
 tion of the thickness, from the apex of the young shoot 
 backwards, is not unfrequently so rapid that the profile of 
 the shoot appears like a very slightly pointed triangle 
 (PL XIII, fig. 11). The continual increase of the breadth 
 of the young shoot dimng its longitudinal growth takes 
 place by the division of the lateral cells of the fore edge by 
 means of longitudinal septa parallel to the longitudinal 
 axis of the shoot (PI. XIII, fig. 4). In a more advanced 
 stage of growth, the cells lying nearer the middle of the 
 fore edge also divide by longitudinal septa, slightly diverg- 
 ing from the direction of the median line. The shoot 
 then exhibits a middle row of cells, from which the other 
 cells diverge right and left at different altitudes, like the 
 rays of a fan. The earliest rudiment of each shoot is 
 a simple cell, having a trapezoidal basal outline, situated 
 in the axil of two older shoots (PL XIII, fig. 4, a) ; at 
 a little later period many such cells lying near one another 
 are found, in consequence of the commencement of the 
 longitudinal growth, to be already several times transversely 
 divided by inclined septa (PL XIII, fig. 4, ö). The 
 shoot, as it becomes developed, springs forth in the form 
 of a short projection, having its cells arranged in the order 
 already described, from the axil formed by the two older 
 adjoining shoots. 
 
 The under side of each joint of the stem of Miccia glauca 
 exhibits on each side of the median line small, distichous, 
 obliquely attached leaves, formed of a simple layer of deli- 
 cate, transparent, cellular tissue (PL XIII, fig. 3). They 
 resemble in all their parts those of the Marchantia?, and, 
 like the latter, are for the most part rapidly destroyed by the 
 bursting forth of hair-like roots. The hollows of the old 
 roots of Riccia, like those of the Älarchantiae, are furnished 
 upon the inner side with very numerous little points pro- 
 jecting inwards (PL XIII, fig 4*). 
 
 On stem-joints which have a tendency to form fruit, in- 
 dividual cells of the upper surface, situated in the angles 
 of the lateral and of the median shoots, protrude out- 
 
THE HIGHER CUYPTO(JAMIA. 93 
 
 wards, and this takes place even during the process of tlie 
 amalgamation of three shoots into one new shoot (PI. XllI, 
 fig. 7 *). From these cells are developed the organs of 
 fructification, the antheridia or archegonia. The arrange- 
 ment of these corresponds to the commissures of the three 
 shoots which are uniting to form a single shoot, thus 
 forming two nearly parallel longitudinal rows right and 
 left of the median line. The hemispherical vesicular pro- 
 tuberance which projects above the surface of the young 
 stem-joint divides by a septum inclined to the horizon. 
 In the upper one of the new cells thus formed division 
 immediately takes place by a membrane inclined in the 
 opposite direction (PL XIII, figs. 5, 7 *). In these phe- 
 nomena of development the archegonia and antheridia, 
 which originate without any regularity, exactly resemble 
 each other ; in their earliest condition they cannot be dis- 
 tinguished from one another. 
 
 The cells of the upper side of the young stem which 
 surround the base of the rudiment of an antheridium ex- 
 tend themselves upwards, and thus form a membranous 
 ring which encircles the lower part of the antheridium. 
 This ring usually consists of six cells (PL XIII, fig. 10); 
 it is seldom wider. It grows longitudinally by repeated 
 transverse division of the cells of its free upper edge. The 
 sheath thus formed soon overtops the apex of the young, 
 small antheridium (PL XIII, figs. 6, 7 *) ; above the anthe- 
 ridium it becomes considerably narrower (PL XIII, fig. 9). 
 The upper part of its inner cavity contains a watery fiuid ; 
 in the lower part, close under the antheridium, air is secreted 
 at an early period, which by careful pressure may be 
 driven out at the narrow mouth of the covering of the 
 antheridium. 
 
 The first appearance of the organs of fructification takes 
 place, as is mentioned above^ long before the termination 
 of the growth of the stem-joint. The increase in thickness 
 of the surrounding tissue of the surface of the stem nearly 
 keeps pace with the longitudinal growth of the archegonia 
 and of the sharply conical covering of the antheridium, so 
 that the organs of fructification, during their longitudinal 
 development, are continually enclosed in the tissue of the 
 
94 HOFMEISTEU, ON 
 
 stem as the latter increases upwards in thickness. In this 
 way the outer side of the covering of the anthericUum 
 amalgamates with tlie adjoining cells of the stem. The con- 
 tents of these united cells of the antheridum-sheaths become 
 exactly similar to that of the cells of the upper half of the 
 flat stem ; numerous chlorophyll-granules are formed in 
 them, and air makes its appearance in the adjoining inter- 
 cellular spaces. The rudiment of the antheridium, which 
 as yet consists of few cells, has in the mean time considerably 
 increased in size, and become transformed into an oval, 
 cellular body by means of repeated longitudinal and trans- 
 verse divisions ; this oval body consists of a central group 
 of cells, with tm'bid, mucilaginous contents, surrounded by 
 a layer of tabular cells with watery contents (PL XII 1, 
 fig. 8). The repeated bisection of the former cells in all 
 three directions leads ultimately to the formation of a 
 spherical mass of numerous, very small, tessellated cells, 
 during the production of which the peripheral layer of 
 tabular cells is gradually entirely displaced (PI. XIII, 
 fig. 9). The skin -like membrane of the ripening anthe- 
 ridium becomes closely applied to the inner side of the 
 covering of the antheridium, but without growing to it. 
 Each of the small cells produce, during the progress of 
 growth of the antheridium, a small, lenticular vesicle. When 
 the antheridium is ripe the walls of those small cells swell 
 up into a tough jelly, and the outer membrane of the anthe- 
 ridium assumes a delicate, gelatinous consistence. 
 
 The amalgamation of the cells of the tissue of the stem 
 Avith the outer side of the antheridium-sheath docs not extend 
 to the young, blunt apex of the latter. Owing to the fact 
 that the longitudinal expansion of its cells first takes place 
 after the complete formation of the stem-joints, this free 
 upper end remains for some time in the form of a rounded, 
 little cone, concealed between the epidermal cells (PI. XIII, 
 fig. 9). Suddenly the apex elongates itself considerably ; 
 by expansion of its cells it often protrudes more than a line 
 above the surface of the stem. The universal expansion 
 of its cells causes a widening of the mouth of the canal 
 which traverses the axis of the sheath, and which leads to 
 the antheridium (PI. XIII, fig. 10). Through this canal 
 
TIIK HIGHER CRYPTOGAMIA. 95 
 
 (according to BiscliofF) the contents of tlie antlieridium 
 escape in the form of mucilaginous drops. 
 
 In the apical cell of the rudiment of an archegonium 
 division takes place in often-repeated succession by alter- 
 nately inclined septa. Here, also, the cells of the second 
 degree divide immediately after their formation by radial 
 septa. Immediately after the formation of the radial 
 septum which divides the cell of the second degree, septa 
 parallel to the axis '^appear in one of the fom' longitudinal 
 rows of cells of the third degree ; these latter septa divide 
 the mother-cells into inner three-sided and outer four- 
 sided cells, so that the organ now consists of a central 
 string of cells, which is surrounded by a single layer of 
 cells arranged in sets of four cells of equal height (PL 
 XIII, figs. 12, 13). The apex of the young archegonium 
 swells to a clavate shape ; contemporaneously, the basal 
 cell of the central row of cells begins to enlarge its circum- 
 ference, whereby the base of the archegonium becomes 
 distended (PL XIII, fig. 13). The cellular tissue sur- 
 rounding the archegonia, so far from amalgamating with 
 their outer cellular layer, is often, on the contrary, ex- 
 panded into a wide cavity surrounding the base of the 
 archegonium (PL XIII, fig. 15). The cells of the stem, 
 on the other hand, usually become very closely approximated 
 to the neck of the archegonium, without, however, be- 
 coming actually united to it. In comparison with other 
 mosses, the basal cell of the central string of cells becomes 
 considerably enlarged; this takes place, however, at a 
 somewhat later period, shortly before the rupture of the 
 apex of the archegonium. Within the fluid contents of 
 this basal cell there is produced a free spherical cell 
 (PL XIII, figs. 14, 15). This grows by degrees, until it 
 fills the mother-cell. There are but few of the Museales 
 in which this cell is so clearly distinguishable as in Riccia. 
 The remaining cells of the central string are dissolved, 
 and the apex of the archegonium opens. The archegonia, 
 thereupon, either wither, which is a rare occurrence, or a 
 fruit is formed in their ventral portion. The first indica- 
 tion of fruit-formation is the division, by means of an in- 
 clined septum, of the free cell which has originated in the 
 
96 HOFMEISTER, ON 
 
 large basal cell of the central string. The upper of the 
 two newly formed cells is then divided by a septum in- 
 clined in the opposite direction (PI. XIII, fig. 10*). In 
 the apical cell of the now 3-cellular young fruit the 
 division is rcp\ated several times by alternately inclined 
 septa. The cells of the second degree divide by radial 
 longitudinal septa, and the cells thus produced divide into 
 three-sided inner and four-sided outer cells, after the manner 
 of the one row of cells of the third degree belonging to 
 the archegonium. In the four- sided cells, the division is 
 repeated by radial septn, and then by longitudinal septa 
 parallel to the axis of the fruit (PI. XIII, figs. 17, IS). 
 When the young fruit, which from first to last is almost 
 globular, has attained its full size, the somewhat tabular 
 cells of its upper surface divide by a longitudinal and 
 transverse septum perpendicular to the outer surface, so that 
 the outermost cellular layer of the fruit consists of cells of 
 which the basal outline is four times smaller than that of 
 the inner cells (PI. XIII, fig. 19). 
 
 In each of the latter there ensues a well-defined, gelati- 
 nous thickening of the cell-wall (PI. XIII, fig. 19). Soon 
 afterwards the cells become disconnected by the dissolution 
 of the oldest outermost portion of the cell-wall. The 
 spherical cells thus set free are the mother-cells of the 
 spores. In each of them four special-mother-cells origi- 
 nate, each of which produces a spore. After the indivi- 
 dualization of the spores the wall of the half-ripe capsule 
 is absorbed, so that the ripe spores lie free in the cavity of 
 the globular calyptra. This latter is formed by the re- 
 peated division into two parts of the cells of the ventral 
 portion of the archegonium, by means of septa perpendi- 
 cular to the outer surface, such division alternating once 
 with a division by septa parallel to the outer surface. 
 The calyptra of the half-ripe fruit consists of two layers of 
 cells (PI. XIII, figs. 17, 19) ; towards the period of maturity 
 the inner one of these disappears. The neck of the arche- 
 gonium lasts till the fruit is ripe. The cells often assume 
 a beautiful wine-red colour. In rare instances those cells 
 of the impregnated archegonium which lie beneath the 
 central cell of the ventral portion multiply, so that the 
 
THE HIGHER CRYPTOGAMIA. 97 
 
 form of the organ becomes similar to that of the arche- 
 gonimii of a moss. 
 
 Riccia glaiica not nnfreqnently produces gemmae in the 
 middle of the tissue of the older shoots — small, fleshy masses 
 of cellular tissue, filled with granular mucilage. Their out- 
 line resembles that of germ-plants ; there is, however, the 
 material distinction that the two lateral portions of the fore 
 edge are not formed at an earlier period than the middle 
 one, or, to speak more accurately, the middle shoot 
 does not, during the formation of the lateral ones, continue 
 in its lowest stage of development, but it forms a prominent, 
 flattened, conical point at the time when the lateral por- 
 tions begin to protrude themselves. The arrangement 
 of the cells agrees with that of the shoots of perfect 
 plants. Gemmae which remain long smTounded by the 
 tissue of the stem exhibit the internal disintegration of 
 the tissue which I have figured in Anthoceros and 
 Blasia. The commonest of all liverworts is, strange to 
 say, one of the least known. The numerous investigations 
 and figures of Riccia relate almost exclusively to the organs 
 of fructification (Schmidel, in ' Icones,' t. xhv, xlv ; Hed- 
 wig, ' Theoria generationis,' ed. ii, 7, 31 ; Bischofi', ' N. 
 A. A. C. L.,' t. xvii, p. ii, fig. 911//; Lindenberg's large 
 monograph in vol. xviii of the last-mentioned Proceedings ; 
 and lastly, linger, ' Linnsea,' 1839). The erroneous notion, 
 that a very low state of development of the fruit must be 
 accompanied by an equally low state of development of the 
 vegetative organs, seems to have prevented the accurate 
 investigation of the phenomena of growth in Riccia, which, 
 in comparison with Anthoceros and Pellia, are very com- 
 plicated. Lindenberg expressly and repeatedly denies to 
 the genus that higher organization, and even the leaves, 
 which he figures most distinctly in very many species. The 
 widely spread notion that the growth of Riccia is radiate, 
 proceeding in all directions from a common median point, 
 may be disproved by the examination of any clod of earth 
 taken from any stubble field in autumn where Riccia 
 glauca has begun to germinate. 
 
 Riella Beuferi, jNIont. — Amongst the various forms of 
 liverworts, Montague's genus Riella (' Ann. Sc. Nat.,' 3rd 
 
 7 
 
98 HOFMEISTER, ON 
 
 ser., t. xviii, p. 111 ; Duriena, 1. c, t. i^ p. 228 ; t. ii, p. 50) 
 is the most remarkable, on account of its very peculiar 
 habit. The Algerian Riella {Buriend) li('Ucoj)hylla'ys> the 
 most striking of all ; its upright leaf, which is three inches 
 high, and shaped like a Avinding staircase, being one of 
 the most wonderful of vegetable forms. My investiga- 
 tions of this remarkable genus were made on a species 
 found by Reuter at Geneva, which represents in miniature 
 the vegetative phenomena of the North African species. I 
 am indebted for the materials for my work to the kindness 
 of the discoverer, who sent me numerous living specimens. 
 
 Young individuals, whether produced from spores or 
 adventitious shoots (PI. XIV, figs. 1 — 4), are formed of 
 short rows of cells, which pass at the fore end into a small, 
 cellular surface. The arrangement of the cells is that 
 which is common to the Riccieae and the Marchantieae, 
 viz., in pairs and flabelliform, originating from two cells of 
 the first degree, which are divided alternately by transverse 
 and longitudinal septa. In the young state of the plant 
 there is an excess of formation of transverse septa, nearly 
 at right angles to its median line, and consequently of 
 longitudinal growth. At an early period the njultiplica- 
 tion and expansion of the cells of one side of the fore edge 
 considerably exceed that of the other side, so that the 
 punctum vegetationis of the young Riella is turned on one 
 side (PI. XIV, fig. 2). 
 
 Contemporaneously wdth the api)earance of the first 
 leaves, the plant develops a mid-rib, by the production in 
 certain cells of septa parallel to its surfaces ; this mid-rib 
 is a strip of massive cellnlar tissue, consisting sometimes 
 of as many as six layers of cells, which rnns along the less 
 highly developed side of the shoot. The rib forms one 
 margin of the flat stem, which may be compared to a stem- 
 joint of Marchantia, of which the membranous left-hand 
 wing has been removed. The helicoid winding of the 
 stem is produced by the lateral twist which takes place in 
 the axis as it grows obliquely upwards, and which is caused 
 by the more rapid development of the left-hand side wing. 
 The twist is always to the right. 
 
 Leaves are formed only on the mid-rib. The fraction 2^ 
 
THE HIGHER CRTPTOGAMIA. 99 
 
 represents their arrangement. Each of the surfaces of the 
 plant has two longitudinal rows. The leaf originates from 
 the multiplication of a single cell protruding above the 
 surface of the terminal bud (PI. XIV, fig. 9). In its early 
 stages, and in those leaves which are nearest to the fore 
 edge of the rib, the successive cell-formation corresponds 
 exactly with that of the scales of ferns. The leaves which 
 lie nearer to the membranous wing are considerably and 
 unsymmetrically developed in breadth in their middle 
 region (PI. XIV, fig. 8). 
 
 The succession of the shoots in Riella, as in the other 
 Riccieae and Marchantiese, is pseudo-dichotomous. The 
 first visible ramification takes place usually in the early 
 youth of new individuals, before the appearance of the 
 first leaves. The relation of the two side shoots to the 
 middle principal shoot, of which the development is ar- 
 rested, and the amalgamation of the latter with the former, 
 may be very easily observed in the simple cellular surface 
 (PI. XIV, figs. 4, 7*). 
 
 The growth of the antheridia commences by the swelling 
 of a marginal cell of the membranous wing close to the 
 punctum vegetationis, and by the separation of the vesicular 
 protrusion from the original cell-cavity by means of a 
 transverse septum. By the exuberant growth of the cells 
 adjoining its base the rudiment of the antheridium is at 
 once surrounded by a closely-fitting sheath (PI. XIV, figs. 
 10, 11). After one or several divisions have taken place 
 in the cell of the first degree by means of transverse septa, 
 and the consequent formation of a short stalk, there occurs 
 in the hemispherical cell a series of divisions coinciding 
 with the like process in Riccia, by which there is produced 
 an oval body consisting of cubical cells, the mother-cells of 
 the spermatozoa, surrounded by a layer of large, flat cells 
 (PI. XIV, fig. 12). The growing antheridia now appear 
 deeply imbedded in the folds of the membranous wing 
 (PI. XIV, fig. 13). Antheridia and archegonia are always 
 situated on different shoots. New individuals first produce 
 antheridia. Archegonia usually appear on their shoots of 
 the third, fourth, or fifth degree. The archegonia are 
 situated in the axils of leaves, and are distinguished by a 
 
100 HOFMEISTER, ON 
 
 large, central cell, with comparatively small germinal vesicles 
 (PL XIV, figs. W- *). 
 
 The base of the young archegonium is surrounded by 
 a small, annular sheath, which, before impregnation, is 
 only from one to four cells in height (PL XIV, fig. 14«^). 
 After the commencement of the formation of the fruit 
 this sheath grows rapidly into a narrow-mouthed, pitcher- 
 shaped covering, consisting of a single layer of cells 
 (PL XIV, figs. 12, 13, 18). 
 
 The impregnated germinal vesicle swells at once to the 
 size of the pear-shaped ventral cavity of the archegoniinn 
 (PL XIV, fig. 13), and follows the enlargement of that 
 cavity, which enlargement is caused by the active multi- 
 plication of the cells enclosing it. The first division of 
 the primary cell of the fruit takes place by a horizontal 
 septum, which divides the cell into a semi-oval superior, 
 and a filiform inferior, moiety (PL XIV, fig. 15). By 
 repeated transverse division the latter becomes the fruit- 
 stalk, consisting of a single row of cells, the lower end 
 of which, at a later period, and by means of divisions 
 caused by septa parallel to the axis, becomes transformed 
 into a clavate, cellular body (PL XIV, fig. IS). The 
 upper half becomes the capsule of the fruit ; according to 
 the general rule in the R,iccica3 and Marchantiese, it mul- 
 tiplies by repeated divisions of the cells of the first de- 
 gree by means of septa inclined alternately to the right 
 and to the left (PL XIV, fig. 15). After about eight 
 such divisions the capsule becomes globular; its outer 
 layer, the cells of which become tabular, forms the w\ill. 
 The cells of the interior, becoming loosened and spheri- 
 cal in shape, perfect themselves in different ways. The 
 contents of half of them become turbid from numerous 
 fine granules, and their w^alls increase in thickness. 
 These are mother-cells, containing in their interior four 
 special-mother-cells, usually arranged in a tetrahedron, 
 from which the spores, which are clothed with a strong, 
 delicately marked episporium, are developed (PL XIV, 
 fig. 19). The formation of only two spores in a mother- 
 cell is an irregularity of frequent occurrence. The other 
 cells of the contents of the capsule remain thin-walled, 
 
THE HIGHER CRYPTOGAMIA. 101 
 
 and starch-granules appear in their interior (PI. XIV, 
 fig. 19 ^). They change no further until maturity. This 
 double nature of the cells of the interior of the capsule 
 brings to mind the development of the elaters of the 
 Targionieae and Marchantieae. The young conditions of 
 the elaters of the latter answer exactly to the permanent 
 state of those cells of Riella which are intermixed with 
 the spores and contain starch-granules. Kiella thus, in 
 more than one point, forms an intermediate link between 
 the Ricciese on the one hand, and the Targionieae and 
 Marchantieae on the other. 
 
 GLASGOW 
 PUBLIC LIBRAR1£; 
 
CHAPTER V. 
 
 MARCHANTIE.E AND TARGIONIEiE. 
 
 Marchajitia polymorpha, Fegcdella coiiica, JRehoviUia hemi- 
 spherica, Lunularia vulgaris. Targlonia ht/popJtylla. 
 
 The growth of the Marchantieae and Targioniese resem- 
 bles in its principal phenomena that of Pellia, Riccia, 
 and Anthoceros. The essential circumstance, viz., the 
 origin of each new shoot by the amalgamation of three 
 shoots, which are developed in one of the two in- 
 dentations of the fore edge of an older shoot, is in these 
 plants, especially in the genera Lunularia and Fegatella, 
 more clearly marked than in any others.* 
 
 The vegetative organs oi Marchaiitia poIi/morpJia, Fega- 
 tella conica, Hehouillia hemispJierica, Lunularia vulgaris, and 
 Targionia liypophylla exhibit great similarity in development 
 
 * The rudiments of those shoots of Tegatalla conica which are to be deve- 
 loped in the early spring originate in the preceding October ; on the right and 
 left of a nearly hemispherical mass of cellular tissue, situated at the bottom 
 of one of the two indentations of the fore edge of the fully developed shoot of 
 the next higher order, there are formed two smaller, almost conical shoots, 
 which, by amalgamating with the one between tliem, form the bud of the new 
 shoot. The shoot grows slowly in a longitudinal direction until the commence- 
 ment of winter; the fore edge of the median shoot becomes, at the same time, 
 continually wider (PI. XVI, fig. 1, middle of November). After the coldest 
 months are over there is formed on either side of the median lobe the rudi- 
 ment of a new shoot, which lias already attained a tolerably perfect condition 
 at the time when the longitudinal expansion of the oldest liinder cells of the 
 shoot formed at the commencement of winter begins to cause the latter to 
 protrude out of the indentation of the edge of the stem-joint of the previous 
 year. The shoot whose longitudinal expansion commences, appears at lliis 
 time as if bent upwards ; a thick-fleshed, small mass of cellular tissue, ah-eady 
 slightly furcate at the fore edge by the commencement of the longitudinal 
 development of the shoots of a new order. The lateral margins of the shoot 
 are bent strongly inwards, and it is closely folded together in its median Hue. 
 
HOFMEISTER, ON THE HIGHER CRYPTOGAMIA. 103 
 
 and structure. The longitudinal growth of each shoot 
 is caused by repeated division in its apical cells, by means 
 of alternately inclined septa (Lunularia, PL XV, fig, 19 ; 
 Fegatella, PL XVI, tig. 3). Soon after the first division of 
 this kind has taken place in the mother-cell of a new 
 shoot (which mother- cell lies at the bottom of the axil 
 of two older shoots), the number of the apical cells is 
 doubled by the appearance of a longitudinal septum 
 (PL XVI, fig. 2). The fore edge of the shoot widens 
 continually during and until the cessation of its longitu- 
 dinal development, by means of repeated division of the 
 apical cells by longitndinal septa ; this increase in breadth 
 is more or less rapid, according to the circumstances under 
 which the plant is growing, and according to the species 
 of plant. The differences in habit in different species, as 
 well as in individuals of the same species growing under 
 different circumstances, depend, in the first place, upon 
 wdiether the lateral margins of the new shoots amalgamate 
 with the adjoining lobes of the fore edge for a considerable 
 length, or not. Those shoots of Fegatella and of 
 Rebouillia wdiich are formed late in autumn, which remain 
 quiescent during the coldest part of the year, and develope 
 themselves in early spring, remain completely separated 
 from the projecting portions of the shoots of the previous 
 year; this is the cause of the jointed appearance of the 
 leaf-like stem of these species. In Marchantia, in Targionia 
 under all circumstances, and in the summer shoots of 
 Fegatella and Rebouillia, the amalgamation is, on the other 
 hand, very complete. In the next place, differences of 
 habit depend also upon the length of the lines of amalga- 
 mation of the three shoots which combine to form one 
 shoot. In Fegatella, and in specimens of Marchantia poli/- 
 morplia and Lunularia vidgaris, which grow in very moist 
 places, the amalgamation is far more considerable than in 
 specimens of the same species from dry habitats,* or than 
 
 * The length of tlie amalgamation is manifestly to be measured by tlie 
 number of cells, and not by lines and inches. The expansion of individual 
 cells lias the greatest influence upon the absolute length of tlie shoots. The 
 hitter becomes quite enormous when new shoots of Marchantia polymorpha, 
 covered by older portions of the mother-plants, are making their way to the 
 light. 
 
104 HOFMEISTER, ON 
 
 is the case in Heboiiillia and Targionia. Differences of 
 habit depend also upon the greater or less rapidity of the 
 expansion of the fore edge of the shoots during their 
 longitudinal growth, and, lastly, upon the fact whether the 
 older shoots die and moulder away with greater or less 
 rapidity. In Rebouillia hemispherica and FegateUa cornea 
 they last for several years ; in Targionia and ]\Iarchantia 
 the decay of the older generation of shoots begins very 
 shortly after the complete formation of the next youngest 
 shoots. It often happens that almost every trace of the 
 (pseudo) furcate ramitication of the plant is obliterated by 
 the fact of a new shoot being developed in one only of the 
 indentations of the fore edge of an older shoot, the other 
 new shoot, situated in the other indentation, becoming 
 abortive. This is often the case in Rebouillia and Tar- 
 gionia. The buds (bulbils according to IMirbel) of Lunu- 
 laria and Marchantia, which are formed in special 
 receptacles on the median line of the shoots, afford a 
 particularly striking example of the above species of rami- 
 fication. These receptacles are formed in the following 
 manner: — in the earliest stageof the shoot, cell- multiplication 
 commences, either all round the spot where the buds are 
 destined to be formed, or in a semicircular chain of cells 
 (the semicircle lying open to the front) of the upper side of 
 the shoot. This cell-multiplication gives rise in Mar- 
 chantia to an annular, in Lunularia to a horse-shoe shaped 
 cushion. The division by septa parallel to the surface, of 
 those cells of the upper side of the shoot which are enclosed 
 by the cushion, soon ceases, whilst it continues for some 
 time in the cells lying outside. Thus the space of the 
 upper sm'face which is enclosed by the celliüar rampart, 
 and is destined to form gemmse, becomes a depression. 
 The margin of the wall grows in Lunularia into a delicate 
 membrane (PI. XV, fig. 19), consisting of a single layer of 
 cells. In Marchantia from sixteen to twenty teeth sprout 
 from it (PL XV, figs. 1, 1*), which incline towards one 
 another when young, and thus cover the gemmae ; after- 
 wards they become upright. The history of the develop- 
 ment of these teeth is as follows : — every other cell of the 
 edge of the annular wall expands considerably outwards. 
 
THE HIGHER CRYPTOGAMIA. 105 
 
 The protruding portion is separated by a transverse septiiin 
 from the rest of the cavity of the cell, which is then divided 
 by a longitudinal septum. The cells which are elevated 
 above the margin of the wall are transformed into flat 
 teeth, consisting of a single row of cells, resulting from a 
 division by transverse septa, which is continually repeated 
 in each apical cell (PI. XV, fig. 1*). Repeated division 
 takes place in the interstitial cells by means of longitudinal 
 septa perpendicular to the broader surface ; and by this 
 division, which begins at the base and progresses to the 
 apex with increasing intensity, the teeth, at a later period, 
 increase in breadth. At the same time the circumference 
 of the annular wall of the bud-receptacle increases, through 
 the division of its cells by means of longitudinal septa. 
 At the points of origin of the teeth this latter increase cor- 
 responds with the expansion of the teeth ; underneath it is 
 much less. By this means the form of the edge of the 
 bud-receptacle becomes that of a cup. 
 
 Some time before the appearance of the marginal teeth 
 the formation of the first gemmae commences. Individual 
 cells of the base of the receptacle produce a papilla upon 
 the middle point of their free upper wall (PI, XV, fig. 1*). 
 This papilla is soon separated by a transverse septum 
 from the rest of the cell-cavity. The new semi-oval cell, 
 after previous longitudinal expansion, is divided by a 
 transverse septum (PI. XV, fig. 1*). The lower one of 
 the cells thus produced is the stalk, the other the mother- 
 cell of the gemma. The latter increases considerably in 
 breadth, and by means of transverse division, which is always 
 repeated twice in the terminal cell, it becomes transformed 
 into a row of four short, wide, and low cells. Each of them 
 divides by a longitudinal septum (PI. XV, fig. 2). The 
 three lower pairs of cells thus formed are divided by septa 
 parallel to the last-mentioned septum ; the lower pair once, 
 the two higher pairs twice. The repetitions of the division 
 occur, as is usual in similar cases, always in the outer cells. 
 Each of the two apical cells of the bud, on the other hand, 
 divide by septa having a strong lateral inclination, into an 
 inner and an outer cell, the former having a trapezoidal, 
 and the latter a triangular basal, outline. The former is 
 
106 IIOl'MEISTER, ON 
 
 soon divided by a septum at right angles to the longitu- 
 dinal line of the bud. The latter cell, after previous trans- 
 verse expansion, divides by a septum parallel to the chord 
 of the arc represented by that portion of the margin of 
 the bud to which the cell in question belongs. The outer 
 ones of the newly formed cells then divide by septa at 
 right angles with the last-formed septum (PI. XV, figs. 
 3 — 5 ; and compare Nägeli's excellent account of this pro- 
 cess, ' Zeitschr. f. Bot.,' lift. 2, S. 150). The further in- 
 crease in the cells of the bud is caused by the growth of 
 septa in the cells of its fore edge alternately at right angles 
 or parallel to its margin, and by the formation of septa 
 parallel to the margin in the cells of the edge of its lower 
 part. The increase in breadth of the apex exceeds, at an 
 early period, that of the base (PI. XV, figs. 3, 4). 
 
 The longitudinal growth of the bud is limited, as is the 
 case with all the shoots of the Marchantiese. When it 
 is finished a very considerable increase in the breadth of 
 the lower part of the bud commences. Here the marginal 
 cells divide repeatedly by septa parallel to the margin, 
 alternating with radial septa. The marginal cells also of 
 the upper part, with the exception of those of the apex, 
 multiply ill like manner, although less actively ; they are 
 soon overtaken by those of the lower part. The cells, 
 however, of those two places on the lateral margins at which, 
 at an earlier period, the upper, wider half of the bud 
 separated itself from the lower, narrower ])ortion, take no 
 part whatever in this multiplication (PI. XV, fig. 7), and 
 as little also in the important expansion in length and 
 breadth which occurs shortly afterwards in the remaining 
 cells of the buds. In this way Iavo very deep, lateral in- 
 dentations are produced in the middle of the buds, the inner- 
 most space of which indentations is occupied by a group 
 of small cells, with a trapezoidal basal outline (PI. XV, 
 figs. 7, 8). At the time when as many as ten cells can be 
 counted in the longitudinal line of the bud, this group 
 appears as a single layer of cells. Then, for the first time, 
 it begins to grow in thickness ; in the first place, by the 
 division of the cells of the middle region by horizontal 
 septa (PI. XV, fig. 1*). For a still longer period the Ion- 
 
THE HIGHER CRYPTOGAM I A. 107 
 
 gitudinal growth of the bud is produced exclusively by di- 
 vision of the apical cells, by means of septa at right angles 
 to the surfaces of the bud ; the transverse septa which 
 appear in the apical cells are strictly vertical ; the fore 
 edge of the bud is a simple cellular layer. Afterwards, for 
 the first time, when the middle region has become more 
 and more thickened by the repeated formation of septa 
 parallel to the surface, and when this thickening has ad- 
 vanced close to the fore edge, the transverse septa appear in 
 the apical cells, inclined alternately upwards and downwards, 
 and parallel to the circumference of the bud. Thus the 
 form of longitudinal growth of the bud passes into that 
 which occurs in the shoots of older plants. 
 
 The arrangement of the buds of Lunularia and of 
 Marchantia, with respect to the longitudinal axis of the 
 shoot upon which they originate, is a very constant one ; 
 their surfaces are always at right angles to that axis 
 (PI. XV, figs. 1*, 19). Until their longitudinal growth is 
 almost completed, the buds are surrounded by a trans- 
 parent gelatinous mucilage. When the growth of the bud 
 in length and breadth is ended, the cell which supports it 
 dies and withers, and the bad becomes free. A moist sub- 
 stratum outside the receptacle is all that is now necessary 
 for its further development. 
 
 Under such circumstances some of the cells of its under 
 side first grow out into rootlets. Then new shoots begin 
 to be developed from the bottom of the lateral indentations 
 of the bud. The middle cell of the group which has been 
 so long arrested in its growth, and which is somewhat 
 larger than its neighbours, becomes the mother-cell of the 
 first new shoot (PI. XV, fig. 8). It divides by a transverse 
 septum, and the front one of the new cells by a longitudinal 
 septum. The division of the latter by laterally inclined 
 septa causes the further growth of the shoot, which pro- 
 ceeds precisely in the same manner as that in which 
 the new shoots of Pellia epiphi/IIa develope themselves, 
 with this difference only, that the transverse divisions of 
 the apical cells are always produced by means of septa 
 inclined to the horizon in alternate directions. The lateral 
 margins of the young shoots thus formed amalgamate 
 
]08 HOFMEISTER, ON 
 
 for a considerable extent with those of the indentation of 
 the bud. The cells which have amalgamated expand con- 
 siderably in length, and to some extent in breadth. AVhen 
 a shoot is formed in each of the two lateral indenta- 
 tions the bud becomes developed into a wide band, on one 
 side of which may be seen the spot at which the bud was 
 attached to the cell which bore it, and which spot is con- 
 spicuous from its brown colour, and by the arrangement 
 of the cells by which it is surrounded. This is the case 
 in MarcUantia polymorplia (PL XV, fig. 9). In Lunularia 
 vul(/aris, on the other hand, it is a rule almost without ex- 
 ception that a shoot is developed only on one side of 
 the bud, the shoot on the other side becoming abortive. 
 Here the bud in its further growth, assumes the form of 
 a disc drawn out in breadth, and having an indentation 
 on one side. On the other side it sends out a long 
 band, constricted at the fore edge, and on a third side 
 the primary place of attachment is still visible (PI. XV, 
 fig. 20). 
 
 On both sides of the new shoot, and in the angles 
 wdiich it forms with the prominent portions of the lateral 
 margin of the bud, two new cellular masses are formed 
 which are capable of development — in the first place a 
 median, and then two lateral shoots. The shoot com- 
 posed of the three amalgamated shoots unites by its lateral 
 margins with those portions of the next oldest shoot 
 which adjoin it on the right hand and on the left, and it 
 soon makes its appearance out of the indentation, in the 
 form of a flat mass of cellular tissue, having two notches 
 at the fore edge, and becoming wider in front. 
 
 A second form of growth, in which the shoots make 
 their appearance in irregular positions, occurs occasionally 
 in Lunularia and Marchantia, and more frequently in 
 Targionia, Rebouillia, and Pegatella. A process of cell- 
 multiplication commences in individual cells (usually near 
 the median line) of the under side of perfect shoots, by 
 means of which slender, delicate shoots are produced, which 
 soon throw out rootlets, and which, by the decay of their 
 posterior parts, separate from the mother-plant and be- 
 come independent individuals. They exhibit exactly the 
 
THE HIGHER CRYPTOGAMIA. 109 
 
 same arrangement of the cells as the vigorous normal 
 shoots of the mother-plant ; this may be observed most 
 clearly in FegateUa conica. The mode of ramification of 
 this second form of bud agrees with that of germ-plants ; 
 the fore edge widens considerably, the lateral portions 
 grow more vigorously than the median point, and from the 
 latter a new shoot protrudes, at whose sides the shoots of 
 a new order originate. This process differs materially 
 from the development of the bulbils. There is here the 
 same difference as exists between the development of the 
 germ-plants and the buds of Riccia. 
 
 The leaves of the Marchantieae are delicate lamellae of cellu- 
 lar tissue, closely pressed to the under side of the flat stem. 
 In an advanced state they sometimes exhibit at the base a 
 double layer of cells containing a small quantity of chloro- 
 phyll, the remainder consisting of a single layer of hyaline 
 cells. They develope themselves in a backward direction, 
 towards the place where three shoots unite to form one shoot, 
 and are situated on the under side of the shoot, in two rows 
 parallel to its longitudinal axis, arranged according to the 
 fraction \. The first rudiments of the leaf are formed as 
 follows : — one of the cells of the under side of the stem 
 protrudes outwardly, and the protuberance becomes divided 
 from the original cell-cavity by a transverse septum (PI. 
 XVI, fig. 15). At this time the stem is but little developed 
 in breadth, and is almost semicircular in a transverse 
 section. The rudiment of the leaf increases in length by 
 repeated transverse division of its apical cell. The cells 
 of the second degree are divided by longitudinal septa 
 (PI. XVI, figs. 15, 16). In FefjateUa conica this division, 
 even in the youngest stage of the leaf, extends as far as the 
 apical cell ; the leaf, when only fom- cells in height, appears 
 to consist of a short, double row of flat cells (PI. XVI, 
 fig. 11). The three pairs of interstitial cells divide by 
 septa parallel to the margin, and the two apical cells by 
 septa inclined somewhat laterally. The two inner ones of 
 the four cells which at this period constitute the fore 
 edge of the young leaf are now divided by transverse 
 septa, and the four cells thus formed by longitudinal septa 
 (PI. XVI, fig. 12). The outhne of the leaf then becomes 
 
110 HOFMEISTER, ON 
 
 rounded by a process of cell-formation which appears 
 very similar to tliat by which the cells of the very young 
 gemmae of JMarciiantia increase in breadth (PI. XVI, tig. 
 13). The cell-multiplication on the side of the leaf furthest 
 from the median line of the shoot soon exceeds that of the 
 other side, causing the one-sided appearance which is 
 usual m the leaves of Marchantia. The cell-multiplication 
 is arrested at the apex, whilst it continues at the base. 
 Many of the marginal cells grow into crooked, short, bi- 
 cellular, clavate hairs, similar to those which are found close 
 under the fore edge of rapidly growing shoots of Pellia, as 
 well as in the young parts of many other Jungermannias. 
 Individual cells, arranged at definite distances on the 
 margin, multiply for a longer period than their neighbours, 
 by which means the leaf soon becomes angular. 
 
 The development of the leaves of Targionia, Rebouillia, 
 Lunularia, and Marchantia, appears not to differ essentially 
 from the above. In Marchantia polt/iuorpha even the 
 leaves exhibit the tendency, common in these plants, of 
 sending out from the margins of their vegetative organs 
 dentate, chaffy processes, a tendency which is seen on 
 the marginal scales on the edges of the bud-receptacles 
 on the perichaete and perigone. By these processes the 
 leaves are beautifully fringed. 
 
 The well known characteristic structure of the flat stem 
 of the Marchantiese is marked by the separation of the 
 tissue of the stem into — first, an inferior layer of large, 
 very elongated cells, without intercellular spaces; — secondly, 
 a layer superimposed upon the latter layer, and con- 
 sisting of moniliform rows of cells, separated by wide 
 air-cavities and rich in chloi'ophyll, which layer is di- 
 vided into partitions by rhomboidal, cellular walls, each 
 consisting of a single stratum ; — and, lastly, an epider- 
 mis with transparent cell-contents, covering the latter 
 layer, which is in close connexion only with the cellu- 
 lar walls just mentioned, and is pierced by a stomate 
 of peculiar structure at the middle point of each of the 
 partitions of the underlying layer. The foundation of 
 this peculiar structure is laid at a very early period. 
 At a little distance behind the punctum vegetationis of 
 
THE HIGHER CRYPTOGAMIA. Ill 
 
 the very young shoot, long before the completion of its 
 growth in thickness, air-cavities are formed just under 
 the upper surface, separated from it only by a smgle 
 layer of cells (PI. XV, fig. 21; PI. XVI, fig. 3). The 
 portions of tissue betw^een the air-cavities form a network 
 of single rows of cells. As these cells continue to divide 
 by septa parallel to the surface of the stem, the lid 
 of the air-cavities is carried upwards. The base of 
 the cavities is quite flat. Lastly, after repeated pre- 
 vious bipartition of the cells of the base, by means of 
 vertical septa placed crosswise, the latter cells protrude 
 upwards (PI. XV, fig. 21), and by repeated transverse 
 division are quickly transformed into the monihform 
 chains of cells which, wdien the shoot is perfected, are 
 pressed closely to one another and fill up the air-cavi- 
 ties. 
 
 The epidermal cell which is situated over the middle 
 of each air-cavity separates by repeated bipartition into 
 four (Marchantia), six (Pegatella, PI. XVI, fig. 4), or 
 more (Rebouillia) three-sided cells arranged in a circle. 
 In the centre of the circle the cells part from one 
 another; a polyhedral opening is formed, the circumfer- 
 ence of which, owing to the expansion in a tangential 
 direction of the surrounding cells, is often considerable, 
 and through which the air-cavities, in which air is secreted 
 at an early period, conies into contact Avith the atmo- 
 sphere. The first development of the stomata of the Mar- 
 cliantieae is only distinguished from that of higher plants 
 by the fact that more than one bipartition of the mother- 
 cell precedes the opening of the commissure of the cells 
 which form the boundary of the opening. 
 
 The cells, from four to eight in number, which sur- 
 round the stomata of the Marchantiese divide, dmlng the 
 expansion of the stem to which they belong, by means 
 of septa parallel to the small side walls ; this often occurs 
 repeatedly, so that a hollow arch, with a perforated apex, 
 is formed over the middle point of the air-cavity. The 
 outer walls of the circular, wart-like protuberance of the 
 epidermis divide also by radial septa. 
 
 The inflorescence of a Marchantia owes its origin to the 
 
112 HOFMEISTER, ON 
 
 preponderating development in thickness and length, and 
 the proportionally small development in breadth, of the 
 median component of the last vegetative shoot. In its 
 earliest youth it exhibits a hemispherical, and at a some- 
 what later period a cylindrical, mass of fleshy, celhdar 
 tissue, with a bluntly rounded apex (PI. XVI, fig. 5 ; 
 PI. XI, fig. 10). Its longitudinal growth results, as is 
 the case in vegetative shoots, from repeated division of the 
 apical cell by means of alternately inclined septa, except 
 that at the first connnencement of the formation of the in- 
 florescence no more than one apical cell is present (PI. XVI, 
 fig. 5). During the further development there is formed 
 on its under side a deep channel, which is (PI. XVI, 
 fig. 7) destined to receive the rootlets which are produced 
 at a later period by the upper pileate portion, into which 
 the apex of the young rudiment of the head of the fruit is 
 transformed by means of active growth in the direction of 
 its breadth. The under side of the stem of some species 
 {Marchantia pol(j)iiorpha, PI. XVI, fig. 17, for instance) 
 exhibits two such channels. In both cases the channels 
 appear to originate in an active multiplication of the cells of 
 the inverted sides of the stem of the receptacle. The root- 
 lets first appear from the lower end of the channel, and pene- 
 trate into the ground. 
 
 The shoot which produces tlie inflorescence bears nu- 
 merous narrow, scattered leaves, in which the apex always 
 consists of one cell and the base of (at the most) a few 
 cells. The leaves are not produced on the apical portion, 
 which eventually forms the fruit. It may often be observed 
 that the cells of the base in these leaves multiply for a much 
 longer period than those of the apex. 
 
 The lateral portions of the undermost oldest parts of the 
 common stem of RehoiiiUia hemispherica extend consider- 
 ably forwards ; they close together so as to form a very 
 narrow, linear fissure in front of the transversely oval chan- 
 nel, and they amalgamate Avith the prominent lateral por- 
 tions of the fore edge of the shoot upon which the fruit- 
 stem is situated. The outer surface bears connivent leaves 
 above the apex of the rudiment of the inflorescence. The 
 longitudinal channel of the under side of the fruit- stem does 
 
THE HIGHEPx, CRYPTOGAMIA. 113 
 
 not reacli quite to its base ; it projects in the form of a 
 blunt knob into the indentation of the fore edge of the last 
 vegetative shoot (PI. XII, fig. 17). 
 
 The differentiation of the tissue of the leafy, expanded, 
 vegetative shoots is not continued into the stem of the fruc- 
 tifying shoot. At the point where it is attached to the next 
 older shoot the upper side of the stem decreases by a steep 
 inclination to the extent of the height of the layer which 
 bears the air-cavities (PI. XV, fig. 12 ; PI. XVI, fig. 17). 
 
 The archegonia spring from the lateral margins of the 
 receptacle in the form of cylinders of cellular tissue directed 
 obliquely upwards (PL XV, fig. 6). The essential features of 
 their development and structure correspond with those of 
 the Jungermannige and the mosses. Very soon after the 
 appearance of the arcliegonia the ])ortion of the recejitacle 
 above them begins to grow considerably in breadth, and 
 also downwards. The archegonia, in consequence, appear 
 shortly afterwards to be situated on the under side of the 
 expandedreceptacle(Pl. XV,fig. 11; PI. XVI, fig. 7). The 
 receptacle of RehouiUa heudspherica usually produces only 
 four archegonia ; sometimes one more, frequently less. The 
 cells of the upper surface of the ventral portion of the 
 archegonium divide at an early period by septa parallel to 
 the axis ; even before the bursting of the apex the central 
 cell is surrounded by a double layer of cells (PL XVI, 
 fig. 17). The neck is considerably bent upwards. The ex- 
 pansion of the receptacle above the archegonia takes place 
 at a late period compared with the other Marchantiea^, 
 i. e. not till after the opening of the apices of the arche- 
 gonia. The growth of the margin of the receptacle down- 
 wards is at first more vigorous between the archegonia than 
 above them. 
 
 In the neighbourhood of impregnated archegonia these 
 circumstances are altered. The tissue of the receptacle 
 above them increases in mass not less actively than in their 
 neighbourhood. Afleshysheath is formed, encircling the fore 
 part and sides of the swollen ventral portion of the arche- 
 gonium. Behind the young calyptra also the margins of the 
 sheath approximate to one another, so as to form a narroAV 
 fissure ; the bent neck only of the archegoniiun projects out 
 
114 HOFMEISTER, ON 
 
 of the narrow covering whicli is closely attached to tlie 
 caljptra (PI. XVI, fig. 20). Viewed from the outside, these 
 processes of the receptacle appear like fleshy appendages of 
 its margin. The number of them is the same as that of 
 the impregnated archegonia, viz., from one to five. (See 
 Bischotfs figures, ' N. A. A. C. L.,' vol. xvii, part 2, pi. 49, 
 figs. 1—4.) 
 
 The tendency of the ventral portion of the archegonium 
 of Eebouillia to develope itself largely is especially remark- 
 able in archegonia just impregnated. Here the multipli- 
 cation of the cells near the central cell is so rapid that the 
 latter becomes a wide, flask-shaped cavity, even before the 
 occurrence of the first division of the germinal vesicle con- 
 tained in its interior. This elongated, ellipsoidal cell lies 
 free in the cavity, entirely imbedded in transparent muci- 
 lage (PI. XVII, fig. 18). 
 
 The fruit-rudiment in Rebouillia, like that of Riccia, 
 Targionia, Marchaiitia, and Fegatella, exhibits the remark- 
 able species of groAvth which occurs in the fruit of mosses, 
 although, in other respects, the plants just mentioned 
 are nearer to the Jungermanniae than to the mosses. 
 This growth consists in the division of the mother-cell by 
 a strongly inchned septiun, and a continually repeated di- 
 vision of the apical cell of the fruit-rudiment by means of 
 septa inclined alternately in two directions. The form of the 
 young fruit-rudiment is very slender (PI. XVI, fig. 19); it 
 is only a double row of elongated cells. The longitudinal 
 growth, however, soon ends ; a considerable multiplica- 
 tion of the cells commences in a diametrical direction, 
 a multiplication which is more active at the apex (the future 
 capsule) and at the base (the growing knobby enlargement) 
 than in the middle (the future fruit-stalk). The increase 
 in the size of the fruit is so considerable at the approach of 
 maturity that it usually entirely destroys the upper part 
 of the calyptra; it then lies naked in the fleshy sheath 
 formed by the growth of the margin of the receptacle. 
 Fe (J at (diet co?iica developes from six to eight archegonia on 
 the lateral margins of its receptacle (PL XVI, fig. 6). 
 These archegonia are, at an early ])eriod, surroimded by the 
 receptacle, which is growing rapidly in breadth. The mass 
 
THE HIGHER CRYPTOGAMIA. 115 
 
 of the receptacle increases very considerably round the 
 base of each archegoniuni, so that these soon have the ap- 
 pearance of deep, ahnost cyhndrical, cavities, sunk in the 
 under side of the receptacle (PL XVII, hgs. 7, 8). The 
 fructification consists, as it were, of as many amalgamated 
 cornet-sliaped masses of cellular tissue as there are 
 archegonia. The very considerable expansion of the cchs 
 of these masses causes their margins, in half-developed 
 receptacles, to extend close to the point of origin of the 
 common fruit-stalk. 
 
 The archegonia of Fegatella resemble those of Rebouillia 
 in the early and extensive development of their ventral 
 portion. Like the great number of liverworts whose 
 archegonia have to live through the winter, they exhibit the 
 early duplication of the cellular layer surrounding the central 
 cell of the ventral portion, and the extensive growth in 
 thickness of the wall of the young calyptra after the occur- 
 rence of impregnation (PI. XVI, fig. 8). The neck is pro- 
 portionately long. 
 
 The rudimentary fruit, when consisting only of a few 
 cells, may be very easily detached (PI. XVI, fig. 9). The 
 ladder-like arrangement of its cells, caused by the repeated 
 division of an apical cell by means of alternately inclined 
 septa, is unconnnonly sharply defined. The growth of the 
 uppermost part of the yoimg fruit in thickness, i. e. the 
 foundation of the capsule, commences at a very early period 
 (PI. XVI, fig. 10). The lower portion of the fruit-stem is 
 very slightly developed ; the formation of a knotty enlarge- 
 ment of its base is entirely suppressed. As observed by 
 Schmidel (' Icones plant./ p. 121) and Bischoff", the stem 
 detaches itself spontaneously when the fruit is ripe from the 
 tissue in which it is inserted. The first archegonia of 
 Marchantia 2^ohjmorpha appear in like manner at the margin 
 of the young receptacle, usually eight in number, placed at 
 regular distances. Those at the hinder part of the recep- 
 tacle (/. e. turned away from the fore edge of the plant) 
 are developed, as in Rebouillia and Fegatella, much earlier 
 than those on the opposite part (PI. XV, figs. 11, 12). 
 Very soon after the appearance of the first archegonia new 
 ones are formed on the under side of the pilcate receptacle. 
 
116 HOFMEISTER, ON 
 
 and nearer to its centre, arranged in radial double rows 
 (PI. XV, fig. 11). A phenomenon, of wliicli traces are 
 seen in Rebouillia, is very strongly marked in Marchantia : 
 the underside of the mai-gin of the receptacle is developed 
 at a very early period between each two archegonia into a 
 process extending downwards for a considerable distance, 
 whose form gradually passes from that of a hemispherical 
 wart to that of a long, cylindrical prolongation, curved 
 slightly inwards, with deep, longitudinal fmTows on the 
 under side, in Avhich rootlets lie concealed. 
 
 The archegonia oi Marchantia polj/motyha are large-celled, 
 the ventral portion being remarkably swollen at an early 
 period. A single layer of flat, tabular cells surrounds the 
 pi'oportionably large central cell of the ventral portion, 
 which is attached almost immediately to the under side of 
 the receptacle. The neck of the archegonium, which in its 
 earliest youth is curved strongly upwards (PL XV, fig. 12), 
 is pointed directly downwards at the time when the apex 
 opens (PL XV, figs. 13, 14). 
 
 After the parting asunder of the cells of the apex, the 
 central cell of the ventral portion of the impregnated arche- 
 gonium enlarges very considerably. A free, oval cell entirely 
 fills its inner cavity. Its large central nucleus is very 
 plainly distinguishable as a clear vesicle in the thick 
 granular mucilage (PL XV, figs. 13, 14). The transforma- 
 tion of this cell into the rudimentary fruit is introduced by 
 the appearance of a much inclined longitudinal septum 
 PI. XV, fig. 15). The septa, which are formed at a later 
 period in the apical cell, diverge only very slightly from the 
 longitudinal axis of the fruit. I have but seldom and only 
 imperfectly succeeded in detaching the young rudimentary 
 fruit. It remains for some time spherical ; its cells soon 
 become very small by repeated cell-divisions. 
 
 After the first divisions of the primary cell of the rudi- 
 mentary fruit, the cells of the young calyptra double them- 
 selves by the formation of septa parallel to the outer surface. 
 A special covering has at an earlier period been formed 
 close round each impregnated archegonium. The ring of 
 bells of the under side of the receptacle which surrounds the 
 case of the archegonium protrudes outwards ; the protru- 
 
THE niGHER CRYPTOGAMIA, 117 
 
 ding portions are separated from tlie original cell-cavity by 
 transverse septa (PI. XV, fig. 13). By repeated transverse 
 divisions of the apical cells of the membranous sheath, pro- 
 duced by septa parallel to the free margin, the young 
 covering grows in length (PI. XV, fig. 14). Its fur- 
 ther development, viz., the transformation of the cylin- 
 drical shape into that of a distended pitcher (PI. XV, 
 fig. 15), corresponds to that of the covering of Frullania 
 dllatata. 
 
 Close under the arched upper surface of the receptacle 
 of Marchantia, including the outer surfaces of the 
 upward-growing shoots of the lateral margin, numerous air- 
 cavities are formed, even before the first appearance of 
 the archegonia. They are formed in the same manner as 
 the air-cavities of tlie stem. At the first appearance of the 
 air- cavity one epidermal cell only detaches itself from the 
 underlying tissue of the receptacle (PI. XVI, fig. 17, un- 
 derneath, to the right). By repeated transverse division 
 of the mural rows of cells lying between the air-cavities, 
 the lid of the cavity is carried rapidly upwards. This 
 epidermal cell, which closes the air-cavity, forms itself into 
 a stomate. It divides by a septum perpendicular to the 
 outer surface, as is the case in the first stage of the 
 stomata of the upper side of vegetative shoots ; both 
 daughter-cells then divide by a septum at right angles to 
 the one last formed (PI. XVl, fig. 17, in the middle). The 
 four cells part asunder at their edges of contact, and the 
 air-cavities come into connexion with the outward air. 
 The four cells of which the young stomate now consists 
 divide repeatedly by transverse septa. The first partitions 
 thus formed are parallel to the upper side of the receptacle ; 
 the later ones, which are produced in the upper and under 
 of the newly formed cells, are strongly inclined either towards 
 or away from the passage which traverses the axis of the 
 stomate. The apex of the organ protrudes above the upper 
 side of the receptacle in the form of a conical w^art, open at 
 the apex ; the base lies deep down in the air-cavity 
 (PL XVI, fig. 7). The middle part of the canal, which 
 traverses the stomate, is strongly distended. In the mean 
 time the apical cells of the cellular walls, which separated 
 
118 HOFMEISTER, ON 
 
 the individual air-cavities from one another, have also 
 multiplied considcrahly. A remarkable transverse ex- 
 pansion has preceded the repeated bipartitions (PI. XVI, 
 fig. 17, at the bottom, on the left side); the sides of the 
 cells are at an early period forced above the air-cavity, to 
 which they are contiguous. The process of the production 
 of those cells of the epidermis of the receptacle, which are 
 in connexion with the cellular layers separating the air- 
 cavities, consequently soon helps to form the lid of those 
 cavities, which at an earlier stage was represented only by 
 the young stomate or its mother-cell. 
 
 The base of the side walls of the air-cavities of Mar- 
 chantia soon produce moniliform chains of cells filled with 
 chlorophyll. In Rebouillia most of the cells of those walls 
 do not usually do more than project considerably, but 
 individual cells grow out into short, cellular rows. The 
 walls of the air-cavities of the receptacle of Fegatella remain 
 for a very long time smooth and even. 
 
 The median component part of the fructifying shoot of 
 Tarcjionia Jii/poj)/ii/II(i docs not become changed into a 
 specially formed receptacle, but developes the archegonia at 
 once, the latter being from one to five in number (PL XV, 
 fig. 21). The lower half of the archegonia is pressed into 
 the exceedingly narrow fissure, within which the lateral 
 wings of the fore edge of the fertile shoot confine the rudi- 
 mentary median part. The necks of the archegonia, M'hich 
 are bent upwards, project from the fissure into space. A 
 considerable increase of the parts of the tissue adjoining 
 the archegonia in front commences even during the longi- 
 tudinal growth of the latter. At the junction of the 
 median shoot with the lateral wings of the fore edge, 
 above the point of attachment of the archegonia, the cellu- 
 lar layers expand and midtiply vigorously in a longitu- 
 dinal direction ; their thickness is proportionate to the 
 development of the layer of air-cavities. Before the apices 
 of the archegonia open, a flat covering is formed, which 
 exceeds the archegonia in height, and which unites the 
 approximated lateral portions of the fore edge into one 
 surface. The separation of the upper side of the stem into 
 the layer of air-cavities and the epidermal layer takes 
 
THE HIGHER CRYPTOGAMIA. 119 
 
 })lacc within this covering (PL XV, fig. 21). At the same 
 time broad, fleshy, cellukir masses, concave above and 
 within, rise out ot the angles between the median shoot 
 (which bears the archegonia) and the lateral wings. They 
 amalgamate Avith one another, and by their upper margin 
 they unite with the above-mentioned covering. Thus, there 
 is formed a blunt, triangular envelope, enclosing the lower 
 part of the archegonia, from the narrow three-sided opening 
 of which the apices of the unnupregnated archegonia pro- 
 trude (PI. XV, fig. 21). Tlie rather thin walls of the enve- 
 lope, which are tm-ned downwards, consist of homogene- 
 ous cellular tissue. 
 
 When a rudimentary fruit is formed in an archegonium 
 the envelope enlarges with wonderful rapidity, especially by 
 expansion of its cells. It very soon entirely encloses the 
 impregnated archegonium. The cells adjoining the mouth, 
 which continues very narrow, grow out into short papillae. 
 
 The archegonia are slender, almost cylindrical. The 
 cropped api}earance of the apex, which occurs also in the 
 archegonia of the ^.larchantieae, is seen with remarkable dis- 
 tinctness (Pl.XVjfigs. 22,23). The cells of the ventral portion 
 double themselves at an early period by septa parallel to the 
 circumference. The inner cells adjoining the central cell be- 
 come filled with granular matter, as in Pellia (PI. XV, fig. 
 22). Immediately after impregnation the cells of the incipient 
 calyptra multiply very rapidly, so that, as in Rebouillia, 
 the central cell becomes a fusiform cavity, in which the 
 mother-cell of the rudimentary fruit lies free (PL XV, 
 %-22). 
 
 The rudimentary fruit in its earliest youth is narrowly 
 spindle-shaped, composed of two double rows of cells (PL 
 XV, fig. 24, detached; fig. 23, enclosed by the calyptra). The 
 growth in thickness begins much earlier at the upper end 
 than at the lower (PL XV, figs. 23, 25). The latter pene- 
 trates deeply into the tissue of that portion of the stem 
 which bears the impregnated archegonimn, and which has 
 become transformed by active and repeated division of its cells 
 into a conical, cellular mass. The lower end of the rudi- 
 mentary fruit, which is originally of a pointed, conical form, 
 changes gradually into a spherical enlargement by trans- 
 
120 HOFMEISTER, ON 
 
 verse expansion and siihsequent repeated bipartition of 
 the cells of its circumference (PI. XV, fig. 2G). 
 
 The arrangement of the spore-mother-cells and of the 
 elaters in Targionia, and also, it Avould seem, in the Marchan- 
 tieae, is \ery much the same as in Fossomhronia pusilla. 
 At the time of the differentiation of the two kinds of contents 
 of the capsule, the cells destined to form the elaters are 
 hardly pcrce[)tibly longer and thinner than the future 
 mother-cells of the spores (PI. XV, fig. 59). The elaters 
 and spore-mother-cells lie across one another somewhat 
 like the chlorojjhyll-cells and the air-cells of the leaf of 
 Sphagnum. A remarkable longitudinal expansion of the 
 elaters first occurs when the prominences of the inner wall 
 of the spore-mother-cell begin to be seen (PI. XV, fig. 30). 
 
 The antheridia of the JMarchantieae are, as is well 
 known, united in large immbers on the upper side of pecu- 
 liarly formed shoots, and enclosed in flask-shaped cavities 
 of the tissue. 
 
 The first stage of development of these shoots in MarcJian- 
 iia poli/morpha exactly resembles the first rudiments of the 
 head of the inflorescence. Here as there the forward, upper 
 portion of the narrow, almost cylindrical shoot becomes 
 developed considerably in breadth, j)rotruding beyond the 
 lower, stem-like portion, like the pilcus of a fungus. A 
 number of ceHs of the upper side of this disc, which is 
 slightly convex above and strongly so beneath, protrude 
 outwards in the form of papillae ; between them the epi- 
 dermis detaches itself from the underlying tissue. The 
 shortly cylindrical cellidar processes, the first rudiments of 
 the antheridia, are outgrown by the cells smTounding them, 
 and are sunk down into circidar cavities of the upper 
 surface. This arises from the rapid multiplication of the 
 cells of the circle which bears the detached fragments of the 
 epidermis, which multiplication is caused by rapid and 
 frequently repeated division of these cells by means of 
 sejjta parallel to the surface of the antheridial disc (PI. XV, 
 fig. IG). The above process coumiences in the middle 
 point of the young antheridial disc, and progresses from 
 thence to its growing margin. 
 
 The mother-cell of the antheridiimi assumes the form of 
 
THE HIGHER CRYPTOGAMIA. 131 
 
 an elongated, oval cellular mass, consisting of four rows of 
 cells (PI. XV, fig. 16). This arises from frequently re- 
 peated division of the apical cell by means of alternately 
 inclined septa, and by the production of radial longitudinal 
 septa in the cells of the second degree. The cells of one 
 of these rows, with the exception of the two at the base, 
 and the one next to the apex, divide by septa parallel 
 to the longitudinal axis of the antheridium, and cutting the 
 side v/alls of the mother-cells at an angle of 45°. The 
 antheridium now consists of a short, central string of cells, 
 surrounded by a single layer, the cells of which are 
 arranged in successive sets of four cells of equal height. 
 The further development, like the preceding, corresponds 
 with that of the antlieridium of Anthoceros and Pellia, 
 with this distinction, that the multiplication of the cells in 
 the direction of the longitudinal axis, exceeds that in the 
 direction of the thickness. The ripe antheridium is oval. 
 The apices of the cellular masses which arise between 
 the antheridia expand considerably in breadth as soon as 
 they have outgrown the antheridia. They consequently 
 soon close together over the antheridium, so as to form 
 narrow passages, hardly perceptible from the outside. The 
 cell which covers the air-cavity develops itself into a 
 stomate, exactly in the same way as the median cell of the 
 covering of the air-cavities on the upper side of the recep- 
 tacle (PL XV, fig. 16). The cells adjoining this cell divide 
 by slightly inclined longitudinal septa parallel to the axis 
 of the stomate. The inner of the cells thus produced, 
 Avhich form a ring round the stomate, take part in the 
 formation of the covering of the air-cavity, expanding at 
 the same time in breadth. In the air-cavities in the 
 middle of the antheridial disc these cells divide frequently 
 by longitudinal and transverse septa perpendicular to the 
 outer surface. The cells of the base of the disc grow into 
 the expanding air-cavities, and form chains of cells filled 
 with chlorophyll. When the antheridia are ripe, the cells 
 of the apical, covering layer separate from one another, the 
 internal mucilage, swarming with thousands of active, 
 motile spermatozoa, is forced through the narrow canal at 
 the apex of the antheridia which opsjus externally, and ap- 
 
122 HOFMEISTER, ON 
 
 pears in drops of considerable size upon the upper surface 
 of the antheridial disc. The spermatozoa, which are hardly 
 half as large as those of PelHa, consist of a delicate 
 thread, sliditlv thickened at one end, and drawn out into 
 a thin long process at the other. I could perceive no trace 
 of lateral cilia.* 
 
 I have only been able to examine the antheridia of 
 IlehoiiiUia heiiilspherica when fully developed. They arc 
 imbedded, as Bischofl"s beautiful observations have shown,+ 
 in half-moon-shaped cushions, which appear su])erimpose(l 
 upon the median line of vegetative shoots, usually upon 
 those which bear a fruit-receptacle. As the outside of these 
 cushions often bear rudimentary leaves, it appears to me 
 probable that these cushions may be considered to be weakly 
 developed shoots, resembling to some extent, in their deve- 
 lopment, the portions of the stem of Pellia which bear 
 archegonia (PI. XVI, fig. 17). The antheridia are pro- 
 portionably large, surrounded by flask-shaped cavities. In 
 the youngest which I have examined there was still to be 
 seen the covering layer of tabular cells (PI. XVI, fig. 17), 
 which, at a later period, is entirely supplanted, so that a 
 membranous sac alone encloses the cells which produce the 
 spermatozoa. The mouth of the antheridial cavities is 
 not often on the level, like that of Marchantia polymorpha 
 (PI. XVI, fig. 17). It more frequently protrudes to a consi- 
 derable height, in the form of a thick, conical point, like the 
 antheridial envelopes of Riccia. The tissue of the anthe- 
 ridial cushions consists of very large cells, with transparent 
 fluid contents. 
 
 The history of oiu' knowledge of the INIarchantieae is 
 most fully treated in Bischoff 's work, already so often cited, 
 and in the fourth part of the ' Naturgeschichte Euro- 
 paischer Lebermoose,' by Nees von Esenbeck. Except this 
 volume, I know of no connected treatise on the develop- 
 ment of the ]\larchantiea3 since the almost contemporane- 
 ous appearance of Bischoff"s and Mirbel's j large works, 
 
 * Compare Thuret, 'Ann. d. Sc.,' iii ser., torn. 3, pp. 13, 14. 
 t ' N. A. A. C. L./ vol. xvii, pi. kix, f. 1, 6, 7. 
 
 X " Rcclicrclies sur la Marclniutia polj/moqilui," 'Mem. de I'xVcad. des Sc. de 
 riust. de France.' vol. xiii. 
 
THE HIGHER CRYPTOGAMIA. 123 
 
 Many of the most interesting specialities are to be found in 
 Gottsclie's two writings above referred to. The above 
 investigations of Mirbel and Bischoff are so generally 
 studied and known that it would be superfluous to give 
 even a short smnniary of the valuable results obtained by 
 them. Good representations of the fruit and perianth of 
 ]\h(rchantia poI^iiiorjjJia are to be found in Micheli's ' Gen. 
 PI.,' p. 2, and in Dillenius's ' Hist. Muse.', pi. xxviii, 
 figs, m, n, who also figures the germination of the gemmae. 
 Micheli considered the male and female plants as different 
 species ; the relation of the two was first noticed by 
 Kupp ('Flora Jenensis,' ii, 276), then by Dillenius (1. c, 
 p. 524), and with certainty by Linnaeus (SP. PL. 1137). 
 Our present more accurate knowledge of the Marchantieae 
 dates from the publication of Schmidel's observations 
 ('Icones pi.,' ed. ii, p. 109 M. polymorph a ; p. 120 Fcga- 
 tella conica ; p. 133 Prcissia commutatci). Schmidel 
 isolated the antheridia, and pointed out their mode of attach- 
 ment to the tissue supporting them ; he gave an accurate 
 figure of the structure of the receptacle, and described the 
 spontaneous detachment of the fruit- stalk of Fcgatella conica 
 from the tissue of the mother-plant. Hedwig (' Tlieoria 
 gen erat ionis,' ed. ii, 1798) distinguished the enveloping 
 cellular layer of the antheridia (p. 176), and found that 
 in the young fruit the young perianth did not reach 
 to the height of the mouth of the archegonium (p. 177). 
 
 The object of Mirbel, in his remarkable work on Mar- 
 ch cüitia poly moipha ('Mem, Acad, des Sciences de I'lnst. 
 de Prance,' xiii, 1835) was to investigate fully the 
 history of the development of this plant in all its speciali- 
 ties. This object was only imperfectly attained. Mirbel 
 observed the germination of the spores. He came, how- 
 ever, to the erroneous conclusion that the newly added 
 cells were produced on the outside of the existing cells 
 (I.e., p. 347). This error arose from the circumstance 
 that in yoimg multicellular germ -plants which are fur- 
 nished with only one rootlet, the cell out of which the root- 
 let is formed is very similar in shape and size to the 
 germinating spore, whilst the latter is still unicellular, but 
 Avhen it has already developed a rootlet. His view of 
 
124 HOFMEISTER, ON 
 
 the origin of the quadrangular stomate upon the vegetative 
 shoots is to some extent erroneous, for he assumed such 
 origin to he in the disintegration of one four-sided cell, 
 surrounded by four epidermal cells, which (four-sided) 
 cell is, in reality, the mother-cell of the cells which enclose 
 the stomate, and which afterwards separate from one 
 another. H. von j\Iohl commented upon this error in the 
 * Linnaea' (1838) and in his ' Vennischte Schriften/ p. 25.2. 
 Mirbel's representation of the origin of the stomate sur- 
 rounded by more than four cells is, on the other hand, 
 quite natural (1. c, p. 356). 
 
 AVith regard to the receptacles of the gemmae, IMirbel 
 believed that, at the time of their appearance, the super- 
 ficial cellular layer of the flat stem became detached from 
 the underlying tissue, and separated into converging 
 teeth, which soon constituted the margin of the receptacle. 
 Mirbel has rightly apprehended the unicellular, earliest 
 state of the gemmae (1. c, p. 350) ; his notion of the con- 
 temporaneous metamorphosis of the contents of the uni- 
 cellular gemmae into a multicellular tissue filling the cell 
 was confirmed by Nägeli in 1845 (' Zeitsclnift f. wnss. 
 Bot.,' ii, p. 150). Mirbel's investigations of the germina- 
 tion of the gemmae of Marchantia are of especial interest. 
 He showed that that svnface of the gemmae which happens 
 to be in contact with the ground develops rootlets, whilst 
 the other one forms the upper surface by development of 
 stomata and air-cavities ; but that, twenty-four hours after 
 being sown, and when only a few rootlets have grown 
 out of the under side, the upper and under surfaces of 
 the future plant have already become permanently dif- 
 ferentiated. When gemmae, which had been sown for this 
 short period, were reversed, rootlets grew from that side, 
 which having been formerly the upper, had become the 
 under surface, whilst those rootlets which had sprung 
 from the quondam upper, then the under surface, con- 
 tinued to grow, and bending themselves downwards, pene- 
 trated the soil. During the further growth of the gemmae, 
 however, each of the cloncratino; lateral halves effected a 
 semi-revolution around its axis, so that the surface which 
 had been formerly the upper one again became the upper 
 
THE HIGHER CRYPTOGAM I A. 125 
 
 surface of the newly developed portions. In cases where 
 obliquely incident light intersected the smaller diameter of 
 the inverted gemmae, the younger portions of the latter 
 bent themselves simply backwards, so that the original 
 upper side was again turned to the light, and only rested 
 upon the soil by the one reflexed end. 
 
 The under side, which by inversion had become directed 
 upwards, never developed stomata, not even at the points 
 directly exposed to the light ; on the other hand, when 
 kept in the shade and sufficiently moist, it sent out roots 
 in every direction, and as it advanced in age exhibited pro- 
 minent ribs (1. c, p. 355). Mirbel thought that the cell- 
 multiplication in the interior of the gemmae, was an inter- 
 polation of new cells between those already present (1. c, 
 p. 352). He has not discussed in detail the mode of rami- 
 fication of the Marchantiese, although the inquiry into this is 
 closely connected with the investigations as to the mode of 
 development of the gemma3. Even at a still later period, 
 up to the present time, this ramification has generally been 
 described as dichotomous (as, for instance, by Nees v. 
 Esenbeck, ' Naturgesch. Europ. Lebermoose' iv, (1838) 
 p. 83), whereas, in point of fact, it represents a Dichasium. 
 We are indebted to Mirbel for very accurate accounts of 
 the structure of the developed fructification, especially of 
 the relation of the longitudinal forks of the stem, which are 
 ti'aversed by the rootlets, to the pileate expansion which 
 bears the reproductive organs (1. c, pp. 346, 376). Mirbel 
 was least successful in his investigations of the structure 
 and development of the organs of sexual reproduction ; his 
 figures are certainly beyond all comparison more elegant 
 and satisfactory than those of Schmidel and Hedwig, but 
 in the knowledge of the more important circumstances he is 
 not really a step in advance of the observers just named 
 (1. c, pp. 377 — 381). Mirbel's investigations of the develop- 
 ment of the spores and elaters were of great scientific im- 
 portance, the more so because, in conjunction with Mohl's 
 contemporaneous works on the same subject, they gave an 
 impetus to the more accurate investigation of the visible 
 processes of cell-formation and cell-multiplication. IMirbel 
 pointed out the division of the contents of the spore-mother- 
 
126 HOFMEISTER, ON 
 
 cell into four masses, each of which becomes a spore, and 
 also the origin of the elaters, out of a previously thin-coated 
 elongated cell (1. c, pp. 371, 382). In a treatise more par- 
 ticularly devoted to systematic questions relative to the 
 Marchantiese, Bischofl" (' Nova Acta A. C. L.,' xviii, 1835) 
 has conununicated some interesting results ; he proved 
 that the presence of male plants of Lunularia vulga- 
 ris \'& necessary for the development of the fruit (p. 925) ; 
 he pointed to the simple nature of the structure of the first 
 shoot of the germinating spore in comparison with that of 
 the shoots of the fully developed plant (p. 953). He has 
 repeatedly and emphatically dwelt upon this point, and has 
 endeavom^d to distinguish these first shoots (as a prothal- 
 lus) from the later ones (' Handb. Bot. Term.,' ii, p. 733 ; 
 'Bot. Zeit.,' 1853, p. 113), starting manifestly from the 
 supposition that the formation of a prothallus is pecidiar to 
 the order Muscinese, and that it must, therefore, be proved 
 to exist generally in all liverw^orts (see BischofF's definition 
 of the Muscincffi in ' N. A. A. C. L.,' xviii, p. 958). Both 
 Gottsche and myself have proved that there is no essential 
 difference between the first shoot of the germ-plant and 
 the later shoots (' Botan. Zeit.,' 1858, Supp., p. 45). 
 
 This difference of opinion can give rise to no real con- 
 troversy. The formation of a prothallus is a universal j)he- 
 nonienon in the embryonal life of plants. The development 
 of the germinal vesicle of the phaenogams into the embryo, 
 of the germinal vesicle of the vascular cryptogams into the 
 rudiment of the leafy plant, and of the germinal vesicle of 
 the Muscinese into the fruit all commence with a kind of 
 cell-multiplication, wdiich, at least during the first process 
 of division, differs from the later stages of develojmient. 
 The first, at least, of the permanent cells thus formed does 
 not enter into the composition of the mass of the organ 
 which is to be constructed ; very frequently it dies. The 
 same law prevails in the germination of the spores of ferns 
 and of the Muscinese. In the leafless Jungermanniese, the 
 Riccieae, and the Marchantiea:^., however, the boundaiy 
 between the prothallus and the developed plant is not, as 
 Bischotf considers, to be looked for at the ])oint where the 
 second shoot is attached to the first, but at the point wliei-e 
 
THE HIGHER CRYPTOGAMIA. 127 
 
 the primary, atypical divisions of the spore-cell terminate, 
 and the regular arrangement of the cells of the first shoot 
 commences. As far as present observations extend, this 
 point is generally only a few cells distant from the hinder 
 end of the germ plant. 
 
 Few works upon the Marchantieae have appeared since 
 those of Mirbel and Bischoff, Gottsche has given a very 
 accurate account of the germination of Prcissia commuted a 
 ('Nova Acta A. C. L.,' xx, p. 388) ; Grönland has pub- 
 lished some observations upon the same subject, and upon 
 the germination of Marchantia polymorplia and Lunularia 
 vulgaris ('Ann. d. Sc. Nat.,' iv ser., vol. i, 1854, p. 22); 
 and lastly, Henfrey has written upon the development of 
 the spores and elaters of Marchantia poly mor'pUa ('Trans. 
 Linn. Soc.,' vol. xxi). The latter paper contains the 
 important observation that the interior of the young capsule 
 is filled with elongated, closely packed cells. A portion of 
 these radiating cells consists of narrow, thin tubes, tapering 
 at both ends ; these are the young elaters ; the wider cells 
 are the primary mother-cells of the spores. These wider, 
 elongated cells are divided by transverse septa into rows of 
 cubical cells, the spore-mother-cells. Sometimes longi- 
 tudinal division also takes place in some of the rows of 
 cells thus formed (1. c, p. 107). The process is, therefore, 
 very similar to that which I have described in FruJJania 
 dilatafa. The development of the spores of Marchantia 
 polymorpha affords very little opportunity for the study of 
 the processes of cell-multiplication, on account of the 
 sensitiveness of the membrane and of the contents of the 
 mother-cells. It is quite conceivable that Henfrey might 
 have failed to see nuclei during the examination of the cells 
 in water or iodine (1. c, p. 109). 
 
 Motile spermatozoa were first observed in Marchantia 
 by Unger (' N. A. A. C. L.,' xviii, p. 791, 1837). In 
 his figures (1. c, pi. Ivii, fig. 4) he represents correctly 
 the relation of the two oscillating cilia of the fore end of the 
 spermatozoon to the body of the latter, but without noticing 
 that the duality of these cilia is normal. Meyer also 
 (' Wiegman's Archiv,' 183S, i, p. 212) believed the sper- 
 matozoa of Marchantia to be furnished with only one long 
 
r28 HOFMEISTER ON THE IIIGIITTv CRYPTOGAMIA. 
 
 " tail," an unfortunate expression, inasmuch as the fihform 
 portions take the lead when the spermatozoon is in motion. 
 Thuret's figures of the spermatozoa of the Marchantiesc arc 
 very accurate ( ' Ann. d. Sc. Nat.,' iii ser., xvi, pi. xii ; 
 Marchantia, Fegatella, and Targionia). 
 
CHAPTER VI. 
 
 MOSSES. 
 
 The stems of mosses grow by coiitmually repeated 
 divisions of the blunt, conical, apical cell. This cell is 
 pointed beneath ; the division takes place by means of 
 septa inclined in different directions. All mosses are 
 alike in this. The form of the terminal bud is very various ; 
 it is narrowly pointed in Sphagnum and Racomitrium 
 ericoides (PI, XXI, fig. 19); it is blunt in Phascum and 
 in many others ; hemispherical in Hypnum ; and very 
 slightly arched in Polytrichum and Bicraiium scoparimn, 
 where it is, in fact, almost a level surface, upon which the 
 youngest leaves are arranged concentrically. 
 
 The apical cell of the stem of Sphagnum is pointed be- 
 neath, where it has three surfaces ; and this three-sided 
 pyramid is deeply imbedded in the adjoining next older 
 cells of the end of the stem. These cells were separated 
 fi'om the inner cavity of the terminal cell by the formation 
 of septa traversing that cavity. Each new septum which 
 is produced in the apical cell is parallel to one (and that 
 one the oldest) of the lateral smfaces, and cuts the two 
 others. The newly formed cell of the second degree has 
 the form of a body with rhombic fore and hind surfaces 
 and with four rectangular lateral surfaces, one of which, 
 the smaller one (the free outer wall of the cell), is slightly 
 arched. The successive septa produced in the apical cell 
 are therefore arranged spirally, and the spiral is nonnally 
 a left-handed one, in accordance with the arrangement of 
 
 9 
 
130 HOFMEISTER, ON 
 
 the leaves.* Each cell of the second degree divides very 
 soon after its separation from the apical cell, by a septum 
 at ridit angles to the lono;itudinal axis of the stem, which 
 septum cuts the free outer wall, and also that lateral wall 
 of the cell which is turned towards the apical cell. 
 
 * The first correct account of the cell-multiplication in the outermost apex 
 of the stem of Sphagnum was given by Kägeli ('Pflanzen. ])hysiol-Uiiter- 
 suchungen/ i, Zurich, 1855, p. 76). I had previously ('Vcrgl. Unter- 
 suchungen,' p. 60) erroneously conceived the process to consist in the repeated 
 division of a two-surfaced, pointed, apical cell, by means of septa alternately 
 parallel to either of the two lateral surfaces. The origin of tiiis error was as 
 follows : — When the arched apex of a very slender paraboloidal cellular body 
 consists of a single terminal cell (as is the case with the ends of the stem of 
 Sphagnum and Equisetum), a portion of the lateral edges of tiie apical cell will 
 usually be the only part clearly visible when the body is viewed from above. 
 The edges of the neighbouring cells of the second degree will not be seen. 
 These edges form arcs, the curvature of which is greater in proportion to the 
 size of the cells of the second degree, i. e. in proportion to the size of that por- 
 tion of the terminal cell which is cut off to form the cell of the second degree. 
 If the edges of the apical surface of the terminal cell of the bud extend so deep 
 down that at the spot where each two intersect the sides of the bud possess a 
 high degree of inclination, then, when the body is viewed from above, the 
 middle part only of each edge of the apical surface can be clearly seen. 
 
 When the apical cell has the form of a three-sided inverted pyramid, with its 
 apical surface highly arched, and divides by septa arranged in a continuous 
 spiral order, and parallel to one of tlie lateral surfaces, then one of the edges of 
 the apical surface must, immediately after each division, be considerably shorter 
 than the two others. This fact is more clearly perceptible in proportion to the 
 size of that portion of the cell which goes to form the cell of the second degree. 
 In a system of similar spherical triangles, with a common centre, constructed by 
 drawing successively within each triangle arcs parallel to each one of its sides, 
 it will be found tliat one of the three arcs of each successive triangle is con- 
 siderably shorter than the other two, the difference being greater in proportion 
 to the curvature of the arcs, and to their distance from the respective parallel 
 sides of the next outer triangle (see the Diagram, PI. XVII, fig. 5*). When 
 the length of the arcs exceeds 90°; when the length of the transverse diameter 
 of the outer surface of a cell of the second degree amounts to one half of the 
 diameter of the cell of the first degree from the division of which it originates; 
 and lastly, when at the moment of division (by virtue of the innate growing 
 power of the plant) the form of the apical surface of the cell of the first degree 
 IS not that of an equilateral, but of an isosceles spherical triangle, then it may 
 happen that the points of intersection of the two larger arcs with the third 
 (very short) arc may fall quite outside the apical, vaulted surface of the organ, 
 when the latter surface is viewed under the microscope directly from above. 
 These remarks apply almost exactly to the apices of the stems of Sphagnum and 
 Equisetum, if observed immediately after the occurrence of division in the apical 
 cell. A figure of the upper surface of the terminal cell is then obtained, which 
 is strikingly similar to the apical aspect of tiie two-surfaced segment of a 
 spheroid (PI. XXII, fig. 4). Now, since in other instances (as in the apices of 
 the stems of liverworts, of Selaginella and of certain ferns, and in the organs 
 of fructification of mosses &c.) 1 had frequently ascertained that the multipli- 
 cation of the apical cell undoubtedly took place through division by means of 
 
THE HIGHER CRYPTOGAMIA. 131 
 
 The cell of the second degree is thus divided into an 
 upper daughter-cell, with three-sided fore and hind surfaces, 
 and an under, four-sided cell (PI. XVII, fig. 2). The free 
 outer wall of the former forthwith becomes arched outwards, 
 and is recognisable as the rudimentary cell of a leaf. The 
 latter (the lower cell) divides by means of longitudinal 
 septa, alternately tangential and radial to the axis of the 
 stem, which division continues until the completion of the 
 full number of the cells of the portion of the stem in 
 question. There is no very great regularity in the suc- 
 cession of these divisions. Sometimes one, sometimes the 
 other, occurs first ; frequently one step of the ordinary suc- 
 cession is passed over, and made good at a later period. In 
 every case, however, one phenomenon is constant — at a point 
 near the end (of the stem), about three cells downwards 
 from the apical cell, the number of the cells of the circum- 
 ference of the young stem is eight. An inequality in the 
 multiphcation by radial longitudinal septa of the cells of 
 the third degree also occurs regularly ; one of these cells in 
 each zone of the stem must lag about one division behind 
 the two others. For if this midtiplication in the cells of 
 the third degree were uniformly active, it would follow that, 
 inasmuch as three cells of the third degree must occur in 
 each transverse section of the stem, the number of cells of 
 each girdle of the outer surface of the stem must be a 
 multiple of three. 
 
 A transverse section of the perfect stem usually exhibits 
 a number of peripheral cells which is a multiple of eight. 
 
 septa inclined alternately in only two opposite directions, I was led to believe 
 that I must necessarily assume the same to be the case in Sphagnum and Equi- 
 setum, where 1 observed the pointed apical cells of the stem-bud had the 
 appearance of being two - surfaced. The cases of three-sided apical cells 
 which came under my observation, and of which I have given figures in 
 pi. xix, fig. 7, of the 'Vergleichende Untersuchungen,' I considered to be 
 instances of a mode of growth which caused a change in the form of the 
 apical cell between the period of each two divisions. Later observations 
 have convinced me that Nägeli's representation of the mode of increase of 
 the apical cell of the stem of Sphagnum, and Cramer's account of the similar 
 process in Equisetum, are correct. Erom this error there necessarily arose, 
 in tlie case of Sphagnum, an additional one, viz., in the account given of the 
 further division of the cells of the second degree, and in the statement that 
 the rudimentary cells of the leaves were derived from these latter cells, 
 which error I have corrected in the text above. 
 
132 HOFMEISTER, ON 
 
 In slender branches, especially those which hang down- 
 wards, the hark consists very regularly of only eight longi- 
 tudinal rows of cells. In the younger parts of the bud 
 the axile cells of the stem are more elongated longitudinally 
 than the peripheral cells, a circumstance Avhich has a 
 remarkable influence upon the slender form of the end of 
 the stem. The arrangement of the cells of the interior of 
 the stem into triangular plates, inclined inwards to the 
 axis of the stem, arises from the fact that all the cells of 
 the third part of a transverse section of the stem are 
 derived from a single cell of the third degree. Each of 
 these plates is higher by a portion of the length of a cell 
 than the adjoining plate on one side of it, and is exceeded 
 by the same portion of the length of a cell by the similar 
 plate on the other side of it. The difference of height of 
 two such cellular plates is almost always less than half a 
 cell, a circumstance from which it must be concluded that 
 the elongation of the cells of the stem preponderates in 
 their upper portions. The above-mentioned ari-angement 
 is most clearly seen in a perfectly axile longitudinal section 
 of a Sphagnum bud, made at some distance from the apex ; 
 if the section deviates only slightly from the longitudinal 
 axis of the bud, the arrangement is partially or entirely 
 imdistinguishable. 
 
 In all the cells of the periphery of the stem (with the 
 exception of the cells of insertion of the leaves) a transverse 
 division occurs a short time before, or contemporaneously 
 with, the termination of the cell-multiplication of the end 
 of the stem, in a radial direction (PI. XVII, figs. 1, 7). 
 This multiplication does not continue in the cells of the 
 interior of the stem, which are elongated, instead, during 
 its continuance, to about double their former length ; by 
 this means the short-celled bark is differentiated from the 
 long-celled axile-tissue. The multiplication of the stem- 
 cells in the diametral direction is caused by the division 
 of the slightly elongated cells of the interior of the 
 stem, by means of septa tangential to the axis of the stem, 
 alternating with divisions by radial longitudinal septa. 
 The number of these cells in the transverse diameter of 
 the stem increases tenfold from the place of insertion of 
 
THE HIGHER CRYPTOGAM lA. 133 
 
 the youngest (already nuilticelliilar) leaf, to the place 
 where the stem ceases to mcrease in thickness (PI. 
 XVII, fig. 1). This cell-multiplication does not, how- 
 ever, occur exclusively in a specific group of cells, such as 
 is found in many vascular plants somewhat in the form of 
 a cylindrical envelope. It is no doubt true that the cells in 
 which division especially occurs are those of a conical 
 envelope lying underneath the outermost cellular layer of 
 the conical mass of cellular tissue. But the cells of the 
 inner layers are by no means passive (PI. XVII, fig. 1). 
 During these processes the cells of the outer surface divide 
 by radial longitudinal septa, and the cells of more vigorous 
 shoots also hy tangential longitudinal septa, so that the 
 above peripheral cellular layer becomes transformed into a 
 double, triple, or quadruple layer of cells (PI. XVII, fig. 1). 
 In more slender shoots the latter form of cell- division is 
 suppressed : the cells of the periphery of the stem certainly 
 increase in number, by the formation of radial longitudinal 
 septa, whilst they keep pace with the increase of the peri- 
 phery of the axile cellular string ; the bark, however, re- 
 mains, for a time at least, a simple cellular layer (PI. XVII, 
 figs. 7, 9). The basal cells of the leaves, which are buried 
 to a certain depth in the tissue of the stem, and which are 
 easily recognisable by their peculiar tabular, flattened shape, 
 present in their ends, which are turned inwards, certain 
 indications from which it can be determined whether a 
 multiplication of the peripheral cells of the bark of the 
 stem has taken place or not (PL XVII, figs. 1, 7, 8, 9). 
 
 Whilst the growth in thickness of the stem is thus in 
 course of completion, its longitudinal growth is at a 
 stand-still. It commences with increased activity at the 
 spot where the conical form of the end of the stem passes 
 into the cylindrical form of the older portion. All the 
 cells become extended to at least twelve times their former 
 length, and during this elongation one more final process 
 of cell-multiplication takes place in them. The cells of the 
 interior of the axile string are often (although not with any 
 regularity) divided by transverse septa (PI. XVII I, fig. 8). 
 The cells of the periphery of this string divide still oftener 
 by radial and tangential longitudinal septa. They become 
 
134 HOFMEISTER, ON 
 
 very narrow and elongated (PL XVII, figs. 8, 9). Lastly, the 
 cells of the bark, in all tolerably vigorous shoots, divide 
 once more by tangential longitudinal septa, and in all cases 
 very frequently by transverse septa (PL XVII, fig. 8). 
 The bark thus becomes a stratum, consisting of from two 
 to foiu' layers of cells. In slender shoots this duplication of 
 the cellular layers of the bark does not take place ; trans- 
 verse divisions only occm* in their cells, so tliat even the fully 
 grown bark consists of only one layer of cells. 
 
 A considerable thickening takes place in the walls of the 
 cells of the axile tissue of the ends of the stems of fully formed 
 shoots, whose longitudinal growth remains dormant from the 
 end of autumn until the following spring, and whose densely 
 crowded lateral shoots form a capitate accumulation round 
 the end of the stem. This thickening is observable in a 
 transverse section, when made about ten cells underneath 
 the terminal bud. The thickened cell-membranes exhibit 
 delicate pits (PL XVII, figs. 9, 9 *), which bring to mind 
 those of the Coniferse, inasmuch as they are usually 
 (not always) arranged in longitudinal rows.* There are 
 not any lenticular air-cavities between the ends of two con- 
 tiguous pits ; the ends are divided from one another by a 
 thin, apparently homogeneous, membrane. The pits, when 
 seen from the surface, exhibit within their circumference a 
 narrow oval, but this appearance is probably caused by an 
 interference of the rays of light incident from beneath. 
 Dming the final longitudinal growth of the stem, during 
 the remarkable expansion of the axile tissue of the inter- 
 nodes (which expansion is rarely accompanied by a trans- 
 verse division), the thickening of these cell-membranes for 
 the most part disappears. In old stems the membranes of 
 the middle cells become rather thin again, and less brittle 
 than in the younger portions. It is now diflicult to dis- 
 tinguish any traces of the pits, which at an earlier period 
 were so distinct. They have now the form of short, oblique 
 fissures. The above-mentioned peculiar thickening of the 
 cell-membranes only extends a short distance into the axile 
 
 * rigures of these pitted cells, agreeing with those previously published by 
 me, have also been given by 'Schimper, M^m. pres. p. div. savauts,' xv, pi. iv, 
 f. 4. 
 
THE HIGHER CRYPTOGAMIA. 135 
 
 tissue of the thin, Literal shoots. No trace of it is to Ijc 
 found in the innovations* which are developed from the 
 ends of older, thinner, lateral shoots, and which, growin«- 
 rapidly in length and thickness, ultimately exactly resemble 
 the principal shoots in their mode of vegetation. On the 
 other hand, after the completion of the final longitudmal 
 expansion, a different mode of thickening occurs regularly 
 in the elongated cells of the axile tissue of these thin- 
 ner shoots, and also in that of the thick, principal shoots 
 and of the lateral shoots. After the completion of this 
 thickening the cell-membranes appear thick and indis- 
 tinctly stratified, their colour being yellowish-brown or 
 greenish lirown, and sometimes very intense. This thick- 
 ening is most highly developed in the narrowest peri- 
 pheral cells of the axile cylinder; it diminishes rapidly 
 in the wider, median cells. 
 
 \Mien, from the arching outwards of its free surface, the 
 rudimentary leaf-cell is recognisable as the mother-cell of 
 the leaf, it embraces rather more than a third part of the 
 circumference of the stem (PI. XVII, figs. 3, 4, 5). At 
 this period it still lies on the immediate boundary of the 
 apical cell of the tip of the stem (PI. XVII, fig. 2). 
 When view^ed from above it is clearly seen that the tan- 
 gent of its free outer margin is parallel to the tangent of 
 the arc which is represented by that one of the lateral edges 
 of the apical surface of the terminal cell of the tip of 
 the stem which is turned towards the rudimentary leaf- 
 cell (PI. XVII, figs. 4, 5). If, now, the successive divisions 
 of the terminal cell were such that each third w^all were 
 parallel to the third last one (as in the diagram, PI. XVI, fig. 
 5*), it would follow that, inasmuch as each cell of the second 
 degree produces a leaf, the leaves must be arranged under 
 one another on the stem, in three exactly parallel, longi- 
 tudinal rows. Accurate examination, however, of a termi- 
 nal bud shows that even in the youngest portions of the bud 
 this is not so. Even here also the youngest leaf-rudiments 
 have the arrangement which is characteristic of a later 
 
 * Schimper, 1. c, pi. xvi, f. 1. 
 
136 HOFMEISTER, ON 
 
 period, viz., that of a spiral, usually a left-handed one, 
 with divergence represented by the fractions |, |, or ^.* 
 This circumstance can only be accounted for in two ways. 
 It is possible that, contemporaneously with or immediately 
 after, the formation of each leaf, a certain twisting of 
 the portion of the stem beneath it might occur. This 
 assumption, however, is negatived by observation. It is 
 easily seen that even the two youngest leaves of the bud 
 have always the same divergence as the older ones (PI. 
 XVII, figs. 3, 4, 5). The only other possible process is 
 that the apical cell of the stem may change its form between 
 each two divisions in such a manner tb.at each cell of the 
 second degree, which is cut off from it by the formation 
 of a septum parallel to one of its lateral surfaces, is with- 
 drawn from the next previously formed similar cell by so 
 much of the circumference of the stem as is equal to the 
 distance of each leaf from the next youngest leaf beneath it. 
 Observation shows that both immediately before and imme- 
 diately after each division, the apical surface of the terminal 
 cell has the form of an isosceles triangle (PL XVII, figs. 4, 
 5). The change of form of the cell, therefore, must arise 
 from the fact that its increase in size, after division, takes 
 place more particularly in a direction perpendicular to the 
 new wall formed by the division ; the youngest edge of the 
 apical surface, which immediately after division represented 
 one of the legs of the isosceles triangle, becomes, until the 
 next division, relatively the shortest side ; it forms the base 
 of the triangle, which, by the greater elongation of the two 
 other sides, has become again isosceles, but which deviates 
 to the extent of the angle of divergence of the phyllotaxis 
 from its previous position. The conclusions necessarily to 
 
 * A. Braun ('Nova Acta, A. C. L.,' xv, p. 279) and Scliimper (1. c, p. 28) 
 agree in representing the pliyllotaxis on the middle of the stem of Sphagnum 
 as having | divergence. I have previously spoken of | as the normal 
 arrangement ('Vergh Unters.,' p. 61), and I find this confirmed by subserpicnt 
 observations of the median shoots (PI. XVIII, fig. 5) of vigorous innovations 
 and of germ-plants. Doubtless the § arrangement also often occurs, of which I 
 myself have figured an example (PI. XVII, fig. 4), but, however frequent, I find 
 it much less common than the other. IS'ägeli also found the f and fj ar- 
 rangements more frequent than the |. (' Pflauzeu-pliysiolog. Untersuchungen,' 
 i, Zurich, 1855, p. 77.) 
 
THE HIGHER CRYPTOGAMIA. 137 
 
 be drawn from the position of the youngest leaves, and 
 their relation to the apical cell of the stem in Sphagnum, 
 lead to the same results which I had previously arrived at 
 from direct measurement of the sides and angles of the 
 three-sided apical cells of the stems of ferns.*' In Sphagnum 
 the object is not fitted for direct measurement ; the steep 
 inclination of the arch of the apical surface renders the 
 accurate determination of the length of its edges impracti- 
 cable. It is worthy of mention, however, that in the apical 
 cells of Sphagnum- stems, with § phyllotaxis, the apical angle 
 of the triangle is visibly much more acute than in stems 
 with I or /a phyllotaxis. Probably in Sphagnum, as in 
 ferns, the change of form which the terminal cell u.nder- 
 goes between two divisions does not depend upon a capa- 
 city for change of form innate in the cell alone, but is 
 caused by the definite expansion of the cells of the second 
 degree adjoining the apical cell. 
 
 The youngest conditions of lateral shoots wdiicli have 
 come under my observation have the form of hemispherical 
 arched cells, which are situated on the outer surface of the 
 terminal bud, at a distance of three or four cells in a 
 straight line from the apical cell, near the left margin of 
 the third or the fourth leaf, and above the middle line, in 
 the first case of the sixth, in the second case of the seventh 
 leaf t (PL XVIII, figs. 16, 17). When a longitudinal sec- 
 tion of a principal shoot is made through the longitudinal 
 axis of the median shoot, and through that of a young 
 lateral branch, it is clearly seen that the place of attachment 
 of the young lateral branch, together with the cortical cells 
 which lie between it and the next lower cell, occupies a 
 portion of the outer surface of the stem exactly as large as 
 that occupied by the insertion-cell of a leaf together with 
 the cells of the tissue of the stem which are produced from 
 the same cell of the second degree as the insertion-cell ; 
 one of the oblique rows in which the elongated cells of the 
 interior of the stem are arranged reaches up to the place of 
 attachment of the branch (Pl.'XVII, fig. 1; PI. XVIII, figs. 
 
 * 'Ablmndl. Kön. Sachs. Ges. d. Wiss.,' v, C)i2. I shall return to this subject 
 hereafter in speaking of the developnieut of ferns. 
 
 f Considering the leaf as viewed from the outside and from beneath. 
 
138 HOFMEISTER, ON 
 
 16, 17).* This circumstance justifies the conckision that at 
 the conimenceinent of the formation of a hiteral branch a 
 portion of the apical ceU-cavity, which, under ordinary cir- 
 cumstances, becomes the primary cell of a leaf, is applied to 
 the formation of the rudimentary cell of the branch. It is 
 probable that the formation of the branch takes place earlier 
 than that of the leaf which stands at the same elevation in 
 the ascendhig line of the spiral of the phyllotaxis. Assuming 
 this to be so, the process can hardly be viewed otherwise 
 than as a separation from the fom'-sided terminal cell, of an 
 irregularly shaped cell of the second degree with a three- 
 sided apical surface ; after which separation the apical cell 
 divides by a septum which is parallel to one of the shorter 
 sides of the apical surface, and is inserted in the angle 
 formed by the oldest lateral wall of the apical cell with one 
 of the lateral surfaces of the rudimentary cell of the branch. 
 This latter division would restore the apical cell to its three- 
 sided pyramidal form. The direct observation of this pro- 
 cess can only be accidental. Indications, however, of such 
 a state of circumstances clearly exist in the occasional 
 occurrence of very slender apices (of stems), whose conical 
 end extends far above the last leaf-rudiment which is visible 
 in profile, so that in the optical section of the naked cone 
 two superposed cells of the second degree can be distin- 
 guished on one or on both sides. f 
 
 ]\Iost lateral branches ramify soon after their formation. 
 Schimper (1. c, p. 30), judging from the anatomical struc- 
 tm-e of the points of origin of perfect branches, concludes 
 
 * In the 'Vergleichende Untersuchungen,' p. 62, 1 made use of an expression 
 ■which might lead to the belief that I considered the lateral branches as axile in 
 their origiu. This arose from my having only had in view the relation of the 
 elementary cell of the lateral branch to the leaf below it. Schimper, at p. oO 
 of his work on Sphagnum, has rightly objected that, the position of the rudi- 
 mentary as vrell as of the perfect lateral branches is always at the side, near 
 the margin of the leaf which stands at the same elevation. 1 consider Schimper, 
 however, to be in error (1. c, p. 30) in supposing that certain oval (occasionally 
 stalked) cells, which are interjjolated between each two moderately distant 
 leaves, and which are seated upon the outer surface of the stem, are to be 
 looked upon as the rudimentary cells of lateral branches. These cells are 
 nothing more than the young state of the bicellnlar hairs, with oval terminal 
 cells, ^vhicll occur not unfrequeutly upon the stem of Sphagnum, and which 
 are figured by Schimper himself (pi. v, f. 2). 
 
 f Such terminal buds have often been figured, for instance, by myself in the 
 'Vergl. Uuters.' (pi. xiii, f. 1), and by Schimper (1. c, pi. iii, f. 2, 7). 
 
THE HIGHER CRYPTOGAMIA. 139 
 
 that the branch developes a number of lateral branches 
 before the commencement of the formation of leaves ; and 
 he treats the scale-like appendages of the young branch- 
 buds, which I considered to be leaves, as being the rudi- 
 ments of hxteral branches (PI. XVII, fig. 6). Continued 
 observations have not afforded me a single phenomenon 
 confirmatory of this opinion of Schimper's. I have found, 
 without exception, that the lateral branches develope indis- 
 putable leaves at a very early period, almost close to their 
 place of insertion into the principal stem (PL XVII, fig. 1), 
 and I have never seen a branch of the second order inserted 
 on a primary branch underneath the place of origin of the 
 first leaf. The points at which the axile cellular strings 
 are separated from the branches^, often appear to be enclosed 
 within the bark of the fidly developed principal shoot (1. c, 
 pi. iv, fig. 4) ; but this appearance is caused by the com- 
 paratively late commencement of the growth of this l^ark in 
 the direction of its thickness ; the bark is closely attached 
 to, and grows round, the base of the branches, and strips 
 off their lowest leaves. 
 
 I found that the development of the stem and branches 
 of Ortliotrichum aßne agrees in all essential particulars with 
 that of Sphagnum. 
 
 The first division of the rudimentary leaf-cell, which pro- 
 trudes slightly above the circumference of the terminal bud, 
 takes place by means of a septum springing laterally from 
 its longitudinal axis, and perpendicular to the surfaces of 
 the leaf. This division is succeeded by that of the apical 
 cell, which takes place by means of a septum inclined in 
 the opposite direction, meeting the one previously formed 
 at an angle of 90° (PL XVII, fig. 3). By the repeated 
 division of the apical cell by means of alternately inclined 
 septa, the leaf grows in length. During this time the form 
 of the apical cell is that of a low, three-sided prism, and the 
 form of the cells of the second degree is that of a procum- 
 bent parallelopiped. 
 
 Contemporaneously with or very shortly after the forma- 
 tion of a new cell of the second degree, the next older one 
 divides by a transverse septum, which, like all those which 
 take part in the formation of the leaf of Sphagnum, is per- 
 
140 HOb'MEISTER, ON 
 
 pendicular to the surface of the leaf. The edge formed by 
 the contact of this hotter septum witli the upper side wall 
 of the mother-cell coincides exactly with the line in which 
 the membrane just produced in the apical cell cuts the 
 boundary wall of the cells of the first and second degree. 
 The septum in question forms a right angle with the side 
 walls of the cell of the second degree; its direction is, 
 therefore, exactly the same as that of the septum by which 
 the apical cell was contemporaneously divided. The inner 
 of the cells into which the second youngest cell of the 
 second degree is divided has a rather long, rectangular, 
 basal surface. Both the cells of the third degree, which are 
 produced by the division of the cells of the second degree, 
 are soon divided, by longitudinal septa parallel to the side 
 walls, into ecpial parts, whose basal surfaces are almost 
 exactly square (PL XVIII, fig. 1). A similar process takes 
 place upon each further division of the apical cell of the 
 leaf. All the cells of the edge of the leaf which lie in the 
 course of the prolongation of the line of direction of the 
 newly produced septum of the apical cell divide, almost 
 contemporaneously, with the apical cell, by septa Avliose 
 direction coincides with that of the above-mentioned line 
 (PL XVIII, fig. I'). The result of these processes is that 
 in all species of Sphagnum the young leaf, with the excep- 
 tion of its margins, appears divided into regular squares. 
 With the exception of its edge, which appears composed of 
 somewhat elongated cells, the entire surface of the leaf con- 
 sists of cells whose basal outline is square, and each four 
 of which are in contact at their edges. It is only occa- 
 sionally that in these divisions one cell is passed over, and 
 then one cell of the interior of the leaf is twice as wide as 
 its neighbours, and its basal surface has the form of a paral- 
 lelogram (PL XVIII, fig. I ; see one of the cells of the fifth 
 of the oblique rows to the left).* 
 
 It is self-evident that, by the repeated division of the 
 cells, the lower, older portion of the leaf increases consider- 
 
 * From the abovc-nieiitiüned processes by which the chess-board-like 
 arrangement of the cells of the young leaf is produced, Niigeli concludes that 
 the division of one cell has a manifest etl'ecfc u|)on the neighbouring cell, and 
 causes the division of ihe latter in the same direction ('Pflanzeu-piiys. Uuters.,' 
 i, p. 78). On the other hand, 1 find iu these facts u new ground fur the con- 
 
TH»SBOOK 
 THE IIIGnKR CRYPTOGAMIA. 141 
 
 ably in width. Reckoning from the youngest leaf backwards, 
 the sixth leaf of a shoot embraces one hjilf of the stem ; the 
 twelfth embraces from five eighths to six eighths. Inasmuch 
 as, during the multiplication of the cells of the base of the 
 leaf, the cells of the stem upon which they are seated are 
 in an active state of multiplication in a tangential direction, 
 it follows that the place of attachment of the leaf to the 
 stem continues, relatively, of a considerable width, amount- 
 ing to one third of the circumference of the stem. Every 
 section made through that part of a principal shoot which 
 lies nearly under the apex meets, not only the longitudinal 
 line of each eighth leaf, but also lateral portions of five 
 intermediate leaves ; so that, in most cases, the points of 
 insertion of two leaves are only separated by one cell of the 
 cortical layer. 
 
 When the division of the apical cell of the leaf (which 
 division takes place by means of septa diverging alternately 
 from the median line) ceases, a multiplication of all its cells, 
 excepting those of the margin, commences ; this multipli- 
 cation begins at the tip, and progresses rapidly from thence 
 to the base. Each of the square cells divides into tAvo 
 rather unequal parts by means of a septum parallel to one 
 of the sides, but not exactly traversing the middle point of 
 the ceU (PI. XVIII, fig. 2, below, to the left). The larger 
 of the two is then divided, by means of a septum parallel 
 to the narrow sides, into two cells of unequal size, the 
 larger being square and the other somewhat elongated 
 (PI. XVIII, fig. 2). After the termination of these divi- 
 sions the surface of the leaf consists of a system of 
 square cells, each of which is surrounded by four oblong 
 cells. 
 
 In the oblong cells chlorophyll-granules are produced, 
 which increase rapidly and considerably in number and in 
 size (PL XVIII, figs. 3, 9). On the other hand, the pale- 
 green, highly refractive, and finely granular mucilage, which 
 
 elusion which I had previously drawn from similar appearances ('Abliandl. Kön. 
 Sachs. Ges. d. "VVissenscli.,' vol. iv, p. 161), viz., that the growing power which 
 regulates the form of conipound vegetable organs is mainly proportionate to 
 the form and number of tlie new cells in process of production, and that such 
 power does not exhibit itself in each peculiarity of the process of cell-multipli- 
 cation. 
 
142 HOFMEISTER, ON 
 
 fills the larger square cells, disappears, after having become 
 turbid and griimous, but without dividing into bodies of 
 any definite form. The contents of these latter cells 
 become clear like water. A considerable expansion of the 
 leaf-cells now ensues, especially in the longitudinal direc- 
 tion. It begins at the apex of the leaf, and proceeds from 
 thence rapidly downwards. The cells of the margin, which 
 divided once, and only })artially, by means of septa at right 
 angles to the edge of the leaf, cannot keep pace with the 
 increase in size of the numerous median cells ; the leaf 
 assumes more and more the form of a cap. At the same 
 time the first traces of the well-known annular and spiral 
 threads begin to be visible upon the inner walls of the 
 larger square cells. A longitudinal division of many (often 
 of all) of the cells with watery contents frequently precedes 
 the appearance of the threads, especially in Sphagnum squar- 
 rosmn, so that each two thread-cells lie near one another 
 (PL XXIII, fig. 4). Not unfrequently, also, many of the 
 small chlorophjdl-bearing-ceUs divide by transverse septa 
 (PL XXVIII, fig. 3). In the mean time the chlorophyll- 
 gvaniües in the small cells, which form a complicated net- 
 work between the thread- cells, increase considerably in 
 size. 
 
 In the greater number of mosses, e.g. Phascmn, Bryum, 
 Hypnum, Polytrichum, whose early development has been 
 admirably figured by Nägeli, the formation of the leaves 
 agrees in the principal featm'e — that is to say, in the 
 nature of the repeated division of the one apical cell — with 
 Sphagnum. An essential difference exists, however, in the 
 fact that the number of the cells in the leaves of these 
 mosses increases considerably by the repeated bisection of 
 the cells of the lower part of the leaf, even after the division 
 of the apical cell has ceased, after the latter cell and its 
 neighbours have expanded considerably, after the contents 
 have become transparent, and the walls of the cells of the 
 apex of the leaf have become considerably thickened. In 
 Sphagnum this supplementary multiplication of the cells of 
 the base of the leaf can never be distinguished. Upon the 
 last division of the apical cell the lateral margin of the leaf 
 consists of a number of cells (normally from eighteen to 
 
THE HIGHER CRYPTOGAMIA. • 143 
 
 twenty in Sphagnum acufifolium), whicli is afterwards only- 
 doubled by transverse division of tlie marginal cells. The 
 above-mentioned phenomenon, on the other hand, is very 
 distinctly marked in Polytrichnni and Fissidens. It is well 
 known that the leaves of the latter genus are arranged in 
 two rows. The terminal bud is surrounded by the peculiar 
 pocket-shaped duplication of the base of the last-formed 
 leaf; each older leaf of the bud also encloses the younger 
 leaves and the summit of the shoot in the akeady perfected 
 duplication of its base. The very young leaves resemble 
 the first rudiments of the leaves of Sphagnum. But when 
 the leaf is only five cells in height, the method of cell- 
 multiplication changes. As in Sphagnum, the cell of the 
 second degree divides by a septum at right angles to the 
 side walls. The septum which thereupon divides the outer 
 of the newly formed cells into two, stands at right angles 
 to the above septum, like the similar septum in Sphagnum ; 
 on the other hand, the membrane which originates in the 
 inner cell is at ris^ht angles to the median line of the young- 
 leaf (PL XVIII,^fig. 17, ß). The two cells of the fourth 
 deQ;ree belono-iug to the marginal cells of the leaf divide, 
 at first, by a septum parallel to the margin of the leaf. The 
 next septum, however, in both cells is at right angles to 
 the margin of the leaf. The transverse division corre- 
 sponding to this division is suppressed in the cells of the 
 two rows adjoining the longitudinal axis of the leaf, in con- 
 sequence of which these cells are double the length of the 
 neighbouring cells (PI. XVIII, fig. 17). The leaf continues 
 to widen by the further division of the cells of its margin, 
 caused by septa parallel to the edge. Sometimes indi- 
 vidual marginal cells are divided also by longitudinal 
 septa. 
 
 The formation of the pocket at the base of the leaf com- 
 mences when the base of the leaf has attained a width of 
 eight cells. At this time from five to eight of the lowest 
 cells of that margin of the surface of the leaf which is turned 
 towards the terminal bud become arched upwards to a con- 
 siderable extent ; the protruded portions are then separated 
 from the primary cell-cavities by means of septa parallel to 
 the surface of the leaf. By this means a raised line origi- 
 
144 • HOFMEISTER, ON 
 
 nates, which is attached laterally to the margin of the leaf, 
 and consists of a longitudinal row of cells. These expand 
 downwards from the longitudinal axis of the leaf, and exactly 
 keep pace with the further multiplication of the cells from 
 which they sprang. As the increase in width of the leaf is 
 nuich less at the base than close above it, it follows that 
 in the perfect leaf the commissure of the two parallel cel- 
 lular surfaces appears to be considerably inclined sideways, 
 running obliquely from the margin of the leaf to the base 
 of the mid-rib. By the peculiar development of the bases 
 of the leaves, nature has more than sufficiently compensated 
 the youngest portions of Fissidens for the deficient protec- 
 tion which, owing to their mode of arrangement, the leaves 
 would be able to afford. 
 
 When the young leaf of Fissidens has attained a length 
 of |-'", the multiplication of the apical cell terminates. At 
 this time the leaf retains the form which it had when in 
 a younger state ; it is less slender than when more fully 
 grown. The further multiplication of its cells is produced 
 exclusively by the continual division of those of its lower 
 portion. The great activity of this nuiltiplication is shown 
 from the simple statement that the number of the cells of 
 the proportion ably small point of attachment of the leaf, 
 when reckoned transversely, amounts to thirty. 
 
 The six longitudinal rows of cells adjoining the median 
 line of the leaf of Fissidens become transformed into the 
 mid-rib, by division produced by sei)ta parallel to the sur- 
 face of the leaf, and by the division of the newly formed 
 cells by septa perpendicular to the surface of the leaf. The 
 base of the mid-rib in the perfect leaf is innnediately adja- 
 cent to the duplication of the lower part of the margin of 
 the leaf. 
 
 The examination of half-develo])ed leaves of mosses which 
 are undergoing this process of cell-multiplication will afford 
 one of the most convenient methods for the accurate inves- 
 tigation of the process of cell-division and the formation of 
 chlorophyll. The object is not large enough for the micro- 
 scopes of the present day. I believe, however, that I have 
 already made out some interesting peculiarities in Fissi- 
 dens. In the cells close to the base of the leaf the nucleus, 
 
THE HIGHER CRYPTOGAMIA. 145 
 
 which has the appearance of a bright circle, is surrounded 
 by an apparently homogeneous, pale greenish mucilage. 
 The intensity of the green colour increases towards the 
 apex. In cells which are about to divide, the formation of 
 two nuclei, in the place of the primary one which has dis- 
 appeared, precedes the formation of the transverse septum, 
 as is the case generally in the higher plants ; but, besides 
 this, the green mucilage divides into two globular masses, 
 each of which surrounds one of the newly formed nuclei 
 (PI. XVIIl, tig. 18). Higher up, in cells whose multipli- 
 cation has ended, the nucleus is no longer seen, but two 
 large chlorophyll-bodies are found in the cell-cavity, in the 
 interior of which bodies some starch-grains occur (PI. XVIII, 
 fig. 19). In the cells close to the apex of the leaf, whose 
 walls have already become thick, the number of chlorophyll- 
 bodies amounts to four, six, eight, or even more. The 
 appearances which are seen during the formation of the 
 chlorophyll-bodies in the leaves of Sphagnum and of Phas- 
 cum cuspidatum are essentially the same as those observed 
 in Fissidens. In leaves of Sphagnum where the division 
 of the cells into three parts has extended as far as the base, 
 and at whose apex the last active process (viz., the differen- 
 tiation of the cells into those with, and those without, chlo- 
 rophyll) has occurred, the cells of the base of the leaf are 
 found to be quite filled with finely granular, yellowish green 
 protoplasm, within which the nucleus appears in the form 
 of a bright circle. Somewhat nearer to the apex of the leaf 
 this protoplasm exhibits numbers of immeasm^ably small, 
 dark-green particles, not individually distinguishable, by 
 which the proto})lasm is rendered turbid. 
 
 Hitherto all the cells of the leaf develope themselves 
 equally. Towards the apex, however, the coloured matter 
 within the quadrate cells diminishes more and more until 
 it disappears altogether, whilst in the oblong cells it appears 
 suddenly conglomerated into one or two spheroidal masses 
 or chlorophyll-bodies. Nearer still to the apex of the leaf 
 the chlorophyll-bodies in the oblong cells increase in number 
 and diminish in size ; this is manifestly caused by the divi- 
 sion of the existing bodies, inasmuch as some of them may 
 
 10 
 
146 HOFMEISTER, ON 
 
 occasionally be seen in tlie actual process of constriction 
 (PI. XVIII, fig. 4). 
 
 'i'he perfect chlorophyll-bodies are small ellipsoids, some- 
 what flattened in the direction of the shorter axis, and 
 having the substance of their periphery somewhat denser 
 and more strongly coloured than that of their interior, so 
 that they present a vesicular appearance. They usually 
 contain one or more very small starch-granules. 
 
 In young leaves of Phascum ciispidatiim, also, the less deve- 
 loped cells exhibit only one or two large chlorophyll-bodies ; 
 in more fully developed cells they become continually more 
 numerous and smaller. The perfect bodies have a vesicular 
 appearance, and usually contain several starch- granules ; 
 when the cell which surrounds them is ruptvu'ed, so that water 
 is brought in contact with them, their entire mass swells up 
 larp;ely, running together ultimately into a shapeless jelly. 
 
 The previously described process of the formation of the 
 large chlorophyll-bodies of Anthoceros is similar to that 
 here mentioned. From these facts I drew the conclusion* 
 that in young cells the chlorophyll is colourless, inasmuch 
 as the colouring matter is dispersed throughout the muci- 
 laginous cell-contents in the form of immeasurably small 
 particles. As the development of the cell proceeds, the 
 coloiued portions unite to form globular drops, which are 
 capable of multiplying themselves by division. This opi- 
 nion Avas opposed to that of Nägeli (' Zeitschr. f. wissensch. 
 Bot.,' H. 3 &4, Zurich, 1840, 111), who assumes that the 
 chlorophyll-bodies originate in the form of small, coloured 
 granules, Avhich gradually increase in size : it was, however, 
 in accordance Avith Nägeli's view to the extent of assuming 
 a vesicular structure in the chlorophyll-bodies, and it con- 
 firmed the fact, first pointed out by Nägeli, of the division 
 of the latter bodies. The idea of a vesicular structure in 
 the chlorophyll-bodies was opposed by H. v. Mold, who 
 relied u]3on certain appearances exhibited by those bodies 
 when distended Avith water (' Bot. Zeit.,' 1855, 107, 109); 
 but V. Mohl also, having eventually modified an earlier opi- 
 nion, came to the conclusion that, hoAvever chlorophyll may 
 
 * ' Vergleicliemle Uutersuchuugeu,' Lpz., 1851, p. 10. 
 
thp: higher cryptogamia. 147 
 
 be formed, nothing more seems necessary for its production 
 than that green colouring matter should be formed in a 
 cell, and should enter into combination with a mass of pro- 
 teine substance. The investigations of Arthur Gris (' Ann. 
 des Sc. Nat.,' iv ser., t. vh, p. 79), and of Sachs ('Sitzungs- 
 berichte AViener Akademie,' xxxvii, (1859,) p. 108), have 
 since shown that even in higher plants the chlorophyll- 
 graniües are formed by the disruption of a shai-ply-defined 
 mass of protoplasm, often of no determinate shape, the 
 green colour of which in certain cases becomes apparent 
 before the disruption, in others dim7ig that process, and in 
 others again after the disruption, and wdiich mass of proto- 
 plasm is usually agglomerated round the nucleus. 
 
 The development of the leaves of mosses has lately been 
 a matter of discussion. Nägeli asserted that the leaf 
 grows exclusively at the apex and the edge. (' Zeitschr. 
 für wiss.. Bot.' ii, 175). Schleiden, on the other hand 
 (Grundzüge, 3 Aufl), advanced a diametrically opposite 
 opinion. According to him the leaf is pushed forwards by 
 the multiplication of cells lying inside the circumference 
 of the stem ; the apex of the leaf being the oldest, and 
 its base the youngest portion. With regard to the moss 
 which Schleiden examined, viz.. Sphagnum, this is abso- 
 lutely incorrect ; Avith regard to the leaves of liverworts 
 and phcenogams it is only true in part, and to a very 
 limited extent. Both observers have generalised too ex- 
 tensively from the results they have obtained in their 
 investigations of mosses, although Nägeli subsequently 
 limited his too vague conclusions, by acknowledging the 
 frequent occurrence of intercalary cell-multiplication,* a 
 very manifest fact long previously pointed out by Grisebach 
 (' Wiegm. Arch.' 1846, p. 1). I have before attempted 
 to show that, with regard to mosses, the truth lies 
 between the two opinions. The first rudiment of the leaf 
 is formed from an outwardly-protruding cell of the circum- 
 ference of the terminal bud, by means of continually 
 repeated division of the apical portion. In this rudiment 
 
 * Nägeli called this " accidental cell-forwaiioii,^^ an expression the iiieorrect- 
 uess of which he subsequently acknowledged, 'Pflanzen physiol. Unters.,' 
 i, p. 83. 
 
148 HOFMEISTER, ON 
 
 of the leaf, wliicli in Polytriclium, for instance, attains a 
 length of t^A'enty-fou^ cells, the apex is the youngest, the 
 base the oldest portion. In most cases the cells of the 
 base of the leaf-rudiment multiply actively, by which 
 means the leaf acquires its ultimate number of cells. Then 
 the cells of the base of the leaf are relatively younger than 
 those of the apex. 
 
 The naked ends of those branches which are destined 
 to bear fruit change the conical form of the vege- 
 tative bud into a flattened hemispherical one. j\lany 
 of the cells of its upper surface grow out into short 
 papillae (PI. XIX, fig. 1). Each of them divides by a 
 septum inclined to the horizon ; the upper one of the 
 newly formed cells divides by a septum perpendicular to 
 that already formed and inclined in an opposite direction. 
 In the terminal cell of the cellular body, which makes 
 its appearance above the surface of the bud, the divi- 
 sion is continually repeated by septa inclined in dif- 
 ferent directions (PI. XIX, fig. 1 ; PI. XX, fig. 1). The 
 cells of the second degree, except some of the lower, 
 oldest (from two to six in number) cells, divide soon after 
 their formation by radial vertical septa. Thus, in a short 
 time, there is formed in the space surrounded by the 
 youngest leaves, a number of short, cylindrical, cellular 
 bodies, composed of four vertical rows of cells, intermixed, 
 in many of the mosses, with long multi- cellular hairs, 
 which have originated in the division by transverse septa of 
 certain of the papillate superficial cells of the bud. These 
 clavato- cylindrical masses of cells are the first rudiments of 
 the archcgoniti as well as of the antheridia. 
 
 When the young arehegonium has attained a height of 
 I'rom six to eight cells, all the cells belonging to one of the 
 four perpendicular rows of cells of w^iich (irrespective 
 of the base and the growing apex) it consists, divide 
 by septa parallel to the chord of the arc of the free, arched, 
 outer wall, and cutting the side walls of the cell at an angle 
 of about 45°, by which means the mother-cell is divided into 
 an outer four-sided, and an inner three-sided cell. Each 
 one of the newly-formed cells of the third degree (which 
 form the continuation upwards of the string of diagonally- 
 
THE HIGHER CRYPTOGAMIA. 149 
 
 divided cells) divides in the same manner immediately 
 after its formation, such division being, in most instances 
 exactly contemporaneous with the next division of the 
 apical cell, very seldom somewhat later, often earlier (PI. 
 XX, figs. 2, 3). 
 
 The arcliegonium now consists of a central string of 
 cells, which is surrounded by from four to six longitudinal 
 rows of cells. There are far more frequently six rows, in 
 consequence of the division of two of the original four, by 
 radial longitudinal septa (PI. XX, fig. 7). The arche- 
 gonium resembles, therefore, in its development, as well 
 as in its structure, the like organ in the liverworts. One 
 of the cells of the central string swells to a remarkable 
 extent, especially in width, whilst the upper end of the 
 arcliegonium continues to grow. This cell, however, is 
 never so near to the base of the archegonium, as in the 
 liverworts ; amonost the mosses which I have examined 
 it lies lowest in Phascum and Archidium, where it is the 
 third, fourth, or fifth, reckoned from below (PI. XX, fig. 
 2 ; PI. XXIII, fig. 13). Soon after it begins to swell the 
 cells underneath it divide by transverse, and partly by 
 longitudinal septa, whereby they expand only in length, 
 not in breadth. This cell-multiplication is more active 
 close under the swollen cell, than at the base of the arche- 
 gonium. In Phascum those cells which surround the sides 
 of the swollen cell divide, in the first instance, only by 
 transverse septa and by longitudinal septa perpendicular 
 to the outer surfaces (PI. XX, fig. 4) ; the division of the 
 above cells, by longitudinal septa, parallel to the axis of 
 the organ, commences at a somewhat later period (PI. XX, 
 fig. 5). In other genera, as for instance, Funaria, Pissi- 
 dens, Dicranum, and Polytrichum, the cells which cover 
 the central cell of the ventral portion of the archegonium, 
 are already divided by longitudinal septa parallel to the 
 outer surface, long before the bursting of the apex of the 
 archegonium ; and this occurs particularly early in Sphag- 
 num (PI. XV 111, fig. 14), where, even before the opening 
 of the top of the archegonium, this division is repeated in 
 the inner as well as in the outer cells (PI. XVIII, fig. 15). 
 In this genus, consequently, the ventral portion of the 
 archegonium is larger than in any other moss. 
 
150 HOFMEISTER, ON 
 
 By these processes the lower portion of the archegoniiim 
 becomes a pear-shaped celhilar mass, which, at the point 
 where it passes into the upper cyhndrical portion (the neck) 
 of the archegonium, surroiuids the enlarged cell of the cen- 
 tral string. In most instances the cell of the central string 
 lying immediately above the enlarged cell, exhibits a con- 
 siderable increase of its dimensions (PL XIX, fig. 5 ; PI. 
 XX, fig. 4) ; this is especially remarkable in Sphagnum 
 (PL XVIII, fig. 15). 
 
 Like all the cells of mosses the enlarged cell in question 
 exhibits, from its first appearance, a manifest nucleus. In 
 the very young archegonium the nucleus lies free in the mid- 
 dle of the cell, surrounded on all sides by protoplasm of 
 uniform density (PL XVIII, fig. 14 ; PL XX, figs. 2, 4) ; at a 
 later period, after the separation of the contents of the cell 
 into two parts, — viz., the thick coating of the wall, and the 
 less dense fluid contents of the median cavity, — the nucleus 
 lies close to the side wall of the cell, surrounded by a thick 
 accumulation of granular protoplasm, which sends forth 
 radiate prolongations over the inner surface of the cell 
 (PL XIX, figs. 5, 6). At this time there is seen under- 
 neath the primary nucleus of the cell, which is still very 
 distinct, a small daughter-cell, occupying about an eighth 
 part of the cell cavity, and having highly refractive con- 
 tents, and a bright nucleus without nucleoli (PL XIX, 
 figs. 5, 6). Contemporaneously with the appearance of 
 this cell, the transverse septa, by which the separate cells 
 of the axile longitudinal string of cells forming the neck 
 of the archegonium are divided from one another, begin 
 to dissolve. Even before these transverse septa have 
 altogether disappeared, even before the dissolution of the 
 transverse septa of the lowest of the cells of the axile 
 string, and therefore before the formation of the canal 
 which traverses the neck of the archegonium longitudinally, 
 the central cell is found to be almost filled by a free 
 spherical cell, which is either suspended freely, or touches 
 the wall of the mother-cell on one side, and which contains 
 a globular central nucleus (PL XVIII, fig. 15; PL XIX, 
 figs. 7, 8, 20; PL XX, figs. 5, 6, 8). The primary 
 nucleus of the cell is no longer present. These circum- 
 stances must lead to the conclusion, that the germinal 
 
THE HIGHER CRYPTOGAMIA. 151 
 
 vesicle (i. e., the small free daughter-cell of the central cell 
 of the archegonium), grows with extraordinary rapidity, 
 and displaces the dissolving primary nucleus of the central 
 cell. In Fnnaria hjjgrometrica the ripe germinal vesicle is 
 usually in close proximity to the transverse septum, which, 
 even after the canal of the neck is fully formed, and some- 
 times even after the apex has opened, still shuts off the 
 central cell of the archegonium (PI. XIX, fig. 8). It often 
 happens, however, in Funaria, in Phascum, and in Liver- 
 worts, that the germinal vesicle rests upon the bottom of 
 the central cell (PI. XIX, fig. 7 ; PI. XX, fig. 9), or that 
 it lies against one of the side-walls of the latter (PL XX, 
 figs. 5, 6, 8).* 
 
 After the termination of the longitudinal growth, the 
 cells of the apex of the archegonium divide by radial septa 
 which are partly vertical and partly inclined sideways ; and 
 to some extent also by transverse septa. In many genera, 
 such as Polytrichum and Sphagnum (PI. XVIII, fig. 15), the 
 new cells thus formed expand in a radiate manner, in con- 
 sequence of which the apex of the archegonium appears 
 strongly clavate. In the mean time, the walls of the string 
 of cells which traverses the neck of the archegonium dis- 
 solve. The dissolution progresses from above downwards. 
 Thus there originates in the axis of the neck a canal, con- 
 taining only mucilaginous fluid, which leads to the large 
 cell in the upper end of the ventral portion. Suddenly the 
 cells of the apex separate from one another, and bend them- 
 selves backwards in the form of irregular flaps ; in this state 
 they form the so-called stigma (PI. XX, figs. 6, 9, 13). 
 The archegonium is now in the condition in which I con- 
 sider it to be ready for impregnation. After the rupture of 
 the apex of the archegonium, the mucilage which fills the 
 canal of its neck not unfrequcntly oozes out of the opening, 
 protruding above the funnel-shaped mouth in a hemisphe- 
 
 * The rapid disappearance of the primary nucleus of the central cell, and the 
 agreement with it in size and form of tiie nucleus of the germinal vesicle, led 
 me at first to the conclusion (' Vergl. Unters.,' p. 67) that the germinal vesicle 
 might originate by free cell-formation round the primary nucleus of the central 
 cell. The mode of if s development, as given above, was first arrived at by me 
 in 1S54 ('Berichte Köu. Sachs. Ges. d. Wissensch. Math. Phys. CI.,' ]854, 
 p. 95). 
 
152 HOFMEISTER, ON 
 
 rical form. Afterwards it is often agglomerated into glo- 
 bular masses, — some small and some large, — of transparent 
 hyaline matter, as is the case in the Jungermanniae. 
 These processes may be seen especially clearly in Archidiuni 
 phascoidcs (PI. XXIII, figs. 1—3). 
 
 The product of the dissolution of the transverse septa of 
 the string of cells which traverses the longitudinal axis of 
 the neck of the archegonium frequently consists, in mosses, 
 of a vermiform mass of highly refractive, hyaline, transpa- 
 rent mucilage (PL XIX, fig. 8). It seems that the forma- 
 tion of this string of mucilage is favoured by drjaiess of 
 habitat. I seldom failed to find it in plants of Funaria 
 hyf/rometnca which had grown in dry places. It is much 
 less often found in plants taken from moist situations. 
 In Phascum cusjndatum, a part of the contents of the wide 
 axile string of cells lying immediately over the centi'al cell 
 of the archegonium very often assumes the form of an irre- 
 gularly-shaped heap of coarse granules (PL XX, figs. 5, 8). 
 
 The first stages of development of the antheridia of 
 mosses entirely correspond, as has been already stated, 
 with those of the archegonia. A clavate mass of cellular 
 tissue protrudes in a precisely similar manner above the 
 upper surface of the end of the stem, consisting, — with the 
 exception of the continually multiplying terminal cell and 
 the cells of the base, — of four vertical rows of cells : in an 
 almost precisely similar manner, a string of cells traversing 
 the axis of the organ is formed by the division of the cells 
 of one of the above rows; this occurs in the species of 
 Phascum, Gymnostomum, Bryum, Eucalypta, and Funaria 
 (PL XIX, figs. 1, 2, 3). In other cases diagonal septa ori- 
 ginate in each of the four rows of cells, after which radial 
 septa are formed in the outer ones of the new cells ; by this 
 means the antheridium becomes much more massive. This 
 is the case in Polytrichum. 
 
 The inner cells of the young antheridium multiply very 
 actively in all three directions (PL XIX, fig. 4). The cells 
 of the upper surface divide only by septa perpendicular to 
 the outer walls, and much less frequently than the inner 
 cells. The antheridium thus becomes a clavate sac, con- 
 sisting of a single layer of cells, which encloses an elongated 
 
THE HIGHER CRYPTOGAMIA. 153 
 
 ellipsoid group of very small cellules adhering firmly to one 
 another. In each of the latter, a spiral thread, consisting 
 of nitrogenous matter which is coloured brown by iodine, 
 is produced inside a lenticular vesicle wdiich lies free in the 
 interior (PL XX, fig. 16). 
 
 The tabular cells of the walls of the antheridimn contain 
 chlorophyll, and in the young state a flat lenticular nucleus 
 also, whose major axis is parallel to the outer surface of the 
 cell (PI. XIX, fig. 4). AVlien the antheridimn approaches 
 matmity, the colour of the chlorophyll-granules in many 
 mosses becomes a yellowish-red. This is the case in Ficnaria 
 hygrometrica, Brijinn ccespiticium, Polytrichum juniperinum, 
 Gym)iostomum jjyriforme, and Neckera conijjianafa. The 
 antheridia are usually intermixed with jointed hairs, the 
 so-called paraphyses, whose terminal cells are often (as is 
 the case in Mniuin hornuiu and Funaria hygrometricct) 
 swollen to a clavate form, and in Polytrichum produce a 
 lancet-shaped expansion at the apex, originating from con- 
 tinual cell-division by means of differently inclined septa. 
 The fuUy-ripe antheridimn opens at the apex, and permits 
 the escape of the small, enclosed cells, which contain the 
 spermatozoa. The process is very easily seen in water on 
 the stage of the microscope ; and that the same thing takes 
 place in nature, appears from the fact, that in every rich 
 male inflorescence in mosses, empty antheridia, open at 
 the apex, are found in company with ripening and ripe 
 antheridia. 
 
 The bursting of the apex of the ripe antheridium of 
 Funaria Iiyyroinetrica occurs thus : — the apical cell, and 
 the youngest cell of the second degree, which is separated 
 from the latter by a steep septum, exhibit a considerable 
 enlargement of their outer wall, which expands in a 
 vesicular manner ; but the red coloiu-ing corpuscles of the 
 cell contents, (whose interior is now usually occupied by a 
 starch granule) do not enter into the expanded space. 
 Careful investigation shows that the cuticle only of the 
 cells of the apex of the antheridium is forced outwards,* 
 and that the cavity between it and the firm membrane 
 
 * See Unger's figure of an aiitlieridium of Polytrichum in the act of bursting 
 'N. A. A. C. L.,' V. xviii, p. II (1837), p. 790. PL 57, f. 1. 
 
154 HOFMEISTER, ON 
 
 which immediately encloses the contents of the epidermal 
 cells, is filled with a transparent, almost fluid, jelly, which 
 can be nothing else than a product of the swelling np of 
 the median layer of the walls of those cells Mdiich occupy 
 the apex of the antheridium. Suddenly the cuticle of both 
 the above-mentioned cells splits transversely ; the contents 
 of the antheridium are driven out between the detached 
 cells of the epidermal layer in the form of a mucilaginous 
 mass, shaped like intestines ; these contents escape at first 
 with great rapidity, and afterwards with a slower motion, 
 which sometimes, by fits and starts, exhibits a momentary 
 acceleration. The walls of the cellules in which the len- 
 ticular vesicles, which produce the spermatoza, are gener- 
 ated, are now swollen to a mucilaginous jelly. The latter 
 is rapidly dissolved in water on the stage of the microscope, 
 the vesicles are dispersed in the fluid, and are soon rup- 
 tured by the spermatozoa in their efforts to escape. The 
 latter move about for some little time in the water, but 
 with no very great rapidity. I have observed the motion 
 to last for four hours in Folytrichimformosum. The mode 
 of bursting of the antheridium leads to the conclusion that 
 a radial expansion, and swelling up of the walls of the 
 epidermal cefls, especially of those of the apex, are at least 
 as effective in producing the rupture, as is the outward 
 pressure produced by the swelling of the contents. 
 
 The development of the antheridia of Sphagnum, which 
 are situated singly in the axils of short lateral shoots, differs 
 in some points of secondary importance from that which 
 occm's in Phascum, Bryum, Funaria, &c. There is a long 
 row of cells of the second degree in which division does not 
 take place ; a thin cylindrical double row of cells is pro- 
 duced, the end of which swells in a clavate manner. A 
 few only (two or three) of the cells belonging to the double 
 pairs of cells of the third degree which lie nearest to 
 the apex of the organ, divide, by means of a septum 
 parallel to the outer surface, into inner and outer cells 
 (PI. XVIII, fig. 11). The former become the mother- 
 cells of the vesicles which produce the spermatozoa ; they 
 divide actively in all three directions until at last they form 
 a spherical or oval group of closely-packed, smalb tessellated 
 
THE HIGHER CRYPTOGAMIA. 155 
 
 cells (PL XVIII, fig. 12), in each of which a spirally 
 folded spermatozoon is produced in the interior of a len- 
 ticular vesicle. The cells which surround these central 
 cells multiply by division, which takes place by means of 
 septa perpendicular to the outer surface, and become the 
 covering layer of the antheridium. On their outer side 
 there is formed a glassy, transparent, very tough cuticle, 
 which may be easily detached. When the organ is ripe 
 the cuticle bursts at the apex ; the vesicles enclosing the 
 spermatozoa, having become free by the dissolution of the 
 walls of their mother- cells escape at the opening, disperse 
 themselves when under water in the surrounding fluid, and 
 set the spermatozoa free, which then commence their 
 revolving motion. Their spiral has from two and a half 
 to three turns, and is sometimes a right-handed, some- 
 times a left-handed one. The anterior end of the sper- 
 matozoon carries two thin motile cilia attached laterally 
 (PI. XVIII, fig. 13). The covering cells* of the antheridia 
 usually become isolated after matm'ity, like those of Antho- 
 ceros, Fossombronia, &c. ; the cuticle holds together for a 
 considerable time. 
 
 Schleiden was of opinion that the antheridium of Sphag- 
 num was a laro-e sac-like cell, in whose fluid contents the 
 vesicles which produce the spermatozoa swam about treely. 
 This notion is quite erroneous. Until just before matu- 
 rity, the walls of the small, tessellated, closely-packed cells 
 remain quite intact, each of them enclosing one of the 
 vesicles. The natm-e of their arrangement is such, that the 
 directions of the primary divisions of the seven-surfaced 
 central cell of the very young antheridium may be easily 
 recognised. 
 
 Pruit is developed only in those mosses where the arche- 
 gonia are in the neighbourhood of antheridia. Any Botanist 
 paying attention to the growth of mosses will be able to 
 produce instances, in addition to those afforded by the older 
 observers, to prove that female dioecious mosses, in whose 
 neighbomliood no male plants of the same species occur, 
 produce perfect archegonia, but never fruit. At Leipzig, in 
 
 * The chlorophyll granules of these cells do not change colour when the 
 antheridium is ripe. 
 
156 HOFMEISTER, ON 
 
 certain localities, female plants only of Mnium undidahim, 
 Mniiim pundafum, and Biyuin ccesjnlicium occur. In such 
 places I have found every year numerous vigorous arche- 
 gonia, but never a single fruit. When fruit is found in 
 these species, male plants are invariably to be met with in 
 the immediate neighbourhood. 
 
 I have not yet succeeded in finding spermotozoa in the 
 central cell of the archegonia of Mosses near the germinal 
 vesicle, as I liave done in Ferns.* I have, however, seen 
 in Punaria a moving spermatozoon which had penetrated 
 through a third part of the length of the neck of an arche- 
 gonium, which was ready for impregnation. 
 
 The first symptoms of the conunencement of the deve- 
 lopment of a fruit, are a considerable enlargement of the 
 germinal vesicle of the elongated ellipsoidal cell which fills 
 the large cell in the upper end of the ventral portion of the 
 archegonium (PI. XIX, fig. 17 ; PI. XX, fig. 10), and the 
 appearance in it of a horizontal or slightly-inclined trans- 
 verse septum (PI. XIX, fig. 21 ; PL XX, fig. 10). In Bri/um 
 argenteum the upper part of the two cells divides again, 
 once or twice, l^y means of septa parallel to that first formed 
 (PI. XIX, fig. 22"' h). A septum inclined at a considerable 
 angle, and seated upon the uppermost of these horizontal 
 septa, is then produced. In Phascum, Punaria, and Fissi- 
 dens, this inclined septum is formed immediately after the 
 production of the first horizontal one (PL XX, figs. 11, 12). 
 The upper terminal cell of the young fruit-rudiment is then 
 divided by a septum inclined in a contrary direction to the 
 one last formed, then by another parallel to the last but 
 one, and so on. The longitudinal growth of the fruit- 
 rudiment is carried on by division of the terminal cell by 
 means of differently inclined septa (PL XIX, figs. 9 — 11, 
 22; PL XX, figs. 11—15). 
 
 The young rudiment of the fruit, when consisting of from 
 one to four cells, may be easily detached (PI. XX, figs. 11*, 
 12*-''). It occupies only a very small space of the upper 
 half of the ventral portion of the archegonium, in the cavity 
 of which it lies free (PL XX, figs. 11, 13). During its 
 
 * 'Ber.der K. Sachs. Ges. d. Wiss.,' 1S5-1-, p. 54. 
 
THE HIGHER CRYPTOGAMIA. 157 
 
 further longitudinal growth, it presses together the neigh- 
 bouring cells of the ventral portion, which have multiplied 
 considerably during the development of the fruit-rudiment. 
 This is very remarkable in Funaria (PI. XIX, fig. 11). At 
 the same time, the fruit-rudiment penetrates by its lower 
 conical end continually deeper into the tissue of the arche- 
 gonium. 
 
 The cells of the second degree which are formed by the 
 continually-repeated division of the apical cell, and wdiose 
 form is that of a flat semi-cylinder, divide by a radial 
 vertical septum. This division usually takes place before 
 the next division of the apical cell. The cells thus formed, 
 each of which has a three-sided basal sm'face, divide by a 
 septum parallel to the chord of the arc of the free outer sur- 
 face, into an inner eel] with a three-sided, and an outer one 
 with a four-sided, basal surface (PI. XIX, figs. 9, 10, 11, IP, 
 22, 22*; PL XX, figs. 14, 1 5; PL XXI, fig. 2"' *'^; PL XXIII). 
 The undermost margin of each such septum extends a little 
 beyond the line of contact of the corresponding septum of 
 the next lower cell. The next cell-division is that of the 
 outer cells by a radial longitudinal septum. Then all the 
 outer and inner cells of the group formed by the division of a 
 cell of the second degree divide by horizontal septa, the 
 inner ones often sooner than the outer ones (PL XIX, 
 fig. 10). In the simplest moss-fruits, such as that of 
 Phascum for instance, there ensues a repeateddivision of 
 the cells of the circumference by means of horizontal 
 septa, so that these latter cells appear only half as high as 
 those of the centre (PL XXI, fig. 1, a). The cells of the 
 periphery now divide by diagonal septa, the outer ones 
 again by radial septa, and so on alternately, until the 
 entire thickness of the fruit-rudiment is attained. At the 
 same time division commences in the central cells of the 
 middle and lower portions of the fruit-rudiment by means 
 of septa parallel to the chord of the arc of the periphery, 
 alternating with radial septa. This division leads to the 
 formation of the string of elongated cells, v/hicli traverses 
 the axis of the seta (PL XXI, fig. 1). 
 
 In mosses with more complex fruit, such as Funaria 
 hygrometrica, and Gymnosiomum pyriforma, the division 
 
158 HOFMEISTER, ON 
 
 of the cells of the circumference by transverse septa first 
 occurs after the production of an entire row of vertical 
 septa, so that the string of elongated cells in the axis 
 of the organ is far thicker. Even in vigorous specimens 
 of Phascum, a division by a septum parallel to the chord 
 of the arc of the outer surface precedes the formation of 
 horizontal septa in the outer cells. 
 
 The above account of the division of the cells of the 
 second degree does not apply in its entirety to the oldest 
 of such cells. In the latter the above cell-nuiltiplication 
 proceeds only to a certain point ; in the first two, three, 
 or four of such cells, only the radial vertical septum is 
 formed, and in the two three-sided cells thus produced, a 
 tangential septum only ; in the next the formation of radial 
 vertical septa occurs in the four cells of the circumference, 
 and the eight cells thus formed divide by septa cutting 
 the last-mentioned septa at an angle of 90°. Thus the cell- 
 multiplication progresses gradually upwards. 
 
 The thickness of the fruit-rudiment increases conse- 
 quently from below upwards ; it assumes the form of 
 a spindle-shaped cellular mass. As long as the multi- 
 plication of its apical cell continues, the active increase of 
 the cells in the direction of the thickness is always arrested 
 for some considerable distance beneath the apex (PI. XXI, 
 fig. 3, 8*), 
 
 In the mean time the cells of the ventral portion of the 
 archegoniam increase actively : so far as they encircle 
 the fruit-rudiment this increase takes place only by divi- 
 sion by means of septa perpendicular to the outer surface, 
 but in the lower portion it is ])roduced by septa turned 
 in all three directions. The cells also of the hitherto flat end 
 of the stem which bears the archegonia (both the impregna- 
 ted and the unimpregnated),* cx})and and nmltiply actively, 
 those in the middle more actively than those at the sides. By 
 this means the end of the stem becomes conical ; it bears at 
 its apex the impregnated archegonium, and on its inclined 
 surface the abortive archegonia and the paraphyses. This is 
 
 * In several species of Mniuni, which exhibit a very large number of arclic- 
 gouia (as many as fifty) hi one inflorescence, several archegonia are usually 
 impregnated. 
 
THE HIGHER CRYPTOGAMIA. 159 
 
 the origin of the Vaginula, the formation of which commences 
 in Phascum and Bryiun at a very early period, at the 
 time when the fruit-rudiment only occupies the upper two- 
 third parts of the archegonium (PL XX, fig. 15 ; PL XXI, 
 fig. 4; PL XXIII, fig. 3). In Sphagnum the vigorous in- 
 tercalary multiplication of the cells of the end of the 
 stem which bears the archegonia begins at a much 
 earlier period : even before the young archegonium has 
 attained its full number of cells. The very short fructify- 
 ing side-shoots of Splicignum cymhifolivm and 8. squarrosiim 
 usually develope one, at the most two archegonia, with 
 a remarkably fuUy developed ventral portion, and a strongly 
 clavate apex. When the latter is about to burst the 
 number of the cells of the end of the stem which bears 
 the archegonia (and which in Sphagnum is conical) in- 
 creases, without any change occurring in the circumference 
 of the conical mass of tissue. Its upper surface bears rudi- 
 mentary leaves destined to develope themselves in the fol- 
 lowing summer, at the commencement of the ripening of 
 the fruit (PL XVIII, fig. 15). 
 
 By the continuous longitudinal growth of the fruit- 
 rudiment its lower end is pressed continually deeper into 
 the tissue of the lower part of the archegonium, until at 
 last it reaches the parenchyma of the vaginula, to the 
 base of which it penetrates. The pressure is caused by 
 the resistance which the arcuate portion of the archego- 
 nium underneath its neck exerts upon the apex of the 
 fruit-rudiment. The tissue of the stem itself resists the 
 further penetration of the lower end of the fruit-rudiment. 
 The ventral portion of the impregnated archegonium 
 which has become the calyptra, now usually assumes the 
 shape of a bell, in consequence, it would seem, solely of 
 the expansion of its cells (Phascum, PL XXI, fig. 24, 
 Gymnostonium, Eucalypta, Orthotrichum). The cells of 
 its inner tissue become dissolved, only the single layer of 
 the outer surface remaining (PL XXI, fig. 4). The hollow 
 cavity between the latter, and the fusiform fruit-rudiment, 
 is filled with watery fluid. The increased tension of the 
 side walls of the calyptra, which is produced by the 
 sudden and considerable expansion of the median cells of 
 
160 HOFMEISTER, ON 
 
 the fruit-rudiment, causes the calyptra to break away by a 
 circular fissure uear its place of junction with the vaginula. 
 The calyptra is carried upwards by the rapid elongation of 
 the fruit-rudiment, upon whose apex it is placed. 
 
 At this period an active cell-multiplication commences 
 (especially in the direction of the thickness) in the upper 
 part of the fruit-rudiment, a little beneath the apex. The 
 cells of the apex itself take no part in this new production 
 (PL XXII, fig. 6). AVhen the repeated division of the 
 cells of the outer surface of the rudimentary fruit has in- 
 creased the diameter of the part nearly under the apex by 
 a certain number of cells (in Pliascum cmjjidatum, for 
 instance, to sixteen, in Gymiiostomum pyriforme to eighteen) 
 an air-cavity in the shape of a hollow cylinder is formed 
 nearly under the outer side of the slightly swollen upper 
 end of the rudimentary fruit. This cavity divides the 
 axile portion of the rudimentary capsule from the peri- 
 pheral part, or capsule-wall. The latter in most species of 
 Phascum has only three layers of cells (PI. XXI, fig. 5) ; 
 in Phascum hryoides and Archidium phascoides, it has only 
 two (PI. XXIII, figs. 5, 6, 8) ; in Gymnosfomum pyrifonue 
 it exhibits in its lower portion five, in its upper, three 
 layers of cells (PI. XXII, fig. 7). 
 
 The primary mother-cells of the spores originate in an 
 annular layer of cells of the axile portion of the rudimentary 
 capsule. In Phascum and Eucalypta this layer is the 
 second, in Gymnostomum and Punaria the third, reckon- 
 ing inwards from the periphery of the central ])ortion of the 
 young capsule, which central portion is surrounded by the 
 swollen, hollow, cylindrical air-cavity. The adjoining outer 
 cells divide at a very early period by septa })arallel to the 
 axis of the fruit, and most of the inner ones of the newly- 
 formed cells divide by horizontal septa (PI. XXII, fig. 8). 
 In consequence of this Phascum and Eucalypta have two, 
 Gymnostomum and Funaria three layers of cells separating 
 the hollow, cylindrical air-cavity from the layer of primary 
 mother-cells (PI. XXI, fig. 5; PL XXII, figs. 7, 10). 
 
 When the young capsule of Phascum cuspidatum is from 
 5'" to 1"' in length, the primary mother-cells (in which by often 
 repeated cell-production the spores are formed) surround 
 
THE HIGHER CRYPTOGAMIA. 161 
 
 the columella. The latter consists of a central group of 
 smaller cells with thinuer walls, and a peripheral layer of 
 cells containing chlorophyll, which adjoins the mother-cells 
 of the spores. The cells of the outermost of the two layers, 
 which adjoin the primary mother-cells, are four times as 
 large as those of the inner layer. 
 
 The cells of the layer of the columella adjoining the 
 primary mother-cells, as well as those of the future inner 
 wall of the capsule, are distinguished in a remarkable 
 manner from all other cells of the tlieca, by the great concen- 
 tration of the cell-contents, which are rich in dextrine. 
 The large cells of the centre of the columella contain small 
 amyloid masses of peculiar structm-e : minute firm granules, 
 which become intensely blue under the action of iodine, are 
 endDcdded in a gelatinous mass, which assumes a light blue 
 coloui" under the same action. 
 
 The primary mother-cells, at this stage of their develop- 
 ment, contain a large central nucleus, which has usually 
 only one nucleolus, and somewhat transparent fluid con- 
 tents (PI. XXI, fig. 5 ; PI. XXII, fig. 9). The remaining 
 contents of the cell, which consist of a thick fluid 
 mucilage rendered turbid by numerous granules, make it 
 somewhat difficult to distinguish the outline of the 
 nucleus. 
 
 The greater number of the primary mother-cells divide, as 
 the fruit becomes developed, by means of a longitudinal or 
 transverse septum perpendicular to the outer surface of the 
 theca; more rarely by means of a longitudinal septum 
 parallel to that outer surface (PL XXI, fig. 6). The dis- 
 appearance of the primary nucleus of the cell, and the pro- 
 duction of two new nuclei, precede the appearance of this 
 septum. The contents divide into two halves, each of which 
 surrounds one of the newly-formed nuclei (PI. XXI, fig. 6,(5) ; 
 at the point of contact these two halves secrete the new 
 cell-wall, which consists of a very delicate layer of cellulose 
 (PL XXI, fig. 6, a)* 
 
 Sometimes when the development of the fruit is very 
 active, the above division is repeated in the secondary 
 
 * The two halves represented in the figure have contracted under the in- 
 fluence of water, to which, in Phascum, they are very susceptible. 
 
 11 
 
162 HOFMEISTER, ON 
 
 mother-cells. Usually, however, immediately after the for- 
 mation of the secondary mother- cells, the tertiary mother- 
 cells, i. e., the spore-mother-cells, are produced. 
 
 Owing to the want of transparency of the cell-contents 
 the nucleus of the secondary mother-cells can with difficulty 
 be distinguished. It is, perhaps, impossible to make out 
 w^hat part it plays in the formation of the spore-mother- 
 cells. A nucleus with a large nucleolus is very indis- 
 tinctly seen through the grumous contents of the perfect 
 tertiary mother-cell. The spore-mother- cells lie in twos, 
 very rarely in fours (PI. XX, fig. 7), quite free and de- 
 tached in the inner cavity of the primary mother-cells. The 
 second condition can easily be looked upon as the result of 
 the suppression of the formation of the secondary mother- 
 cells. A long series of comparative measurements has con- 
 vinced me that the latter do not increase in size during or 
 after the formation of the spore-mother-cells, and if this be 
 so, the formation of the last-mentioned cells can only take 
 place by the occurrence of a considerable contraction of the 
 entire contents of the cell, either before or immediately 
 after its division into two halves, upon the entire surface 
 of which (two halves) cellulose is then secreted. I believe 
 that I have actually seen such a process of transition (PL 
 XXI, fig. 9). 
 
 The membrane of the mother-cells, primary, secondary, 
 and tertiary, is coloured pale blue by iodine. When 
 brought under water its substance swells rapidly, espe- 
 cially that of the inner younger layers. The membrane 
 of the tertiary mother-cells swells the most, that of the 
 primary ones the least. This peculiarity of the wall of the 
 spore-mother-cell affords one of the most striking proofs 
 of the independent nature of the primordial utricle. The 
 spore-mother-cell, when placed in water on the stage of 
 the microscope, rapidly swells to double its original size, 
 its wall being excessively distended. The cell contents, 
 which are plainly surrounded by a thin layer of soft matter 
 very like a delicate membrane, swxll slightly or not at all ; 
 they (the cell-contents) lie free in the inner cavity of 
 the cell in the form of a closed vesicle, surroiTuded by 
 watery fluid. Individual points of the primordial utricle 
 
THE HIGHER CRYPTOGAMIA. 1G3 
 
 sometimes exhibit slow expansions and contractions similar 
 to those of many of the inferior animals ; for instance, the 
 smaller Amcebaj. It is especially in snch cases that the 
 delicate mucilaginous membrane which encloses the cell- 
 contents may be most clearly observed. 
 
 By continued absorption of water the primordial utricle 
 becomes pressed laterally against the cell-wall ; the granules 
 which float in its fluid contents exhibit active molecular 
 motion. Ultimately, the cell-membrane is ruptm^ed, usually 
 at the spot where the primordial utricle is in contact 
 with it, and the latter escapes through the fissure. It 
 then usually bursts, but occasionally I have seen the 
 primordial utricle glide out through the fissure of the cell 
 in the form of a closed, tightly stretched globular vesicle 
 (PI. XXL fig. 8). The internal granules (consisting of 
 starch and a substance rendered brown by iodine), conti- 
 nued their active molecular motion, which stopped sud- 
 denly, when a drop of diluted watery tincture of iodine 
 was applied. The membrane of the primordial utricle 
 shrivelled up to some extent, and assumed a yellowish- 
 brown colour (PI. XXI, fig. 8, h). 
 
 In one instance I observed a very peculiar state of the 
 primordial utricle. As I brought the object under the 
 microscope, it floated freely in the form of a globular 
 vesicle in the interior of the swollen cell. Afterwards it 
 approached the cell-wall, and attached itself to one of the 
 sides, assuming the form of a slightly compressed sac 
 (PL XXII, fig. 1.) Half the cell-cavity remained empty, 
 or at least contained only water. The primordial utricle 
 gliding up to the inner wall of the cell commenced a slow 
 rotatory motion. 
 
 It has been already mentioned that the walls of the 
 secondary mother-cells swell rapidly until they burst. If 
 a section of a capsule containing fully formed tertiary 
 mother-cells enclosed within secondary mother-cells is 
 placed under water, it often happens that all the spore- 
 mother-cells escape out of the ruptured secondary mother- 
 cells, and become dispersed in the water upon the slide. 
 At this stage of development of the capsule the fluid con- 
 tents even of the cells of the outer capsule- wall attract 
 
164 HOFMEISTER, ON 
 
 water powerfully. If a tliin section of these cells is placed 
 in water, very active currents may be observed over these 
 cells, and in their interior. 
 
 In Gymnodomiim ovafum the affinity of the substance of 
 the walls of the tertiary spore-mother-cells for water is 
 even stronger than in Phascum cmpidatum. If these 
 cells are placed in water, the substance of the cell-mem- 
 brane is almost immediately distributed through the fluid, 
 so that the cell-contents remain behind^ a shapeless, dis- 
 solving, round mass. In order to get a sight of these 
 thick cell-membranes, it is necessary to observe the cells 
 with the greatest promptitude immediately after they have 
 been prepared for the microscope. On rare occasions the 
 outermost lamella of these membranes holds together for a 
 somewhat longer period in the form of a sac open at one 
 end, after the rupture, by pressure, of the more highly 
 swollen inner layers. 
 
 The contents of the mother-cell of the spores of Phascmn 
 divide into four portions, which after some time become 
 clothed with a stiff membrane, and shrivel up under the 
 action of alcohol. The first indication of this division 
 is the appearance of a transparent line in the turbid cell- 
 contents, passing transversely through the cell (PI. XXII, 
 fig. 2), or of two such lines cutting one another at right 
 angles (PI. XXII, fig. 3). The contraction of the contents 
 manifestly occurs for the first time after their division into 
 halves. The opacity of the cell-contents entirely prevents 
 the observation of the behaviour of the nucleus of the spore- 
 mother-cell during the formation of the spores. 
 
 The young spores lie in fours quite free in the mother- 
 cell (PI. XXII, fig. 4). Each spore exhibits a central 
 nucleus, with a manifest nucleolus (PI. XXII, fig. 5). The 
 cell-contents consist of proteine combinations, dextrine, and 
 starch-granules. Afterwards, when the formation of the 
 exosporium commences, (at which period the absorption of 
 the spore-mother-cells begins), oil-drops are visible in the 
 interior of the spore, which, as the spore becomes mature, 
 increase in number and size. During the time that the 
 spores lie free between the inner wall and the columella, 
 the cells of the innermost cellular layer of the former, and 
 
THE IlIOHER CRYPTOGAMIA. 1G5 
 
 of the outermost layer of the latter, abound with a saturated 
 Solution of dextrine, in which the nucleus floats in the foria 
 of a very sharply defined vesicle with less highly refractive 
 contents. 
 
 During the secretion of the exosporium, the walls of 
 those cells which are adjacent to the columella towards the 
 apex of the fruit assume a deep-brown colour. It is in 
 these cells that the partial disruption of the theca com- 
 mences, by means of which the spores, which in the mean 
 time have fully ripened, become free. 
 
 In Gymnostomum ^^yrifoniie, the multiplication of the 
 cells of the upper part of the spindle-shaped rudiment of 
 the fruit extends downwards far beyond the base of the 
 future fruit. In this way an apophysis originates, which in 
 the earliest stages of development far exceeds the fruit in 
 size. After the separation of two annular layers of cells 
 beneath the apex of the rudimentary fruit, by which means 
 the vacant space between the outer and inner wall of the 
 theca is formed, individual cells of the inner side of the 
 outer wall grow so as to form chains of cells, the uppermost 
 of which remain in connexion with the upper surface of the 
 inner wall (PL XXII, fig. 7). 
 
 In the very young capsule of Gymnostomum jjyri- 
 forme, at the time of the division of the cells which 
 adjoin the outer and inner sides of the primary 
 mother-cells, the latter have the form of very flat plates 
 parallel to the axis of the fruit (PL XXII, fig. 8). During 
 the fm-ther development of the theca, the transverse dia- 
 meter of these cells increases considerably. A proportion- 
 ably large nucleus with a large nucleolus becomes visible, 
 floating freely in the fluid contents (PL XXII, figs. 9, 10). 
 The length of the cell soon considerably exceeds its height 
 and width. 
 
 At this time two new globular nuclei appear in the place 
 of the vanishing primary nucleus (PL XXII, fig. 11). Half 
 of the granular mucilaginous cell-contents accumulates 
 round each of them ; two globular masses of protoplasm 
 are formed, which, after secreting cellulose over their entire 
 surface, constitute the free spherical mother-cells of the 
 spores (PL XXII, fig. 12). 
 
166 HOPMEISTER, ON 
 
 If the primary mother-cells are unusually long or wide, 
 they divide, according to the ordinary method of cell-multi- 
 plication, before the formation of the spore-mother-cells. 
 Two of such primaiy mother-cells then adjoin one of the 
 cells of the neighbouring cellular layers (PI. XXII, fig. 12). 
 In rare instances, fom- spore-mother-cells are found in one 
 primary mother-cell (PI. XXII, fig. 12^). 
 
 The walls of the primary mother-cells, which at an early 
 period are very sensitive to the action of water, become 
 more so after the formation of the spore-motlier-cells. If 
 a longitudinal section of a fruit in this stage of development 
 be placed in water upon a slide, the walls of the primary 
 mother-cells immediately burst, and the spore-mother-cells 
 are dispersed over the field of view. It is necessary to 
 examine the preparations in some saline solution. A solu- 
 tion of carbonate of ammonia is the most useful. 
 
 In the natural course of things, the dissolution of the 
 walls of the pnmary mother-cells follows soon after the 
 formation of the spore-mother-cells. The spherical s])ore- 
 mother- cells then lie free between the columella and the 
 inner wall of the theca. Numerous mucilaginous granules 
 surround the central nucleus, the substance of which is as 
 clear as water (PI. XXII, fig. 13). 
 
 During the further development of the fruit, the nucleus 
 of the spore-mother-cell approaches the cell-wall, and usu- 
 ally assumes a lenticular shape. The graniües of the fluid 
 contents of the cell accumulate at its middle point, so as to 
 form a spherical group (PL XXII, f. 14), in which the 
 nucleus is sometimes partially embedded. This accumula- 
 tion of granides divides afterwards into two halves (PI. 
 XXII, fig. 15); a spherical nucleus may often be seen in 
 each of these granular masses (PI. XXII, fig. 16). Each of 
 the elongated groups of mucilage and granules divides anew 
 into two parts ; and then four spherical accumiüations of 
 coarsely granular protoplasm are found in the mother- 
 cell. They are usually arranged at the four corners of 
 a tetrahedron (PL XXII, figs. 17, 18), and very seldom 
 lie in the same plane (PL XXII, fig. 19). Each of them 
 contains a nucleus. The outline of the primary nucleus 
 of the mother-cell becomes less and less distinct during 
 
THE HIGHER CRYPTOGAMIA. 167 
 
 these processes, and at last that nucleus disappears alto- 
 gether. 
 
 A spore is formed round each of the four secondary 
 nuclei. The four spores do not nearly fill the mother-cell. 
 A viscid fluid jelly tills the space between them (PI. XXII, 
 figs. 20, 21). 
 
 A layer of similar jelly is previously visible, forming 
 the innermost layer of the membrane of the mother-cell ; a 
 bright space is formed between the firm lamella of the 
 membrane and the boundary of the cell-contents (PI. XXII, 
 figs. 17, 19). 
 
 The first stages of development of the spore-mother- cell 
 of Funaria hj/(jrometnca resemble those of Gyinnostomum 
 pi/riforme. Two secondary nuclei are formed outside the 
 primary nucleus of the cell in the middle of an accumula- 
 tion of granular mucilage (PI. XIX, fig. 12). After- 
 wards four nuclei appear in the place of the two (PI. XIX, 
 fig. 14). The primary nucleus, which has become paler, now 
 disappears. Suddenly the mother-cell divides into four 
 parts of the form of a tetrahedron Avith a convex basal surface. 
 This division is produced by six septa passing through 
 each two of the four secondary nuclei. These four divi- 
 sions constitute the special mother-cells, which in this 
 genus have firm rigid w^alls, which at first are very thin 
 (PI. XIX, fig. 15). After the walls of these special- 
 mother-cells have become considerably thickened by the 
 deposition of gelatinous layers, a spore is produced in 
 each of them, which, at its first appearance, entirely fills 
 the mother-cell (PI. XIX, fig. 16). 
 
 The formation of the spores of Funaria more nearly 
 resembles that of the pollen of phsenogamous plants, than 
 the spore-development of Phascum, the similar process in 
 Eucalypta, and that in Gtjmnostomum puriforme. The 
 material differences in the process of development of the 
 spore-mother-cells in plants which are in other respects 
 so closely alhed, may, without hesitation, be considered 
 as an indication of the fact, that the greater or less degree 
 of firmness of the walls of the special mother-cells is 
 an unimportant circumstance. The essential phenomenon 
 in the formation of four spores or pollen-cells in the 
 
168 HOFMEISTER, ON 
 
 interior of a mother-cell, is the contraction of the contents 
 of the mother-cell (which contraction usually follows 
 the division into two parts, or the repeated division into 
 two parts of such contents), and the foniiation round 
 the contracted mass or its divided portions of a new mem- 
 brane, not attached to the inner surface of the membrane 
 of the mother-cell. In plants, where the contents of the 
 mother-cells divide into several portions before the con- 
 traction, the question whether special mother-cells with 
 firm rigid walls are developed or not, depends simply 
 upon the greater or less firmness of the substance which 
 must be secreted by the cell-contents in order that the 
 latter may be able to contract into a smaller space. This 
 substance is always gelatinous, and usually tolerably firm. 
 The thin, fluid nature of the jelly in Gi/mnosiomum ppnforme 
 forms a gradual transition to the state of circumstances 
 found in Phascum, where the fluid substance which 
 is found between the inner wall of the mother-cell and the 
 contracted portions of the contents, behaves under iodine 
 just like pure water. The latter cases seem to show that 
 the contraction of the cell- contents depends upon an 
 innate vital action, and not upon a mechanical compres- 
 sion (accompanied by the witlidrawal of water), caused by 
 the distension of the innermost lamella of the membrane of 
 the mother-cell. 
 
 A great uniformity prevails in the process of develop- 
 ment of the fruit of mosses so far as regards the most 
 prominent features, viz., the cell-multiplication of the 
 young fruit-rudiment, the separation of the sporiferous 
 cellular layer from the remaining tissue of the theca, and 
 the separation of the outer wall of the capside from the 
 inner one. The deviations from this process exhibited 
 in Archidium johascoides, the ripe fruit of which is itself 
 remarkable, are, therefore, the more surprising. These 
 deviations are reducible to two: — 1. Spores arc developed 
 by one cell only of the hollow cylindrical layer whose 
 cells in other mosses become, one and all, ])rimary mother- 
 cells : — 2. This cell and the daughter-cells produced by 
 the division of its contents, gradually displace tlie whole 
 of the inner tissue of the capsule. The peculiarities of 
 
THE HIGHER CRYPTOGAMIA. 1G9 
 
 Archidiiim are, therefore, not altogether a departure 
 from the typiral development of moss-fruit, but are rather, 
 with regard to the first point, a diminution, and with 
 regard to the second, an increase, of the growing power 
 usual in the allied forms.* 
 
 The antheridia do not differ essentially from those 
 of the species of Phascum. The spermatozoa are rather 
 large ; they exhil)it, very clearly, the two cilia shown by 
 Thuret, to exist in the mosses generally. The structure of 
 the unimpregnated archegonia is distinguished from that in 
 Phascum only by the slight extent of the longitudinal deve- 
 lopment of the lower part (PI. XXIII, fig. 1). I cannot 
 confirm P. W. Schimper's statement as to the pleuro- 
 carpus fructification of Archidium. I find rather that the 
 position of the archegonia and fruit exactly agrees with 
 that which obtains in Phascum. The germinal vesicle is 
 usually attached to one of the side wahs of the central cell 
 of the archegonium (PL XXIII, fig. 1). After impregna- 
 tion the germinal vesicle enlarges to a remarkable extent, 
 considerably expanding the ventral cavity of the archego- 
 nium, and pressing together the adjoining cells (PI. XXIII, 
 fig. 2). The cell- succession of the fruit-rudiment is that 
 which is common to all mosses, depending upon the re- 
 peated division of the apical cell, by septa inclined alter- 
 nately in two different directions (PI. XXIII, fig. 3). 
 The upper half of the fruit-rudiment soon increases in 
 thickness, and ruptures the calyptra on one side, dis- 
 placing it laterally (PI. XXIII, fig. 4). 
 
 In the interior of the fruit-rudiment, underneath the 
 second cellular layer (reckoning from the outside inwards), 
 layers of cells parallel to the outer surface become discon- 
 nected : an intercellular space is formed, having the shape 
 of an ellipsoidal covering, truncate at either end (PI. XXIII, 
 
 * Scliimper attempted to explain the nature of the ripe fruit of Archidium 
 (PI. xxiii, f. 11) by supposing that the whole of the interior of the fruit-rudi- 
 ment became converted into mother-cells, and that only one spore was formed 
 in each of them (' Rech, sur Ics Mousses,' Strassburg, 1848, ßrjiol. Europ. 
 1st ed., p. 2). In the ' Vergl. Untersucliungen,' I have objected to the above 
 view, on the ground that imperfectly ripe spores exhibit a junction in fours. 
 The observations given above (which were first published in the ' Reports of 
 the Royal Academy of Saxony,' 1854, p. 103) were made upon living plants, 
 kindly furnished by Messrs. Schultz, Bitsch, Tulasne, and Durieu. 
 
170 HOFMEISTER, ON 
 
 figs. 5, G, 7). This is exactly the process which in all 
 mosses causes the separation of the outer capsule-wall 
 from the inner portion. 
 
 One of the cells of the interior of the capsule grows to a 
 considerable extent, pressing the adjoining cells together. 
 Its walls become thickened, and its contents rich in 
 granular mucilage (PI. XXIII, fig. 5). This cell is the sole 
 primary mother-cell of the spores. Its primary position is 
 always excentrical, separated by two layers of cells from 
 the hollow cavity which adjoins the inner surface of the 
 outer capsule-wall. Its vigorous power of growth con- 
 tinues whilst the surrounding tissue becomes disintegrated 
 and dissolved. It now lies quite free in the cavity of the 
 capsule, and falls out of the opened capsule without assist- 
 ance. Four freely- floating mother-cells of the second 
 degree are produced in its interior (PI. XXIII, fig. 7), 
 each of which divides into four special mother-cells (PI. 
 XXIII, fig. 8). Each of the latter produces one spore, 
 so that the whole number of spores is sixteen. I have met 
 with no exception to this in my numerous investigations. 
 
 The diameter of the newly-formed spore measm'es only 
 one-sixth that of the ripe one. A delicate exosporium 
 is distinguishable even in the earliest stages of develop- 
 ment (PI. XXIII, fig. 9). Afterwards it increases consider- 
 ably in thickness, even before the entire dissolution of the 
 mother-cells and the special mother-cells. 
 
 The inner capside wall, and the inner cellular layer of 
 the outer wall, are present for some time after the forma- 
 tion of the spores. These masses of cells are displaced, as 
 far as the outermost cellular layer of the (now spherical) 
 capsule, by the gradual growth of the spores. The mem- 
 brane of the primaiy mother-cell remains to the last, en- 
 closing all the spores. It is the membrane spoken of in 
 the ' Bryologia Europaea ' as the delicate spore-sac. 
 
 Few processes in the vegetable kingdom are so 
 thoroughly understood as the germination of the spores 
 of mosses, the production of leafy axes from individual cells 
 of the confervoid pro-embryo. The admirable observa- 
 tions of Schimper* have entirely solved the last remaining 
 
 * 'Reclierches surles Mousses/ Strasburg, 1848. 
 
THE HIGHER CKYPTOGAMIA. 171 
 
 difficulty. The investigations of Hedwig and his successors 
 can be so easily repeated in many species, as, for instance, 
 Funaria hjgrometrica and Barhula muralis, that it would 
 be waste of time to give a description of the phenomena. 
 I will mention only some peculiarities which are not so 
 well known. 
 
 The threads of the pro-embryo, whether they arise 
 from the development of a spore, or from a cell of 
 the surface of the stem or of a leaf*, exhibit in many 
 species two very different modifications of development. 
 The principal ramifications of the confervoid rows of cells 
 are filled with assimilated matter, and contain very 
 numerous chlorophyll bodies ; their longitudinal groAvth, 
 which results from repeated transverse divisions of the 
 terminal cell, is unlimited. The lateral ramifications of 
 these principal branches of the pro -embryo have only a 
 limited growth ; the terminal cells, when they cease to 
 divide, assume a conical form. Moreover the lateral 
 branchlets ramify in a complicated manner. Their con- 
 tents are far less concentrated, their transverse diameter 
 narrower, their chlorophyll more inclined to a yellowish 
 tinge than is the case with the principal branches. These 
 latter only are capable of producing true germs or leafy 
 axes. The principal branches of the pro-embryo may, 
 perhaps, be compared to stems ; the lateral branches with 
 limited growth to leaves. These phenomena are very 
 remarkable in the pro-embryo of Bacomitrium ericoides. 
 Here, owing to their peculiar habit, the lateral shoots of 
 
 * I wisli to add a few words as to the meaning of the expression " pro- 
 embryo." By the word "embryo," is meant the bud capable of developing 
 leaves and roots. Thus, we speak of the embryo of the onion, the potato, the 
 bop. Now, when we find in the vegetable kingdom organs which differ from, 
 and are of an essentially simpler structure than the leafy stem-rudiments which 
 afterwards spring from them, but which must normally and necessarily in the 
 course of their development produce embryos, I consider that I am justified ia 
 calling these organs " pro-embryos." Thus, 1 designate as a pro-embyro the proto- 
 uema of a moss, whether it owes its origin to the germination of a spore or to the 
 independent development of an individual cell of the leaf- bearing plant. I treat 
 in the same manner the suspeusor of Selaginella, of the Couiferae, and of the 
 phanerogamia. On the other hand, I do not designate as a pro-embryo ihe 
 body which is jn-oduced directly from the germination of the spores of ferns, 
 Equisetacece, Rhizocarpeae, and Lycopodiaces, and which bears antheridia and 
 archegonia, usually only the latter. This organ I call a " prothallium." 
 
172 HOFMEISTER, ON 
 
 the principal branches, bring to mind most forcibly tlie 
 leaves of Trichocolea tomentella. The i)ro-cmbryo of Phas- 
 cum serratum is also remarkable, especially Avhen it 
 originates from the lower leaf-axils of developed plants. 
 It is a fact, noticed especially by Nägeli, that the shoots of 
 the pro-embryo are often subterraneous for a considerable 
 distance ; the transverse septa of such subterranean threads 
 of the pro-embryo are not perpendicular to their cylindrical 
 outer surface, but strongly niclined to it. The pro- 
 embryonal threads of ScJiis foster/a osimmdacea creep about 
 for a considerable distance in the damp sand upon which 
 this delicate moss is accustomed to vegetate. These sub- 
 terranean rows of cells have such a narrow cavity, and their 
 fluid contents are so transparent, and so deficient in 
 granular matter, that they may be mistaken for some of 
 the most delicate microscopical forms of moulds. When 
 the terminal cell of such a thread is exposed to daylight, it 
 immediately swells to a spherical form, and some beautiful 
 emerald green chlorophyll-bodies are formed in its fluid 
 contents. It would seem that a single chlorophyll-body is 
 first formed, which is then increased by self-division 
 (PI. XVIII, fig. 16). The multiplication of the cells of the 
 subterranean green portion of the pro-embryo, takes place 
 by the continual division of its cells by means of transverse 
 septa. The process is somewhat peculiar. The new septum 
 does not pass through the mother-cell transversely, but the 
 division commences by the protrusion, from the apex, of a 
 small swelling which is at first hemispherical. The upper 
 part of this protuberance increases rapidly in circumference, 
 and becomes spherical ; the lower part, on the other hand, — 
 viz., the place of junction of the protuberance with the 
 mother-cell, — widens to a very small extent, or not at all. 
 Finally, when the size of the protuberance has nearly reached 
 that of the mother-cell, a transverse septum is produced at 
 the point of constriction, which cuts off the protuberance 
 from the mother-cell (PI. XVIII, fig. 16). Some time 
 before the appearance of this septum, the first chlorophyll- 
 vesicles are perceived within the protuberance. Usually 
 only one such vesicle is at first visible, and the first symp- 
 
 * ' Zeitsclirift für Wiss. Bot.,' lift. 2, s.l72. 
 
THE HIGHER CRYPTOGAMIA. 173 
 
 tonis of it appear to be the production of colouring matter 
 within a spherical drop of semi-fluid mucilage. It is cer- 
 tain that no chlorophyll-vesicles pass from the original cell- 
 cavity into the enlarging protuberance. The single chloro- 
 phyll-vesicle often attains a very considerable size : in other 
 cases four or more chlorophyll-vesicles are found in the 
 protuberance before the formation of the septum which 
 divides it from tlie original cell-cavity. Probably these 
 have been produced by the repeated division of the original 
 individual chlorophyll-vesicle. The number of chlorophyll- 
 vesicles in the recently-formed cells of the pro-embryo is 
 very frequently four. Older cells usually exhibit a larger 
 number. It is but rarely that the chlorophyll-vesicles are 
 asQ-lomerated in the middle of the cell : when this is the 
 case, the condition appears to me to be a diseased one. 
 
 The well-known metallic lustre which marks the spots 
 overgrown by Schistostega is not, caused by the chloro- 
 phyll-vesicles, but is fully accounted for by the spherical 
 form of the individual cells. Dew drops upon spiders' webs 
 produce a precisely similar optical appearance. 
 
 I could not discover any nuclei in the dividing pro- 
 embryonal cells of Schistostega. My observations having 
 been made whilst travelling, I had not any tinctm-e of 
 iodine at hand. 
 
 Some of the older observers entertained curious opinions 
 as to the influence of the nioniliform rows of cells of the 
 pro-embryo upon the development of the young plants. 
 The most peculiar notion is that of Hiibener, who says, 
 '• These bodies afford, by reflexion, the hght which is neces- 
 sary for the life of Schistostega ; and in this way, as Esch- 
 weiler has very correctly remarked, they represent the 
 moons of the vegetable kingdom." The glimmer of the 
 protonema of Schistostega cannot be explained by phos- 
 phorescence. The plant never shines in the dark, even 
 although previously exposed to a rather intense light, such 
 as that reflected from a white cloud. The direct action of 
 sim-light almost immediately destroys the vitality of the 
 cells. This unusual sensitiveness to the rays of the sun is 
 common to a number of other mosses also ; for instance, 
 Calypogeia Trichomanes. 
 
174 HOFMEISTER, ON 
 
 It is a widely-spread notion that the pro-cnibryo of 
 mosses, irrespective of its entirely different physiological 
 nature, is distinguishable from the prothallium of ferns by 
 the fact that the former consists of confcrvoid cellular 
 threads, the latter of an ulva-like cellular superficies. I 
 was much surprised, therefore, when I found that certain 
 crisped vegetable formations resembling the prothallia of 
 the Equiseta or plants of Anfhoceros jmncfatus and which 
 had grown as weeds amongst some unsuccessful sowings of 
 Lijcopodwm Selar/o, proved to be the pro-embryos of a 
 moss. Sphagnum cuspidati/m. 
 
 Schimper (' Rech, sur les Mousses') has figm-ed the 
 ramified rows of cells which are the first products of the 
 development of S})hagnum-sporcs wiien sown in water. 
 Afterwards the same observer noticed certain shoots pro- 
 ceeding from short lateral branches, during the vegetation 
 of the pro-embryo in water. These shoots are very pro- 
 bably the rudiments of leafy branches. When germinating 
 upon moist earth, one of the ramifications of the thread- 
 like pro-embryo becomes a cellular superficies (PI. XVIII, 
 figs. G, 8). The disposition of its cells fluctuates between 
 an arrangement in pairs and a simple cross-bar arrange- 
 ment ; this is caused by the repeated division of a single 
 apical cell, by means of septa perpendicular to the surface, 
 turned alternately to the right and to the left. The former 
 kind of cell-succession usually prevails. The copious rami- 
 fication of the pro-embryo appears sometimes truly, some- 
 times spuriously, dichotomons ; it is rendered indistinct by 
 the appearance of numerous adventitious basal shoots. A 
 vigorous pro-embryo forms a tangled tuft which it would 
 be lost labour to attempt to reduce to any regular system 
 of ramification (PI. XVIII, fig. 5). 
 
 Two phenomena distinguish these pro-embryos in a 
 remarkable manner from the prothallia of ferns and Equi- 
 setaceae. ^Phe crisped cellular surfaces are single throughout 
 their whole extent even after ten months' growth. The 
 parenchymatal tissue, from which the female organs of 
 reproduction are produced in the green prothallia, is never 
 seen. The base and the side-edges of the lobes of the pro- 
 embryo are fm-nished with thread-like processes which arc 
 
THE HIGHER CRYPTOGAMIA. 175 
 
 branched and divided by septa, differing herein consider- 
 ably from the simple radical threads of prothallia. Such 
 of the above-mentioned processes as are rich in chlorophyll 
 are divided by septa perpendicular to the longitudinal axis ; 
 those which are deficient in chlorophyll, by oblique septa. 
 Tliese widely-creeping cellular threads have the capacity of 
 prodncing new expanded pro-embryos, by enlargement and 
 division of the terminal cells. 
 
 In individual cells of the lobes of the embryo, usually in 
 those very near the base, a multiplication commences diifer- 
 ing essentially in direction and in kind from that hitherto 
 spoken of A hemispherical knot of cellular tissue is pro- 
 duced, which by degrees becomes cylindrical, and which, 
 developing, as it does even at an early period, some rudi- 
 mentary leaves, may be recognised as the shoot of a moss 
 (PL XVIII, fig. 10). The arrangement of the cells of the 
 leaves brings to mind Sphagnum ; a suspicion which is 
 reduced to certainty by the characteristic thickening layers 
 of the leaf-cells which appear in the fifth leaf I find the 
 phyllotaxis to be from the beginning § (PI. XVIII, fig. 10). 
 Rootlets springing from the leafy root are not to be found 
 in Sjjhagnum acutifolium. 
 
 Hedwig's observations* were the commencement of an 
 accm^ate knowledge of the sexual reproduction of mosses. 
 He pointed out the antheridia as the male organs, recognised 
 their structure, and observed the escape of their contents. 
 He figured the archegonia as flask-shaped bodies, closed 
 when young, and afterwards opening at their apex. He 
 also pointed out the conversion of the ventral portion of the 
 archegonium into the calyptra, and the formation of the 
 fruit-rudiment within it. Lastly, he showed by experiment 
 that the spores of the mosses are their true seeds. He 
 sowed the spores of Gj/mnostomuvi j)i/riforme, and observed 
 their germination, and the development of the inner spore- 
 membrane into a cellular thread, or, as Hedwig called it, a 
 cylindrical cotyledon (1. c, 153, pi. xvi, fig. 9). After some 
 time scales were seen on these threads, which scales, when 
 examined with the microscope, proved to be young plants, 
 the bases of which were attached to branched pro-embryonal 
 
 * 'Theoria gcnerationis,' ed. ii, p. 134, et seq. 
 
176 HOFMEISTER, ON 
 
 threads. The same was the case with Funaria hjgrometrica. 
 The production of leafy plants out of pro-cnibryonal threads 
 was considered by Hedwig's followers to arise from the 
 amalgamation of several threads of the pro-embryo, so as 
 to form the leafy stem (see Schleiden, 'Grundzuge,' 
 2nd edit., vol. ii., p. OG), an error which was grounded 
 upon the fact that numerous cells of the base of the 
 young leafy plant usually grow into new pro-embryonal 
 threads, the Bnitkeimfadeii of Nligcli. Niigeli clearly 
 explained the development of the leafy axis out of the 
 pro-embryo. He showed* that at the commencement 
 of the formation of the moss- stem, the terminal cells of 
 individual branches, or of the principal axis of the spores 
 or brood-germ-threads, expand, and, through division by 
 means of septa inclined in different directions, become con- 
 verted into a cellular body, which afterwards produces 
 leaves, and thus indicates the rudiment of a stem. The 
 results obtained by Nägeli have been extended by P. W. 
 Schimper (' Rech, sur les Mousses,' Strassburg, 1848, 
 ss. 1 — 4) to such a number of different species, that there 
 is no doubt of their general application. 
 
 The spermatozoa of the mosses, and (with the exception of 
 an imperfect observation of Bischoff's,) of the cryptogamia 
 generally, were discovered by Unger in 1834 ('Flora,' 
 1834, p. 145 ; more fully in ' N. A. A. C.,' xviii, pp. 2, 
 690, 790). Unger describes the spermatozoa as con- 
 sisting of a thick body, and a thin thread-like prolonga- 
 tion, which goes in advance when the body is in motion, 
 and is of a spiral form.f The motion of the spermatozoa 
 
 * ' Zeitschrift f. wiss. Bot.,' 2, 168. 
 
 •j- ' Bisclioff, Kryptog. Gewächse ' (Nürnberg, 182S), p. 13 note, mentions 
 that he has always noticed in freshly-opened globules (antlieridia) of Chara 
 hiqnda, a medley of numberless infusoria. They appeared to consist of small 
 dark points, which were connected by transverse lines like little strings. They 
 exhibited a continuous tremulous motion, by means of which the individual 
 points, with their stems, revolved round one another. Bisclioff was doubtful 
 whether these "infusoria" originated from cellular threads in the interior of the 
 antheridia. It is hardly necessary to remark that Bischoff's dark points are 
 only the optical sectious of the turning points of the spiral spermatozoon. 
 Schmidel's observations on Fossombromia (Ic. pi., p. 85) and those of Nees v. 
 Eseubeck ('Flora,' 1822, p. 31) on Sphagnum afford still less claim to the dis- 
 covery of the Spermatozoa, inasmuch as both observers only saw the motion o. 
 the escaped contents of ruptured antheridia, but did not distinguish the forms 
 of the motile bodies. 
 
THE HIGHER ClllPTOGAMIA. 177 
 
 is accompanied by continual revolution of the body round 
 its own axis : that is, round the axis of the spiral. Be- 
 fore maturity the spermatozoa are enclosed in quadran- 
 gular cells. Later observations have only added one fact 
 to those of Unger, viz., that the thin fore- end of the 
 spermatozoon bears two long oscillating cilia (Thuret, 
 ' Ann. Sc. Nat./ ii Ser., vol. xiv, ]). 68, and iii Ser., vol. 
 xvi, p. 73; Schimper, 'Rech, sur les Mousses/ pi. xv, 
 figs. 25 — 29 ; ' Mem. sur les Sphaignes/ pi. viii, figs. 23 — 
 25). Unger noticed the cuticle of the antheridia of 
 Sphagnum, but could not decide whether the structureless 
 membrane, which is capable of being detached from the 
 chlorophyll-bearing cells of the covering layer, was on 
 the outside, or on the inside of those cells. He was in- 
 clined to assume the latter. Schleiden seems fo have 
 fallen altogether into the mistake of supposing the cuticle 
 to be the membrane of a large central cell of the anthe- 
 ridiuni surrounded by the covering layer, for he alleges 
 (' Grundzüge,' ed. iii, p. 577), that this organ in Sphag- 
 num is a stalked oval sac, formed of a large central cell, 
 and a surrounding cellular layer. This erroneous state- 
 ment has been entirely refuted by P. W. Schimper ('Rech, 
 sur les Mousses,' p. 52), by means of the history which 
 he gives of the development of the antheridia, and also 
 by his accm'ate description of the anatomical structure 
 of these organs when they are mature and ruptured. 
 
 In the same manner as he has done in the case of the 
 antheridia, P. W. Schimper has recognised the rudi- 
 mentary formation of the archegonia, by means of the di- 
 vision, by septa inclined in different directions, of an out- 
 wardly-protruding papillary cell of the external surface 
 of the apex of the stem. This division is continually re- 
 peated in the apical cell of the cellular body, as it gra- 
 dually becomes cylindrical. 
 
 Until the publication of my observations, however, the 
 continental botanists attained no greater knowledge of the 
 structure of the archegonium when ready for impregnation, 
 than was possessed by Hedwig. 
 
 In the mean time, in the year 1833, Valentine had dis- 
 covered the simple rudimentary cell of the moss-fruit, in 
 
 12 
 
178 HOrMElSTER, ON 
 
 the interior of the archegou^uii ('Trans. Linn. Soc./ 
 vol. xvii, p. 465). liu succeeded in detaching this 
 cell (p. 466). He recognised it also in archegonia, whose 
 apices were still closed, but failed to disco^ er it in Bryuni 
 roseum, which in England often bears healthy archegonia, 
 but rarely fruit. He describes the development of the 
 rudimentary cell of the fruit as follows. " Soon after the 
 opening of the upper extremity of the style, another cell is 
 formed on the upper surface of the first. The two adhere 
 firmly, and may be dissected together. Presently another 
 cell is formed, either on the upper surface of the second, or 
 on its side ; then appears another, and so on. * * The 
 base of the style increases not by distension, but by 
 addition of fresh matter. * ^ The fusiform mass Avithin 
 passes 'its conical extremity deeper and deeper into this 
 tissue, until at last it reaches the branch itself." Valentine 
 observed further that after the separation of the calyptra 
 from the vaginula, the seta increased in growth only at the 
 apex, and he figures accurately the separation of the outer 
 capsule-Avall from the inner, by the formation of an annular 
 intercellular space. 
 
 Strange to say these observations of Valentine have 
 remained to this day wholly unknown in Germany and 
 France. They are not mentioned by De Candolle 
 (' Organographic vegetale,' ed. ii, vol. ii, p. 146) ; 
 Treviranus (' Pflanzenphysiol,' vol. ii, p. 46) ; ]\Ieyen 
 ('System d. Pflanzenphys.,' vol. iii, p. 385); Schleiden 
 (' Grundzüge,' ed. ii, vol. ii, p. 68) ; or P. W. Schini- 
 per ('Rech, sur les Mousses,' p. 67). I was myself 
 ignorant of them when I published my observations upon 
 the subject in'Botan. Zeit.,' 1849, p. 798, and in the 
 '^Vergleichende Untersuchungen,^ p. 69. JMolil in 
 Wagner's ' Handwörterbuch der Physiol,' vol. iv (1853), 
 p. 279; P. W. Schimper, 'Mem. surges Sphaigncs (1859), 
 p. 10; and Gottsche, 'Botan. Zeit.' (1858), supplement, 
 p. 42, make no mention of Valentine's discoveries. 
 Valentine himself was far from appreciating the importance 
 of his own observations. He expressly disputes Hedwig's 
 views of the sexuality of mosses. He says " If sexes are 
 to be found in mosses tliey must be sought in the theca 
 
THE HIGHER CRYPTOGAMIA. 179 
 
 (I.e., p. 777). The sporules of mosses and of all eellular 
 plants are analogous to the pollen of the vasculares." I can 
 claim as my own the accomit of the origm of the germinal 
 vesicle, of the dependence of its development upon the fact 
 of its impregnation, and the proof of the conformity between 
 the process of formation of the moss-fruit, and that of 
 the embryo of the vascular cryptogams, of the Coniferee, 
 and of the phanerogamia. 
 
 The first accurate account of the development of the 
 moss-capsule was given by H. v. Mohl, ('Flora,' 1833, 
 p. 1 ; 'Vermische Schriften,' p. 72). He places in a very 
 clear light the relation of the columella of Sphapmm gracile 
 to the two walls of the capsiüe, of the apophysis, and 
 of the peristome. The original homogeneity of the cel- 
 lular tissue of the young, few-celled fruit-rudiment, has 
 often been noticed by Bischoff {e.g., in ' Nova Acta,' vol. 
 xvii, p. 917). The development of the spores in fours 
 in one mother-cell, was pointed out by Mohl (1. c, p. 72). 
 Lantzius-Beninga showed (' De evolutione sporidiorum 
 in capsulis muscorum,' Göttingen, 1844, pp. 7, 11, 17), 
 that a single annular cellular layer of the interior of the 
 capsule represents the primary mother- cells of the spores, 
 and that the mother-cells, in which the spores originate, 
 are formed out of these primary mother-cells, by their 
 repeated chvision into two parts. He recognised, in many 
 instances, the free state of the mother-cells within the 
 primary mother-cells, as for instance, in Orthotriclmm 
 speciosiim, Trichostomum jy^/Z^V/^^w, and Gymnostoynum 
 pyriforme ; and lie discovered that the membrane both 
 of the primary mother-cells and of the mother-cells 
 became blue with iodine. In a later work, ' Bot. Zeit.,' 
 1847, p. 17, and more clearly in ' Nova Acta,' vol. xiv, 
 the same observer gives an admirable account of the anato- 
 mical structure of the perfect moss-capsule, especially of 
 the peristome, which up to that time had been almost en- 
 tirely misunderstood. Lantzius-Beninga stated that the 
 teeth of the peristome (except in Splachnum and Polytri- 
 chum,) do not consist of perfect cells, but that during the 
 development of the peristome-teeth, a partial thickening 
 occurs in the walls of the cells belonging to a conical 
 
180 llOl'JMHISTKB, ON 
 
 enveloping layer found in the interior of the upper conical 
 part of the capsule, Avithin and beneath the layers Avhich 
 afterwards fall off in the form of the operculum. The 
 thickening of the cell-membranes always occurs on both 
 sides. When a thickening takes place in the outer wall 
 of a cell wdiich is occupied in forming the peristome, then 
 a portion, exactly corresponding in extent and form, of 
 the inner w^all of the cell adjoining it on the outside becomes 
 thickened. When the thickened portion of the peii- 
 stome-cell is found on the wall which is directed tow^ards 
 the axis of the capsule, then the corresponding portion of 
 the outer wall of the neighbouring cell adjoining it on 
 the inside, is thickened in like manner. These thick- 
 enings have usually the form of longitudinal stripes, and 
 are so arranged in each of the ceils which help to form the 
 peristome, that they look like direct prolongations of the 
 stri])cs of the "wall of the cell next bclow^ AVlien the 
 thickenings of the })eristoinc-cells fill up the adjacent angles 
 of two laterally adjoining peristonie-cells which are bounded 
 on the outside or on the inside by a cell of double width, 
 then the thickening of the wall in this wide cell occurs in 
 the form of a median stripe, wdiich has the width of the 
 two corner stripes of the smaller neighbouring ])eristome- 
 cells. In the formation of the teeth of a moss with a single 
 peristome the outAvardly-directed walls only of i\\v ])eris- 
 tome-cells (and the correspondhig nnu-al stripes of the cells 
 adjoining on the outside) are partially thickened. In 
 mosses with double peristomes the inwardly-directed walls 
 of the peristome-cells are also thickened. AVhen the cap- 
 sule becomes mature, the cell-walls which ha\e jemained 
 unthickened become torn during the separation of the 
 operculum from the capsule, and the thickened longitudinal 
 stripes remain as the peristome teeth. In Splachnum and 
 Polytrichium the peristome-cells are thickened on all sides ; 
 in Splachnum hoAvever the thickenings are irregular, those 
 wdiicli m-e directed outwards being much the strongest. 
 
 Some interesting observations of Bruchs have very lately 
 been published. G umbel's ol)servations have shown the 
 occurrence of abnormal fruitiu mosses ('Nova Acta,' vol. xxiv, 
 p. 65.2). Those portions of the latter observations which 
 
THE HIGHER CRYPTOGAMIA. 181 
 
 relate to the production in Mnhmi verrat tim of two capsules 
 upon one seta, and of two capsules upon one apophysis in 
 Bri/iim argenteuri}, and Splacluuuu vasculosiim, seem to in- 
 dicate the possibility of a bifurcation of the growing upper 
 end of the fruit-rudiment. Those portions which relate to 
 the discovery of two fruits and two fruit stalks imderneatli 
 one conunon calyptra in Poljjfricht/ui jiuiijjcri/iuni and of 
 two stalked fruits upon one seta in Ilypnum jjifciiiosiim, ap- 
 pear to point to the existence in the central cell of one and 
 the same archegonium, of two germinal vesicles capable of 
 impregnation. There is hardly a doubt of the occiu-rence 
 of such a polyembryony, the development of which however 
 must assume a different form, when it is considered that 
 (1. c, p. 653) the case of an amalgamation of tw^o capsules, 
 each furnished with a peristome, has been observed in 
 Hypnurn lutescens. The mouths of the two capsules are 
 tm'ued to one another, the smaller one having grown up 
 upon the larger one. Both arc united by a median 
 process. 
 
 In order to arrive at a perfect proof of the sexuality of 
 mosses, it is desirable that hybrids between different species 
 should be artificially produced : ?'. e. that fruits should be 
 obtained by the impregnation of the archegonia of one 
 species by the antheridia of another. Bayrhotfer suggested 
 that some mosses found by him growing wild were hybrids 
 between Gymnostomum pyriforme and fasciculare on the 
 one side, and Funaria hygronietrica on the other side (see 
 Braun's 'Verjüngung,' p. 330). I have not yet succeeded 
 in producing such hybrids experimentally, although I 
 brought together antheridial plants of Gymnosiomum pyri- 
 fonue and plants of Funaria hyyvometrica with their anthe- 
 ridial shoots cut off. The mutilated plants of Funaria 
 Iryyromefrica always perished. This is however no reason for 
 giving up the attempt. By changing the method of culti- 
 vation the right one will probably be attained at last wliich 
 will lead to the desired result. 
 
CHAPTER VII. 
 
 FERNS. 
 
 1. Their fjermination. — The spores of feiiis usually 
 exhibit a tolerably thick, brittle, outer membrane, which is 
 furnished with prominent linear markings, or with wart- 
 like protuberances. When exposed to moisture and warmth 
 the inner membrane swells and ruptures the brittle outer 
 shell : this rupture usually occurs at the point of junction 
 of those three prominent lines of the outer membrane which 
 correspond with the lines of contact of the spore with the 
 three sister-spores which originated in the same mother- 
 cell and which, with the spore, formed a tetrahedron. In 
 the spores of those species in which the spore-mother-cell 
 divides into four cells having the form of quadrants of a 
 sphere and lying in one plane (which spores when ripe have 
 the shape of an elongated kidney) the exosporium usually 
 bursts i)y a longitudinal fissure, the course of which in like 
 manner corresponds with the line of contact of the spore 
 with its sister spores ; as for instance in Plafi/cerium 
 alcicorne (PL XXIV, fig. I). A portion of the inner 
 membrane protrudes through the fissure of the exosporium, 
 and some chlorophyll-ljodies are formed in this protruded 
 portion. The latter is soon afterwards separated by a par- 
 tition from that portion which remains inside the outer 
 membrane. In the outer of the two newly formed cells 
 the transverse division is repeated ; it usually occurs several 
 times (from three to five) in the terminal cell, so that the 
 young prothallium is converted into a row of cells (PI. 
 XXIV, fig. 1). Sometimes the undermost cell, the one 
 which adjoins the exosporium, becomes considerably elon- 
 
HOFMEISTER, ON THE HIGHER CRYPTOGAMIA. 183 
 
 gated; as may be observed in AsjjJenium septentrional e 
 (PI. XXIV, fig. 3). In most cases however this elonga- 
 tion does not occur. I have never seen it in Fteris aquilhm, 
 Aspidhim. ßJix-mas, Ceratopteris or Adiantum. In those 
 species where considerable elongation of the lowest cell 
 occasionally takes place, it seems to be caused by deficiency 
 of light. The first rootlet is produced during the con- 
 tinuance of the transverse division of the terminal cell of 
 the young prothalliuni : it has the form of a cylindrical 
 process developed from a protrusion of the membrane of 
 the lowest, more rarely of the second lowest, cell of the 
 prothallium. The rootlet very soon after its appearance is 
 separated from the original cavity of its mother-cell by a 
 septum convex towards the interior (PL XXIV, figs. I — 3). 
 After about the fifth transverse division of the apical cell 
 of the young prothallium, this cell divides by a longitudinal 
 septum. The two apical cells afterwards divide frequently 
 by transverse septa. In the cells of the second degree 
 which are thus formed transverse septa are produced. The 
 formation of these septa is however usually suppressed in 
 the two or three first-formed lowermost pairs of cells and 
 often also in one of the two next equal-aged cells (PI. XXIV, 
 fig. 2). Thus the prothallium begins to be converted into 
 a cellular surface. At the same time the direction of its 
 growth is turned more and more from the light, so that it 
 soon assumes a position parallel to the surface of the 
 ground : when the light is powerful it adheres closely to 
 the earth.* 
 
 The apical cells often divide also by longitudinal septa, 
 Avhich diverge slightly from the longitudinal axis of the 
 , prothallium, and which, like all septa which are produced 
 during the early growth of the organ, are perpendicular to 
 its sm-face. The prothallium has now four apical cells, of 
 which the two outer ones grow more rapidly in length than 
 the median ones, and immediately divide repeatedly by 
 
 * The turning away of the prothallium from the light, by which the fore 
 edge of each prothallium is continually diverted from the source of light, was 
 first observed by Wigand (''Beiträge zur Botanik/ 1851', p. 35). His explana- 
 tion however is altogether erroneous ; he assumes that the upper surface of the 
 prothallium was drawn from the liglit. If this were so the prothallium must 
 turn itself to the light. 
 
184 HOFMEISTER, ON 
 
 septa cutting tliosc which diverge from tlic longitudinal axis 
 of the organ at an angle of about 45° (PI. XXIV, fig. 3). 
 By this nicaus the foundation is laid for the two-lobcd form 
 of the prothallium. The cells of the edge of the wings of 
 the fore end of the prothallium then divide very frequeutly 
 by septa parallel to the chord of the arc of their circum- 
 ference. After a series of such divisions there are produced 
 in the marginal cells, longitudinal sei)ta at right angles to 
 the latest formed transverse septa. This cell-multiplication, 
 by which both lobes of the prothallium are rapidly and 
 remarkably enlarged, is least active on the outside of the 
 lol)es, where it soon ceases. The cessation progresses from 
 the hinder part of the protallium to the apex of each of the 
 side lobes. On the other hand those cells of the two lobes 
 which are directed towards the deep indentation of the 
 fore edge, continue to multiply for a longer period. The 
 nuütiplication, however, is most active in the two cells 
 which occupy the base of the notch between the two wings 
 of the prothallium, Avhich notch is constantly increasing in 
 depth. These cells divide continually and repeatedly by 
 means of transverse septa at right angles to the longitudinnl 
 axis of the prothallium, alternating with divisions by means 
 of longitudinal septa which converge slightly to the longi- 
 tudinal axis. Those of the new cells thus formed w^hich are 
 farthest from the middle point of the indentation begin 
 immediately to diverge in their growth from the longitu- 
 dinal axis of the prothallium to the extent of about 05°. 
 By this means the new cells thus produced drive the cells 
 adjoining them on the outside upwards and outwards. 
 During their change of position the growth of these cells 
 diverges more and more from the longitudinal axis of the. 
 prothallium, ultimately to the extent of 90°. Those 
 daughter-cells which arc separated from the cells in the 
 loAvest portion of the indentation push themselves upwards 
 laterally by the side of their mother-cells, by means of an 
 innate power of growth. Whilst they push the adjoining 
 older cells outwards, they take part in the formation of the 
 two side wings of the prothallium, which consequently in- 
 crcnsc continnally in size and in the number of their cells, not- 
 withstanding the progressive cessation of the nuütiplication 
 
THE HIGHER CllYPTOGAMIA. 185 
 
 of the cells of their outer edge (PI. XXIV, fig. C). The 
 npical cell for the tmiebehig of the wmgof theprotlmlliuin, 
 is contiiuially pushed downwards and outwards and re- 
 placed by a younger one. The growth of the youngest 
 cells in the direction diverging from the longitudinal axis 
 of the side wings is frequently more active at their inner 
 than at their outer end. Where this phenomenon is very 
 strongly manifested it leads to such a remarkable develop- 
 ment of the breadth of the two wings of the prothallium 
 that the one overlaps the other. This circumstance how- 
 ever occurs, for the most part at least, only in prothallia of 
 exuberant growth ; it does not take place until the termina- 
 tion of the normal growth of the prothallium. 
 
 Individual cells of the under side of the prothallium pro- 
 trude outwardly in a hemispherical form. In very young 
 prothallia, or in thin shoots of old exuberant prothallia, the 
 same thing occurs in the marginal cells (PI. XXIV, fig. 4). 
 The development of these cellular excrescences usually 
 commences at the hinder part of the prothallium, proceed- 
 ing from thence towards the front part, but without any 
 very great regularity. As a rule one excrescence only is 
 developed on one cell of the prothallium. In the median 
 line of the latter, one of these excrescences is produced from 
 almost every cell ; towards the sides their number dimin- 
 ishes, and at the edges of the wings of the prothallia the 
 formation is entirely suppressed. Their expansion coincides 
 with that of the radicidar appendages. The protruding 
 portion of the free outer smface of the cell is soon separated 
 from the primary cell-cavity by a transverse septum. This 
 transverse division is often repeated a second time, more 
 rarely several times, so that the hemispherical terminal cell 
 of the excrescence is supported by one, or by several, discoid 
 shortly cylindrical cells. The nature of their contents 
 differs little at first from that of the vegetative cells of the 
 prothallium. The walls are covered by a layer of chloro- 
 phyll having somewhat smaller granules than that of the 
 neighbouring cells ; their supply of protoplasm is somewhat 
 larger. Prom this period the highly refractive protoplasm 
 of the young antheridium accunuilates to such an extent, 
 that the arrangement of its component cells is very difficult 
 
186 HOFiMEISTEK, ON 
 
 to recognise. There can however be no doubt that after 
 some time the antheridium is composed of a cyhndrical or 
 angular, ahiiost cubical, central cell of large size, very rich 
 in granular protoplasm, supported by one cylindrical or two 
 semi-cylindrical cells, covered by a cell having the form of 
 a segment of a sphere, and surrounded laterally by a gii'dle, 
 which in most cases looks at first sight like a simple 
 annular cell, or two such cells standing one over the other, 
 but which, after more careful examination, and especially 
 after treatment with a saccharine solution and iodine, may 
 often be seen to be composed of several cells, from two to 
 four in number, lying in one plane. 
 
 Those states of the antheridia which, judging from their 
 size and their position on the prothallimn, are intermediate 
 between the condition just mentioned and the unicellular 
 condition, may be distinctly recognised by the sharply de- 
 fined, circular boundary line of the apical cell ; and, less 
 distinctly, by the appearance of the central cell which is rich 
 in protoplasm. In some young antheridia the best object- 
 glasses especially when combined with the use of a solution 
 of sugar and iodine exhibit the lines of contact of the cell- 
 walls with the outer surface of the antheridia. These lines 
 run obliquely downwards, usually in a left-handed spiral 
 which describes about a sixth part of a circumference (PI. 
 XXIV, fig. 9). The analogy to be derived from the pro- 
 cess of development of the antheridia of the Muscineae ren- 
 ders it probable that the large central cell is formed by the 
 production of an excentrical, inclined, longitudinal septum 
 in the young antheridium, followed by the production of 
 another excentrical septum cutting the latter at right 
 angles, and the subsequent formation of a longitudinal 
 septum cutting both the above at an angle of 45°, such 
 formation taking place after the apical cell of the antheri- 
 dium has been isolated by a strongly inclined almost hori- 
 zontal septum cutting the primary longitudinal septum. 
 Where the central cell is surrounded by two zones of en- 
 veloping cells it is manifest that the two zones originate in 
 the transverse division of the primary single zone. 
 
 The structure of the prothallia' and antheridia of all the 
 Polypodiaccae which have been yet examined is identical in 
 
THE HIGHER CRYPTOGAMIA. 187 
 
 all essential points. The only specific differences are, that 
 in certain species {swch as Jspiduwi ßlicv-7nas, and several 
 species of Adiantum) certain marginal cells of the pro- 
 thallium grow into papillae, which in Aspidiuni are thin and 
 cyhndrical with a clavate end, and in Adiantum are very large 
 and flask-shaped, whilst in the prothallia of other ferns the 
 margin is destitute of such protuberances, as is the case 
 in Fteris aqidlina and serrulata. The only known instance 
 of variation is afi'orded by Ceratopteris thalictroides. When 
 the large spores of this species germinate, and the exospo- 
 rium bursts, it is seen that the portion of the prothalHum 
 which is enclosed within the lobes of the exosporium, is a 
 multicellular roundish body. The conclusion from this fact 
 is that the inner cell of the spore is divided into several 
 daughter-cells before the bm-sting of the exosporium. The 
 prothallium moreover does not develope two lateral lobes 
 with a deep indentation between them, having the focus of 
 continuous cell-multiplication, at its base, but the point of 
 most active cell-multiplication is situated sideways on the 
 prothallium (PI. XXIV, fig. 16). One wing only of its 
 fore edge is developed. The rudimentary cells of the 
 antheridia are for the most part marginal cells of the pro- 
 thallium somewhat deeply buried between the vegetative 
 cells of the margin. The process of cell-division in them 
 coincides Avitli that which is supposed to exist in most of 
 the Polypodiacese (PI. XXIV, figs. 17—19).- 
 
 * Wigand states that the mother-cells of spermatozoa, and even motile 
 spermatozoa themselves, are sometimes found in the chlorophyll-bearing vege- 
 tative cells of the prothallium. This statement has not been confirmed by any 
 other observer. Wigaud has probably seen appearances which I have myself 
 met with, though on rare occasions. I iiave found iu many of the vegetative 
 cells of old, abnormally developed, prothallia, globular or elongated, sharply 
 defined masses of a thick mucilaginous substance which for the most part hung 
 together in arborescent ramifications, but were to some extent detached, and 
 formed entirely free globular bodies. The diameter of these bodies is but little 
 (about a third) greater than that of the mother-cells of the spermatozoa. They 
 were present in individual cells sometimes in greater sometimes in less num- 
 bers. The arrangement of the chlorophyll of the cells in which they were 
 enclosed was not materially disturbed although the colour of the chlorophyll 
 was slightly faded. Some of the arborescent groups were drawn out at one 
 end into a thin thread-like cell which had quite the appearance of a fungoid 
 filament, and which was attached at its extremity to the free outer M'all of the 
 cell of the prothallium. iu otiier cells of the same prothallium the chlorophyll 
 had disappeared and they were filled with empty cells having a firm membrane 
 and looking like the mother- cells of zoospores. These structures arc certainly 
 
188 HOFMEISTER, ON 
 
 The cells of the authcridia, which surround the central 
 cell, do not multiply any furtlier. The latter, however, 
 after a considerable increase of its circumference, is trans- 
 formed by a series of divisions into a globular group of 
 cubical cells (PI. XXIV, figs. 10, 11). By the growth of 
 this cellular mass the cells of the covering layer are ex- 
 tended more and more into a tabular form, sometimes to 
 such an extent, that their cavities are entirely obliterated. 
 During the multiplication of the central cell their fluid 
 contents have become as clear as water. 
 
 In each of the small tesselated cells within the antheri- 
 dium there is produced a flat spirally twisted spermatozoon 
 in the interior of a lenticular or globular vesicle, the latter 
 being apparently the primary nucleus of the small cell. 
 The turns of the spiral are but few in number. 
 
 As the antheridium approaches maturity the w^alls of 
 the small internal cells are dissolved and the vesicles en- 
 closing the spermatozoa then lie free, enveloped in a granu- 
 lar mucilage, and surrounded by the compressed covering 
 cells. If the antheridium is now exposed to moisture, 
 its contents swell, the flatly compressed cell of the apex 
 bursts in the middle in a stellate manner, and the vesicles 
 enclosing the spermatozoon escape through the fissures. 
 If the spermatozoa are fully- formed and ripe, the vesicles 
 when lying in water, exhibit a rotatory motion shortly after 
 their escape from the antheridium. I have often observed, 
 that at the commencement of this motion, one of the ends 
 of the spermatozoon (usually the fore-end, which is the 
 thicker one and bears the cilia), protrudes from a fissure in 
 the vesicle. Suddenly the vesicle bursts by a wide open- 
 ing, the spermatozoon becomes free, and shoots out from it 
 in very rapid motion. 
 
 The expanded fore-end of the spermatozoa, as has been 
 mentioned, is compressed laterally to a considerable ex- 
 tent; the outer side of its spiral coils bears numerous deli- 
 cate cilia, which vibrate actively during its motion (PI. 
 XXIV, figs. 13, 15). At the opposite end the sperma- 
 tozoon gradually fines off into a very long hair-like termina- 
 
 always foreign to the prothallium and arc probably states of development of an 
 cntophytal fungus. 
 
THE HIGHER CRYPTOGAMIA. 189 
 
 tion. The latter often retains its original spiral form, and 
 remains attaclied to the interior of the vesicle within which 
 the spermatozoon originated (PI. XXIV, fig. 14"'*). The 
 forward motion of the spermatozoon is ahvays accompanied 
 by a rapid rotation romid the axis of the spiral, and follows 
 the direction of this spiral, Avhicli is sometimes a right- 
 handed, sometimes a left-handed one.* 
 
 AVhen the prothallium has become two-lobed, and has a 
 deep indentation on its fore-edge, the cells of that portion 
 of it which lies immediately behind the indentation, divide 
 by means of septa parallel to tlie sm-face of the prothal- 
 lium. This division is repeated two or three times, always 
 in the lower one of the ncAvly-formed cells. By this 
 means a flat cushion of cellular tissue is formed on the 
 imder side of the prothallium. On its hinder i)art, new 
 antheridia continue to be formed for a considerable time. 
 The archegonia are produced at the fore-part adjoining the 
 indentation. t 
 
 The mother-cell of an arche<i;onium is distinoiuished from 
 the adjoining cells by an abundance of finely granular 
 nuicilage, and by the presence of a larger less flattened 
 nucleus. The adjohiing cells just mentioned are rich in 
 chlorophyll : their contents are clear like water, and they 
 have a small lenticular nucleus adherent to the cell- wall. 
 
 * The statements of authors with regard to the form of tlie spcrniafozoa of 
 Terns, their number, tlieir nature, and the mode of attaclimont of their cih'a arc 
 in some respects very contradictory. Their discoverer, IS';iL;eh", makes no 
 mention of cilia. Lesczyc-Sumiuski in his account of tlie development of Ferns 
 (Berlin, ISiS) speaks of a few larj^e cilia as attached to the clavate fore end 
 of the spermatozoon oi Ftcris serrulala. 'J'his is an error, as the spermatozoa of 
 the latter species are similar to those of Asplenium. Schacht ('Linna^a,' Bd. 
 xxii) considered the vesicle in which the spermatozoon is produced, and which is 
 often dragged along by the whip-shaped end of ihe latter, to be an essential 
 ])orl.ion of it. This accounts for the ditfcrencc between his observations and 
 those of other botanists. He considered tlie vesicle to be the fore end of the 
 spermatozoon and that the hinder part preceded the narrower ciliated coils 
 when in motion. Thuret's statcmenis ('Ann. des Sc. Nat,' iii ser., vol. 11} 
 agree with mine except that he does not mention the tail of the spermatozoon. 
 
 f In order to justify the apjdication to the organs of Ferns, of an expression 
 hilhcrlo only used when speaking of the female organs of mosses, I must refer 
 to a subsequent part of this work ; where I endeavour to show that the fruit 
 (capsule and fruit stalk) of a moss answers to that which in ferns (taken in the 
 most extended sense) is simply called the plant ; and that the prothallium of 
 the fern is equivalent to the moss-stem, bearing autheridia and archegonia, 
 which is often much branched. 
 
190 HOFMEISTER, ON 
 
 The hinder end of the spermatozoon is frequently drawn 
 out into a narrow prolongation, but this is not a constant 
 character. It arises probably from the fact that during 
 the parting asunder of the spermatozoon and its mother-cell, 
 the plastic substance of the spermatozoon remains attached 
 to the membrane of the latter cell, and is mechani- 
 cally drawn out into a thin filament, which eventually 
 breaks off. 
 
 The first division of the primary cell of an archegonium 
 can only be seen by means of careful transverse sections of 
 the prothallium made perpendicularly to its surface. The 
 cell divides into an inner and an outer daughter-cell by 
 means of a septum parallel to the free outer surface. The 
 former becomes the central cell of the archegonium — the 
 embryo-sac. At a later period it is the place of formation 
 of the embryo. The neck of the archegonium is produced 
 by the multiplication of the outer cell (PI. XXV, figs. 1, 2). 
 This cell protrudes outwardly, and is divided into two 
 daughter- cells by a septum strongly inclined to the surface 
 of the prothallium, and often almost perpendicular to it. 
 This septum is sometimes at right angles to a plane passing 
 through the longitudinal axis of the prothallium, sometimes 
 it forms an acute angle with that plane, and sometimes it 
 is parallel to it. One of these positions is as frequent as 
 the others. The larger of the two daughter-cells is divided 
 anew by a septum super-imposed upon the latter septum, and 
 inclined in an opposite direction. The two-surfaced wedge- 
 shaped apical cell then divides from four to ten times by 
 means of septa inclined in different directions (PL XXV, 
 fig. 2). With this process the longitudinal growth of the 
 organ terminates. Each of the cells of the second degree — 
 which cells originate in the division of the apical cell by a 
 septum parallel to one of the lateral surfaces — divides im- 
 mediately after its production, by means of a longitudinal 
 septum radiating from the axis of the archegonium. The 
 neck of the archegonium consequently consists of fom- 
 parallel longitudinal rows of cells. Each of the cells con- 
 tains a lenticular nucleus, lying close to the cell-wall, and 
 from which strings of granular protoplasm radiate. Gran- 
 ules of a firm consistence are dispersed throughout the 
 
THE HIGHER CRYPTOGAMIA. 191 
 
 protoplasmic covering of the cell- wall. These granules are 
 usually very few in number ; sometimes however they are 
 more abundant, and they are not unfrequently furnished 
 with a thin coating of chlorophyll. 
 
 The necks of the archegonia when perfect frequently 
 exhibit a central string of cells in their longitudinal axis 
 (PI. XXV, figs. 3, 5, 6). The position of the cells of this 
 fifth longitudinal row relatively to those of the four sm-- 
 rounding rows, leads to the conclusion that the axile row 
 of cells is formed by the division of the cells of one of the 
 primary longitudinal rows into three-sided outer and four- 
 sided inner cells by means of septa parallel to the chord of 
 the arc of the free outer surface ; a process analogous to the 
 development of the axile string of cells in the neck of the 
 archegonia of liverworts and mosses. This formation of 
 axile cells frequently does not extend throughout the whole 
 length of the organ. It is sometimes suppressed in the 
 cells immediately adjoining the embryo-sac (PI. XXV, fig. 5). 
 More rarely it occurs only in the latter cells, in which case 
 the upper part of the neck of the archegonia consists of 
 four, and its loAver part of five rows of cells. Immediately 
 after the formation of the axile string, the contents of the 
 cells are found to be of a grumous nature, and the trans- 
 verse septa which separate the individual cells are soft and 
 gelatinous. AVhen treated with a solution of glycerine, or 
 with any substance which abstracts water, the cells become 
 contracted, and form granular mucilaginous matter, some- 
 times in separate spherical lumps, sometimes in the shape 
 of a single vermiform body (PL XXV, fig. 8). I attribute 
 the formation of the similar masses which occur in the 
 canals of the necks of archegonia which are approaching 
 maturity, to a similar transformation of the axile string 
 during the further normal development of the archegonia 
 (PL XXV, fig. 11). 
 
 Quite as often however, or even oftener, the formation 
 of an axile row of cells in the neck of the archegonium is 
 suppressed. Both forms of archegonia occur upon pro- 
 thallia of the same species, and even upon one and the same 
 prothallium. The one form is as common as the other in 
 Pteris serrulafa and Cerafopferis thalidroides. In Asj)i- 
 
192 HOFMEISTER, ON 
 
 dlum filix-mas and Gijmnogramma calomdanos the first- 
 inentioned form is more frequent. This form answers to the 
 structure of the archegonia in liverworts and mosses, the 
 other corresponds with that of the archegonia of tlie 
 Equisetaceas, Khizocarpese, and Lvcopodiaceae. Ferns con- 
 stitute the intermediate link between these groups, so far 
 as regards the organization of the female reproductive 
 apparatus. 
 
 During the longitudinal development of the neck of the 
 archegonium it bends backwards from the indentation of 
 the fore edge of the prothalhum. The amount of curva- 
 ture varies slightly in the archegonia of the same pro- 
 thallium. The archegonia of prothallia which bear those 
 organs on both sides are bent in the same direction, those 
 of the upper surface being usually more curved than those 
 of the lower surface. The curvature is very considerable 
 in the necks of the archegonia of those prothallia Avhich 
 are not close to the earth, but Avhich (in consequence of 
 their growing in masses) have become diverted obliquely 
 upwards. Thus it Avould seem that the curvatm'e of the 
 necks of archeo;onia affords another instance of negative 
 heliotropisnuts, i. e., of the turning away of an organ from 
 the rays of light. 
 
 The number of archegonia is far less than that of the 
 antheridia. On normally developed prothallia which con- 
 tain an embryonal rudiment, there are seldom more than 
 eight. The development of the archegonia commences 
 close behind the indentation of the fore edge of the pro- 
 thallium, and progresses from thence both forwards and 
 sideways during the continuance of the growth of the 
 prothallium. 
 
 In some prothallia, when growing under a sufficient 
 exposure to light, the rudimentary cells of the archegonia 
 are always on the under surface of the prothallium. Pro- 
 thallia how ever of the most different species, when growing 
 erect in closely packed tufts, or in places where few rays 
 of light penetrate, develope archegonia on both surfaces. 
 On the upper surface, wdiich is usually distinguishable by 
 the paucity or absence of rootlets, the archegonia are 
 usually mixed with antheridia. It is evident that shade is 
 
THE HIGHER CllYPTOüAMIA. 193 
 
 favorable to the production of sexual organs as well as of 
 roots. 
 
 In Ceratopferis fhaUctroides, the antlieridia of which 
 arc abnormal in position and structure, prothallia occur 
 having numerous cushion-like masses of tissue in which 
 archegonia are produced, each one of such cushions being 
 situated behind one of the numerous indentations of the 
 edge of the prothallium. 
 
 At an early period, even before the complete fonnation 
 of the neck, a secondary free nucleus appears in the 
 upper part of the central cell of the archegonium. The 
 large primary nucleus of the central cell is still ])resent. 
 The secondary nucleus is soon seen to be surrounded by 
 a free spherical cell, in close proximity wdtli the internal 
 surface of the apex of the central cell (PI. XXV, figs. 
 5 — 9). This is the germinal vesicle. When it first 
 ai)pears its diameter is only about one sixth of that of the 
 central cell, but, even before the bursting of the apex of the 
 archegonium, it grows, to almost one half the size of its 
 mother-cell. For some time after its appearance the 
 primary nucleus of the central cell remains unchanged 
 (PL XXV, figs. 3, 5, 8) : at a later period it disappears ; 
 this takes place before the opening of the apex of the neck 
 of the archegonium (PL XXV, figs. 4, 7, 11). 
 
 The cells of the inner tissue of the prothallium which 
 are adjacent to the central cell of the archegonium, di- 
 vide repeatedly by septa at right angles to the bounding 
 sm'faces, and by this means are converted into a kind of 
 epithelial layer, consisting of narrow cells containing a 
 quantity of finely granular protoplasm (PL XXV, figs. 3, 
 5, 11). The period of the commencement, and the in- 
 tensity of this multiplication, are very different in indivi- 
 dual instances. (Compare PL XXV, fig. 3, with PL XXV, 
 figs. 4, 7.) 
 
 During the formation of the germinal vesicle a wide 
 canal leading to the embryo-sac is formed in the longi- 
 tudinal axis of the neck of the archegonium. The apex 
 of the neck of the archegonium remains firmly closed 
 during the development of this canal. In most cases 
 during the proa;rcss of this development, the cells of the 
 
 13 
 
194 HOFMEISTER, ON 
 
 arcli of the apex of the archegonium muUiply by division 
 which takes place by means of septa at right angles to the 
 outer surfaces. This process is especially remarkable in 
 Gymnocjranuiia calomelanos (PI. XXV, fig. 7). Where the 
 neck of the archegonium consists of only four longitudinal 
 rows of cells the axile canal is manifestly formed by the 
 parting asunder of the angles of contact of the latter cells. 
 The membranes of the cells grow in the direction of tan- 
 gents to the cylindrical organ : thus an intercellular space 
 originates between them, which is often of considerable 
 width. The process commences underneath the arch of the 
 apex of the archegonium and proceeds from thence to its 
 base (PI. XXV, fig. 4). When the neck of the archegonium 
 is traversed by an axile string of cells the canal can only be 
 produced by the dissolution of the transverse septa of these 
 cells. In this case also the dissolution is preceded by an 
 increase in growth of the peripheral cells in a tangential 
 direction, which is especially remarkable at the apex of the 
 neck of the archegonium, so that the axile string of cells 
 assumes a clavate form (PI. XXV, figs. 5, 7). 
 
 Within the canal of the neck of the archegonium, whilst 
 the latter is still closed at the apex, there is sometimes (but 
 by no means always) to be found an elongated vermiform 
 body, of a finely granular, tough, gelatinous consistence, 
 club-shaped at the upper, and tapering towards the lower 
 end. At other times there may be seen several similar 
 bodies within the canal, of wliich the uppermost are 
 usually elongated, and the lower ones spherical. The re- 
 verse is however sometimes the case, the lower bodies being 
 sometimes longer than the upper ones (PI. XXV, figs. 7, 
 11). These bodies are very probably nothing more than 
 the altered contents of the cells of the axile string of the 
 neck of the archegonium, which upon the dissolution of the 
 transverse septa run together more or less completely into 
 one mass. The elongated clavate form of the upper of these 
 bodies (a form which is of frequent occurrence when 
 several of such bodies are present) probably results from the 
 fact that in this case also the formation of the canal of the 
 neck, the dissolution of the transverse septa of the axile 
 row of cells, and consequently also the flowing together of 
 
THE HIÜHEH CRIPTOÜAMIA. 195 
 
 the contents of these cells, proceed from above doAvnwards ; 
 the process taking place rapidly at first, and afterAvards 
 more slowly. 
 
 After the formation of the canal of the neck, and whilst 
 the apex of the archegonium is still closed, the walls of the 
 cells of the peripheral layer become arched inwards to a 
 considerable extent, and protrude into the canal : a mani- 
 fest proof that these cells, being in a state of active expan- 
 sion, exert a great pressm'e upon, and displace the fluid 
 contents of the canal. Ultimately the cells of the apex 
 part asunder, by which means a portion of the mucilaginous 
 fluid contained in the canal usually escapes through the 
 opening. Bv this means individual cells are not unfre- 
 quently detached and thrust off (PL XXV, fig. 12). The 
 canal is now open externally, and exhibits an uninterrupted 
 communication from without inwards, up to the central 
 cell of the archegonium. 
 
 The membrane of the arch of the apex of the latter has 
 in the mean time become softened. A gentle pressure upon 
 the covering glass not only forces the mucilage of the canal 
 out of the mouth of the latter, but a portion also of the 
 contents of the embryo-sac is gradually driven into, and 
 through the canal. The motion however is not so sudden 
 as in the case where the contents of a cell escape through a 
 fissm'e produced by the bm'sting under pressure of an elas- 
 tic membrane. In one case I observed that one of the 
 bodies in the canal had made its way into the central cell ; 
 a circumstance which proves clearly the exposed nature of 
 the embryo-sac (PI. XXV, fig. II). The membrane of the 
 germinal vesicle on the other hand, even before the burst- 
 ing of the archegonium, is somewhat firmer. It is clearly 
 seen, when an embryo-sac and the germinal vesicle within 
 it are injured in making a section, that the membrane 
 exhibits folds (PI. XXV, fig. 9). 
 
 Most archegonia are not developed any further. The 
 cell-walls which adjoin the canal, as well as the large cell 
 at the base of the archegonium, assume the purplish-broAvn 
 colour, which is peculiar to the fading cell-membranes of 
 almost all the higher cryptogams. This is the fate not 
 
196 liUliMElbTJiK, UN 
 
 only of all except onc='= of the arclicg-oiiia of the same i)rothal- 
 liuui, but by far the greater niunber of prothallia are en- 
 tirely abortive, and produce no young plant. It is not too 
 much to say that hardly one })rothallium in ten produces 
 a frond-bearing plant. Prothallia Mhicli are dcAoid of 
 embryos, do not, however, by any means die ; when they 
 are not deprived of the conditions essential to their vitality, 
 that is to say, moderate Avarmth, subdued light, and 
 abundant moisture, they continue to develope themselves 
 for several months. In the simplest case the side lobes of 
 the prothallium increase very considerably in size ; they 
 overlap one another to a great extent in front of the inden- 
 tation of the fore edge. The prothallium when growing 
 exuberantly becomes circular ; it attains a diameter which 
 is from four to six times larger than that of the prothallia 
 of the same species which have produced young plants. 
 This is the regular rule in abortive prothallia of Gyh}no<j- 
 ramma chrt/sophi/l/a and others. Tiie cushion of the under- 
 surface grows at the same time in thickness and in length. 
 The latter growth is })roduced by repeated division of the 
 cells w^hich adjoin the bottom of the slit of the fore edge, aiul 
 which division takes place by means of septa at right angles 
 to the u})per sm'face of the prothallium. At the same 
 time a number (often a very great number) of archegonia 
 are usually produced upon the prominent cushion of tieshy 
 cellular tissue on the under side of the prothallium. These 
 archegonia, with the rarest exceptions, are all abortive, 
 probably in consequence of the fact that no more new 
 antheridia are produced upon the hinder, oldest portions, of 
 the same prothallium. The earliest of these archegonia 
 have the same form as those which are produced contem- 
 poraneously with the latest antheridia. The later ones, 
 however, either develope a rudimentary neck only, or no 
 neck at all. The large central cell and the canal tilled with 
 mucilage which leads to it appear to be sunk into the under 
 side of the prothallium (PI. XXVIII, fig. 2). The obser- 
 
 * With the rarest cxccptious, such as the case of Ceratopteris thcdidroides, 
 observed by Merekliu ('Beobachtungen au Prothallium der Farrnkr.' Peters- 
 burg, 1850) and Pleris aqinlina and Af^pulinm filix-mas observed by myself. 
 
THE HIGHER CRVPTOGAMIA. 197 
 
 vation of such arcliegonin, and tlio coHipavison of tliem witli 
 those placed farther backwards and having perfect necks, 
 seems to have led Lesczyc-Suminski, and after him Merck- 
 lin, to the erroneons conclusion, that the archegonium in 
 its earliest youth was a short canal opening upon the under 
 side of the prothallium, and that the neck was formed by 
 repeated division, in a direction parallel to the surface of 
 the prothallium, of the cells surrounding the mouth of that 
 canal. 
 
 The abortive protliallia of Nothochlaena, Allosurus, and 
 Gymnofjramma caJomelanos often exhibit shoots. The ar- 
 rangement of the cells of the prothallium of ferns generally 
 resembles that of the leaf-like shoots of Pellia, Riccia, and 
 ^larchantia. It might be supposed from this that a new 
 shoot would originate at the bottom of the notch of the 
 fore edge, and that new shoots again would arise in the 
 axils which the last-mentioned shoot would form with the 
 side win^s of the fore edo-e. This, however, is rarely the 
 case (Pl.^XVIII, fig. 1). \Tsually several of the cells of the 
 edge of the prothallium grow into adventitious shoots, which 
 generally have the shape of a large spatula. The activity 
 of the multiplication of their cells breadthwise is ex- 
 ceedingly various. Very slender adventitious shoots 
 with imicellular bases often become detached from their 
 prothallia at an early period by the death and disso- 
 hition of the cells attached to them. They then represent 
 independent, very small prothallia (PI. XXIV, fig. 4), and 
 often bear very numerous antheridia. 
 
 The development of a very great number of antheridia 
 is an especial peculiarity which often occurs in the shoots 
 of tlic prothallia of ferns. They are either entirely barren, 
 or if antheridia are found, the latter are in great multitudes 
 and closely pressed together, there being often as many 
 as a hundred upon one shoot. I have never seen archegonia 
 upon one of these shoots ; they certainly have a tendency 
 to produce only male organs of fructification. 
 
 Old abortive prothallia of Gymnogramma chrysoplujlJa 
 often exhibit a very remarkable appearance in winter. 
 Near the hinder end several small oval knots of cellular tissue 
 are formed ; little knots varying from the size of a millet- 
 seed to that of a pea, and consisting of narrow cells filled 
 
198 HOFMEISTER, ON 
 
 with starch and oil-drops (PL XXVI, fig. 33\) In the 
 earher stages these knots are whitish or yellowish in colour ; 
 afterwards their outer side becomes brownish by the forma- 
 tion of from two to three layers of cork-cells. Perhaps 
 these wonderful organs are genunse, destined to reproduce 
 the prothalliuni. 
 
 It may be considered as beyond question that the pene- 
 tration of a spermatozoon into the open canal of the neck of 
 the archegonium is necessary in order that the spherical 
 cell within the central cell may be further developed, so as 
 to become a frond-bearing plant. Under ordinary circum- 
 stances the spermatozoa have the means afforded them of 
 swimming to the opening of the archegonium. Whenever a 
 dew occurs, numerous drops of water are found on the 
 under side of the parenchymatal cushion of the prothal- 
 lium. The flat space between the prothalliuni and the 
 ground is often filled with water. Under such circum- 
 stances, as the ground becomes gradually drier, air-bubbles 
 are formed under the prothalliuni, and their presence is 
 shown by the silvery-green glimmer which is exhibited by 
 the tissue above them. 
 
 The spermatozoa enter the canal, pass through it, and 
 ultimately reach the interior of the central cell, piercing 
 through the softened membrane of the apex of the latter. 
 Here theymove about for some time, sporting actively around 
 the germinal vesicle, which is in close proximity to the 
 inner wall of the central cell near the place of entry of the 
 spermatozoa.* Immediately after the arrival of sperma- 
 tozoa in the embryo-sac the interior of the mouth of the 
 canal is closed by the transverse expansion of its bounding 
 
 * I repeat here, with some additions, the course of observations upon wiiicli 
 the above statements are founded, an account of which I have ah-eady given in 
 the ' Reports of the Royal Scientific Society of Saxony.' 
 
 When a quantity of fern-spores are sown, the germinating prothaUia are 
 developed at very dififerent periods. Tiie earliest prothallia produce in the first 
 instance only anthcridia, afterwards antlieridia and archegonia together, and 
 when advanced in age, only archegonia. The earliest prothallia have already 
 attained the latter stage at' the time when the later prothallia, the development 
 of which has been retarded by the shade afforded by the earlier ones, are 
 thickly covered with anthcridia. If the plants are now kept for some days 
 rather dry, and then saturated with water, the result will be that numbers of 
 anthcridia will emit spermatozoa, and numbers of arcliegonia will open contem- 
 poraneously. The water should not be poured over the plants, but the pot 
 should be placed in water nearly up to its margin, by which means capillary 
 
THE HIGHER CRTPTOGAMIA. V\*^^\199 
 
 cells. This process is the first visible effect of impregm 
 tion ; in abortive archegonia the canal remains open. In 
 the latter the walls of the canal throughout, and also those 
 of the central cell, assume a deep brown colour. In im- 
 pregnated archegonia this colour only extends downwards 
 over that part of the canal which is not closed. Immedi- 
 ately after the closing of the lower end of the canal, and 
 during the progress of active multiplication in the cells 
 adjoining the embryo-sac, the impregnated germinal vesicle 
 attains the size of the sac. Even before it arrives at this 
 stage two secondary nuclei usually appear in its interior in 
 the place of the primary one which has disappeared (PL 
 XXVI, fig. 5). The first septum by which the germinal 
 vesicle is divided, is not however formed until the latter 
 has entirely filled the embryo-sac. This septum stands at 
 right angles to the longitudinal axis of the prothallium, and 
 almost perpendicular to its surface. It diverges from a 
 perpendicular erected upon that surface, downwards and 
 forwards towards the indentation of the prothallium {a, h 
 in PI. XXVIII, figs, l^ V; PI. XXVII, figs. 6 *, 7 *). 
 Soon afterwards an oblique septum is formed in each of 
 the two cells into Avhich the germinal vesicle is divided ; 
 
 attraction and condensation will yield abundance of moisture to the prothallia. 
 After one or two hours the surfaces of tlie larger prothallia, which are covered 
 with archegonia, are found almost covered with spermatozoa, partly in motion 
 and partly at rest. If a delicate longitudinal section through the parenchyma 
 of these prothallia be examined immediately, with a magnifying power of from 
 200 to 300 diameters, spermatozoa are sometimes found in all the archegonia 
 along t!ie whole length of the section. I thus found three spermatozoon in 
 active motion in the central cell of the archegouium of Aspidum fiUx-mas. In 
 this case the motion ceased seven minutes after the commencement of the 
 observation, and was accompanied (probably caused) by the coagulation of the 
 albuminous matter of the cell-contents. In the same fern on two occasions, and 
 also in Gymnogramma calomelanos and Ptens aquiliiia, I have seen a spermatozoon 
 in motion in the central cell of the archegonium ; and in the above-mentioned 
 species, and also in Asplenium septertrionale, and filix-femina, I have seen a 
 motionless body near the germinal vesicle (after the growth of the latter has 
 commenced) answering in form to a spermatozoon. Lastly, in Asindium filix- 
 mas and Pleris aquil'ma, I have often seen motile spermatozoa in the canal of 
 the opened archegonia, the motion of which spermatozoa ceased during the 
 continuance of my observation. I may add that these observations were very 
 numerous, and were undertaken with the view of following out the cell 
 development of the embryo. In a single prothallium, cultivated in the manner 
 stated above, and laid open longitudinally as I have mentioned, there will not be 
 found more than three, or at the most, four archegonia open at the apex ; 
 spermatozoa will probably be found in not more than one in thirty of such 
 archegonia, and they will often not be found at all. 
 
200 HOFMEISTER, ON 
 
 the septum in the liindcr cell is inclined downwards and 
 backwards, that in the front cell upwards and forwards. 
 The young embryo now consists of four cells, having the 
 form of segments of a sphere, Avhich fall into a vertical 
 plane passing through the longitudinal axis of the pro- 
 thallium (Pl/XXVIII, fig. 1). Fteris aquiliua m\AJsjj>diuiti 
 fihx-mass exhibit a specific difference in the angles of incli- 
 nation of the newly-formed septa. The upper angle Avhich 
 the newly-formed septum in the front cell forms with the 
 older one (PI. XXVI, figs. 6 ^ 7 *, h, c) is widely open in 
 Aspklimi filix-mas ; it is almost a right angle; the lower 
 angle of the septum in the hinder cell is very acute (PL 
 XXVI, figs. 6 ^ 7 *, a, d). In Pteris aquilvia this state 
 of things is exactly reversed (PI. XXVIII, figs. 1 *, 3*, a, d, 
 b, c). In connexion with this difference there exists also a 
 difference in the further development. In both species the 
 stem-bud and the first frond are formed out of one of the 
 four cells, viz., the lower one of the two front cells (PI. 
 XXVIII, figs. 1, 3, a.r; PI. XXVI, figs. 0, 7, ^/.c), and 
 the first root is produced from another of those four 
 cells. But in Asjud'mm filicc-mas the mother-cell of the 
 root {b,d PI. XXVI, figs. 0, 7) lies opposite to that 
 of the stem ; in Pteris aquilina it lies at the side {a,d 
 PI. XXVIII, figs. 1, 3). In Aspidium the primary 
 abortive axis of the embryo,* is developed almost ex- 
 clusively by continual divisions of that one of the four 
 cells which is most distant from the mouth of the archego- 
 nium. In Pteris the descendants of the two cells which 
 are furthest from the archegonium compose this organ, 
 which in that genus is much larger (PI. XXVIII, fig. 3). 
 The fourth cell of the young embryo Avhich lies under the 
 mouth of the archegonium multiplies still further in Aspi- 
 dium, althougli onlv to a slidit extent. Its derivative 
 cells do not form a detached portion of the germ-i)laut, 
 but go to form the cortical portion between the back of 
 the first frond and the first root (PI. XXVI, fig. 7). 
 
 All the \ascular cryptograms in which the germination 
 
 * The foot-like appendage by wliich tlie young fern is altaclied to tlie pro- 
 tliallium. Only a few of the ceils of the rudiment of the root take part in the 
 formation of tli'is "foot" (PI. XXVI, fig. 7). 
 
THE HIGHER CRYPTOGAMIA. 201 
 
 lias been obser\ed exhibit tlie same aiTaiigeincut of the 
 first four cells of the embryo. This arrangement exists in 
 the Khizocarpene, the Equisetacese, and in Isoetes ; and the 
 position of the first cells of the ruchment of the germ-plant 
 at the lower end of the suspensor of Selaginella, is the 
 same. In these cases the primary leafless axis is formed 
 principally by the multipHcation of the lowest of the four 
 cells ; of that one namely which is turned away from the 
 mouth of the archegonium. One of the side cells produces 
 the primary indefinite axis of the plant. A third cell forms 
 the first root, if the embryo produces such an organ. Sal- 
 vinia is well known to be generally rootless ; Selaginella 
 does not send out the first root until after the first bifurca- 
 tion of the stem. In this prevailing fact there is such a 
 marked diff'erence between the vascular cryptograms and 
 monocotyledons, that the remarkable similarity between 
 the germ-plants of the Naiadese and the grasses, and those 
 of the vascular cryptograms (especially such of the latter as 
 have a prothallium devoid of chlorophyll) upon which 
 similarity I once attempted to ground a comparison of the 
 organs of the two families, appears to be an unessential 
 external resemblance. 
 
 The multiplication of the primary cell of the lateral 
 principal shoot considerably exceeds that of the mother- 
 cell of the primary axis. The same thing prevails 
 although in a less degree in the primary cell of the 
 first root. Both divide by means of septa inclined in 
 diff'erent directions, and, it would seem, in a manner 
 similar to that in which in the m.ore advanced plant, 
 the multiplication of the cells of the first degree takes 
 place. I recognised the triangular form, Avhen seen from 
 above, of the apical cell of the principal shoot in Aspi- 
 (liumjllLv-iuas, and the two edged form of the same cell, 
 when viewed in a similar manner, of Pteris aquiU/ia, 
 after about three divisions had taken place in each of 
 them. Even after the first round of divisions the stem- 
 cell of the first degree ceases to multiply further : * a 
 proportionally more rapid sequence of divisions begins in 
 
 * See the explanation to PI. XXVIII, fig. 3 ^ aud PI. XXVII, figs. G*, 7*. 
 
202 HOFMEISTER, ON 
 
 the cell of the second degree, contiguous to the mouth 
 of the archegonium, which has been cut off from the 
 stem-cell. This cell of the second degree is the primary 
 cell of the frond. 
 
 That moiety of the primary cell of the principal shoot 
 Avhich adjoins the first cell of the primary abortive axis is 
 considered to be a cell of the first degree, the principal rea- 
 son for which ts, that at a later period, and when the germ- 
 plant is more developed, the cell in question appears as 
 the apical cell of the stem. It would be a simpler mode of 
 settling the rank of the cells, if that cell were con- 
 sidered to be of the first degree, in which the successive 
 divisions take place, not only at the earliest period, but in the 
 primary direction'; and according to this method there 
 would be no doubt that the primary cell of the stem, consi- 
 dered in relation to that of the frond, must be looked upon 
 as a cell of the second degree ; an opinion which might be 
 ]nade use of in support of the theory of the origin of the 
 fern-stem from the amalgamation of the stalks of the 
 fronds.* As, however, there are but few plants which ex- 
 hibit so manifest a terminal bud (around and under which 
 the appendicular organs take their rise), as the ferns do 
 Avhen they have attained some growth, it follows that here, 
 as in the similar instances of monocotyledonous embryos, 
 it is necessary in forming an opinion as to the rank of the 
 cells, to have regard to the condition of the plant at a 
 period subsequent to the formation of the cells in question. 
 
 In the two species immediately under consideration, the 
 cell-succession in the first frond agrees substantially with 
 that in the later ones, but at the same time it differs consi- 
 derably. The surface of the first frond is, however, in its 
 inception, parallel to that of the prothallium, as is the 
 case in all the Polypodiacere which have been hitherto ob- 
 served. The primary cell of the root divides in the first 
 instance by septa turned towards the neighbouring cells ; the 
 division takes place tmce by means of opposite septa (concave 
 
 * Considerations of this nature may have led Nägeli to deny that ferns have 
 leafy stems (' Zeitschrift für wiss. Botanik,' Heft 3 and 4, p. 148) ; Hau- 
 steiu's notion of the fern-stem also rests upon this foundation ('Linupea,' 
 1848). 
 
THE HIGHER CRYPTOGAMIA. 203 
 
 to one another in Fteris aquiUnci), so that the cell retams 
 its original two-edged form ; and three times by means of 
 flat septa diverging from one another at angles of 60°, so 
 that the cell assumes the shape of a three-sided pyramid 
 with an arched mider surface (PL XXVI, fig. 6). In both cases 
 a septum is now formed parallel to the chord of the outer 
 arc (PL XXVIII, fig. 1 ; PL XXVI, fig. 7). The flat cell cut 
 off' by this latter septum is the first rudiment of the root- 
 cap, whose outermost, hood-shaped, cellular layer is formed 
 by the miütiplication of this cell. Henceforth the root- 
 cell of the first degree lies surrounded by cellular tissue. 
 Its further increase arises from repeated divisions occurring 
 in the same succession. 
 
 Judging from its position, the first root of the young fern 
 is adventitious^ diflering in no respect from the later 
 adventitious roots of the full-grown plant. This view of 
 the nature of the first root of the vascular cryptogams in 
 general (a view which I expressed many years since*), 
 has lately been objected to by Wigand. His first objec- 
 tion (an unfounded one) rests principally upon a con- 
 jecture that the foot-shaped portion of the germ-plant, that 
 which I have called the primary axis, not only amalgamates 
 with the prothallium, but is prohahJy prolonged backwards 
 so as to form the root. Wigand adds, " I consider that 
 the enlargement of the lower part of the germ -pi ant is of a 
 different nature ; I look upon it as the undoubted rudi- 
 ment of the first main root ; it does not break through 
 after the manner of an adventitious root." A few words 
 of explanation are requisite as to the distinction be- 
 tween main roots and adventitious roots in general. 
 Om^ conceptions of main roots rest entirely upon the 
 observation, that the portion of the embryo of dicotyle- 
 dons, which is situated beneath the cotyledons (and in 
 most instances that portion of the plant alone) is prolonged 
 downwards and becomes the root, and that in a normal 
 state no portion of the plant above the cotyledons sends 
 forth roots. Now, strictly speaking, the root by no means 
 commences close underneath the insertion of the cotyledons, 
 for between the latter point and the root there is to be 
 * Berlin 'Botanische Zeitung,' 1849, 797. 
 
204 HOFMEISTER, OX 
 
 found the small ombiTO-siciu which Inuisch calls the 
 liypocotyledonary axis, and which Clos calls the colhf. The 
 place of origin of the root, /. c, the loAver end of the enibrjo- 
 steni, is difHcult to discover by direct observation, but may 
 safely bo defined as the point at which in the lower end of 
 the very young embryo the cell-multiplication peculiar 
 to the root connnences. IS^ow, whether the young root of 
 the germinating plant has the appearance of an immediate» 
 prolongation downwards of the embryo-stem (as is the case 
 with most dicotyledons, and with a few monocotyledons, 
 such as Juncus, Allium, and Paris) — or whether it (the 
 young root) breaks out from the interior of the low^r end 
 of the embryo, as in the Palms and the Loranthacae — de- 
 pends simply upon the fact whether the place of origin, the 
 focus of cell-formation of the root, lies nearer to or further 
 from the lower end of the embiyo. In both cases the 
 root is a main root. An adventitious root differs only in 
 the fact, that its longitudinal axis does not coincide with 
 the prolongation of that of the embryo, but forms with 
 the latter a considerable angle. For instance, the Oi'chi- 
 dese, the Pluviales, and especially (as Irmisch has well 
 observed), the Grasses, have no radicle, but only adventi- 
 tious roots. The distance from the surface of the place of 
 origin of adventitious roots is variable, being less in some 
 plants than in others. In the former case the surface of 
 the adventitious roots passes gradually into the cortical 
 layer of that portion of the plant from which they spring, 
 as may be observed in the pea when germinating. In the 
 latter the adventitious roots pierce through the outer cel- 
 lular cortical layers, throwing back those layers in the form 
 of a ring round the place of egress of the roots. The 
 absence of tliesc characteristic collars (Coleorhizji'), at the 
 base of the adventitious roots, is by no means unusual.* 
 Perns with creeping stems almost always have them, and 
 those with upright stems not unfrec[uently. It is well 
 known that all ramifications of roots, both those from main 
 roots and those from adventitious roots, are formed from the 
 outer surface of vascular bundles, and must therefore, with- 
 out exception, break through the bark. The reason why 
 
 * See Irmisch's observations on ' Ts^'coftia nidus avis.' 
 
THE HIGHER CRYPTOüAMIxV. 205 
 
 no Coleorhizse are usually visible here, is, that (as in the 
 case of axile superficial adventitious-root-formation) the 
 direction of the root-branch in its earliest stage, generally 
 follows the axis of the root. The bark of the latter is 
 pierced by the former during the young state of the cells 
 before they have attained their final thickness. The con- 
 tinual amalgamation of the contiguous cells of the root 
 and its branch obliterates all traces of the gradual perfo- 
 ration. 
 
 During the first divisions of the rudimentary cells of the 
 stem, frond, and root, the two others of the four primary 
 cells of the embryo multiply by the formation of oblique 
 longitudinal and transverse septa (PI. XXVIII, fig. 3 ; 
 PI, XXVI, fig. 6), so that the embryo assumes altogether a 
 spherical form. Only the rudiment of the first frond ap- 
 pears at an early period as an elongated point. 
 
 Prom the time when the outer linnts of the rudimen- 
 tary cell of the root are fixed by the formation of the 
 first cell of the root-cap, the cells of the upper surface 
 of the primary axis, and also the neighbouring cells of 
 the growing root, enter into close combination Avitli the 
 adjoining cells of the prothallium.* The result is a 
 complete amalgamation of the adjoining outer sm'faces 
 of the cells, which cannot now be detached from one 
 another by mere mechanical means. Henceforth the 
 embryo which up to this point lay free in the cavity 
 of the enlarged central cell of the arehegonium, ad- 
 heres firndy to tlie prothallium. The adjoining cells 
 of each remain toleral^ly even. The attachment of the 
 embryo is not the result of arrangements such as we 
 find in the analogous process of the ingrafting of the 
 fruit of a moss into the axis of the mother-plant ; nor is 
 there any elongation of the basal cell of the fruit rudi- 
 ment into a capillary tube, becoming curved where it 
 penetrates the stem, as is the case in many Jungeimanniae ; 
 nor is there as in Anthoceros any development of pro- 
 cesses from the cells of the broad, slightly convex, under 
 surface of the young fruit. Prom the moment of the 
 commencement of the amalgamation, the cells of the 
 
 * See Mohl in 'Wagner's Handwörterbuch der PliYsio).,' vol. iv, p. 279. 
 
206 HOFMEISTER, ON 
 
 embryo which attach themselves to the prothallium divide 
 by the repeated formation of transverse septa into groups 
 of almost tabular cells. By this means the way is pre- 
 pared for the subsequent not inconsiderable longitudinal 
 extension of the primary axis of the embryo which is the 
 result of cell-expansion. 
 
 The action of concentrated sulphuric acid soon loosens 
 the connexion between the prothallium and the embryo. 
 If the latter is detached the outer surface of its primary 
 axis appears to be surrounded by a gelatinous envelope 
 witli radial markings : this is the loosened adhesive mat- 
 ter by which the embryo and the prothallium were united. 
 The outlines of the cells of the latter are most clearly 
 marked upon it by a net-work of narrow band-like protu- 
 berances. 
 
 The growth of the embryo is accompanied by an active 
 multiplication of the cells of the prothallium adjoining the 
 impregnated archegonium. This multiplication, which is 
 not confined to the cells immediately adjoining the central 
 cell of the archegonium, gives rise to the formation of a con- 
 siderable cellular protuberance, attached to the under side 
 of the prothalliiQu, and which encloses the embryo. The 
 circumference of this excrescence is usually very consider- 
 able in Pteris aquilhia. The increase in growth of this 
 cellular tissue usually keeps pace so completely with that 
 of the embryo, that the expanding cavity is always exactly 
 filled up. The multiplication of the neighbouring cells of 
 the prothallium is not however caused by the pressure of 
 the growing embryo upon the side walls of the central cell 
 of the archegonium : this is manifest from the fact of the 
 occurrence of exceptional cases of imperfect growth of the 
 embryo, as has been observed, not only in many vascular 
 cryptogams, but even in mosses.* The embryo, probably 
 in consequence of imperfect impregnation, only occupies a 
 small portion of the enlarged cavity of the central cell of the 
 archegonimn, as has been obsei*ved by comparing two im- 
 pregnated archegonia of the same prothallium in Pteris 
 aqicillna and in Aspidium filix-mas (PI. XXVIII, fig. 2) \ 
 
 * By Gottsclie iii Cali/imgeia Trichomaiies^ 'X. A. A. L. C.,' and by myself 
 iu FruUania dilatata aud Tatyionia hypo;phi/lla. ' Vergl. Unters,' p. 41. 
 
THE HIGHER CRYPTOGAMIA. 207 
 
 the same thing also has been noticed in Salvinia natans 
 and Pihdaria (/Johulifera. 
 
 The active longitudinal growth of the first frond and of the 
 first root of the young fern produces a constantly increas- 
 ing expansion of the surrounding tissue of the prothallium, 
 until the latter is ultimately unable to keep pace with the 
 increase in size of the young plant. The layer of tissue 
 surrounding the latter underneath, is ruptured transversely, 
 usually somewhat in front of the neck of the impregnated 
 archegonium. The frond immediately curves upwards, and 
 appears between the two flaps of the prothallium. Before 
 this period it has formed the rudiments of its lamina, which 
 in all ferns are much less divided in the young, than in the 
 full-grown plant. The first fronds of JPolypodium vulgare^ 
 for instance, are not unfi-equently undivided and lancet- 
 shaped ; more often however they are divided at the apex 
 into two portions of very unequal size. Contemporaneously 
 with the appearance of the first frond, the fii'st root also 
 pierces downwards through the tissue of the prothallium. 
 Immediately after it makes its appearance it turns doAvn- 
 wards into the ground.* 
 
 If the second frond of the germ-plant is developed 
 very soon after the first, the surrounding celliüar tissue of the 
 prothallium in the neighbourhood of, or above the point of 
 egress of the first frond, is pushed outwards and forwards, and 
 is ultimately broken through. Before the frond makes its 
 appearance out of this covering, the latter resembles a coni- 
 cal wart protruding into the indentation of the fore edge of 
 the prothallium : it is the body wdiich Wigand (' Bot. Zeit.' 
 1849, p. 121) has described as the prolongation of the 
 midrib of the prothallium. 
 
 * Von Mercklin asserts (' Beobacht. am Prothallium der Farrnkr.' Peters- 
 burg, 1850) that soou after the appearance of the embryo in the interior of the 
 prothallium, a dark stripe becomes visible, passing from the base into the mass 
 of the prothallium, and expanding itself there. It contains a bundle of shortly- 
 jointed, striped vessels, the pointed ends of which reach to the neighbourhood 
 of the archegonia. The older the prothallium the more numerous are these 
 vessels, which, in their configuration, answer exactly to those of the large 
 vascular bundles of the first frond, and appear never to be wanting. I 
 find the prothallia of all the ferns which I have examined to be always com- 
 posed of homogeneous parenchyma, and to be devoid of vessels. I have not 
 the least notion what Von Mercklin's supposed striped vessels can be. 
 
2Ü8 HOFMEISTER, ON 
 
 Development of the vec^etatlve organs. — The similarity ii\ 
 the development of the different species of ferns does not 
 extend beyond the formation of the rudiments of the first 
 frond and of the first root. 
 
 So far as regards the mode of development of the vege- 
 tative organs, the two commonest ferns of Germany re- 
 present the terminal points of the long series of multi- 
 farious forms of the most extensive family of the vascular 
 cryptogams. Pfcrls aqnilina affords one of the most ]jer- 
 fect examples of a fern with a creeping stem, having the 
 fronds arranged in two lines, and with a most decided 
 tendency to bifurcation of the terminal bud. The greater 
 number of the ferns inhabiting the forests of the torrid 
 zone comport themselves like Pteris aquilina. Aspidium 
 filix-mas, on the other haud, forms a stem tending up- 
 wards, and agrees essentially in its habit, in the arrange- 
 ment of its fronds, and in the division of its vascular 
 ])undles, with the tree-ferns of the tropics. The follow- 
 ing observations will treat of the history of the develop- 
 ment of the two ferns just mentioned, and we will pi"o- 
 ceecl first Avitli Pteris aquilina. 
 
 Pteris Aquilina, L. — The surfaces of the septa formed in 
 the cell of the first degree in the first frond oi Pteris aquilina 
 arc turned towards the apex of the stem."* A plane passing 
 through the longitudinal axis of the stem ancl of the frond, 
 is at right angles to the lateral surfaces of the wedge-shaped 
 apical cells of both organs (PI. XA'III, fig. 6). Even at a 
 very eiu'ly period, before the enveloping cellular layers of 
 the prothallium are raptured by the longitudinal growth of 
 the first frond, septa are formed in the apical cell of the 
 frond on the right aiul left of its median line. These septa 
 are at right angles to the fore and hind walls, and they change 
 tlie form of the cell, which has hitherto been Avedge-slia])ed 
 like a segment of an ellipsoid, into a three-sided prism Avitli 
 the edge turned downwards and having its hinder surface 
 
 * This is the case also with all ihc subsequent fronds not only of Flcris 
 aquilina but also of other species of the same genus ; as well as Avith the fronds 
 of sueh ferns as Fterls srrrulufa, which have a triple froud-arrangcnient, and 
 wiiere the apical cell of the terminal bud has the form of a three-sided inverted 
 ])yramid. In the Polypodiums and Aspidiums the circumstances arc widely 
 dilTcrent. 
 
THE HIGHER CKITTOÜAMIA. 209 
 
 arched. The longitudinal growth of the frond is also for- 
 warded by the production of septa which are parallel to the 
 fore and hind walls of the cell of the first degree^ and are 
 turned towards the surfaces of the frond. From time to time, 
 however, the apical cell divides anew by longitudinal septa 
 at right angles to those just mentioned, and the end of the 
 young frond is by this means widened. Thenceforward 
 both forms of division continue to take place in the marginal 
 cells of the frond which adjoin the apical cell; but the 
 activity of division diminishes in a lateral direction, and 
 terminates far above the place of insertion of the frond. 
 That portion of the frond which is situated above the point 
 at which the multiplication of the marginal cells terminates, 
 becomes the blade of the frond, and the portion below that 
 point becomes the stem of the frond. The cell-succession 
 of the leafy portion of the frond therefore much resembles 
 that of the flat stem of the Marchantieae and Ricciese ; but 
 there is invariably one cell only of the first degree ; not 
 two. 
 
 The formation of the pinnae of the frond in the species of 
 Pteris, as in the rest of the Polypodiacese, is the result of a 
 true bifurcation of the apical 2mnctum vegetationis. This 
 formation commences with the division of the apical cell by 
 a septum coinciding with the median line of the frond, and 
 perpendicular to its surfaces. Each daughter-cell is divided 
 by a septum almost parallel to the longitudinal axis of the 
 frond (PL XXIX, fig. 3). This latter division occm's either 
 inuuediately, or after the previous formation of septa wdiicli 
 are inclined to the surfaces of the frond, and contribute to 
 its longitudinal growth. The three-sided cell on the right 
 and on the left of each of the two pairs of cells which 
 occupy the middle of the fore edge of the frond, becomes 
 the seat of fresh cell-multiplication, and is the cell of the 
 first degree of a pinna of the frond. Each of the new 
 shoots is alternately more strongly developed, thus changing 
 the direction of the bifiu-cation to the right or to the left. 
 The weaker one is pushed on one side so as to appear to be 
 lateral. The continual change in the direction of the less 
 vigorous bifurcations causes the feather-like form of the 
 frond, ^vhose segments (as is well known) are in no species 
 
 14 
 
210 HOFMEISTER, ON 
 
 exactly opposite to one anotlier. The position of the first 
 hiterai bifurcation on tlie mid-rib is not constant in any 
 species ; in Pteris aquilina it is more often to the left, in 
 AqmUuni fiUx-mcw to the right. The principal segments of 
 the fronds, however, taken in relation to their subsequent 
 ramifications, are very regularly antidromal : on tlie pinnae 
 to the left of the axis of the frond the first segment of the 
 second degree, or the first tooth of the margin, is on the 
 right : on the pinnae to the right of the axis it is on the 
 left. 
 
 From the first commencement of the frond its growth 
 in thickness is most vigorous behind. Its mathematical 
 longitudinal axis is not identical with the morphological 
 one ; it does not coincide with the surfaces of contact of 
 the masses of cells, produced by the multiplication of the 
 cells of the second degree, which are tmrned towards the 
 front and back surfaces of the frond. At the time of the 
 commencement of the formation of the blade of the frond, 
 which is produced by the widening of its apex, the cell- 
 multiplication in a longitudinal direction increases on the 
 hinder surface of the frond. It exceeds that which takes 
 place on the front siu'face and thus leads to the commence- 
 ment of the rolling inwards of the fi'ond (PL XXIX, fig. 1), 
 which is completed by the stretching of the cells of the 
 hinder siu'face which shortly afterwards takes place. Con- 
 temporaneously with the commencement of the rolling 
 inwards, the axile longitudinal rows of cells separate them- 
 selves by the cessation of transverse division, and become 
 transformed into the simple vascular bundle which traverses 
 the stem and mid-rib of the frond. Pour cells of the 
 adjoining parenchyma are about equal in length to one of 
 the cells of the rudimentary vascular bundle. This latter 
 passes through the morphological longitudinal axis of the 
 young frond, near its front surface. It is concave in a 
 transverse section, open towards the front (PI. XXIX, 
 fig. 14). 
 
 Dming this development of the frond, the first root also 
 has grown considerably. Its axile rudimentary vascular 
 bundle becomes visible contemporaneously with that of the 
 frond. The two meeting together in their entire breadth 
 
THE HIGHER CRYPTOGAMIA. 211 
 
 underneath the terminal bud, — which in the meantime has 
 become developed into a cellular wing, — form a connected, 
 slightly curved, string of cambium, upon which the wing is 
 attached sideways (PI. XXIX, fig. 1). 
 
 Now Avhilst the cellular layers surrounding the embryo 
 are ruptured by the longitudinal growth of the frond and 
 root, the cells of the primary axis also become consider- 
 ably elongated, so that the germ-plant is removed from 
 the prothalliimi as if borne upon a short stem ; an appear- 
 ance which brings to mind the normal process in Salvinia, 
 The innermost cells of the primary axis acljoining the vascular 
 bundles of the frond and of the root assume a prosenchy- 
 matal form (PL XXIX, fig. 1), and at a later period become 
 woody scalariform cells, so that the ligneous body of the 
 germ-plant has a blind-ended short prolongation reaching 
 into the primary axis. 
 
 The growth of the stem-bud, which is rapid in com- 
 parison with what occurs in other ferns, and which is 
 observable whilst the embryo is yet enclosed (PI. XXVIII, 
 figs. 4, 5), increases still more after the latter has emerged 
 from the prothallium ; the end of the stem becomes a 
 somewhat slender cone (PI. XXIX, fig. 1). The forma- 
 tion of the second frond commences even before any 
 thickenings of the membrane make their appearance in any 
 of the cells of the rudimentary vascular bundles of the 
 germ-plant. The second frond originates in the multipli- 
 cation of a cell of the apex of the stem situated on that 
 side of it which is turned away from the point of attach- 
 ment of the first frond, and distant from the latter by about 
 half the circumference of the stem. The cell-multiplication 
 of the second, and of all the subsequent fronds, follows the 
 same rule as that of the first : it begins by the continually 
 repeated division of the cell of the first degree, by means 
 of septa inclined alternately towards and away from the 
 top point of the stem. After the rudiments of the stipes 
 of the frond are fully formed, the apical cell divides by 
 longitudinal septa at right angles to the fore and hind 
 surfaces ; in all the cells of the thus expanded fore-edge, 
 division occurs by septa inclined alternately towards the 
 upper and under surfaces of the fi'ond. 
 
212 liOl'MElSTEli, ON 
 
 Almost coiiteinporancoiisly with the appearance of the 
 second frond, numerous celhdar hairs are seen upon the 
 terminal bud of the stem, which have been previously 
 visible, although more sparingly, upon the first frond. 
 Having regard to their position and their centripetal deve- 
 lopment, they are undoubtedly analogous to the scales of 
 other ferns, which indeed also appear primarily elsewhere 
 under the form of simple rows of cells,* In Pteris 
 aqidlhia, Bicksonia ruhiginosa, and Balantium Karstenianum 
 they do not progress beyond this primary stage of develop- 
 ment. 
 
 From the time of the formation of the second frond 
 until the commencement of that of the third, the longitu- 
 dinal growth of the axis increases considerably, as it does 
 Avitli each successive frond during the entire life of the 
 plant, unless prevented by unfavorable influences. At 
 this time, if not (as is not unfrequently the case, PI. XXIX, 
 fig. I) even before the formation of the second frond, a 
 twisting of the stem takes place. If the young stem is 
 supposed to be horizontal, the hinder surface of the first 
 frond is turned downwards ; the rudimentary frond was 
 parallel to the surface of the })rothallium.f By the torsion 
 of the axis the direction of the third frond, and sometimes 
 even of the second, is turned away from it to the extent of 
 90°. Henceforth the fronds are inserted on the sides of 
 the creeping stem, the fraction \ representing as before 
 their mode of arrangement. The plane of involution of the 
 budding stem (that plane in which all the turns of the 
 incurved leafy surface lie, juul Avliicli is perpendicular to 
 the leafy portion of the frond) is at first radial to the axis 
 of the latter. This plane, however, soon stands at right 
 
 ♦ I will return to this subject liercaftcr. Multicellular hairs with intercalary 
 cell-multiplication, even in the ciircetion of llic breadth and thickness, occurs 
 here and there even on the leaves of jjlirenoganis {e.g. Begonia, and the calyx 
 and corolla of Hibiscus Tnoinim). jNly observations do not confirm Kunzc's 
 opinion that the shoots at the base of the stipes of Ilemitelia capc^iisis, which 
 resemble the fronds of Triehonianes, are transformed scales. The reasons 
 therefore which induced me to consider the scales as leaves, and the fronds 
 consequently as leafy branches, fall to the ground. The scales are only a kind 
 of hairy covering ; certainly a very highly developed one, as they frequently 
 contain chlorophyll; for instance in rialycerium. 
 
 ■\ It is self-evident that in speaking thus of the direction of the frond no 
 account is taken of tlic secondary curving upwards of the stipes to the light. 
 
THE HIGHER CRYPTOCiAMIA. 213 
 
 angles to the axis, on account of the rapid horizontal 
 longitudinal growth of the stem, which far outstrips the 
 development of the frond ; and the result is that the sur- 
 faces of the frond are parallel to the axis. The stalks even 
 of the first fronds exhibit the appearance* which occurs in 
 the stipes of almost all fronds, that is to say, prominent 
 bands of loose cellular tissue having the intercellular cavi- 
 ties filled with air pass along the side edges of the stipes ; 
 which bands are in connexion with, and of the same nature 
 as, the inner parenchyma, wdiich latter, except where it is 
 traversed by the bands, is enclosed by a firm cortical 
 tissue (PL XXX, figs. 7, 9). The creeping stem oi Pferis 
 aquUlna (PI. XXX, fig. 3), and the stems of the exotic 
 Dicksoniae, which are similar in their habit, exhibit the same 
 quality. The lateral ridges of the stem pass directly into 
 those of the fronds (PL XXIX, fig. 14). 
 
 At an early period the germ-plant exhibits that prema- 
 ture vigorous development of the peripheral cellular layers 
 of the stem in the immediate neighbourhood of its terminal 
 bud, which afterwards has a marked effect upon the form 
 and position of the apex of the stem. The growth in 
 thickness of the cortical tissue of the next younger portion of 
 the stem is very rapid, and by the time that the third 
 frond is developed, the apex of the stem appears to be 
 sunk in that tissue (PL XXIX, fig. 6). 
 
 The internal structure of the young stem, like that of the 
 first frond, is very simple. From the point of junction of 
 the vascular bundles of the first frond and first root there is 
 developed a central vascular bundle, traversing the young 
 stem (PL XXIX, figs. 5, 6, 7), from which the transformation 
 into vascular bundles of the strings of cellular tissue which 
 pass into the newly-formed fronds commences, and on the 
 outer surface of which the development of new adventitious 
 roots begins (PL XXIX, fig. 6). The direction of the second 
 and of tTie next following root diverges by about 90° from 
 a plane passing through the first frond and the longitudinal 
 axis of the stem (PL XXIX, fig, 6). The subsequent 
 roots exhibit no trace of this regular arrangement. 
 
 After the formation of from seven to nine fronds, the 
 
 * Karsten, ' Vegetatious-orgaue der Palmen,' p. 129. 
 
214 HOFMEISTER, ON 
 
 stem becomes forked by the division of its punctum vege- 
 tationis. Each branch of the fork increases rapidly and 
 considerably, and about equally, in thickness. The first 
 frond of each is usually situated to the right hand (PI. 
 XXIX, figs. 10, 11). From this time forth the course of 
 the vascular bundles of the stem is a compound one. The 
 lateral opening of the central vascidar bundle becomes 
 enlarged (PI. XXIX, fig. 8). Its upper half is soon sepa- 
 rated from the lower; the vascular bundle is prolonged, 
 whilst the tissue of the bud of the stem remains paren- 
 chymatal. The stem has now two flat vascular bundles 
 (PI. XXIX, fig. 9) parallel to the axis, which here and 
 there split into thinner forked branches which soon unite 
 again (PI. XXIX, fig. 9*). When the furcate shoots 
 have attained a length of about three inches, and their 
 transverse diameter is about two lines wide, the two large 
 vascular bundles send out less vigorous bundles which take 
 a direction nearer to the bark, and of which the uppermost 
 one, which passes above the axile bundles, is somewhat more 
 fully developed, and is about equal in breadth to the latter 
 (PI. XXIX, figs. 12, 13). The cortical vascular bundles 
 anastomose in the vicinity of the place of insertion of each 
 frond, and thus form a hollow cylindrical network of elon- 
 gated meshes. But no connecting branches between them 
 and the axile bundles are to be found anywhere in the 
 stem. The latter follow an entirely isolated course within 
 the creeping stems ; ramifications from them enter the 
 fronds, and it is only these ramifications which are 
 met inside the stipes by ramifications from the cortical 
 vascular bundles. Roots originate only from the latter 
 bundles. 
 
 The stems of fully grown plants exhibit, in all essential 
 points, the same distribution of vascular bundles. The 
 number of the peripheral ones amounts to as many as 
 twelve. The two uppermost of the latter are blended to- 
 gether for the greater part of their course, and thus form a 
 Avide bundle, which lies in the same vertical plane as the 
 primary axile bundles. Two masses of cells almost 
 parallel to these primary vascular bundles, and situated 
 between them and the peripheral vascular bundles, become 
 
THE HIGHER CRYPTOGAMIA. 215 
 
 very woody, like bast-cells. Their very thick walls, 
 which are pierced by pits or canals, assume a brown 
 colour throughout. Thin sections of them are of a 
 beautiful golden yellow ; when seen in a mass they 
 are almost black. The axile region of the stem thus 
 appears, even to the naked eye, to be distinctly separated 
 from the bark by a thick hard sheath of vascular bundles, 
 which has a fissure-like longitudinal opening only on each 
 of the two sides parallel to the outer longitudinal bands of 
 the stem (PL XXX, fig. 3). One of these fissures is 
 often closed by an amalgamation on one side of the two 
 halves of the sheath of vascular bimdles. The upper half 
 of the sheath is tolerably flat ; the lower one has the form 
 of a furrow. Dming the transformation of the parenchy- 
 niatal cells of the end of the stem into bast-cells, air- 
 bubbles are formed (PL XXX, fig. 12), between the walls of 
 the latter, in the interior of small n-regularly- defined inter- 
 cellular cavities. These air-bubbles disappear when the 
 thickening of the walls commences. 
 
 The outermost cellular layers of the bark also assume a 
 deep brown colour, but without becoming prosenchy- 
 matous, and without any material thickening of their walls. 
 Those portions only of the tissue which pass towards the 
 lateral longitudinal ridges do not assume this brown colour, 
 which extends to the depth of one-eighth of a line into the 
 cortical tissue. The portions just mentioned, like the 
 parenchyma of the interior of the stem, remain of a dazzling 
 white : they contain starch, and their intercellular cavities 
 are filled with air. Here and there in this tissue, and 
 sometimes also in the brown-coloured outer cortical layer 
 spindle-shaped groups of combined cells become trans- 
 formed into thick-walled bast-cells, similar in all respects to 
 those of the sheath of vascular bundles,* 
 
 As the vascular bundles in the growing stem become 
 more complicated, so also do those in the stipes of the 
 fronds. As in the first, so also in the other fronds of the 
 young plant up to the twelfth, the vascular bundles unite to- 
 
 * Molil objects to these cells being called bast-cells ('Vermischte Schriften,' 
 p. 116), but in their form and mode of development they agree exactly with the 
 bast-cells of phfnnoganis. 
 
216 HOFMEISTER, ON 
 
 getlier to form a single one. The transverse section of 
 this single bundle has the shape of a horse-shoe, of whicli 
 the opening is originally turned towards the apex of the 
 stem-bud, but which in consequence of the rapid longi- 
 tudinal development of the latter, and of the curving up- 
 wards of the frond, appears at a later period to be parallel 
 to the longitudinal axis of the stem. After the splitting 
 of the primary vascular bundle, and the appearance of 
 cortical vascular bundles in the stem, there arise ramifica- 
 tions of both the axile bundles, of the wide bundle above 
 them, and of the rest of the cortical vascular bundles of the 
 adjacent longitudinal half of the stem (PI. XXX, figs. 
 1" to 1', and fig. 2). The sheath of vascular bundles also 
 sends out prolongations into the stipes : from the upper 
 as well as from the lower group of brown bast-cells the 
 same transformation of the tissue advances in a direction 
 parallel to the longitudinal axis of the frond (PI. XXX, 
 fig. 7). At a shoi't distance above the place of insertion 
 of the frond, both longitudinal strings of ligneous tissue 
 unite to form a single one of which a transverse section 
 exhibits the shape of the letter T having the two branches 
 of its head turned to the lateral longitudinal ridges of the 
 frond (PI. XXX, figs. 8, 9). The 'hind angle of the T 
 includes the ramifications of the two axile primary bundlt^s 
 of the stem ; the fore angles those of the wide cortical 
 vascular bundle which runs off in the top line of the hori- 
 zontal stem, as well as the branches of the cylindrical cortical 
 vascular bundle inunediately adjoining. In front and 
 on the outside of the head of the T, run the bundles which 
 sent forth the cortical bundles underneath the place of inser- 
 tion of the frond. In the lowest part of the stiijcs, under- 
 neath the point of junction of the prolongations of the 
 vascular sheath, all these vascular bundles anastomose in 
 a radial direction ; above this point only in a tangential 
 direction. Each of the primary vascular bundles sends 
 two ])roportionally thin cylindrical branches into the frond 
 (PI. XXX, figs, 'Z''"'). All four soon imite to form a wide 
 vascular bundle concave behind (PI. XXX, figs. S, 9). 
 A similar bundle is formed by the junction of those bundles 
 which are enclosed by the fore angle of the T-shaped mass 
 
THE HIGHER CRYPTOGAMIA. 217 
 
 of l)ro\vn cells. It is this distribution of the tissue com- 
 posing the stipes Avhich produces the well known figure of 
 the eagle seen on an oblique section. 
 
 Delicate longitudinal sections through the terminal bud of 
 the stem of Pteris aquilina, exhibit with the greatest clear- 
 ness the transformation of the originally homogeneous 
 parenchymatal tissue into vessels and bast-cells. The in- 
 vestigation is very much facilitated by the course of the 
 inner one of the two primary vascular bundles, which is 
 straight and parallel to the axis. According as the section 
 is taken parallel to the surface of the earth, through the 
 longitudinal ridges of the creeping stem, or at right angles 
 to this direction, the wedge-shaped cell Avhich encloses 
 the apex of the flatly conical deeply buried terminal bud 
 is seen either on its three-sided front aspect (PI. XXXI, 
 fig. 5), or its four-sided lateral aspeet (PI. XXXI, fig, 4). 
 The funnel-shaped depression, at the bottom of which the 
 terminal bud is seated, is strongly compressed from above 
 and below. The walls of the depression are thickly clothed 
 with scale-like hairs. The erect ends of the hairs, which 
 are closely pressed against one another, and fastened to- 
 gether by a hardened mucilage secreted from the bud, 
 entirely close the mouth of the funnel, and shut off the 
 delicate young portions at its base from the outer air. The 
 end of the stem in its longitudinal growth forces its way 
 through the toughest clay, without injury to the delicate bud 
 buried in its apex. 
 
 The clearly defined mode of arrangement of the cells of 
 the second degree, and of their derivatives, affords an im- 
 mediate explanation of the deep depression of the terminal 
 bud. The cell of the first degree is wedge-shaped (PI. 
 XXXI, figs. 2 — 5), as is manifest by comparing its apical, 
 front, and side aspects. It is bounded by three curved 
 surfaces, the upper free wall of the cell representing a 
 portion of a spherical surface enclosed by two flattened 
 arcs, and the side-Avalls being two segments of a conical 
 surface. The septa which arise in the cell, and which are 
 alternately parallel to the one and the other of the simple 
 curved lateral surfaces, form cells of the second degree, 
 having the shape of the fifth part of an oblique hollow 
 
218 HOFMEISTER, ON 
 
 cone. These divide successively by means of longitudinal 
 septa which are parallel to each one of their small lateral sur- 
 faces, and diverge strongly from the radii of the stem, into 
 from three to five cells, adjoining the cell of the first 
 degree (PI. XXXI, fig. 3 *) ; a form of multiphcation in 
 which variations sometimes occur by which the next step 
 in the development is anticipated (PL XXXI, fig. 2). The 
 newly-formed cells then divide gradually by means of septa 
 parallel to the lateral surface of the ajDical cell into twos ; 
 those cells which are situated anteriorly to the middle of 
 the sides of the apical cell dividing sooner than those 
 adjoining the lateral corners. The cells thus formed, whose 
 increase in height and in width {i. e., parallel to the lateral 
 surface of the apical cell) far exceeds their increase in thick- 
 ness, divide by means of transverse septa into low, almost 
 cubical, inner cells, and elongated outer cells, with a free 
 outer wall (PI. XXXI, figs. 4, 5). The expansion and 
 multiphcation of the cells of each of the groups derived 
 from a cell of the second degree, preponderate considerably 
 in the lower portion and in a transverse dii'ection j and 
 the same thing occurs in the cells derived fi'om the youngest 
 of the four cells of the second degree, whose free outer 
 walls compose the conical interior portion of the stem-bud 
 (PL XXXI, figs. 4, 5). In the longitudinal section of the 
 stem the boundary lines which enclose each such group of 
 cells exhibit strongly protruding angles on the side turned 
 away from the apex of the stem : the side walls of the cells 
 composing the outer sm-face of the stem-bud, are inclined 
 inwards towards their summits. In the next older group 
 of cells the direction of the suddenly-augmented cell-multi- 
 plication is reversed. Here the cells of the circumference 
 often divide repeatedly by means of septa parallel to the 
 chord of the arc of the outer wall, and perpendicular to the 
 side-walls. This is a growth in thickness, an increase of 
 the cortical tissue in a direction at right angles to the 
 axis, but in consequence of the unusual direction of the 
 cells in which it occurs, it takes place at first apparently 
 in an upward dh'ection. The bud becomes surrounded by 
 a high, narrow, annular wall. The growth of the latter is 
 particularly active in the direction of a plane cutting the 
 
THE HIGHER CRYPTOGAMIA. 219 
 
 lateral bands of the stem at right angles ; here the internal 
 septa of the annular wall become perpendicular, or even 
 overhanging. Its cells appear arranged in concentrical 
 scal}^ layers round the middle point of the stem-bud. 
 
 During the formation of the annular wall the activity of 
 cell-multiplication in the longitudinal direction (/. <?., in the 
 direction of lines drawn in a radiating manner from the 
 apex of the stem-bud along its sides) increases, and 
 obliterates the arrangement of the cells visible in the apical 
 aspect of the youngest portions of the bud, viz., the system 
 of flattened arcs surrounding the middle point of the stem. 
 In its place the arrangement in (apparently radial) longitu- 
 dinal rows becomes more manifest ; this is produced by the 
 repeated division of the cells by means of septa at right 
 angles to the outer surface, and perpendicular to the radial 
 planes passing through the axis of the stem. 
 
 The prolongation of the two primary axile vascular bun- 
 dles begins to be differentiated from the rest of the tissue 
 at a very little distance beneath the terminal bud, and in 
 or near the mass of cells derived from the eighth-youngest 
 cell of the second degree. The separation of the peripheral 
 vascular bundle commences somewhat further from the 
 apex of the stem. Both phenomena arise from the fact, 
 that in the strings of cells which are transformed into 
 vascular bundles, the transverse division which continues 
 to take place in the neighbouring tissue, diminishes and 
 ceases, whilst the division by means of longitudinal septa is 
 hastened. The rudimentary vascular bundles appear there- 
 fore as streaks of narrow elongated cells, whilst in the cells 
 of the remaining tissue no one of the three dimensions 
 preponderates to any great extent (PI. XXXI, figs. 4, 5). 
 Certain cells of the vascular bundles arranged in longitu- 
 dinal rows, become Avidened at a very early period. After- 
 wards they are transformed into the scalariform cells which 
 form the principal mass of the perfect vascular bundle. 
 In the first instance they are placed one upon another, and 
 furnished with horizontal transverse septa : they assume 
 their permanent spindle shape even before the first traces 
 of thickening layers are visible upon their inner walls (PI. 
 XXX, fig. 12 ; PI. XXXI, fig. 1). The first appearance 
 
220 lIÜl'MKlbTKH, ON 
 
 of the thickenings of the wall is in the form of dehcnte 
 transverse streaks, and commences long before the termina- 
 tion of the longitudinal growth of the cell, and even during 
 the existence of the parietal nucleus and of the strings of 
 granular nmcilage proceeding from it (PI. XXXI, fig. 1). 
 
 Long before the appearance of the first traces of the 
 thickenings of the walls of the scalariform vessels, spiral 
 thickenings are visible in certain cells arranged in groups 
 of twos or threes and which at an early period become 
 spindle-shaped. It is very clearly seen that the formation 
 of the spiral band proceeds gradually from the lower to the 
 upper end of the cell (PI. XXX, fig. 12). In each vascular 
 bundle these small groups of spiral vessels are formed -. one 
 axile group is formed in those vessels which are circular in 
 a transverse section, and three are usually formed in those 
 Inmdles whose transverse section is elongated ; one of such 
 groups being in the centre, and the others in the foci of 
 the figure presented by the transverse section, and whicli 
 bears a distant resemblance to an ellipse. 
 
 The great expansion of the cells of the vascular bundle 
 which go to form the scalariform vessels, causes such a com- 
 pression of the intermediate, narrow, prosenchymatal cells, 
 that in some instances the entire cavity of the latter is 
 obliterated. 
 
 A transverse section of the youngest portion of a vascular 
 bundle taken at a point near the terminal bud where the 
 thickening layers are visible only in the spiral Acssels, 
 exhibits a considerably larger number of cells than is seen 
 in the same vascular bundle at a distance of about a line 
 and a half from the terminal bud after its scalariform vessels 
 are completed (PI. XXX, figs. 10, 10''). A similar state of 
 things exists in the vascular bundles of the stipes. Trans- 
 verse sections of the compressed cells, provided the cavities 
 of the latter are not quite obliterated, bear a considerable 
 resemblance to the lenticular cavities between two pits of 
 coniferous wood (PI. XXX, fig. 2, between the two wide 
 vessels) . 
 
 The course of the vascular bundle nearest to the middle 
 of the stem {i. e. of the upper one of the two })rimary ones), 
 is almost exactly parallel to the longitudinal axis close 
 
THE lUGHEll cripto(;amia. 2.'il 
 
 under the bud of the stem. But in consequence of the 
 subsequent growth in length and thickness of the interior 
 of the stem, the other axile bundle, and still more the cor- 
 tical bundles, are bent strongly inwards towards the longi- 
 tudinal axis of the stem as long as their course passes 
 within the prematurely developed peripheral tissue. This 
 bending iisually amounts to 99° in the cortical bundles 
 (PI. XXX, fig. 4 ; PI. XXXI, fig. 1). A transverse section 
 passing through, or just over, the apex of the bud, exhibits 
 the vascular bundles which run almost horizontally to the 
 apex, in the form of from six to eight light streaks united 
 in a stellate manner. 
 
 Soon after the appearance of thickening layers in those 
 cells of the axile bundles which have become widened into 
 scalariform vessels, there ensues such a considerable growth 
 of the cells of the interior of the stem, that the dispropor- 
 tion of the latter to the peripheral cellular layers disappears. 
 The bent portion of the cortical vascular bundles takes a 
 straight course ; the height of the axile cells becomes 
 almost equal to that of the cortical cells of the same age ; 
 which latter cells had far outstripped the former in 
 development, especially in the thickening of the cell- 
 mendjrane, as is perceptible in the peripheral vas- 
 cular bundles. As the growth of the interior of the 
 stem (by means of the extension of its cells) surpasses 
 that of the bark, which was prematurely developed by more 
 vigorous cell-multiplication, the cells of the interior are 
 three or four times longer than the peripheral cells. The 
 process may be considered as a pushing outwards of the 
 funnel-shaped depression around the terminal bud. It 
 occurs in like manner in Isoctes, Cycas, Mamillaria and 
 elsewhere, but much less distinctly on account of the close 
 crowding together, of the appendicular organs. 
 
 The formation of new fronds always takes place above 
 the point of origin of the youngest scales. At some dis- 
 tance from the top cell of the apex of the stem, and sepa- 
 rated from the latter by from three to six cells, the mother- 
 cell of the frond is first visible in the form of a slight 
 elevation above the flat conical surface of the bud (PI. XXXI, 
 fig. 3). The first step in the formation of a frond however 
 
223 HOFMEISTER, ON 
 
 very probably consists in the occurrence from time to time 
 of the division of a newly formed cell of the second degree 
 by means of a shghtly convex longitudinal septum, turned 
 towards the cell of the first degree, which cuts off from the 
 cell of the second degree a daughter-cell, whose form coin- 
 cides with that of the apical cell of the stem (PI. XXX, 
 fig. 2). The rudiment of the frond bears considerable re- 
 semblance to the end of the stem in the arrangement of its 
 cells, but is distinguishable by the greater curvature of its 
 arcuate siurface, and by the very early appearance, (although 
 at first in small quantity), of chlorophyll in its cells. The 
 growth of the frond in length and thickness is at first very 
 slow. The rapidly elongating apex of the stem soon leaves 
 it behind. Whilst the premature development of its cor- 
 tical tissue commences on the side turned to the young 
 frond, the wall-like elevation of the circumference of the stem 
 in the neighbourhood of the terminal bud pushes itself at 
 an early period into the space between the two. The frond 
 and the end of the stem which at the first appearance of 
 the former are enclosed in the same depression of the bark, 
 are now each of them situated at the base of a special 
 fmmel-shaped depression. The tips of the scales which 
 clothe their walls protrude above each depression in a peni- 
 cillate manner (PI. XXX, fig. 5). 
 
 Whilst the germ-plant in the first year produces as 
 many as twelve slender fronds whose development is con- 
 tinually progressive, the development of the fronds of older 
 plants, which is frequently interrupted by long periods of 
 cessation, requires several years. It is a rule, departed 
 from only in cases of sudden alteration of the conditions of 
 vegetation, (such as the ploughing up of the ground of a 
 wood), that each shoot of the mature plant sends out yearly 
 only one frond.* Ncav fronds are produced towards the 
 end of the vegetative period which lasts from April till 
 October. In the first year the frond assumes no greater 
 development than that of a low, laterally flattened, green 
 wart of cellular tissue, situated at the base of a depression 
 of the bark of the stem, distant at the most not more than 
 a line fi'om the apex of the stem. In the following year 
 * See A. Braun, 'Verjüngung,' p. 63, 
 
THE HIGHER CRYPTOGAMIA. 223 
 
 (until the end of j\Iay) the stem rapidly elongates to the 
 extent of about an inch, and during this period the portion 
 of the stipes of the young frond which afterwards 
 assiunes a brown colour, is formed : it is a cyhndrical 
 body, one or two inches high, having a vertical direction 
 produced by violent cm-vature close to its place of insertion, 
 and clothed with yellowish- white scales (PL XXIX, fig. 14). 
 After the removal of the latter a flat furrow is visible at the 
 apex of the young frond on the side tiuned towards the 
 stem, in which the rudiments of the lamina of the frond 
 are closely folded in the form of a flat cellular mass, about 
 one eighth of a line long, exhibiting two or three furcate 
 ramifications (PI. XXX, fig. 6, 6 *). Towards the end of 
 the second vegetative period this cellidar mass attains the 
 length of one line, and makes fi'om ten to twelve furcations, 
 alternating to the right and to the left hand. The fiu'ther 
 development of the frond goes on in the spring of the third 
 year, at the end of May in which year it appears above the 
 surface of the earth, delicately rolled up like a crosier, and 
 complete in all its parts. 
 
 Roots are developed only from the cortical vasciüar bun- 
 dles of the stem of mature plants, and in fact only from the 
 points of junction of their meshes. Theii* rudiments are 
 formed close under the terminal bud, at the point where the 
 com'se of the cortical vascular bundle exhibits its inward 
 curvatm-e (PI. XXXII, fig. 1). Here cell-multiplication 
 commences in one of the outer cells of the cambium bun- 
 dle, similar to that by which the first root of the germ-plant 
 is formed. As in that case, the three different kinds of 
 septa of the cell of the first degree stand at right angles to 
 a radial plane passing through the longitudinal axis of the 
 stem. A septum is formed tm-ned towards the vascular 
 bundle from which the root is developed, and making an 
 angle of about 80° with the root. This septum has the 
 form of the third part of the surface of a truncate cone, 
 and its formation is foUowed by that of a curved septum 
 inclined in an opposite dii'ection, this again is followed by 
 the formation of an almost flat transverse septum at right 
 angles to the longitudinal axis of the root, and diverging 
 from the two former by about 60°. The form of the pri- 
 
221- HOFMEISTER, ON 
 
 mary cell of the i-oot agrees with that of the apical cell of 
 the stem, except that the side- walls of the former are more 
 strongly curved (PL XXXI, fig. 6* ; PL XXXII, hg. 1 *). 
 The layers of the root-cap, which on account of the more 
 vigorous growth at their median point are convex outwards, 
 are developed from the cells of the second degree, which 
 latter are formed by the production of flat septa parallel to 
 the basal surface of the primary cell. The permanent main 
 portion of the root is produced by the continual division of 
 those cells which have the form of the third part of a 
 hollow cone. The latter cells are first arranged in parabo- 
 loidal layers, which in the one longitudinal moiety of the 
 root protrude for about half the length of a cell beyond the 
 layers of the other moiety of the root. In the cells derived 
 from the third oldest cell of the second degree,this symmetri- 
 cal arrangement is changed into a homogeneous one, whilst 
 transverse septa parallel to the primary septa appear in all the 
 cells of the layer (PI. XXXII, fig. 1 '). The mode of dif- 
 ferentiation and formation of the axile vascular bundle, and 
 the delay which at first occurs in its longitudinal develop- 
 ment compared with that of the bark (a delay which is 
 afterwards compensated by expansion), are common to both 
 the root and the stem. 
 
 Ramifications of the root spring from its vascular bundles 
 in the same manner as the roots spring from the cortical 
 vascular bundles of the stem. The roots of the second 
 degree, as well as their ramifications, which are not of 
 frequent occurrrence, are arranged in two lines. 
 
 The greater the age attained by a shoot of the Eagle 
 Pern — whether such shoot proceed directly from a pro- 
 thalliuui, or from a bud, or whether it be the single branch 
 of a forked stem — the greater is the tendency to furcation 
 of its terminal bud. Ultimately, in really old individuals, 
 Irond-formation ceases entirely on the furcate branch when 
 more strongly developed. Only the more delicate forked 
 shoots which are placed alternately to the right and to the 
 left bring forth fronds ; the first one being always in the 
 inner angle. The naked imbranched terminal shoots of 
 those plants whose sympodium (which has the appearance 
 of a principal axis) bears no fronds, is developed with ex- 
 
THE HIGHER CRYPTOGAMIA. 225 
 
 treme rapidity, and produces an abundance of roots. Un- 
 branclied terminal slioots of this kind, of from six to ten 
 inches long, are not rare. In these shoots the lower part of 
 the annular wall which surrounds the teiminal bud, pro- 
 trudes itself forward in a labiate form, so that it eventually 
 lies upon the upper surface of the gradually flattened 
 shoot (PI. XXX, fig. 4). The distribution of the vascular 
 bundles in these unbranched, frond-less ends of shoots, 
 exactly corresponds with that of the frond-bearing stem ; 
 a convincing proof that the arrangement of the vascular 
 bundles in the stem is not dependent upon the position of 
 the appendicular oi'gans, or the number and form of the 
 bundles occurrins: in such oro;ans.* 
 
 The two wide axile vascular bundles are entirely devoid 
 of branches in each joint of the sympodium. At each fork 
 they send out into the more delicate shoot vigorous branches 
 which constitute the axile vascular bundles of the latter 
 shoot. I have met with sympodia four feet long devoid of 
 fronds. The distances between two fm'cations are very un- 
 equal, and manifestly dependent upon the amount of 
 nourishment being greater or less. The entire ramification 
 •of the plant, so far as it depends upon the furcations of the 
 terminal buds, and the position of the fronds on these 
 ramifications, correspond entirely with the pinnations of the 
 blade of the frond. These latter are only distinguishable 
 in their first rudiments from the furcations of the terminal 
 bud, by the upward direction of the growth of the frond : 
 they do not difi'er in their cell-succession. 
 
 Buds from which new shoots may be, and are developed, 
 are found in Pteris aqiiilina only on the under side of the 
 stipes ; sometimes low down, sometimes higher up. Some- 
 times they appear so early and are so near the place of in- 
 sertion of the frond that at first sight they appear to belong 
 
 * The same conclusion may be drawn from the condition (observed by H. v. 
 Mohl, 'Verm. Schriften,' p. Ill,) of the upper ends of the vascular bundles of 
 all ferns, especially of those with creeping stems and bilinear phyllotaxis (see 
 PI. XXXV, fig. 4) : although the relations in question do not elsewhere stand 
 out in so marked a manuer. The conclusion given above would be valid even 
 if the objections raised by Mettenius against my views of the mode of ramifi- 
 cation of Fteris aquiliiia ('Abhandl. K. Sachs Ges. der Wiss.,' b. vii, p. 
 621,) could be maintained, which, however, as I shall hereafter show, is not 
 the case. 
 
 15 
 
226 HOFMEISTER, ON 
 
 to the stem. They originate from the multipUcation of one 
 of the cells of the free outer sm-face of the very young 
 frond, and are situated on its back or at the edges,* they 
 occur long before the first rudiment of the vascular bundles 
 separates itself from the rest of the tissue (PL XXXII, 
 fig. 2). The divisions of the primary cell of the new shoot 
 follow the same rule as those of the apical cell of the 
 mother-axis. When the development of the bud goes on 
 slowly, the cortical tissue closes almost entirely over it 
 (PI. XXXII, fig. 3). An acciu'ate observer however may 
 even then discover the passage leading to the punctum 
 vegetationis, which is merely stopped up by entangled and 
 agglutinated scales (PL XXXII, fig. 3*) : tlie passage is 
 blocked up by the drying of a portion of the mucilage, 
 which these buds of Pteris aqtiilina secrete in abundance. 
 
 Aspidiiüu ßlix-mas. — The rudimentary and apical cells of 
 the first, and of all the succeeding fronds of this fern, divide 
 by means of septa inclined to the edges of the frond alternately 
 to the right and to the left ; the line in which each new sep- 
 tum cuts the next older one, is radial to the axis of the stem. 
 As far as can be gathered from the result of numerous 
 observations, the first septum which appears in the cell of 
 the first degree, is inclined to the left,f and tm'ned towards 
 the next older frond (PL XXVI, fig. 14). This form of 
 division continues until the completion of the rudiment of 
 the stipes. When the formation of the blade of the frond 
 commences, septa make their appearance in the cell of the 
 first degree, and in the cell next to it of the second degree, 
 which septa are inclined alternately towards the front and 
 the liind surface of the frond. Thus the arrangement of 
 the cells in the growing portions of the frond is coincident 
 
 * Upon the supposition of the adventitious bud being produced by the mul- 
 tiplication of a cell in the interior of the tissue, for instance, a cambial cell of 
 a vascular bundle, the gcmmaB of ferns would not be adventitious buds. But 
 this definition is too narrow, and could not be employed in many of the instances 
 which occur in plioenogams. 
 
 f Following Braun's rule ('N. A. A. C. L.,' xv, p. 220,) of using the ex- 
 pressions riglif and leß with reference to the direction of the development of 
 the organic body in question, I call that margin of the frond the rif/ht margin 
 which would be on the rigiit hand of the observer, supposing him to Ix" 
 placed in the longitudinal axis of the frond, with his face to the upper surface. 
 Tiiis margin of the frond is the frout margin, turned towards the ascending 
 leaf-spiral. 
 
THE HIGHER CRYPTOGAM I A. 227 
 
 with tliat above described in Pteris aquilma^ and tlie mode 
 of ramification of the blade of tlie frond is the same as in 
 the latter plant (PI. XXVI, fig. 8). 
 
 The germ plant of Aspidium filix-mas developes its second 
 frond at a distance of about a third of the circumference of 
 the stem from the first. At the point of junction of the 
 vascular bundles of the first frond and of the first root, 
 there is formed a vascular bundle, which, after traversing 
 the axis for a short distance, bends off into the second 
 frond (PL XXVI, fig. 13). The second root is developed 
 from that part of the vascular bundle which is situated in 
 the stem, and at some little distance beneath the place of 
 insertion of the second frond. The third frond diverges 
 from the second, and the fourth again from the third, at 
 about 120° to the right, so that the fourth stands vertically 
 over the first. At the bending-point of the vascular bundle 
 which passes out of the longitudinal axis of the stem into 
 the second and succeeding fronds, there is produced a 
 vascular bundle, which, after passing along the axis of the 
 stem for a short distance, bends off into the next younger 
 frond. Transverse sections of the stem exhibit only one 
 vascular bundle (PI. XXVI, fig. 12). The length of the 
 stem between each two of the first four, five, or six fronds, 
 is much greater than between two of the subsequent 
 fronds. 
 
 The thickness of the stem increases suddenly and con- 
 siderably above the fifth or sixth frond. This rapid growth 
 in thickness takes place whilst the next younger fronds, the 
 seventh to the tenth, continue in the state of buds. Owing 
 to the vigorous and rapid peripheral development, the 
 apical region of the stem becomes almost a flat sm'face, in 
 the middle of which the outermost point of the stem pro- 
 trudes (PL XXVI, fig. 15). Around it the youngest 
 fronds are arranged spirally. Henceforth the end of the stem 
 retains this form (PL XXVI, fig. 19 ; PL XXVII, figs. 3, 4). 
 
 The flattening of the terminal bud depends upon the 
 fact that the superficial cells of the conical cellular mass 
 divide repeatedly by septa parallel to the chord of the 
 arcuate fi'ee outer wall — (a mode of cell-multiplication 
 which increases continually from the apex of the cone to its 
 
228 UOFMELSTER, ON 
 
 base where it suddenly ceases, and wliich is accompanied 
 by a series of divisions proportionate in number to the in- 
 crease of the circumference of the cone and produced by 
 longitudinal septa radial to the axis of the stem) — whilst the 
 division by transverse septa at right angles to those chordal 
 longitudinal septa occurs proportionably seldom. The 
 conical terminal bud grows upwards by the formation l>e- 
 neath its entire outer surface of a layer of cells having the 
 form of a conical covering thicker towards the base, whilst 
 the angle of inclination of the cone becomes continually 
 narrower. At a latter period, after the formation of the 
 rudiments of several cycles of fronds, the longitudinal 
 grovrth of the stem is so much accelerated by the active ex- 
 tension of the cells of the axile tissue (accompanied by the 
 formation of transverse septa in the peripheral cells) that it 
 exceeds the previous increase in thickness. The cortical 
 region is pushed outwards by the longitudinal extension of 
 the middle of the stem, and passes from the form of a very 
 blimt cone into that of a cylinder ; this complete inversion 
 of the mode of growth is caused by the change of direction 
 of the expansion and multiplication of the cells. The 
 l)rocess (wliich is common to all stems with flat tenninal 
 buds, e. g., Polytrichum, Dracasna) is more easily seen in the 
 slender steni-ends of the germ-plants and gemmae of 
 Aspidium filix-mas or Asplenium ßUx-femina, than in the 
 stems of ol del individuals of the former plant which become 
 too thick. iJ 
 
 After the st^ni of the germ-plant has increased in thick- 
 ness the arrangement of the subsequent new fronds changes 
 from the I to the | arrangement. At the same time the 
 distribution of the vascular bundles in the stem becomes 
 different. At the place where the vascular bundle which 
 passes into the last frond of the 3 arrangement turns side- 
 ways, strings of the cambium which afterwards forms the 
 vascular bundles separate themselves in the direction of 
 each of the three next fronds, and run parallel to the longi- 
 tudinal axis of the stem (PI. XXVI, fig. 15). A trans- 
 verse section of the stem at this spot exhibits three vascular 
 bundles arrang(;d in a circle (PL XXVI, fig. 16). 
 
 The rudiments of the vascular bundles which pass to all 
 
THE HIGHER CRYPTOGAMIA. 229 
 
 the succeeding fronds are already formed whilst the fronds 
 are still in the condition of very yoimg buds, inasmuch as 
 from the place where those vascular bundles which pass to 
 the two next adjoining older fronds bend aside to make 
 their way out of the stem, the cells of the bud-tissue are 
 transformed into cambium-strings as far as the younger 
 frond. Close under the place of insertion of the young 
 frond the two rudimentary vascular bundles unite to form 
 a single one (PL XXVI, fig. 9) which after passing through 
 the stipes for a short distance spHts again into, two (PL 
 XXVI, figs. 10, 11). A vascular bundle passes to the 
 first frond from the fiftli and sixth, and to the ninth from 
 the sixth and seventh, and so on. Thus the vascular bun- 
 dles of the young stem represent in their entirety a tubular 
 net, with rather wide meshes,* from whose angles simple 
 vascular bundles pass off to the fronds. A transverse 
 section of the stem of a seedling of about a year old 
 exhibits five vascidar bundles enclosing a pith. 
 
 In' the second year the plant develops itself much more 
 vigorously. Its fronds attain a foot in length ; their 
 arrangement proceeds normally according to the -% arrange- 
 ment. Henceforth several vascular bundles occur in each 
 stipes. In old vigorous individuals as many as five pass 
 from the knot of vascular bundles vvhich corresponds with 
 the place of insertion of each frond. The lowest and most 
 vigorous of these bundles — which, as it originates out of the 
 lower angle of the knot of vascular bundles, corresponds 
 Tvnth the single bundle of the fronds of the one-year-old 
 plant — passes near the hinder surface of the stipes, and 
 divides into two close above the place of attachment of the 
 frond to the stem, at the place where the protuberant en- 
 largement of the stipes, characteristic of Aspidium filix-mas, 
 begins (PL XXVII, fig. 6). Mature plants produce roots 
 exclusively from these two vigorous bundles of the stipes. 
 The stem, which in the first year of the germ-plant sends 
 out all the roots, afterwards ceases to produce any. From 
 the side angles of each knot of vascular bundles of the 
 stem two thin vascular bundles pass off" into the frond, and 
 
 * jMolil, 'Vermischte Sclinfteu,' p. 115. 
 
230 HOFMEISTER, ON 
 
 two rather more vigorous ones at a little distance higher 
 lip (PI. XXVI, fig, 20). Both pairs run along the protu- 
 berant longitudinal ridges of the frond, the former pair 
 behind, the latter in front (PI. XXVII, fig. 7). The vas- 
 cular bundles not unfrequently anastomose in the interior 
 of the stipes. Hence it arises that transverse sections of 
 the latter sometimes exhibit more than five vascular bun- 
 dles. 
 
 The distribution of the vascular bundles within the stem 
 remains essentially the same during the progress of the 
 arrangement of the fi'onds, except that (as is manifest) the 
 number of loops increases. The first frond of a cycle 
 receives its vascular bundles no longer from the sixth and 
 seventh, but from the ninth and eleventh of the preceding 
 cycle ; the sixth frond from the first and the third, the 
 eighth from the third and fifth of the same cycle, and so 
 on. Or to state it more shortly — the vascular bundles 
 which pass from the right to the new fronds follow (when 
 the turn of the spiral is normal, or to the right hand) the 
 3-numeral fronds ; those which pass from the left follow 
 the 5-numeral ones. Eight transverse sections of vasciüar 
 bundles lie in one plane passing through the stem at right 
 angles to the axis. In mature plants of AspicUum filix-vias, 
 there is a periodicity in the development of the frond which 
 is not foimd in the one-year-old seedling. The growth of 
 the frond in the former is aiTcsted in winter, but not so in 
 the latter. The number of fronds Avhich unfold in spring, 
 and which all grow simultaneously from the end of May 
 till October, is usually thirteen, corresponding with the 
 number of the joints of a segment of the spiral in which 
 the fronds are arranged. A similar state of circumstances 
 is met with also in some other ferns, as in Asjjleniuiit ßlix- 
 femina, where the number of fronds is usually eight or 
 thirteen, and in Aspidium S2)inuJomm and Asplen'mm TricJio- 
 ■manes where eight fronds are usually developed contempo- 
 raneously. As in Pieris aqidlina, the rudiments of the 
 fronds are formed two years before their unfolding. In 
 the first year the stipes only is formed, and in the outer- 
 most fronds of the cycle about three or five of the pinna3. 
 In the second year the pinna) of those fronds which are to 
 
THE HIGHER CRYPTOQAMIA. 231 
 
 open in the spring are completed in all their parts, and 
 after the second winter's rest they are fully developed. The 
 younger fronds of the same season follow step by step in 
 the same development until the month of June. 
 
 The commmencement of the formation of the vascular 
 bundles takes place in the bud even of very vigorous speci- 
 mens from the fifth-youngest frond in a backward direc- 
 tion, and thus, far above the point at which the longi- 
 tudinal growth of the stem begins to exceed its growth in 
 thickness. Thus the wdiole system of vascular-bundle- 
 meshes lies at first in an almost horizontal, very flatly para- 
 boloidal surface, close under the top surface of the stem, 
 and nearly parallel thereto. It is only immediately below 
 the apex that the number of the cells of the tissue of the 
 stem underneath and within the net of vascular bundles is 
 increased ; lower down there occurs an expansion of these 
 internal cells, their longitudinal diameter becoming from 
 four to five times longer, and their transverse diameter 
 from two to three times wider. It is only by this increase 
 (caused by cell-expansion) of the biük of the pith that the 
 net of vascular bundles is lifted up by degrees and pro- 
 jected upon a cylinder. It is easily seen by counting the 
 cells during and after the transition of the net of vascular 
 bundles from the form of a paraboloid to that of a cylinder, 
 that the increase in thickness of the stem is not caused 
 by any subsequent new formation of parenchymatal cells 
 either ^^dthin the pith or in the neighbourhood of, or be- 
 tween, the rudimentary vascular bundles. It is only in 
 front of the youngest rudimentary vascular bundles that a 
 slight multiplication of the cortical tissue takes place, by di- 
 vision of the peripheral cells (PL XXVII, fig. 3). 
 
 If any radial section be taken through the longitudinal 
 axis of the stem the side view thus obtained of the apical 
 cell of the terminal bud is without exception three-sided (PI. 
 XXVII, figs. 3, 4). When viewed from above the upper 
 surface of the same cell exhibits the like shape (PL XXVII, 
 figs. 1, 2). Its form is therefore that of an inverted three- 
 sided pyramid with an arched upper surface. The appearance 
 shews (PL XXVII, figs. I, 2,) that this cell divides re- 
 peatedly by septa, having three directions, and turned sue- 
 
232 HOFMEISTER, ON 
 
 ccssively to one of the lateral surfaces. As far as can be 
 judged from numerous observations, the succession of these 
 septa one after another is to the right hand, more seldom 
 to the left, but always coincident with the spiral in which 
 the fronds are aiTanged. 
 
 There is yet a second point in which the relation of the 
 apical cell to its daughter-cells is affected by the frond- 
 spiral. The apical aspect of the top cell of old speci- 
 mens of Aspidium ßlix-mas is very rarely that of an equi- 
 lateral triangle. One of the sides is usually considerably 
 shorter than the two others, which latter are nearly of equal 
 length. The outline of the apical surface is normally that 
 of an isosceles triangle. Deviations from this form may 
 be easily traced to the disturbances caused in the older 
 lateral surfaces of the apical cell by the growth of the 
 adjoining secondary cells. The one side of the triangle is 
 formed by the upper edge of the youngest side-wall of the 
 terminal cell, and the other side by that of the oldest side- 
 wall of the same cell. The base is formed by the side-wall 
 intermediale in age between the oldest and the yomigest. 
 
 The relation of the length of this base to the younger of 
 the tw^o sides is in most cases a definite one. The follow- 
 ing series of measurements will show this. The younger 
 of the two longer side- walls of the apical cell is the one 
 always measm-ed. Some of the measurements were made 
 on the apical cells of buds which had been separated by a 
 transverse section from the older portion of the stem, and 
 simply cleansed from the adherent mucilage and scales. 
 The greater part of the measurements, however, were made 
 on the transparent membrane formed by the free outer 
 walls of the superficial cells of the bud. These walls have 
 a much stronger consistence than those of the inner tissue 
 of the bud. After a little practice with the microscope it 
 is not difficult to scrape out from the inside of the terminal 
 bud the mass of internal parenchyma, consisting of delicate 
 cell-walls and cell-contents, so as to leave the outer Avails 
 in the form of a connected, slightly arched membrane — 
 (the epidermis, improperly so called, of the young portions 
 of the plant). The lines of contact of the cell- walls 
 which have been attached to this membrane are most dis- 
 
THE HIGHER CRYPTOGAMIA. 
 
 233 
 
 tinctly marked upon the latter in the form of slightly pro- 
 tuberant ridges, and admit of the most accurate measure- 
 ments. Each of the following is the mean of at least five 
 measurements which did not differ from one another by 
 more than half a micro-millimeter.* 
 
 Measurements of the apical cells of Ferns having the j^ frond- 
 arrangement. 
 
 
 
 
 Base. 
 
 Side. 
 
 Relation of 
 the two. 
 
 
 
 
 M.M.M. 
 
 M.M.M. 
 
 
 Aspid'mm filix-mas, 
 
 Spiral 
 
 right . 
 
 33.6476 
 
 47.1618 
 
 1 : 1.401 
 
 
 3) 
 
 11 • 
 
 39.912 
 
 56.542 
 
 1 : 1.416 
 
 
 J) 
 
 >i 
 
 43.3104 
 
 61.0986 
 
 1 : 1.401 
 
 
 
 » • 
 
 45.2312 
 
 63.7098 
 
 1 : 1.408 
 
 
 11 
 
 i> ' 
 
 46.564 
 
 66.52 
 
 1:1.41 
 
 
 11 
 
 95 
 
 49.89 
 
 70.6773 
 
 1:1.416 
 
 
 
 11 
 
 51.8504 
 
 73.6386 
 
 1 :1.42 
 
 
 11 
 
 
 52.859 
 
 75.0198 
 
 1:1.419 
 
 
 J> 
 
 11 
 
 55.7116 
 
 78.593 
 
 1:1.41 
 
 
 11 
 
 >i 
 
 55.7116 
 
 79.5336 
 
 1 ■ 1.427 
 
 
 }i 
 
 11 ' 
 
 55.9874 
 
 78.593 
 
 1 : 1.403 
 
 
 
 >) 
 
 56.542 
 
 79.824 
 
 1:1.411 
 
 „ sinnidosvm „ 
 
 left . 
 
 36.6076 
 
 51.3022 
 
 1 : 1.401 
 
 
 
 11 
 
 40.1194 
 
 56.4582 
 
 1 : 1.406 
 
 
 
 rigLt . 
 
 43.0526 
 
 60.3246 
 
 1 : 1.401 
 
 
 
 >> 
 
 43.0526 
 
 60.8408 
 
 1 : 1.413 
 
 
 
 »> 
 
 44.0838 
 
 61.7421 
 
 1:1.4 
 
 
 
 left . 
 
 52.0756 
 
 73.2152 
 
 1 : 1.407 
 
 
 
 right . 
 
 52.6778 
 
 74.5487 
 
 1:1.401 
 
 
 
 
 52.9536 
 
 75.5692 
 
 1 : 1.428 
 
 Aspl.fiUx-fem. 
 
 
 " 
 
 33.26 
 
 46.564 
 
 1:1.4 
 
 
 
 
 I 
 
 xau . . . 
 
 1:1.4094 
 
 This proportion of the base to the sides is that of an 
 equilateral triangle with an apical angle of 69° 13' 53"3", 
 and whose angles at the base are 41° 32' 13-4"; angles 
 which very nearly approximate to those of a triangle which 
 is bounded by the chords of two arcs of 138° 27' 41-53' — 
 (tAvo successive steps of the smaller divergence of the i^ frond- 
 arrangement) — and by the line uniting the free terminal 
 points of these chords, which line is the chord of an arc 
 of 83° 4' 36 •94", being the difference between the larger 
 and the smaller divergence of the ^ arrangement. The 
 apical angle of such a triangle is 41° 32' 18-47"; each of 
 * 1 m.m m. = 9-0001 millim. 
 
234 
 
 HOFMEISTER, ON 
 
 the angles at the base is 69° 13' 50-765"; the relation of 
 the base to one of the sides is 1 : 1-4067. The divergence 
 of these numbers from the measurement falls within the 
 limits of probable error.* The conformity of the angle of 
 the apical cell of the stem with the divergence of the appen- 
 dicular organs is not limited to the ^ arrangement. The 
 calculated relation of the shorter side of the triangular apical 
 surface of the terminal cell to one of the loniror sides is : 
 
 In the 
 
 ■ST 
 
 2 1 
 
 TT 
 
 arrangemeut 1 
 1 
 1 
 1 
 1 
 1 
 
 >i 
 
 1.618 
 
 1.307 
 
 1.4067 
 
 1.3683 
 
 1.3799 
 
 1.3294 
 
 The observed relations are- 
 
 
 Base. 
 
 Side. 
 
 Relation of 
 the two. 
 
 A.'<jj. fili.c-mas ^ arrangement, Spiral right . 
 » „ „ (seedliug) 
 )> » }> >> j> 
 
 » A »» jj light . 
 
 IS 
 
 W.M.M. 
 
 56.9738 
 27.8558 
 36.1298 
 
 M.M.M. 
 
 74.2464 
 36.6814 
 47.7134 
 
 1 : 1.307 
 1:1.316 
 1 : 1.3216 
 
 63.161 
 63.4386 
 
 86.1052 
 90.23 
 
 1 : 1.363 
 1:1.381 
 
 It would be natural to attempt to explain this pheno- 
 menon by the supposition, that the angle Avhicli a new 
 septum of the apical cell forms Avith the next older side 
 wall, bears a relation to the angle of divergence of the 
 frond arrangement, inasmuch as it equals the half of the 
 latter angle. The necessary result of this would be, that 
 
 * I considered it much better to calculate the angle of the apical surface 
 from the length of its sides than to measure it directly with the goniometer, 
 as the former process gives a more certain result. The credibility of each 
 method dcpend.s u])on the same circumstances as those upon which, in the 
 determination of i)iiyllotaxis, the relative credibility of the results obtained by 
 the direct measurement of the angle of divergence and by the calculation of the 
 latter from the number of the turns, depends. The uunibor of measurements 
 might easily have been increased, but it seemed advisable to exclude all the 
 cases invvhich the imperfect parallelism to the apical surface of the stem of 
 the section separating the outermost apex of the flat bud from the remaining 
 tissue, might have given rise to mistakes. 
 
THE HIGHER CRYPTOGAM I A. 235 
 
 ill each mode of frond arrangement following upon the 
 I arrangement, such as fj, ^ and so forth, the form of the 
 apical sm-face of the cell of the first degree would be that of 
 an isosceles triangle. Each cell of the second degree might 
 be treated as the prhuary mother-cell of a frond, to be pro- 
 duced by the further development of the cells derived from 
 the secondary cell. This supposition would however re- 
 quire that the four sided apical surface of each cell of the 
 second degree^ should, innnediately after its production, be 
 considerably wider on the hinder edge than on the fore 
 edge. The excess of the length of the hinder edge over 
 that of the fore edge would be determined by the difference 
 between the apical angle and one of the side angles of the 
 upper surface of the cell of the first degree. It would 
 necessarily bear the same proportion to the second youngest 
 side of the apical surface of the compound figure formed by 
 the cell of the first degree and the youngest cell of the 
 second degree, as the sine of the apical angle bears to that 
 of one of the side angles. Consequently each cell of the 
 second degree must, immediately after its production, be 
 wider at the hinder end than at the fore end to the following 
 extent in each respective case, that is to say, — in the farrange- 
 ment to the extent of about the whole length of its front 
 wall and of the oldest wall of the apical cell which repre- 
 sents its prolongation, — in the I arrangement to the extent 
 of something more than the half (0-5412) of this length, — 
 in the ^ arrangement to the extent of about j'ö (O'^OOSl) of 
 the same. 
 
 Observation entirely upsets the above supposition. It is 
 true that in older cells of the second degree, especially in 
 those which are already several times divided, the outer side 
 wall normally diverges from the inner one. But the 
 younger the cells of the second degree which are subjected 
 to examination, the more nearly do their side walls approach 
 to parallehsm, until at last it is manifest that the earliest 
 septa of the ceU of the first degree appear exactly parallel 
 to the oldest side wall of the same ceil (PL XXVII, fig. 1). 
 It is plain from this that in point of fact the supple- 
 mentary expansion and the multiplication of the cells of 
 the second degree proceed step by step from back to front 
 
236 
 
 HOFMEISTER, ON 
 
 (by which gradual advance the broken, sharply-angular suc- 
 cession of these cells is converted into a spiral) but that 
 there is no perceptible divergence of the newly formed septa 
 of the cell of the first degree from the oldest opposite side 
 wall of this mother-cell. 
 
 There is a second series of facts which militates not less 
 decidedly against the above assumption, viz., the occurrence, 
 although a rare one, of apical surfaces of cells of the first 
 degree which exhibit angles not corresponding with those 
 of the frond-arrangement. The following instances have 
 been observed, and they are the only ones obtained in a 
 long series of investigations : — 
 
 
 
 
 
 Length of 
 
 Length of 
 
 
 
 
 
 
 tlie oldest 
 side Willi of 
 
 theyuungcsl 
 side Willi of 
 
 R('I;ilion of 
 
 
 
 
 
 the apical 
 ' cell. 
 
 the apical 
 cell. 
 
 the two. 
 
 Asp. sjniitdosum, 
 
 tt: arraiigenieiit, 
 
 Spiral 
 
 right 
 
 60.583 
 
 83.0116 
 
 1:1.37 
 
 ,, ,, 
 
 ,, ,, 
 
 
 J' . 
 
 56.3293 
 
 76.3088 
 
 1:1.355 
 
 3) 3> 
 
 J) 3) 
 
 
 left 
 
 52.7201 
 
 68.783 
 
 1 : 1.307 
 
 3J » 
 
 
 
 right 
 
 45.5017 52.4623 
 
 1:1.152 
 
 3> >> 
 
 J) J> 
 
 
 left 
 
 59.5518 
 
 61.0986 
 
 1 : 1.026 
 
 ,, fiUx-mas, 
 
 5) 1) 
 
 
 riglil 
 
 55.427 
 
 73.9886 
 
 1:1.335 
 
 » » 
 
 ■JT „ 
 
 
 JJ 
 
 71.1528 
 
 88.1676 
 
 1 : 1.239 
 
 „ spi/iulosum, 
 
 1 
 
 
 J) 
 
 69.8638 
 
 75.7932 
 
 1 : LOSS 
 
 „ ßlü'-mas, 
 
 5 
 
 
 )j 
 
 88.4254 
 
 85.074 
 
 1:0.961 
 
 j> jj 
 
 JJ JJ 
 
 
 JJ 
 
 69.Ü904 
 
 63.161 
 
 1 : 0.913 
 
 In the greater number of these irregularly shaped cells 
 their size is very remarkable. In none of the foregoing 
 tables did the base of the triangle attain the leno-th of 
 64 m. m. m., a length which is hero often surpassed. 
 
 But the measurements of those apical cells in which the 
 length of the oldest side-wall considerably exceeds that of the 
 youngest, are very instructive. Taken in connexion with the 
 fact, that in by far the greater number of instances the 
 angles of the apical cell correspond with the divergence of the 
 frond-arrangement, these phenomena indicate that after 
 each division the apical cell does not become enlarged 
 equally in all directions so as to attain the size which it 
 had before the division, but that the expansion which 
 
THE HIGHER CRYPTOGAMIA. 237 
 
 ensues takes place, if not exclusively, at all events prin- 
 cipally, in a direction at right angles to the septum last 
 produced. This septum which, at the instant of one divi- 
 sion, forms one of the sides of the isosceles triangle repre- 
 sented by the upper surface of the cell of the first degree, 
 is, until the next division, far surpassed in longitudinal 
 growth by the two other side walls of the apical cell, so 
 that the latter then constitute the sides and the newly- 
 formed septum the base of the triangle. The new division 
 is produced by a septum which is parallel to the second 
 side wall of the apical cell, which side-wall at the time of 
 the preceding division was the longer one, and which in the 
 mean time has become elongated and displaced. 
 
 The diagram given in PL XXXII, fig. 5, of the mode of 
 succession of four such divisions of the apical cell of a bud 
 with the - arrangement, will explain the above sugges- 
 tion. 
 
 The triangle enclosed by the lines 1, 2, 3, represents 
 the apical cell before the first of these divisions ; the line 4 
 represents the com'se of the dividing membrane. This 
 cell (which we will designate with the figure II until the 
 next division) now expands to the left : the line 4 now be- 
 comes the base of the triangle ; the line 1, increased by the 
 line 1" becomes one side of the triangle, and the line 3, 
 displaced to 3^^ and lengthened, becomes the other side of 
 the triangle. The next division is represented by the 
 line 5. This line becomes the base of the upper surface 
 of the cell, which is enclosed by the lines 3", 4, and 5, and 
 which expands again to the left. By this expansion the 
 line 3 becomes the line 3^^\ and the Ime 4 becomes 4"^ 
 The line 6 represents the third division. The apical cell is 
 now first bounded by the lines 4, 5, 6. By a fresh expan- 
 sion of the cell the line 5 is increased by the line 5^^, 4 is 
 shifted to 4^'', 2 to 2^^ and 1 is extended to 1^^. 
 
 PI. XXXII, fig. 6, exhibits the somewhat complicated 
 mode of arrangement and displacement of the cells of the 
 second degree after three more such divisions of the apical 
 cell. 
 
 All the above facts can easily be brought under the one 
 point of view of the above supposition. The latter explains 
 
238 HOFMEISTER, ON 
 
 tlie frequency of the correspondence in form of tlie npper 
 surface of the cell of the first degree with the frond 
 arrangement, as well as the rarity of the deviations from 
 this form. Moreover, the observation confirms the conse- 
 quent backward curvature of the lines uniting the project- 
 ing angles (which are turned to the same side) of the dif- 
 ferent com'ses of the successive cells of the second degree 
 aroimd the axis of the stem ; — which lines represent three 
 similar tiuns of the frond-spiral. The above opinion is 
 further supported by the fact, that the expansion and dis- 
 placement snp])osed to occur in the apical cell, must neces- 
 sarily follow from the enlargement and multiplication, 
 progressing gradually from the older to the younger ones, 
 of the cells of the second degree. The marginal angles 
 of the lateral surfaces of the cell of the first degree, must, 
 in the direction of the ascending spiral which represents the 
 course of the divisions, become more acute at the fore 
 edges, and more obtuse at the hinder ones, if — as observa- 
 tion proves — the multiplication of the older cells of tlie 
 second degree in the direction of a tangent to the stem is 
 more active than that of the youngest cells. In this process 
 the apical cell may be looked upon as to a certain extent 
 passive. 
 
 The supposition of a high degree of expansive and for- 
 mative power in the walls of the young cells of a portion 
 of a plant in process of development, is indispensable for the 
 purpose of explaining the change in the position and form 
 of the individual cells, which is caused by the growth of the 
 entire portion of the plant, and by the influence of the expan- 
 sion (and the multiplication of the older cells and masses of 
 cellular tissue) upon the younger ones, and conversely. In 
 the terminal bud of ferns expansion and multiplication of the 
 secondaiy cells, and of the groups of cells produced by their 
 divisions, advance in an ascending spiral from below up- 
 wards. In the neighbourhood of the apical cell this expan- 
 sion occurs at an early period (and is consequently more 
 advanced and productive of greater results) in the oldest 
 wall which forms the base of the upper surface of the cell, and 
 in the next oldest, whose margin forms the penultimate side 
 ofthat surface. The growth of the apical cell, which, between 
 
THE HIGHER CRYPTOGAMIA. 239 
 
 eacli two divisions always increases to nearly the original 
 size, become especially active in the direction of the mar- 
 ginal angle formed by these two side-walls. This will 
 cause its form to vary more and more in the manner above 
 pointed out, until the relation between the angles required 
 by the hypothesis is attained. It is easy to imagine that 
 any excess of aperture is prevented by the proportion of 
 the rapidity of the progress of the multiplication of the older 
 secondary cells to that of the youngest. 
 
 In the course of the long inquiries leading to these results, 
 I met with only one isolated fact which militated against 
 the conclusions arrived at. I found the apical cell of a 
 tenninal bud of AspicUuvi spimdosum, the base of whose 
 upper surface measured 4r248 m.m.m., and each side 
 97'808 m.m.m. The stem, which had the left-handed 
 xl arrangement of the fronds, was growing at the edge of 
 a ditch, amongst a mass of briars, being half buried in the 
 earth, and directed downwards : the joints of the stem 
 were unusually elongated. It is probable that the plant was 
 in an abnormal, perhaps in a diseased condition. 
 
 The two-edged form of the apical cell, and the bilinear 
 arrangement of the fronds, of Fleris aquilina, have been 
 already observed upon. The same coincidence is always 
 met with (as far as present observations extend) in 
 NijjJiohohs rupestris and N. Lingua, in Poli/podinm ptinctu- 
 lattim, P. cymatodes, and P. aitreum, and very frequently 
 in P. viilr/are and Dryopferis. 
 
 The determination of the cell-succession in the apical 
 region of the leaf-buds of phccnogamous plants is attended 
 with considerable difficulties. The minuteness of the ele- 
 mentary organs is the least obstacle ; a more formidable 
 one, especially in the Coniferae and Dicotyledons, is the 
 very early occiuTence of rapid and vigorous multiplication 
 of the secondary cells of the flat end of the bud. It is not 
 always that the terminal cell of the bud can be ascertained 
 with certainty. Where however this w^as done the form of 
 this cell corresponded with the phyllotaxis ; it was two- 
 edged in the grasses (/S'r-cfl'/e cereale, Phrafjinifes arimdinaced) 
 and in species of Iris ; and often of the same shape in trees 
 with decussate leaves {Acer, Fraxinus, Cupressus). Here 
 
240 
 
 HOFMEISTER, ON 
 
 however cases occurred, though less frequently, of tri- 
 angular upper surfaces with a very acute apical angle. 
 These irregularities possibly depend upon the fact of the 
 occurrence in each internocle of a gradual ti'ansposition, a 
 deviation of about 90°, of those septa of the apical cell of the 
 bud, which are turned towards the surfaces of the leaves. 
 
 Trees with imperfect 3-numeral phyllotaxis always ex- 
 hibited three-sided apical cells with one shorter edge. In 
 Ttohinia Pseiidacacia (phyllotaxis |) the following measure- 
 ments occmTcd : — 
 
 The base of the triangle. 
 
 9.9288 m.m.m. 
 10.121 „ 
 
 9.875 „ 
 
 One of the sides. 
 15.4448 = 1 : 1.555 
 1G.2936 = 1 : 1.6891 
 15.9975 = 1 : 1.62 
 
 Mean 
 
 = 1 : 1.634 
 
 This result corresponds as nearly with the relation re- 
 quired by calculation, viz. 1 : 1'618, as could be expected, 
 considerino; the errors in measurement likely to arise from 
 the minuteness of the objects. Even if the first of the 
 above measurements may not be attributed to the dis- 
 placement of the apical cell between two divisions, it would 
 only be necessary to introduce a correction of about 5^0 
 millimeter in the first, and the same in the second (where 
 the proportion is too large), in order to make the observed 
 measurements correspond with the calculated ones. 
 
 The following are farther measurements of apical cells : — 
 
 
 Base. 
 
 Side. 
 
 Relation of 
 the two. 
 
 Pinus Jbies, phyllotaxis -i^ turned to 
 
 M.M.M. 
 
 M.M.M. 
 
 
 the right 
 
 13.79 
 
 18.7544 
 
 = 1 : 1.36 
 
 
 15.8569 
 
 21.5124 
 
 = 1 : 1.3566 
 
 „ „ „ ^ turned to 
 
 
 
 
 tlie right ..... 
 
 14.6174 
 
 20.4192 
 
 = 1 : 1.397 
 
 Pinus Balsamea, phyllotaxis -i-^ turned 
 
 
 
 
 to the right 
 
 13.8451 
 
 19.0302 
 
 = 1 : 1.375 
 
 
 14.3416 
 
 19.488 
 
 = 1 : 1.359 
 
 
 13.5422 
 
 18.4615 
 
 = 1 : 1.363 
 
 Zamia longifolia, phyllotaxis ^^^j turned 
 
 
 
 
 to tlie right 
 
 27.58 
 
 38.612 
 
 = 1 : 1.4 
 
TUE HIGHER CRYPTOGAMIA. 241 
 
 The first division — at right angles to the free outer sur- 
 face — of the cells of the second degree oi Asjndium fllix-mas 
 and A. spinulosum is produced sometimes by a septum 
 parallel to the front surface, i. e., the surface by which the 
 cell of the second decree is connected with the cell of the first 
 degree (PL XXVII^ fig. 2, PI. XXXII, fig. 4), and some- 
 times by a longitudinal septum meeting the front wall at an 
 angle of about 70° (PL XXVII, fig. 1). In the former 
 case the second mode of division follows upon the first, in 
 the latter case the first mode of division follows upon the 
 second ; the final result is the same in both cases. The 
 further divisions of the cells of the terminal bud are subject 
 to not less stringent rules. The tendency to transform the 
 zigzag line of succession of the generations of cells resulting 
 from each cell of the second degree into an uniformly ascend- 
 ing spiral line, manifests itself especially in the frequent 
 occurrence of three-jointed groups of cells which originate 
 in the following manner — the septum produced in a cell of 
 the outer sm-face is parallel to no one of the side walls, but 
 cuts tAYO of the side walls of the mother cell which form an 
 edge, in such manner that the latter is divided into a 
 smaller daughter-cell with a three-sided outer wall, and 
 a larger cell with a four-sided outer wall. The latter cell 
 is divided again by a septum almost at right angles to 
 the one last formed. Instead of one cell of the n*'' 
 degree there are now three : one of the ^^ and two 
 of M^*^ degree. 
 
 The cell-succession of the terminal bud, and the form of 
 the terminal cell which is possibly the result not the cause 
 of such cell-succession, are manifestations of the same power 
 of growth, by which the aiTangement of the fronds on the 
 axis is determined. After long extended and often re- 
 peated observations of the attendant circumstances, the 
 conclusion will not be premature, that the power by which 
 the form of the growing portions of plants is determined, 
 is manifested in the details of the cell-multiphcation by so 
 much the less in proportion as the organs in question are 
 composed of a greater number of cells. The main direc- 
 tions in which the cell-multiplication takes place are fixed : 
 the number however and mode of succession of the cell- 
 
 16 
 
242 HOFMEISTER, ON 
 
 divisions in these directions varies within rather wide 
 limits.* 
 
 The younger portions of the bud of Aspidiiim filix-mas 
 are enveloped in transparent mucilage as is usually the case 
 wätli all huds.f Owing to the very imperfect exclusion of 
 the outer air from the terminal bud of this fern, in which the 
 punctum vegetationis is only covered Ijy the connivent 
 scales of the older parts, this mucilage is often partly dried 
 up, and forms a structureless membrane, granular on the 
 outside, covering the top of the bud ; precisely similar to 
 that which is seen on the youngest parts of the fronds of 
 Anthoceros. j In order to obtain a clear view of the top of 
 the bud it is necessary to remove this membrane, wdiich is 
 a laborious and uncertain operation. 
 
 The small scales (whose development differs in no essen- 
 tial particulars from that of the similar organs in Niplio- 
 holiis riq)estris to which w^e shall afterwards refer), make 
 their appearance on the terminal bud veiy far above the 
 point at w^hich the cellular increase of the stem in thickness 
 tenninates, but never above the place of origin of the 
 youngest frond (PL XXVI, fig. 14; PI. XXXII, fig. 4). 
 This holds good in Aspidium as well as in Pteris, Poly- 
 podium, &c. According to Nägeli's definition of leaves 
 and hairs, § the scales would undoubtedly belong to the 
 former, as I also formerly assumed to be the case.|| On 
 the other hand a conclusive method of distinguishing 
 
 * This conclusion is the same as that which I arrived at on a former occa- 
 sion from observations on Isoetes (see vol. ii of the 'Abhandl. der K. Sachs. 
 Ges. d. Wiss.' p. IGl). The statement there made, that all the septa — turned 
 in one of the three directions — of the apical cells of the three-furrowed Isoeteae 
 are at right angles to a plane passing through tliat indentation of the stem 
 which is nearest to them, is too positive aud general. Nevertheless the obser- 
 vations, the number of which was limited by the paucity of the materials, 
 certainly show, that all the septa seen were turned towards one of the indenta- 
 tions ; no one of them was turned towards the space intermediate between two 
 indentations. This fact may have some connexion with the high ratios of the 
 numbers representing the phyllotaxis of those species of Isoetes. 
 
 f See 'Vergl. Unters.,' p. 82, note. 
 
 % See 'Vergl. Unters.,' PI. i, figs. 8, 9. 
 
 § • Zeitschr. f. Wiss. Botanik.,' Heft 3, 4, p. 185. Tlie leaf is formed on the 
 outside at the top of the stem, close under the apical cell, before the growtli iu 
 
 thickness by peripheral cell-formation is ended The luiir, 
 
 &c., is formed on the outside on an epidermal cell by growth of the latter after 
 the termination of the peripheral cell-formation. 
 
 II 'Vergl, Unters.,' p. 87. 
 
THE HIGHER CRYPTOGAMIA. 243 
 
 between the two is arrived at, if the difference between 
 hairs and leaves is sought for in the facts that the youngest 
 hairs are never seen below the first visible rudiments of the 
 leaves, and that leaf- formation on the axis always precedes 
 the formation of hairs. By trusting to these characters the 
 observer will never be in doubt, in any case where the axis 
 of the plant exhibits both these forms of appendicular 
 organs. The scales of ferns therefore, as well as the hairs in 
 the buds of mosses and liverworts, fall under the definition 
 of hairs, and the fronds consequently under that of leaves.* 
 
 The formation of a frond commences thus — one of the 
 superficial cells of the terminal bud, distant from the next 
 older frond by the angle of divergence of the frond-arrange- 
 ment increases in size, and becomes arched outwards in a 
 papillate manner (PL XXVII, fig. 4; PI. XXXII, fig. 4). 
 In this cell there commences a series of divisions which are 
 repeated continually in the apical cell by means of septa 
 tmiied to the right and left towards the future margins 
 of the frond. The secondary cells multiply in all three 
 directions more vigorously on the hind surface of the 
 frond, so that the latter is converted into a somewhat 
 slender cone bent over towards the fore part. Septa are 
 now produced in the apical cell, turned towards the fore 
 and hind surfaces of the frond, and alternating with others 
 turned towards the lateral margins. The fiu:ther formation 
 of the frond, the development of its blade, takes place in 
 the manner pointed out in l^teris aquiUna. 
 
 In the mature plant of Aspidium filix-mas roots (as we 
 have already said) are no longer formed on the stem itself, 
 but exclusively on the protuberant swollen portion of the 
 
 * Two of the main grounds formerly adduced to prove that the scales were 
 of the nature of leaves, and the fronds of the nature of branches, have been 
 set aside. Kuuze's statement, that the delicate bodies, resembling the fronds 
 of Trichomaues, found at the base of the stipes of Hemitelia capoisis are 
 transformed scales, is erroneous, as lias been already observed. They have 
 nothing in common with scales as may be seen at once by the examination 
 even of a dead stem. The course of the vascular bundle within them is con- 
 clusive to show that they have been formed in the earliest stage of the frond, 
 even before the commencement of the formation of the blade of the latter. I 
 have latterly arrived at a very clear view of the growth in the Ophioglossea;. I 
 formerly thought that it must be considered to consist of a successive series of 
 adventitious buds. I now find that the Ophioglosseae agree essentially with the 
 Polypodiacese. 
 
244 HOFMEISTER, ON 
 
 stipes. They originate here from the vascular bundles 
 which run on the hind side of the stipes, parallel to the 
 longitudinal ridges of the latter. Usually two roots are 
 formed on each stipes. Every longitudinal and transverse 
 section of the root-cell of the first degree appears triangular. 
 Its form is that of a low three-sided pyramid. It divides 
 by means of a concave septum turned towards its slightly 
 convex basal surface, and by this means lenticular cells are 
 formed, each of which becomes the mother-cell of two of 
 the cap-shaped cellular layers of the root-cap. The len- 
 ticular cell divides by longitudinal septa into four cells 
 standing cross- wise (PI. XXVII, fig. 10), after which trans- 
 verse septa are formed. In the middle of the circiüar 
 cellular layer, the further division by longitudinal septa 
 occurs more rapidly and more frequently than at the edges, 
 by which means the cellular surface assumes its cap -like 
 shape. Between the older of these cellular layers, whose 
 outer walls become very much thickened, intercellular 
 spaces filled with air make their appearance ; this is the 
 first commencement of the falling ofl* of the cellular layers 
 of the root-cap, which decay by degrees from the outside. 
 Each division which is produced by means of a concave 
 septum turned towards the basal surface of the cell of the 
 first degree, is followed by three divisions of the latter, by 
 means of septa successively parallel to each of its three 
 lateral sm^faces. The three cells of the second degree thus 
 formed, and which stand in a triangle, divide by means of 
 longitudinal and transverse septa, the division being more 
 active in that portion of them which is more distant from 
 the longitudinal axis of the root. The short-celled tissue 
 here formed becomes the cortical layer, whose early growth 
 is afterwards overtaken by the rapid longitudinal expansion 
 of the axile cellidar tissue of the root during the transfor- 
 mation of the latter into the central vascular bundle.^ 
 
 It is only in very rare instances that the terminal bud of 
 the stem, of Jspidiumßlioj-mas di\ideshj true forking of the 
 
 * In consequence of my having examined sections M^liich were not truly 
 axile, I was led to assume that the lenticular cells of the interior of the root of 
 Equisetum variegatum [^ Vergl. Unters.,' pi. xviii, fig. -S), as well as the primary 
 cells of cue of the layers of the root-cap, were root-cells of the first degree. 
 
THE HIGHEll CRYPTOGAMIA. 245 
 
 punctum vegetationis. The multiplication of shoots by 
 means of adventitious buds is proportionably more frequent. 
 These buds always originate on the back of the stipes, at 
 the place where the protuberant swelling of the latter passes 
 off into the more slender upper portion. After the removal 
 from the stipes of the thick covering of scales, the earliest 
 conditions of the adventitious buds may be seen in the form 
 of a disk surrounded by an annular fiUTOw and having a 
 slight protuberance at its middle point which represents the 
 apex of the new axis in process of formation. Somewhat 
 later, other protuberances, being the rudiments of fronds, 
 are seen, arranged in a circle round the central one (PI. 
 XXVII, fig. 5). Whilst on the mother- plant the new 
 shoot begins to send forth roots independently (PL XXVII, 
 fig. 6). The vascular bundles which pass to it from the 
 vascular bundles of the frond on which it is produced, 
 unite at its place of attachment so as to form a closed 
 ring from which their distribution in knots answering to 
 the insertions of the fronds commences (PI. XXVII, fig. 7). 
 Such adventitious buds are formed on vigorous plants in 
 fertile habitats at about every twelfth frond, and much more 
 frequently in plants growing in dry situations.* 
 
 Aspidium spinulosum comports itself in all its parts like 
 AspidiuM filiöß-mas. The adventitious buds are here met 
 with very near the base of the stipes. The scales bear at 
 their apices, and frequently also on the teeth of the margin, 
 very swollen, oval, or pear-shaped cells with mucilaginous 
 contents ; a phenomenon which is also seen in Aspidium 
 Oreopteris, Asplenitim ßlix-femina, StrutJiiopteris germanica 
 and other fems. 
 
 Asphnium ßlix-femina ; Asplenium Bellanfferi; StrutJiiop- 
 teris germanica ; Nep/irotepis undulata ; Nephrolepis splen- 
 dens. — The above-named ferns agree entirely in the principal 
 features of vegetation, viz., in the form and mode of multi- 
 plication of the cells of the terminal bud ; in the position of 
 the frond- cells of the first degree with regard to the apical 
 cell of the terminal bud ; and in the arrangement of the 
 
 * It is probable that Scbleiden had these buds in view -when he spoke of 
 this fern as haviug axillary buds (' Gruudziige ' 2 Aufl., vol. ii, p. 87), which 
 in Js2ndium ßlix-mas, as in all European ferns, are absolutely unknown. 
 
246 HOFMEISTER, ON 
 
 vascular bundles in the stem. Asplenium ßlix-femina is 
 distinguisliable by the more slender form of the terminal 
 bud, the growth of which in thickness terminates at the 
 fourth set of cells, (reckoning doAAiiwards and sideways from 
 the apical cell), the produce of one of the cells of the second 
 degree, so that the frond-less apex of the stem is elevated 
 considerably above the earliest rudiments of the fronds 
 (PL XXXIII, fig. 2). A further peculiarity of this plant is 
 that only one vascular bundle enters each stipes from the 
 upper angle of each knot of vascular bundles. For a con- 
 siderable distance this bundle is simple ; it then divides 
 into two, and further up into several strings. The status 
 which in Aspidmm ßlix-mas only occurs Avhilst the plant is 
 young, that is to say only in the one year old plant, is main- 
 tained here during its whole life. Underneath the place 
 where the vascular bundle of the stipes exhibits its first 
 ramification, one root is normally produced ; each frond 
 has only one, which is developed in a plane passing through 
 the median line of the frond. This circumstance greatly 
 facilitates the investigation of the earliest stages. In well- 
 made longitudinal sections, close outside the rudimentary 
 vascular bundle of the frond, there may be seen the primary 
 cell of the appurtenant root, by the multiplication of which in 
 the manner pointed ont in Aspidi um fUx-vias, the root-cap 
 and the permanent cylindrical portion of the root are pro- 
 duced (PI. XXXIII, figs. 4, 5). The tissue of both halves 
 of the growing root, as well as the cells of the root-cap, are, 
 whilst in this early state, in intimate parenchymatal con- 
 nexion Avith the cortical cells of the stipes. Afterwards, 
 shortly before breaking forth from the hind surface of the 
 stipes, the boundary between the root-cap and the cells be- 
 fore it becomes sharply defined (PI. XXXIII, fig. 6) with- 
 out however any rupture of the tissue, or the appearance of 
 any inter-cellular space. The few cellular layers of the 
 stipes anterior to the apex of the young root, are gradually 
 displaced and dissolved, not broken through ; the cuff- 
 like margin, which is formed from the cellular tissue of the 
 mother-portion of the plant, and which is so remarkable on 
 the adventitious roots of many Monocotyledons, is wanting 
 here. 
 
THE HIGHER CRYPTOGAMIA. 247 
 
 Adventitious buds are very rare in Asplenium filix- 
 femina; it would seem that they never occur when the 
 plant is growing naturally. HoAvever at the base of the 
 stipes of a frond which had been torn off and kept for some 
 time in a closed bottle in moist air, I saw adventitious buds 
 produced underneath the place of attachment of the roots 
 (PL XXXIII, fig. 1). On the other hand the forking of 
 the apex of the stem by division of the frond-less terminal 
 bud is in this fern quite a normal process ; it is the usual 
 asexual mode of multiplication of the plant which it woiüd 
 seem occurs at tolerably regular intervals. The observer 
 will seldom fail to find the bifurcation of the stem in old 
 plants ; specimens often occur with from four to nine 
 heads. 
 
 In Stndhiopteris germanica'^ the formation of numerous 
 adventitious shoots is added to the other peculiarities already 
 mentioned.! As in Aspidiimi spinidosum, they originate 
 on the outside, at the base of the stipes, close above its in- 
 sertion into the stem. The first commencement of their 
 formation occurs unusually early, long before that of the 
 blade of the frond. In their first development they are 
 directed obliquely downwards (PI. XXXIII, figs. 7, 8). 
 
 The copious production of adventitious buds on all parts, 
 even on the ramification of the blade of the frond, is very 
 remarkable in Asplenium Bellangeri. The mode of develop- 
 ment is essentially the same as in Aspidium ßUos-mas. 
 Here also the new shoots do not originate in the interior of 
 the tissue of that portion of the plant which produces them, 
 but outside, on its outer surface. 
 
 It is well known that the species of Nephrolepis send 
 forth long thin runners, whose ends, in Nephrolepis undu- 
 lata and N. tuberosa, swell into knobs. | The stolons 
 originate from adventitious buds, which are produced 
 apparently on the stem, at that part of the base of the 
 frond which amalgamates with, and forms a bark to the 
 stem (PL XXXIV, fig. 3). The nmners are one third of a 
 line thick, and sparingly clothed with pale yellow scales ; 
 
 * On the distribution of the vascular bundles, see Schacht, ' Pflanzenzelle,' 
 PL XV, fig. 3—6. 
 
 f See Braun, * Verjiinguns:,' p. 115. 
 X Kunze, 'Bot. Zeit.,'' 1849, p. 881. 
 
248 HOFMEISTER, ON 
 
 they root here and there, and are traversed by a vascular 
 bundle. The apical cell of the terminal bud is always 
 two-sided in N. undulata. On the thicker stolons of 
 N. splendens it appears to be frequently three-sided. In 
 N. undidata it first assumes this form when the apex of the 
 runner begins to form a knob. Within the swelling mass 
 of parenchyma the central vascular biuidle, which has 
 hitherto been simple, becomes branched (PI. XXXIV, 
 fig. I). The bundles are henceforth arranged in a circle 
 concentrical with the periphery of the knob. 
 
 As far as my observations extend, the vegetation of 
 the terminal bud ceases with the complete formation of 
 the knob, which is about an inch long.* The arrange- 
 ment of the cells admits of the observation of their mode of 
 ceU-multiplication, if followed out in the same manner as 
 in the end of the stem of Aspidium filix-mas. The con- 
 tents of the cells, as well as those of the numerous rudi- 
 ments of withering scales by which they are surrounded, 
 become transparent. The knob sends forth fresh adventiti- 
 ous buds, which originate in numbers on its lateral surfaces 
 (Fl. XXXIV, fig. 2). Soon after the development of these 
 shoots the knob decays. 
 
 PoJi/podmm, Niphohohs. — The species of Niphobolus, 
 which I have examined {N. rupesiris and N. chi/iensis), as 
 well as several foreign species of Polypodium {aiireum,piincia- 
 tum, ct/mafodes), all exhibited the two-edged form of apical 
 cell answering to the bi-linear frond-arrangement. In Poly- 
 podium vulgare it was otherwise. Here the terminal bud, 
 when viewed from above, exhibits sometimes the form of the 
 cell of the first degree and the arrangement of its next deriva- 
 tives as in Aspidium filix-mas (PI. XXXIV, fig. C) ; some- 
 times (and most frequently) the two-edged form of the upper 
 siu-facc of the apical cell (PI. XXXIV, fig. 5) ; sometimes 
 forms which may be looked upon as intermediate between 
 the two, inasmuch as the free outer wall of the cell of the 
 first degree has the shape of a triangle, whose sides are 
 more than three times the length of the base. Deviations 
 from the typical bi-linear frond-arrangement are not un- 
 
 * This is opposed to Kunze's statement. He describes the further develop- 
 ment of the apex of the bud, 1. c., p. 883. 
 
THE IlIGHKR CRYPTOGAMTA. 249 
 
 common in this species. They occur very frequently in 
 plants which grow in places having a comparatively small 
 amount of moisture, as is the case usually in an open 
 plain. The frond-arrangement oscillates unsteadily be- 
 tween ^ and ^. Similar deviations occur in Folypodium 
 Dryopteris. 
 
 The walls, by whose appearance in the first cell of the 
 rudimentary frond the formation of the stipes commences, 
 are radial, not tangential to the axis of the stem (PI. 
 XXXIV, fig. 4), agreeing in this respect with those of 
 Aspidium ßlix-mas, and differing from those of Pteris 
 aquilina. At the slender ends of the stems of Niphobolus 
 rupestris and N. splendens, the development of the scales 
 may be very conveniently traced. This development takes 
 place at some little distance underneath the apical cell of 
 the stem. The formation of the scales begins at a distance 
 of eight cells from the top, reckoning downwards, by the 
 formation of a papillate protuberance of the free outer wall 
 of a cell of the circumference (PI. XXXII, fig. 9). The pro- 
 tuberance is soon cut off from the original cell-cavity by a 
 transverse septum. The appearance of a new transverse 
 septum then divides the cell, which is already much flattened 
 laterally, into an upper and a lower cell (PI. XXXII, fig. 10). 
 Repeated transverse divisions, not only of the apical cell, 
 but also of the interstitial cells (PI. XXXII, figs. 11, 12), 
 transform the rudimerit of the frond into a short series of 
 low cells with an elliptical basal surface. The phenomena 
 which become visible from these divisions, and especially 
 the gradual dissolution of the prmiary nucleus of the divid- 
 ing cell and the appearance of two new nuclei in its place, 
 are precisely the same as those which are observed in the 
 nuütiplication of the cells of the hairs of pliaenogamous 
 plants (PI. XXXII, fig 11). 
 
 The cells of the lower portion of the young frond now . 
 divide by longitudinal septa which coincide Avith the me- 
 dian line of the frond. These longitudinal septa are per- 
 pendicular to the surface of the frond, like the walls of 
 almost all the cells which take part in the formation of the 
 scales of ferns. The division progresses from the base 
 of the frond towards its apex, extending in Niphobolus ru- 
 
250 HOFMEISTEll, ON 
 
 pestris to about the sixth, in N. splendens as far as the 
 third cell from the apex, reckoning backwards. The upper- 
 most cells of the frond, those into which the above division 
 does not extend, now expand considerably lengthwise, 
 the expansion commences with the apical cell and the 
 others follow step by step (PL XXXII, figs. 13, 14). The 
 termination of the multiplication of these cells is mani- 
 fested by the thickening of their walls, and by their con- 
 tents becoming transparent. On the other hand a partial, 
 very considerable multiplication, ensues in the remaining 
 cells of the frond. It is most considerable in the cells at 
 the base, where the divisions by means of septa at right 
 angles to the longitudinal axis of the frond are most fre- 
 quently repeated, alternating with divisions parallel to 
 such axis. The activity of the cell-multiplication dimi- 
 nishes continuously towards the apex of the frond. The 
 divisions first cease in the cells of the upper half of the 
 frond, wdiich become elongated at the earliest period and to 
 the greatest extent. The division of the cells of the 
 frond by means of septa parallel to the longitudinal axis, 
 appears not to be contemporaneous ; it is repeated oftener, 
 and 'extends nearer to the apex of the frond in one longitu- 
 dinal moiety of the frond than in the other (PI. XXXIII, 
 fig. 8). 
 
 Owing to the gradual increase in breadth of the base of the 
 fi'ond, its cells in Niphoholus rupestris, Nephrolepis splendens^ 
 and Polypodhim aureiim, do not amalgamate with the cells 
 of the circumference of the stem with which they are in 
 contact. The place of attachment of the frond does not 
 become wider, and moreover consists, even when the frond 
 is perfected, of only two cells, which have been produced 
 by the division by means of a longitudinal septum of the 
 luidermost cell of the rudiment of the frond. The cells 
 of the free margin of the base of the frond nudti ply actively 
 in many species (as for instance in Niphobolus rupestris 
 and TV. splendens), through division by means of septa 
 parallel to a tangent to the circumference ; those cells 
 which adjoin the place of attachment of the frond and the 
 angle of the lateral margins multiplying less actively than 
 those between them. The base of the frond thus becomes 
 
THE HIGHER CllYPTOGAMI A. 2.~>1 
 
 heart-shaped. The cells of the place of attachment, and 
 often also those near it, divide, when the frond is almost 
 perfect, by means of septa parallel to the surface of the 
 frond (PI. XXXIV, fig. 7). The cells of the lateral margins 
 of the leaf often grow into delicate little teeth, which are 
 usually curved backwards. 
 
 Scales which run through all the stages of development 
 here represented are found not only on the principal axis 
 of the plant but also on the lower portion of the frond. In 
 the greater number of ferns the bases of the fronds exhibit 
 scales at least in their youth. The arrangement of the 
 scales both on the principal axes and on the fronds is 
 governed by well-defined rules.* The reason why the 
 arrangement is often undistinguishable on the fronds is 
 that after the last important longitudinal expansion of the 
 stipes individual scales fall off" abnoruially much earlier than 
 the neighbouring ones. 
 
 In the earliest stages of Polypodium vulgare scales are 
 found whose almost circular forui indicates the tendency to 
 assume the shape of a shield which is ultimately arrived at 
 by the exuberant growth of the hinder margin, in which 
 growth those daughter-cells take part which are derived 
 from the primary cell, which after numerous divisions by 
 means of longitudinal septa has become the attachment-cell 
 (PL XXXIV, fig. 7). 
 
 The separation of the vascular bundles from the rest of 
 the tissue of the stem, and the formation of roots from 
 them, take place as in Aspidium and Pteris. In Foly- 
 podium vulgare, as in Poh/podium aureum, the vascular bun- 
 dles run off" into a cylindrical annular net of meshes, which 
 have no immediate relation to the insertions of the fronds, f 
 
 Platycerium Alcicorne. — The first frond of the germ- 
 plant is erect and fleshy, having the shape of a spatula, 
 and being slightly bent over behind. It is clothed with 
 the stellate hairs characteristic of the plant, and has but 
 few scales. The latter are more abundant on the young 
 
 * For instance, on the principal axis and fronds of Niphoholns ckinensis the 
 arrangement is fij. The regularity of the arrangement is beautifully shown on 
 tiie procumbent stem of Poli/podium aureum by the little depressions, of which 
 each one indicates the place where a scale has been attached. 
 
 t See V. Mohl, 'Vermischte Schriften,' p. 115. 
 
252 HOFMEISTER, ON 
 
 stem, and are remarkable for their rapid development, 
 especially in thickness, even in the early youth of the 
 plant. The fronds which follow the first frond differ 
 rcmarkahl}^ in form, direction, and strncture. Their 
 ontline is circular or rcniform ; they are developed in 
 a horizontal direction, bending backwards and downwards 
 to such an extent from the point of attachment, that they 
 touch the base of the plant. Their thickness far exceeds 
 that of the upright frond; their vascular bundles lie, not in 
 one, but in two planes parallel to the surfaces of the frond. 
 These bundles form two many-meshed nets, one close under 
 the upper side, and the other inmiediately above the lower 
 side of the frond ; the two net-works are united in many 
 places by frequent ramifications which pass through the 
 mass of the frond in a transverse direction. 
 
 When the plant has attained a certain amount of vigour, 
 erect fronds are again formed, which hang over gracefully, 
 and exhibit slightly spreading forks upon which spo- 
 rangia sometimes appear. After six or eight such erect 
 fronds have been produced, a pair of simple fronds is de- 
 veloped, one on the right and the other on the left of the 
 stem. These latter fronds curve downwards. All the 
 fronds, as well the thick flat recurved ones as also those 
 which are slender and erect, are arranged accurately in two 
 lines ; this is seen clearly by cutting through the fronds as 
 ftU- back as the primary place of attachment. The direction 
 of the frond-arrangement, judged by reference to the mode 
 of succession of tAvo neighbouring flat fronds, is sometimes 
 to the right and sometimes to the left. A bud is usually 
 formed deep down on the hinder side of the stipes of each 
 of the erect fronds. This bud, when laid bare by the re- 
 moval of the flat frond which forms a thick covering over 
 it, becomes developed into an independent plant. 
 
 It is not difficult to conjecture the part which the thick 
 recurved fronds play in the economy of the plant. They 
 prevent the drying up of the place of growth. The thick 
 covering which they form causes that portion of the bark 
 of the trunk of the tree upon which the fern grows, to be 
 retentive of moisture. Those species of the same genus 
 whose fronds spread over the smface of the ground, — thns 
 
THE HIGHER CRYPTOGAMIA. 253 
 
 forming a wide covering over the places of attachment of 
 the older fronds and the gronnd beneath as in Plaiyceruim 
 grande, — are entirely devoid of the irregularly-shaped, 
 fleshy, recurved frond. 
 
 The vascular bundles of the horizontal stem are arranged 
 in a simple circle (PI. XXXIV, figs. 8, 9) ; they form on 
 the upper side a polygonal net, and on the under side a 
 net with very narrow, parallel meshes. The arrangement 
 of the meshes in both nets is shown in PI. XXXIV, figs. 
 10, 11. The vasciüar bundles pass to the fronds from 
 the angles of the meshes of the upper side. These bun- 
 dles anastomose frequently in the cortical layer of the upper 
 side of the stem. The vascular bundles of the roots originate 
 at the upper and lower terminal points of the narrow 
 meshes of the under side of the stem, the roots themselves 
 being arranged in transverse rows. Roots very frequently 
 penetrate into the substance of the decayed flat fronds, 
 where they ramify considerably. 
 
 The cortical layer of cellular tissue which smTounds the 
 central vascular bundle of the root, exhibits an anatomical 
 peculiarity, having a remarkable analogy with what is seen 
 in the epiphytal Orchids and the Aroiclese. The walls of 
 its cells, which become brown at an early period, are 
 thickened by a net-work of filaments. Narrow flat de- 
 pressions are seen between the very delicate threads of the 
 net (PI. XXXIV, figs. 12, 12*). The outermost cellular 
 layer of the root of Platycerium, from which rootlets are 
 emitted, has the depressions, but not the reticulate threads. 
 
 The apical cell of the end of the stem of Plaff/cerium 
 cdcicorne is two-edged, having the form of a strongly-com- 
 pressed cone. The arrangement of the surrounding cells 
 discloses the fact that the multiplication of the cells of the 
 terminal bud is brought about by the continuously repeated 
 formation in the cell of the first degree of septa inclined in 
 two opposite directions. A parabolical line drawn through 
 the middle point of the places of insertion of all the younger 
 fronds, cuts the upper smface of the apical cell of the stem, 
 not in its shortest but in its longest diameter. The top 
 cells of the young fronds have their edges, and not their 
 surfaces, turned towards the ends of the stem, whose apical 
 
 PLEASE CO NOT SOIL, MAMR 
 
251 HOFMEISTER, ON 
 
 cell turns its own edges towards them. These facts are 
 directly contrary to what occurs in Pteris aquilina, but on 
 the other hand they agree with what takes place in the 
 Polypodiese. 
 
 Marattia Cicutcefolia.^ — The flat terminal bud of this 
 fern exhibits, when viewed from above, a three-sided apical 
 cell as in Aspid'mm filix-mas. Longitudinal sections show 
 a very oblique arrangement of the side walls of the apical 
 cell and of the neighbouring cells. The rudiments of the 
 young fronds surround the flat conical end of the stem in 
 a spiral. The latest formed have the appearance of sharply 
 conical protuberances of cellular tissue flattened in front, 
 hardly distinguishable from the first rudiments of the fronds 
 of the larger Polypodiaceae. 
 
 In consequence of its increased longitudinal groAvth the 
 top of the young frond bends over in front. Dming this 
 process the stipula makes its appearance, in the first in- 
 stance at the fore surface of the yomig frond, in the shape 
 of a transverse protuberance (PL XXXIII, fig. 11). Shortly 
 afterwards a membranous cellular mass grows in a forward 
 direction out of each of the lateral margins of the rudiments 
 of the frond. Those surfaces of the two cellular masses 
 which are turned towards the protuberance of the fore-side, 
 amalgamate with the side margins of the latter (PI. 
 XXXIII, figs. II, 12). The fore margins of the two 
 lateral lobes of the stipula remain free. In consequence of 
 their rapid further development they almost entirely en- 
 velope the younger portions of the stem-bud. In the 
 mean time the upper margins of the two lateral portions of 
 the stipula grow rapidly and vigorously upwards and back- 
 
 * De Vriesc and llartings Monograpli of tlie Marattiaceae (Lcyde et Dussel- 
 dorf, 1S53, pp. 49 and 51) contains statements as to the development of the 
 fronds of tlie Marattiaccre, which, if correct, sliow that the process is very 
 peculiar. It is there said, " Tlie formation of each frond is preceded by tliat 
 of its Perula. ... It covers even tlie younger fronds partially. . . . 
 The cellular ))rotuberance, in the form of which the younger frond makes its 
 appearance laterally near the terminal bnd, consists in Angiopteris originally of 
 cells of equal size, and of equal capacify for multiplication. The outer cells 
 grow and multiply more rapidly, in consequence of which they separate from 
 tiic inner ones. The former constitutes the membranous portion of the Ferula, 
 the latter that of the fronds." My observations on Maral I'm ricuttrfoUa, from 
 which in this respect Angiopteris certaiidy docs not differ, lead to entirely 
 diflcreut conclusions. 
 
THE HIGHER CRYPTOGAMIA. 255 
 
 wards. Tliey assume a cap-like form, and laying hold 
 of one another they envelope the apex of the rudiments of 
 the frond, which now for the first time slowly elongates 
 itself (PL XXXIII, figs. 15-19). Thus the rudimentary 
 Ferula is formed in all its parts, but nevertheless as an 
 organic closed veil : its principal portion, viz., the two 
 membranous lobes which enclose the involute frond, con- 
 sists of two entirely distinct moieties overlapping one 
 another and leaving a wide opening at the place where 
 they impinge upon that part of the stipula which has origi- 
 nated from the fore surface of the rudiment of the frond 
 (PL XXXIII, fig. 19). By further development this trans- 
 verse portion of the stipula becomes divided at the upper 
 margin into two cellular surfaces, one of which is bent 
 backwards over the involute special frond, the other for- 
 wards over the rudiments of the younger fronds. By fur- 
 ther advance in growth all the parts of the stipula, especially 
 the basal portions, are developed to a great degree, so as 
 to form a tissue of considerable extent, of a dark red coloilr 
 on the outside and rose red within, and traversed by an 
 intricate complication of numerous vascular bundles and 
 passages containing gummy matter. The cells of this 
 tissue abound with large starch-grains. Even now, how- 
 ever, no amalgamation takes place anywhere between the 
 hitherto distinct portions of the stipula. 
 
 The development of the scales and roots of Marattia 
 differs in no material respect from that of the Polypodiacese. 
 The root-cell of the first degree appears three-sided both in 
 a longitudinal and in a transverse section of the root. 
 
 It is generally known amongst gardeners that fragments 
 of the fleshy adventitious fronds of the Marattiacese can be 
 used to produce new individuals. In Marattia cicutafolia 
 this mode of reproduction maybe practised with exceeding 
 facility. The stipules, even of the most slender fronds, of 
 specimens grown in the same manner only a few months pre- 
 viously, may be employed for the experiment. If these 
 stipules be cut into pieces about half a square inch in size, 
 and simply placed in a stoppered bottle, adventitious buds, 
 produced at some of the numerous vascular bundles, will be 
 seen in ten or twelve weeks to break through the bark of 
 
256 HOFMEISTER, ON 
 
 the fragments of the stipules. Tlie first fronds of these 
 shoots have no lamina ; they are entirely stipulseform. 
 
 Developinoit of the fruit and spores. — Although 
 much variety exists in the process of formation of those 
 organs of ferns which surround and cover the sori, ne- 
 vertheless the development of the capsules of the Poly- 
 podiaceae exhibits, as far as present observations extend, 
 a marked uniformity. At the place of attachment of 
 the sorus the rudiments of the capsules are developed 
 (contemporaneously with the appearance of the indusium 
 where the latter is present), under the form of short multi- 
 cellular hairs. The terminal cell of each swells to a globular 
 form, and, by the effect of a series of cell-divisions, assumes 
 the form of a body consisting of a single central cell and 
 a peripheral cellular layer. The central cell is the primary 
 mother-cell of the spores. By division in all three direc- 
 tions of space it is transformed into a globular mass of 
 polyhedral cells — the spore-mothor-cclls — the walls of which 
 become somewhat thickened. Whilst the internal cavity of 
 the young sporangium becomes enlarged by the expansion 
 of the peripheral layer, the walls of the spore-mother-cells 
 swell, and the latter become disconnected, and assume a 
 globular form. They then divide into four special -mother- 
 cells, which in certain species are situated at the angles 
 of a tetrahedron, in others are arranged in a decus- 
 sate manner. A spore is formed in each of these 
 special mother-cells. The membrane of the primary 
 mother-cell is still existent at the time of the commence- 
 ment of the individualization of the spore-mother- cells, and 
 can be detached from the peripheral cellular layer.* This 
 development of the capsule has been observed by Schacht, 
 
 * Schacht, 'Bot. Zeit.,' 1S49, figs. G, 7. The membrane of the primary 
 mother-cell, like those of the mother -cells, is somewhat distended ; the 
 latter appear to be snspended freely in the former. Schacht was thus led to 
 assume that the mother-cells originated by free cell-formation in the primary 
 mother-cell (I. c, p. 544). Schach t's statement that the nucleus of each 
 primary mother-cell separates by division into four secondary nuclei, is not 
 confirmed by the observations which 1 have made upon Asplcnium filix-femina 
 and Ci/stopleris fragilis. In the former I found at first two secondary nuclei iu 
 the place of the primary one, and afterwards four tertiary ones in the place of 
 the secondary ones. It appeared to me that here also the dissolution of the 
 })riiiK\ry nucleus of the mother-cell preceded the formation of the nuclei in 
 daughter-cells. 
 
THE HIGHER CRYPTüGAMIA. 257 
 
 in Ptetis serrulata, Aspleninuni F et rar ice, and Scolopendrium 
 oßcinarum ; and by myself in AsjjI. fdlx-femina, and 
 Cydonterls fragilis. H. v. Mold, in 1883, described 
 the development of the spores in special-mother-cells 
 (four being contained in each mother-cell), whose mem- 
 branes possess a remarkable power of distension (see 
 'Mora,' 1833, B. i; ' AYu'mischte Schriften,' p. 69). In 
 the families of ferns other than the Polypodiacese, few ob- 
 servations have been made. I may remark here, that I 
 have clearly seen a single central cell in very young 
 sporangia of Osmuiida regcdk. In this respect, therefore, 
 ferns seem to agree Avith the rest of the vascular crypto- 
 gams, viz., that a single cell situated in the interior of the 
 young sporangium represents the primary mother- cell of all 
 the spores. 
 
 Historical Beview. — The reproduction of ferns by means 
 of spores was first pointed out by Morison, who states (' His- 
 toria plantarum,' Oxford, 1699, iii, p. 55) that after sowing 
 the spores oi Scolojjendrium oßcinarum upon moist ground in 
 the shade, he obtained in the following year numberless little 
 plants of the same species, with delicate and at first 
 roundish leaves. Ehrhart first made known with certainty 
 that the production of the perfect fern is preceded by the 
 development of a deeply two-lobed leaf-like body, upon 
 the under side of which, between the indentations and the 
 hinder end, the perfect fern is attached (' Beiträge,' iii, 
 Hanover, 1788, p. 75). For the first accurate micro- 
 scopical investigations of the germination of fern- spores we 
 are indebted to Kaulfuss, who clearly and accurately 
 described the ruptm^e of the outer spore-membrane, the 
 protrusion of the inner one, and the development of the 
 prothalliura ('Das Wesen der Farrn-kraüter,' Halle, 1827, 
 p. 61). The sexual organs of the prothallium entirely 
 escaped his observation, as well as the enclosure of the 
 young embryo in the tissue of the prothallium. The dis- 
 covery of this fact is due to Bischoff" (' Handb. botan. Ter- 
 minologie,' b. ii, Nürnberg, 1842, p. 640), who states that 
 a wart-like excrescence originates on the back of the pro- 
 thallium underneath its indentation, and that out of this 
 excrescence the first frond breaks forth in an upward 
 
 17 
 
258 HOFMEISTER, ON 
 
 direction and the first root downwards, the latter being 
 surrounded at its base by the ruptured membrane of the 
 cellular protuberance, as % a sheath. Upon the plate ex- 
 planatory of this process (1. c, t. 41, fig. 2385) an empty 
 antheridium is shoAvn upon the prothallium, without how- 
 ever any mention of this organ being miide in the text. 
 Two years afterwards Niigeli published the discovery of the 
 antheridia and spermatozoa of the ferns (' Zeitsclu'. f. 
 Avissensch. Bot.,' Zurich, 1844, p. 168). He describes 
 the origin of the antheridium, of the mother-cells of the 
 spermatozoa, and of the spermatozoa themselves, essentially 
 in conformity with the account given in the preceding 
 pages ; he brings clearly forward the similarity of the an- 
 theridia of the ferns with those of the Muscineae and asserts 
 that the antheridia are very probably the male organs, 
 although it remained almost inexphcable to him in what 
 relation they could stand to the impregnation, which he 
 considered only to affect the spores. It is beyond ques- 
 tion that Nageli also observed the archegonia of ferns, but 
 misunderstood them : they are the organs which he describes 
 and figures (1. c, p. 171, t. iv, fig. 11 — 15) as many-jointed 
 antheridia. The real nature of the archegonia was first 
 correctly ascertained by Count Leszyc-Suminski ('Zur Ent- 
 wickelungs-geschichte der Farrn-kräuter,' Berlin, 1848). 
 He pointed out (1. c, p. 13) that the rudiments of the frond- 
 bearing plant always appeared on the underside of one of 
 the archegonia, inside a cavity sunk in the tissue of the 
 cushion of the ]3rothallium, and he assumed that in order 
 to excite the development of this embryo, the entrance of 
 one or more of the spermatozoa was necessary. He ob- 
 served the cilia of the spermatozoa, but did not figure them 
 quite accurately. Suminski's correct conclusions Avere 
 arrived at ])y observations which were to a great extent 
 erroneous. He believed that the archegonium in its 
 yomigest condition, and before its neck protruded above 
 the surface of the prothallium, was open at its apex ; and 
 that at this period the entrance of the spermatozoon into the 
 central cell took place, He called the latter the cavity of 
 the germinal vesicle and its nucleus the germinal vesicle 
 itself. He considered that the longitudinal development 
 
THE HIGHER CRYPTO GAMI A. 259 
 
 of the neck of the archegoniuni and the closing of its mouth 
 did not take place until after the entrance of the sperma- 
 tozoa. According to his view one of those spermatozoa 
 which had first effected an entrance into the archegoninm 
 then penetrated with its pointed end into the embiyo-sac 
 which in the mean time had become multicellular; the 
 pointed end then became SAvollen and converted into a 
 spherical cell which gradually displaced the tissue of the 
 embryo-sac, formed new cells in its interior, and thus con- 
 stituted the embryo. He thought that the spermatozoa 
 which had entered the archegoninm at an early period, 
 and which had not aided in the formation of the embryo 
 but had reached the canal of the neck, were there trans- 
 formed into the worm-shaped masses which I have pointed 
 out as the product of the transformation of the cells of the 
 axile string of the neck of the archegoninm. From the 
 erroneous notion entertained by Suminski as to the de- 
 velopment of the archegoninm, it is quite clear that his 
 observations upon the entrance of the spermatozoa into the 
 central cell must be founded on a misconception, and that 
 he ne^^er really saw the spermatozoa enter the archegoninm 
 at all. His idea of the formation of an endosperm in the 
 embryo-sac is founded upon an incorrect arrangement of the 
 different stages of development which he olDserved; the 
 body which he designates as endosperm, as " multicellular 
 parenchyma filling the embryo- sac," is in fact the young 
 embryo. L. Suminski first observed the cilia of the fore- 
 end of the spermatozoa, but did not draAV them quite cor- 
 rectly (1. c, t. ii, figs. 20, 21). Thuret gave the first 
 accurate figures of them (' Ann. d. Sc. Nat.,' 3rd ser., vol. 
 xi, p. 5). A succession of works by other observers fol- 
 lowed quickly upon the publication of Leszyc-Suminski's 
 treatise. First came Wigand in the ' Bot. Zeitung,' for 
 1849. He disputed most of the statements of his prede- 
 cessor, even those which were quite accurate, such as the 
 constant occurrence of the cavity (of the central cell) 
 beneath the free portion of the archegoninm (1. c, p. 78) ; 
 the regularity of the pressure of the neck of the arche- 
 goninm upon that layer of the tissue of the prothallium 
 which covers the enclosed young embryo (1. c, p. 77, 106) ; 
 
260 HOFMEISTER, ON 
 
 tlie iioniial concealuient of tlie young embryo in llie tissue 
 of the prothallium (1. c, p. 106), and even the possibility 
 of the access of the spermatozoa to the archegonia (1. c, 
 p. 78). On the other hand in the ' Bot. Zeitung,' for 
 1849, p. 796, I have given my opinion confirmatory of 
 the principal point in L. Suminski's statements, viz., the 
 regular development of a young plant in the interior of one 
 of the organs called Ovula by L. Suminski. I added that 
 the parting asunder of the four longitudinal rows of cells 
 which form the neck of the archegonium, is the cause of 
 the opening of the passage which leads to the large cell at 
 the bottom of the female organ, and that Suminski's " En- 
 dosperm " is in fact the young plant. At the same time 
 I called attention to the facts that the antheridia and 
 archeo;onia of mosses exhibit in their structure the most 
 striking similarity to the like organs in ferns, and that 
 the development of the embryo of the vascular cryptogams 
 coincides in its principal features with that of the fruit in 
 mosses, inasmuch as in both those large groups of plants 
 the fruit is not developed in a continuous course of vegeta- 
 tion from the germination of the spore, but in both families 
 the development suffers a discontinuance ; in an organ 
 which has essentially the same structure in both families, a 
 cell originates, in Avhich, after exposure to the access of 
 spermatozoa, an independent cellnlar body is formed, mor- 
 phologically distinct from the mother-plant, upon mIucIi 
 the mosses are dependent for the development of their 
 fruit only, Ijut to which the ferns owe by far the most im- 
 portant part of tliei]- vegetative growth. In a work which 
 appeared shortly afterwards (' Linna^a,' B. xxii, 1850, p. 
 753) Schacht also pointed out that the archegonia of ferns 
 are formed just like those of mosses ; that they arc at first 
 closed, and are fnrnishcd at the base Avith a cavity sunk in 
 the tissue of the prothallium, which cavity is in comnuuiica- 
 tion with the canal which traverses the neck of the organ; 
 that in the interior of the cavity, and probably inside a cell 
 clothing the cavity, the emlnyo is formed. Like myself, 
 Schacht considers that the filiform nuicilaginous bodies in- 
 side the closed canal, which L. Suminski looked upon as 
 transformed spcrmntozoa, are tlie })roducts of the transfoj'- 
 
THE HIGHER CRYPTOGAMI.A. 261 
 
 Illation of the primary contents of the canal, and that 
 Snminski's endosperm is the embryo (L c. p. 780). On 
 the other hand V. Mercklin's conchision from the exami- 
 nation of the same object (' Beobachtungen am Prothalhum 
 der Farrn-kräuter/ Petersburg, 1850) was more in favour of 
 Suininski's ^ iews. V. jMerckhn also thought that the young 
 arohegonia were open, and believed that he had seen the 
 entrance of spermatozoa into such .young archegonia, and he 
 assumed that it was not until a subsequent period that the 
 apex of the neck of the archegonium became closed 
 (1. c. p. 46). On the other hand he observed correctly the 
 bursting of the apex of the archegonium after its complete 
 formation (1. c. ]). 33) as well as the presence of a globular 
 cell in the central cell (which like Schacht and Suminski he 
 took to 1)6 an intercellular space) before the bursting of the 
 latter (1. c. p. 31). To Y. Mercklin also is due the merit of 
 the first reliable observations of the entrance of the motile 
 spermatozoa into the mouth of the neck of an opened 
 archegonium (1. c. p. 46 in A^pleniutu Serrci). Mettenius 
 ('Beiträge zur Botanik,' Frankfurt 1850, p. 18) arrived at 
 the same results as Schacht and myself. He first pointed 
 out that the development of an archegonium from a cell of 
 the prothallium, commences with the division of this cell 
 into two cells lying underneath one another (1. c. p. 19). 
 
 In my 'Vergleichende Untersuchungen' Leipzig 1851, 
 p. 81, I added to the account which I had published two 
 years before. The principal points in the literature of the 
 sexual reproduction of ferns received a further confirmation 
 from a paper of Henfrey's in the ' Transactions of the 
 Linnean Society,' vol. xxi, p. 117, 1852. In 1851 I was 
 under the impression that the germinal vesicle of ferns 
 originated by renewed cell-formation round the primary 
 nucleus of the central cell, an error which I corrected in 
 1854 ('Sitzungsberichte K. Sachs. Gcsellsch. d. Wissen- 
 schaft,' J\Iath. Phys. CI. 1854, p. 54) Avlien reviewing my 
 first observations on the motile spermatozoa in the central 
 cell of the archegonium. In a publication which appeared 
 soon afterwards, Wigand retracted his previous contradic- 
 tions of the statements of other observers, (Botanische 
 Untersuchungen, Braunschweig, 1854, p. 151) so that 
 
26.2 HOFMEISTER, ON 
 
 botanists are now unanimous upon all the essential points 
 of the question. 
 
 The anatomy of the stems of ferns (the coiu'se of whose 
 vascular bundles had been supposed to be very similar to 
 that of the monocotyledons) was first clearly explained by 
 H. V. Mohl (de structurä caulic. filic. arbor, in v. INIartius' 
 Icon, plant, cryptog. Brasil. München 1835 ; translated in 
 H. v. Mold's ' Vermischte Schriften/ p. 108). lie pointed 
 out that the closed vascular bundles (which do not increase 
 in thickness after they are first formed) in tree ferns as well 
 as in the herbaceous species form a hollow cylindrical net 
 concentric with the periphery of the stem, whose meshes, in 
 the species with crowded fronds {Jsjjl.ßlix-mas for instance), 
 are arranged with the greatest regularity in the following 
 manner, that is to say ; from the place where each frond is 
 attached to the cyhnder, two bundles pass to the bases of 
 the two next higher fronds, and two to the bases of the two 
 next lower ones. This regularity in the relation between the 
 anastomoses of the vascular bundles and the places of in- 
 sertion of the fronds, docs not occur in the species with 
 distant fronds, such as Poh/poduoii aicreum. The difference 
 between the tree-ferns and the herbaceous species is im- 
 material, depending upon the breadth of the vascular 
 bundle, and the development of the sheaths of the latter out 
 of woody prosenchyma. At the place where a vascular 
 bundle passes into a frond an entire bundle is never found to 
 bend itself outwards for that piu-pose, as is almost always 
 the case in phaenogams, but small ramifications only are sent 
 off into the fronds.* Later obseiTations have not yielded 
 any additional results of importance. 
 
 Brogniart first made known that the ramification of the 
 stems of ferns is caused exclusively by bifurcation of the 
 extremity (' liistoire des vegetaiLx fossiles,' ii, p. 30), an 
 opinion which has been supported by Stenzel (' Jahresb. 
 Schles. Ges.,' 1857, p. 85), and bymyself.f On the other 
 
 * Unger's notion of the ferns and tlieir allies as " Phintce acrobri/a " is founded 
 upon this important pecularity ('Uuger Bau und Wachsthum der Dikotjle- 
 doncn-stamen/ Petersburg, ISIO; ' Anat. und Physiol, d. Pfl.,' 1S50, p. 225). 
 
 t My observations on tliis subjeet which are given in the preceding pages 
 were first published in the Transactions of the Royal Society of Sciences 
 of Saxony^ vol. v, p. GO. 1857. 
 
THE HIGHER ORYPTOGAMIA. 263 
 
 hand, Karsten (' Vegetationsorgane der Palmen,' Berlin, 
 1847, p. 125), called attention to the definite relation which 
 so often occurs between the ramifications of fern-stems 
 and the insertion of their leaves ; and Mettenius lately en- 
 deavoin*ed ('Al)handl. K. Sachs. Ges. d. AViss./ vol. vii,) 
 to show that no essential difference exists between the 
 mode of ramification of ferns and of the vascnlar crypto- 
 gams generally, and that of phsenogamons plants, inas- 
 nuicli as the ramification of ferns owes its origin to the 
 development of lateral buds, which are normally situated 
 in a definite position with regard to the bases of the leaves. 
 Mettenius draws his conclusions from a number of species 
 of Trichomanes, whose lateral buds he considered to be un- 
 doubtedly situated in the axils of the fronds. He finds 
 even in Hymenophyllum instances of the transition between 
 axillary buds and buds springing from the fore side of 
 the stipes. With these he classes the Davallieae, which 
 exhibit transitions from axillary buds to buds which ori- 
 ginate in front of and underneath the axil. Mettenius 
 finds the buds of PlaU/ceruim alcicorne and of many other 
 species behind and underneath the insertion of the fronds, 
 and in Poh/jwdium vulgare (amongst others,) he finds the 
 bud so far removed from the point of insertion of its 
 own proper frond, that it appears to be opposite the next 
 older one. Mettenius considers these lateral buds to be 
 of the same nature as those found on the stipes of Pteris 
 aquilina and Aspidiiim flix-mas, which I look upon as 
 adventitious buds distinct from the true ramifications of 
 the stem. He adopts Karsten's view, that in Dicksonia, 
 in consequence of a bud of this natui'e being developed at 
 an early period before the development of tlie frond be- 
 longing to it, the frond which originally belonged to the 
 stem is Avithdrawn from the latter, and transferred to the 
 apparently dichotomous ramification of the principal stem. 
 Mettenius also ao-rees with Karsten as to the mode of 
 branching of the stem of Pteris aquilina. 
 
 If the object of this conception is to point out the 
 essential ao-reement between the ramification of the vas- 
 cular cryptogams and the axile position of the lateral 
 branches of phsenogams, it may be objected that the agree- 
 
264 HOFMEISTER, ON 
 
 nient in question assumes a very different aspect, if the 
 view suggested by Pringslieim (' Bot. Zeit./ 1853, p. 
 609), and supported by Irmisch ('Bot. Zeit.,' 1858, p. 
 492) be adopted. According to this view (which I con- 
 sider correct), all normal ramification rests upon bifurca- 
 tion of the end of the stem above the youngest leaf of the 
 bud, the result of which usually is, that one fork of the 
 branch developes itself more vigorously than the other, and 
 forms the prolongation of the principal axis, whilst the 
 other which is less strongly developed and is displaced side- 
 ways, forms a lateral branch. It is hardly necessary 
 to remark that the existence of a definite relation between 
 the positions of the branches and the leaves is entirely recon- 
 cileable with this view. No supporter of it has denied 
 the fact. In phsenogams the less-developed branch, — 
 which, in consequence of its inferiority of development 
 becomes a lateral branch of the more vigorously developed 
 one, — is usually inserted in the axil of the next lower 
 leaf, but this circumstance is of little importance, inasmuch 
 as no causal connexion is anywhere proved to exist, or as 
 far as we know even suspected, between the anatomical rela- 
 tions of the axil of the leaf and the insertion of the lateral 
 branch. Nothini^ is more certain than that the rudiment 
 of the lateral branch in all cases hitherto examined is formed 
 immediately after the commencement of the formation of 
 the phyllophore, and that the next higher leaf in a 
 vertical direction is first formed at a much later period. The 
 essential difference between the existing opinions relates 
 therefore only to the question whether the dichotomous 
 ramification of fern-stems and the formation of buds at the 
 base of the stipes of ferns are processes of a similar 
 nature ; wdiether both stand in the same relation to the 
 principal axis as the axillary buds of phaenogams. Obser- 
 vation gives immediately a negative answer. The adventi- 
 tious buds which are situated upon the back of the stipes 
 of Aspidium ßJix-mas, as well as those which are inserted 
 lower down in Pterls aqinlina and Struthiopteris, are not 
 formed until the frond has reached a high degree of deve- 
 lopment, a fact quite at variance with the mode of produc- 
 tion of the axilc buds of monocotyledonous or dicoty- 
 
THE HIGHER CRYPTOGAMIA. 265 
 
 ledonous plants, and of the forked brandies of ferns. I 
 should not adopt the definition given by Mettenius of 
 lateral and adventitious buds. I should call those buds 
 lateral buds, which originate from the naked apex of the 
 stem above the insertion of the youngest leaf, and are thus 
 formed by bifurcation of the end of the stem, whilst 
 owing to their inferiority of development they are pushed 
 aside by the other division of the forked end of the stem. 
 I should call those buds adventitious which make their 
 appearance underneath the insertion of the youngest appen- 
 dicular organ, whether on the outer sm-face or in the interior 
 of the tissue. The term Dichotomy might then be applied 
 to the cases of equal development of the two ends of 
 the fork of the stem. These definitions leave the doctrine 
 of ramification as established by Schimper imtouched. 
 The fact, that in phcenogams that branch of the end of the 
 stems which is situated in the axil of the next lower leaf 
 is usually less vigorously developed than the other one, 
 justifies the assumption, that the cases in which the former 
 is, more vigorously developed than the latter must be 
 looked upon as special instances of ramification. If a 
 comparison be made between the adventitious l)uds of 
 Aspiclium flhv-mas (which are of frequent occurrence), and 
 the early conditions of the bifurcations of the apex of the 
 stem of the same species (which are of rare occurrence), 
 or between the bifurcations of the apex of the stem of 
 Asjplenium fiUx-femina (which are of frequent occurrence), 
 and the adventitious buds at the base of the stipes of 
 the latter plant (which are ofvery rare occurrence), it will be 
 self-evident than in these instances the two things are (piite 
 as distinct as (for example) the bifurcations of the end of the 
 stem of Metzgeria furcata , and the adventitious shoots 
 which are developed from the marginal cells of the flat 
 stem of the latter plant. 
 
 Upon examining the bifurcations of Aspleniuvi filix- 
 femina whilst in a very early stage of development, after 
 having removed all the older fronds and scales, I found that 
 the two ends of the axis, when viewed from above, presented 
 the appearance of conical protuberances of equal size, 
 each surrounded by the rudiments of only three fronds. 
 
366 HOFMEISTER, ON THE HIGHER CRYPTOGAMIA. 
 
 The arraugement of the fronds in both was antidromal, 
 and in one of them always passed by degrees into that of 
 the older undivided axis, whilst the frond-arrangement of 
 the adventitious shoots of Aspidium ßliv-mas is usually 
 homodi'omous with that of the principal stem, and rarely 
 antidromous to it. 
 
 With regard to Pteris aquilina the inadmissibility of the 
 views of Karsten and Mettenius is still more manifest. I 
 have seen stems of Pteris aquilina with naked frondless 
 unbranched ends of considerable length, whose youngest 
 branch disclosed no rudiment of a frond. This was the 
 case (amongst many other instances) throughout a length 
 of eight inches in a portion of the end of a stem, and 
 throughout a length of 2^ inches in the youngest branch. 
 This is proof of undoubted bifurcation. The supposition of 
 Mettenius woidd also require that (Avhen the first frond of 
 the sub-axis is inserted on the side turned towards the 
 principal axis) a bud inserted on the hinder edge of the 
 stipes should, by its early development, push away the 
 frond from the principal axis to which it belongs. It would 
 follow also that the front surface of its lamina must be 
 turned towards the latter, or in other words its stipes must 
 exhibit a tension of 180°. Neither of these two circum- 
 stances occurs. 
 
 Finally a real difference exists betAveen the internal 
 structure of the forked branches of the stem and that of 
 the place of junction of the principal stem with the buds 
 which I have considered as adventitious and seated on the 
 stipes. The former exhibit throughout their entire length 
 the peculiar structure of the stem. Their two axile vas- 
 cular bundles, and the sheaths of the latter, are united 
 immediately with the corresponding portions of the tissue 
 of the principal axis. The tissue on the other hand which 
 lies between the principal axis and the place of origin of an 
 adventitious bud, exhibits the characteristic arrangement 
 of the vascular bundles of the stipes. 
 
CHAPTER VIII. 
 
 EQUISETACEiE. 
 
 Equisetum arvense, pratense, varie^atum, hyemale, pahisfre, 
 
 limosum. 
 
 The growing end of the stem of each shoot of the Equi- 
 setaceae consists of a blunt conical mass of cellular tissue, 
 and projects considerably beyond the place of origin of the 
 youngest leaf. The latter encloses the terminal bud in the 
 form of an annular cushion of uniform height. The next 
 youngest leaves are immediately underneath it, and closely 
 packed together. Their upper margins already exhibit the 
 first indications of the pointed lobes, into which the sheaths 
 which surround the base of each joint of the stem are pro- 
 longed (PL XXXV, figs. 6, 7). 
 
 The longitudinal growth of the stem* is produced by 
 repeated division of the large apical cell of the terminal bud, 
 which cell is three sided beneath, and sharply pyramidal. 
 The division takes place by means of septa which, following 
 a left-handed spiral direction, are successively parallel to 
 each one of the lateral surfaces (PL XXXV, tigs. 3, 4). 
 The cells of the second degree thus formed divide imme- 
 diately twice over, by means of vertical septa which make 
 acute angles with the lateral surfaces of the cell and pass 
 to its fi*ee outer surface in a gentle curve concave towards 
 these lateral smfaces. That septum is usually formed first 
 which is seated upon the older side-wall of the cell 
 
 * The cell-succession in the end of the stem of Equisetum was first correctly 
 described by Cramer (Nageli and Cramer, ' Pflanzen-physiol. Untersuch.,* 
 Heft 4, Zurich), I had previously erroneously considered the form of the 
 apical cell to be tliat of a wedge. I have mentioned the cause of this erroneous 
 assumption in speaking of the cell-successiou in the growing end of the stem in 
 Sphagnum. 
 
268 HOFMEISTER, ON 
 
 (PI. XXXV, fig. 3). The middle one of the three cells 
 which are produced in the interior of the cell of the second 
 degree (all of which lie in one plane) is the only one which 
 reaches to the middle point of the stem. It divides into 
 an inner and an outer cell by means of a longitudinal 
 septum almost parallel to the chord of the curved free outer 
 surface (PI. XXXV, fig. 5). Poth arc divided by a trans- 
 verse septum, the outer one usually before the inner one 
 (PL XXXV, fig. 2). In the former this septum is parallel 
 to the upper and under surface of the cell ; in the latter it 
 is usually horizontal, and at right angles to the longitudinal 
 axis of the shoot (PI. XXXV, fig. 1). The stem fortliA^th 
 increases in thickness by repeated division of the cells of 
 the circumference by means of septa parallel to the fi'ce 
 outer wall. In very vigorous shoots, as for example in the 
 autumn shoots of Eqf'lsrfum limo.wDi, the like division occurs 
 several times in the cells of the next inner layer also 
 (PI. XXXV, fig. 1). In such buds the cells of the circum- 
 ference usually di^■ide once more by transverse septa close 
 above the place of origin of the yomigest leaf. During the 
 increase of the stem in thickness the number of the cells of 
 its circumference increases continually by the division oi' 
 these cells by means of septa radial to the longitudinal axis 
 of the shoot or at least only slightly diverging from the 
 radial position. At first, in the upper part of the conical 
 cellular mass, this division alternates very regularly with 
 division by longitudinal septa parallel to the outer wall of 
 the cells ; lower down, where the stem becomes thicker, 
 division by a radial septum does not occur until after 
 several divisions by septa parallel to the axis of the stem. 
 The mass of the end of the stem which lies above the 
 youngest leaf, and the number of the cells of its longitu- 
 dinal axis and of its circumference are very different in 
 different species and even in the shoots of the same plant ; 
 they vary with the vigour of the shoots. By the early 
 occurrence of transverse division in the cells produced by 
 the multiplication of a cell of the second degree, the ladder- 
 like interweaving of the cells of the two longitudinal halves 
 of the stem is equalised at an early period. In those cases 
 in which this division does not extend into the cells adjoin- 
 
THE HIGHER CRYPTOGAMIA. 269 
 
 ing the axis of the stem, it occurs at least once in the cells 
 of the circumference. On the upper surface of the stem 
 therefore an extremely regular circular girdle of cells is to 
 be distinguished. At a definite distance from the apex of 
 the terminal bud all its outer cells which lie at the same 
 altitude (a girdle of cells enclosing the end of the stem) 
 divide contemporaneously by a septum inclined to the 
 horizon (PI. XXXV, fig. 2). In the outer (the upper) of 
 the two cells thus formed, a division takes place by a sep- 
 tum inclined in an opposite direction. Thus an annular 
 Avail of uniform height and embracing the terminal bud is 
 raised a little beneath the apex of the latter : this is the 
 first rudiment of the youngest leaf. All the cells of its free 
 upper edge continue to divide by alternately inclined septa 
 (PL XXXV, fig. 1). The leaf at first grows upwards in 
 the form of a cylindrical sheath of uniform height enclosing 
 the terminal bud (PI. XXXV, figs. 6, 7). 
 
 The place of origin of the youngest leaf, the girdle of its 
 mother-cellsj is close above the place of attachment of the 
 next younger leaf. The leaf very soon after its production 
 begins to nicrease in thickness, the cells of its base, — those 
 of the under surface exclusively (PI. XXXV, fig. 1), — 
 dividing repeatedly by septa parallel to this surface. This 
 cell-multiplication progresses slowly from the base of the 
 leaf to its apex, and finally ceases at a considerable distance 
 beneath the latter. The outer (or lower) ones of the cells 
 thus formed, divide by transverse septa (septa parallel to 
 the ideal longitudinal axis of the leaf) the division being 
 more frequent in proportion as the shoot is destined for 
 more vigorous development. The great excess in the 
 number of the cells of the under surface of the leaf over 
 that of the upper, causes the free upper edge of the leaf 
 to bend inwards. By the vigorous multiplication of the 
 lower portion of the outer surface of the leaf, the base of 
 the leaf is soon transformed into numerous layers of cells, 
 parallel to the longitudinal axis of the shoot, and repre- 
 senting the outer circumference of the stem (PI. XXXVI, 
 fig. 1). The subsequent increase in length and thickness 
 of the joints of the stem depends upon the increase in 
 
270 HOFMEISTER, ON 
 
 length and breadth of this ceUular mass which has arisen 
 from the development of the basal portion of the leaf-rudi- 
 ment. The central cellular cylinder of the stem which has 
 arisen immediately from the terminal bud becomes exclu- 
 sively pith.* In the mean time by longitudinal division of 
 the cells of the leaf in a direction radial to the axis of the 
 stem — a division which occurs as well in the cells of the 
 imder part which represents the outer layer of the stem, as 
 also in the free sheath-shaped upper portion — the number 
 of the cells of the circumference of the stem-joint and of the 
 hollow cylindrical leaf continually increases. 
 
 Shortly after the first appearance of the leaf there may 
 be observed an inequality in the activity of the growth of 
 its free npper edge. In the first place, at fom* points of 
 the leaf, one of the cells is about one step in advance of 
 all the rest in the process of division, which division takes 
 place by septa turned alternately towards and away from 
 the longitudinal axis of the stem (PL XXXV, fig. 8). The 
 neighbouring cells on the right and left are about one step 
 in arrear : the cells adjoining the latter cells remain one 
 step further in arrear. Four short blunt points are thus 
 produced, placed in pairs opposite to one another upon the 
 upper edge of the sheath-like leaf. The multiplication of 
 the cells of the circumference of the free upper edge of the 
 leaf is produced exclusively by the division of the apical 
 cells of these points by means of longitudinal septa 
 (PL XXXV, fig. 8).t This division of the apical cells of 
 the tip of the leaf by septa radial to the circumference of 
 the leaf-sheath is often repeated at certain stages of the 
 growth of the leaf, and increases the breadth of the tip 
 more and more. Shortly afterwards the widened apex of 
 the tip of the leaf exhibits the first indication of a rapid 
 })ifurcation (PL XXXV, fig. 9). Thus with the age of the 
 leaf the number of the teeth of its edge increases; in 
 
 * Trom au opposite point of view, viz., tlie comparison of finished stages of 
 development, Spring arrives at the same conclusion for larger divisions of the 
 vegetable kingdom (' Monographie des Lycopodiacees, extraite des Memoires de 
 I'Academie Royale de Belgique,' Bruxelles, 1849). 
 
 t This mode of growth of the tip of the leaf brings strongly to mind that of 
 the shoots of Riccia, &c. 
 
THE HIGHER CRYPTOGAMIA. 271 
 
 strong shoots of JEquketum limosum this increase takes place 
 with great regularity according to the progression 1 . . 4 
 7 . . 8 . . 9 . . 10 . . 11 and so on to 20 (PL XXXV, fig. 7). 
 At about the fourth or fifth leaf (reckoning backwards from 
 the uppermost youngest leaf) there occurs a very remark- 
 able longitudinal elongation of the cells of the apices of the 
 tip of the leaf. Even after its commencement, the multi- 
 plication of the cells of the base of the leaf in a longitudinal 
 direction by means of septa at right angles to the axis of 
 the stem continues for some length of time. 
 
 The relation of the outer cellular layers of the stem 
 (which are produced by the development of the outer side 
 of the base of the leaf-rudiment) to the central pith cylinder, 
 which corresponds with the cells of the free portion of 
 the terminal bud, is very different in the different forms of 
 shoots. In the few vigorous shoots which are usually 
 developed in autumn by the subterranean internodes of 
 Jllquisdum 2icdustre ^\\{^ pratcn8e,m\A in a still more marked 
 manner in Equiselum limosum and hi/emale, the distinction 
 between the pith and the outer layer of the stem is visible 
 at a very early period : the cells of the latter even in the 
 youngest joints of the stem often divide repeatedly ni a 
 longitudinal direction, whilst the multiplication of the pith 
 cells is quite at a stand-still. On the other hand this dis- 
 tinction occurs at a comparatively later period, and is not 
 nearly so well defined, in the delicate shoots which break 
 forth from the bases of the leaves high up on the stem, 
 especially in the thin shoots of the second, third, or fourth 
 order of Eqiiisetum pratense, arveuse and limosum, or even 
 in the shoots of the first order of Eqiiisetum variegatum. 
 The following table shows the number, in a longitudinal 
 direction, of the cells of the pith {ci) and those of the 
 outer layers {h). 
 
272 
 
 HOFMEISTER, ON 
 
 
 11 
 
 In tlie 2nd. 
 In the 3rd. 
 
 In the 4th. 
 
 In the 5th. 
 Li the 6th. 
 
 
 
 a 
 
 b 
 
 a 
 
 h a 
 
 h a 
 
 J 
 
 a 
 
 4 a J « 
 
 b 1 
 
 i 
 
 lü Equiselum iialustre (a vigorous 
 shoot) 
 
 The same species, a very delicate 
 shoot 
 
 Hq. Umosmi (a shoot formed at 
 j the end of May) 
 
 'Eq. limosuiu (a vigorous autumn 
 shoot) 
 
 Eq. pi-ateme (a vigorous autumn 
 shoot) ..... 
 
 Eq. tariegatim (a delicate shoot) 
 
 The number of cells of the trans- 
 verse diameter in a vigorous 
 autumn shoot of Eq. limosum 
 amounted to . 
 
 In a delicate shoot of Eq. variega- 
 ium to . 
 
 4 
 4 
 4 
 4 
 4 
 
 4 
 5 
 4 
 4 
 4 
 
 4 
 
 4 
 8 
 4 
 4 
 
 4 4 
 
 5 7 
 
 K 8 
 
 7 
 
 9 
 
 10 
 7 
 fi 
 
 4 
 9 
 8 
 4 
 4 
 
 8 
 
 12* 
 17 
 
 7 
 
 7 
 13 
 
 4 
 
 8 
 
 
 
 1 ' 
 
 
 
 
 
 6 
 
 6 
 
 7 
 
 4 
 
 4 
 
 7 
 
 40 
 9 
 
 4 
 4 
 
 10 
 
 7 
 
 410 8 
 
 ! 
 
 1 
 13ti 
 
 8 
 
 3 
 
 7 
 
 7 7 
 
 
 1 
 
 
 
 22 
 5 
 
 
 32 
 
 8 
 
 
 48 
 12 
 
 58 
 12 
 
 
 
 
 1 
 
 ... 
 
 12... 
 
 ... 
 
 
 This comparison appears at the first glance to be quite at 
 variance Avitli the common notion that the cells of tlie stem 
 are multiplied in a longitudinal direction only at the apex 
 of the organ. This opinion is untenable in any extended 
 sense. As far as observations go there are no plants, from 
 the mosses upwards, in which the cells of the stem arc nml- 
 ti])lied in a longitudinal direction exclusively l)y division 
 of the terminal cell. Generally the division of the daughter- 
 cells of the cells of the second degree by septa at right 
 angles to the longitudinal axis, plays an important part in 
 the production of longitudinal growth. On a more accu- 
 rate examination, however, the above table, shows that 
 there is a special tendency to multiplication in the cells of 
 those parts of the leaves which have been already some 
 time formed. It is only the cells of the cortical layers 
 (which my figure PI. XXXV, tig. 1, sho\vs clearly to have 
 been produced by the nuütiplication of the cells of the leaf- 
 rudiment) which exhibit the long-continuous longitudinal 
 
 * Those of the epidermis 14. This fourth inlernode exhibited the first 
 indications of annular vessels, 5 — 6 rings in each of the cells of a longitudinal 
 row adjoining the pith. 
 
 t A trace of annular vessels was first visible iu the 15th internode. 
 
THE HIGHER CRYPTOGAMIA. 273 
 
 multiplication extending in many cases even beyond the 
 twelfth internodc. In the cells of the pith only a single 
 transverse division occurs. From the fact that the thick- 
 ness of the shoot is in such manifest connexion with the 
 period of the occurrence of the transverse division of the 
 pith-cells, it may perhaps be concluded that the immediate 
 operation of the outer air upon the tissue of the growing- 
 stem has an especial effect in promoting transverse division 
 in the cells. 
 
 The formation of the epidermis of the young stem-joint 
 is contemporaneous with its longitudinal extension, with its 
 appearance abo^'e ground, and with the formation of nu- 
 merous chlorophyll bodies in the cells of its circumference. 
 All the cells of the outer surface divide twice by transverse 
 septa, then by longitudinal septa, and lastly by septa paral- 
 lel to the outer surface. A double layer of cells is thus 
 produced, enclosing the circumference of the stem, the cells 
 being one-eighth the size and eight times as numerous as 
 those of the next inner layer. The outermost are trans- 
 formed into the epidermis ; every second cell of the epider- 
 mis of the above-ground shoots becomes the mother-cell of 
 tAvo stomatal cells ; these as well as the tabular cells of the 
 epidermis exhibit upon the outer surface very regular pro- 
 jections the form of which is constant for each species (PI. 
 XXXVI, fig. 2). These projections contain more siHceous 
 matter than any other part of the stem. 
 
 The differentiation of the vascular bimdles from the 
 smTOunding tissue commences a short time before the for- 
 mation of the epidermis. The first commencement of the 
 vascular bundle consists in the appearance of annular fibres 
 in a vertical row of cells the position of which answers 
 exactly to one of the tips of the next higher leaf. From 
 five to six of these annular fibres occur in each cell (PI. 
 XXXV, fig. 13). A plane passing through the middle of 
 the lip of the leaf cuts the string of cells of the stem-joint 
 which bears the leaf, in each of which cells annular fibres 
 are formed. 
 
 The horizontal septa which separate the ring-bearing 
 cells from one another are very soon absorbed, and a circle 
 of annular vessels traversing the entire length of the stem- 
 
 18 
 
274 HOFMEISTER, ON 
 
 joint is thus produced. At the time when the annular 
 vessel becomes continuous a multiplication commences in 
 the neighboui'ino; cells — those situated in front (towards 
 the outside) and to the side — by means of vertical septa 
 alternatino" with radial septa and with septa parallel to 
 the periphery of the stem (PI. XXXVI, fig. 1). Thus a 
 thick string of cambial cells is produced in which more 
 annular vessels (with much narrower rings) are shortly 
 afterwards formed in a similar manner, and where at a 
 much later period spiral vessels are also formed. In the 
 developed internode this string of cells represents a closed 
 vasctilar bundle. 
 
 The tips of each leaf and the corresponding vascular 
 btmdles of each stem-joint alternate with those of the next 
 lower one. Soon after the first separation of the vasctdar 
 bundle from the surrounding tissue of the stem — which 
 separation takes place whilst the vascular bundle has still 
 the appearance of a string of cambial cells and exhibits 
 only a single annular vessel on its inner side — the cells of 
 the node from the base of the vascular bundle as far as 
 the two adjoining ones of the next lower stem-joint are trans- 
 formed into short spiral cells arranged in a moniliform 
 manner ; the cells which adjoin these stnngs in a lateral 
 and outward direction are transformed into a thin layer of 
 cambial cells which at a later period silso take part in the 
 formation of vessels. 
 
 After the conunencement of the formation of the \ascular 
 bundle of the stem the corresponding leaf-tip exhibits the 
 transformation of a string of cells into a vascular bundle 
 traversing its median lono-itudinal line. The first vessels 
 which ap})ear in the leaf are elongated, narroAv, spiral 
 vessels. The vascular btmdles of the leaf attain only a 
 slight thickness. 
 
 The distance from the middle point of the stem at which 
 the formation of vascular bttndles commences — in other 
 words the bitlk of the pith and the number of leaf-tips and 
 the (corresponding) number of the vascular Ijundles of the 
 internode Avhich bears the leaf — is very variable according 
 to the activity of the growth of the shoot, and according to 
 the number of its diametral cells. In thin shoots of Eq^. 
 
THE HIGHER CRYPTOGAMIA. 275 
 
 vane(/atiim ^ndipahsfre the number of cells in the diameter 
 of the pith is only 6 ; in vigorous shoots of Eq. limosum it 
 is 40. The number of leaf-tips and vascular bundles 
 appears not less variable ; in the main shoots of Eq. varie- 
 gatiim it is 7; mEq. palusfre 7 — 10; in Eq. pratense 10; 
 in Eq. limosum 10—20. Most striking differences in this 
 respect are found even in the axes of different orders of one 
 and the same shoot. 
 
 The connexion between the cells of the pith of all the 
 indigenous (German) species of Equisetum is very soon 
 dissolved. The numerous intercellular spaces become filled 
 with air. The cells of the pith are soon unable to keep 
 pace with the longitudinal groAvth of the periphery of the 
 stem. All connexion between the pith-cells ceases, they 
 are torn fi'om one another, they become shrivelled, and in a 
 short time disappear altogether with the exception of a flat 
 double layer of cells in each internode which lasts as long 
 as the stem itself. Thus there is produced in each inter- 
 node a central pith-cavity covered above and filled with 
 air, having smooth side walls and a base rough with the 
 debris of the pith- cells. In just the same way — by the 
 separation of a string of cells from the adjoining tissue, 
 by the early cessation of the multiplication of these cells, 
 and by their shrivelling and desiccation — an air-cavity is 
 produced, in Equisetum limosum, around each vascular 
 bundle ; and ultimately by the decay of the central por- 
 tion of the vascular bundle, a narrow air-cavity is formed 
 in the interior of each of them. 
 
 Normally, the terminal bud of the Equisetacese never 
 ramifies. There is hardly any other group of plants which 
 exhibit such a well-defined, exclusively apical, growth. 
 Ramification is caused solely by adventitious buds. 
 These are produced in definite positions, viz., in the an- 
 nular locus of insertion of the sheathing leaf ; each adventi- 
 tious bud, with rare exceptions, being seated under the 
 angle between each two leaf-tips. The rudiment of the 
 adventitious bud appears long before that of the vascular 
 bundles of the same internode. In the autumn shoots of 
 Eq. pratense which are developed in the following spring, 
 a cell, situated in the defined position at the base of the 
 
276 HOFMEISTER, ON 
 
 leaf (oftüii of the third or fourth-youngest leaf), and in 
 the second or third layer beneath the surface of the latter, 
 becomes distinguishable from the neighbonring cells (which 
 often already contain chloroi)hyll), by its increase in size, 
 and still more by its colourless thickly nmcilaginous 
 contents. This cell often lags behind its neighbours in 
 longitudinal groAvth, in consequence of which its connexion 
 Avith the cells above it and at its sides is dissolved. Division 
 soon commences in it, and is repeated in different directions 
 in rapid succession in the terminal cell. (PI. XXXV, figs. 11, 
 12). Thus a cell-multiplication is set on foot which corre- 
 sponds in all respects with the preceding multiplication of 
 the apical cell of the terminal bud. The presence of the 
 adventitious bud is soon indicated by a protrusion of the 
 outer sm-face of the stem close under the place of insertion 
 of the leaf. Ultimately by further longitudinal growth 
 it breaks forth from the under-side of the sheath-like 
 leaf. 
 
 The adventitious buds of Equisetum liave the peculiarity 
 of being able, under certain circumstances, to remain long 
 dormant, a peculiarity which they possess in conmion with 
 the adventitious buds which are produced in mosses and 
 phoenogams upon the outer surface of the young stem 
 in the axils of leaves. They often pass the greater portion 
 of a period of vegetation in the most rudimentary condi- 
 tion, consisting of one or at most of a few cells. This is 
 the case Avith the adventitious l)uds of E. prafoise, 2ialudre, 
 and Vuiiomm, Avhich are destined to reproduce the species. 
 Although in spring numerous thin branches break out from 
 the base of the leaf-slieath of tlie middle and upper part 
 of the above-ground shoots, the number of wdiicli branches 
 is usually the same as that of the leaf-tips, yet the adven- 
 titious buds of the lowest internodes — those which are 
 bmied in the earth — remain entirely dormant imtil late 
 in autunui. At that time, however, one only of the buds 
 of each of those internodes developes itself but with a 
 strength and activity which far exceeds that of the subter- 
 ranean branchlets. 
 
 Individual internodes of the lower subterranean portion 
 of the main shoots of Eq. arcense become swollen, whilst 
 
THE HIGHER CRTPTOGAMIA. 277 
 
 the cells of the tissue which siuTOimcls* the circle of vas- 
 cular bundles multiply vigorously. Vigorous adventitious 
 buds are formed at the base of the rudimentary leaf of such 
 internodes ; seldom more than two in the same intcrnode. 
 The cellular tissue of the swollen internodes contains starch 
 and a good deal of sugar, I believe not crystalHzed. 
 The different habit of the species of Equisetum depends upon 
 the relation of the adventitious lateral shoots to the principal 
 shoot. In all the above-named species [arvense, prafense, 
 variegatum , InjemaJe, jjal/fsfre, liinosi(m), the lowest leaves 
 of those shoots which have completed their subterranean 
 development, send out vigorous shoots destined for develop- 
 ment in the following season, a process which brings to 
 mind the buds m hich occur in the cataphyllary region of 
 many phsenogams. These shoots are the least developed 
 in Eq. arvense ; they are of an elongated cylindrical form, 
 and very beautiful and vigorous in Eq. prateme and limomm. 
 In the latter species they protrude, even in autumn, for 
 a distance of several inches from the base of the sheathing 
 leaves ; in Equisetum palusfre they appear at the beginning 
 of spring; in Eq. hj/emale at the end of April. Those 
 of Eq. limosum deserve a closer investigation, not onty 
 on account of many peculiarities dependent upon habitat, 
 but also on account of the injury produced by its abundant 
 growth in the richest w^ater- meadows of North Ger- 
 many, where the hay is frequently uneatable from the ad- 
 mixture of numerous shoots of the Equisetum. As in the 
 other species of the genus, the lower part of each shoot 
 (unlike the portion above ground), does not die until the 
 autumn. The epidermis of this portion of the stem assumes 
 a beautiful red-brown colour; from one to three shoots, 
 destined for development alcove ground in the following- 
 year, bm'st forth in an upward direction out of the hollow 
 cylindrical leaves, whose upper portion dies and withers. 
 The epidermis of these Avinter shoots is of the colour of 
 ivory, and the tips of their leaves of a chestnut-brown. If 
 the shoots are exposed to the light, chlorophyll is developed, 
 even in autumn, in the cells of the circumference. Be- 
 
 * Compare Bischoff ' Kryptogamisclie Gewächse,' Numb., 1828, Heft i, 
 p. 29. 
 
278 HOFMEISTER, ON 
 
 sides these shoots others are developed here and there 
 on individual joints of old stems : the latter have a lateral, 
 not an upward direction ; their colom* in the young state 
 is a deep citron -yellow, and their leaf-sheaths are of a deep 
 black-brown. Unlike those first described, they are not 
 blunt at the top, but the connivent tips of the sheathing 
 leaves of the terminal bud form a sharp apex. These 
 shoots are the foundation of the creeping rhizome, and some- 
 times attain a length of twenty feet. When they emerge 
 from the leaf-sheaths of the mother-shoot they are of the 
 thickness of a slender goose-quill, but afterw'ards by expan- 
 sion of their cells, and by gradual increase in the number 
 of the cells of the new internodes in a diametral direction, 
 they attain fi-om half to three-fourths of an inch in thick- 
 ness. From the bases of their leaf-sheaths a few shoots are 
 produced separated from one another by considerable in- 
 tervals (by several internodes, which produce no adventitious 
 buds), and which are destined partly for development above 
 ground, and partly for the formation of new Rhizomes. 
 
 In those species of Equisetum which are found in damp 
 localities away from the light, a girdle of adventitious roots 
 is formed at each node of the stem, on a level with the 
 septum Avhich traverses the pith cavity, and close under- 
 neath the rudiments of the adventitious buds. They 
 originate close underneath the bark, immediately below the 
 lower ends of the vascular bundles of the next superior 
 internode, and consequently meet the upper ends of the 
 septa which separate the cortical air-cavities of the next 
 lower internode. In the lower nodes of the vigorous 
 autumn shoots one at least, usually two, and often three 
 such adventitious roots are formed close to one another. 
 At an early period the cells of that portion of the partition 
 wall of two cortical air-cavities which leads from the 
 adventitious roots to the convergent prolongations of 
 the vascular bundle are transformed into a single vascular 
 bundle traversed by numerous short spiral vessels. The 
 origin of these thick vascular bundles, which are attached 
 to the spreading prolongations of the vascular bundles 
 of the internode, renders the course of the vascular bundle 
 of the stem within the node quite indistinct ; they 
 
THE HIGHER CRYPTOGAMIA. 279 
 
 may have given rise to the opinion that the vascidar bundles 
 of the stem of the Eqiiisetaceao miite in each node to form 
 a confused mass of tissue.* 
 
 The normal mode of cell-multiplication in the punctum 
 vegetationis of the adventitious roots is identical with that 
 in A-spidluiu filiv-nia<t. The cell of the first degree, whose 
 continuous division is the cause in the first instance of the 
 growth of the root lies in the interior of the tissue, nearly- 
 above the apex of the root. Its form is tetrahedral. It 
 divides by septa of which three in succession are each of 
 them parallel to one of the three lateral surfaces, and of 
 which the fourth forms the surface of a segment of a sphere 
 seated upon the basal surface which is tm-ned towards the 
 apex of the root. In this way sets of four cells of the 
 second degree are formed, of which the three upper, which 
 adjoin the cell of the first degree, take part in the forma- 
 tion of the permanent portion of the root ; the foin^th, by 
 its multiplication produces one of the hood-shaped layers of 
 the root-cap. Soon after its formation four cells, having 
 a quadrantal basal outline, are produced in its interior 
 by a twice repeated division by means of vertical septa. 
 The cells produced by the multiplication of one of the lower 
 cells of the second degree henceforth divide only by septa 
 perpendicular to the basal surfoce of the mother-cell and 
 consequently to the next adjoining portion of the surface of 
 the root. AH the daughter-cells of such a cell of the second 
 degree lie in one place which is curved parabolically ; they 
 form a blunt hollow cone, and the number of these cones 
 whicli envelope the apex of the root is the same as that of 
 the cells of the second degree directed downwards which have 
 originated in their puncta vegetationis. The oldest, outer- 
 most of them, reaches as far as the place of origin of the 
 root, the younger, inner ones, are gradually less in proportion 
 to their age. The oldest outermost cellular layers of the 
 apex of the root scale off" by degrees and become decayed. 
 
 The cell-nmltiplication of those cells of the second degree 
 which are directed upwards tends much more to the increase 
 of the number of cells in height than in breadth. The lon- 
 gitudinal division of each such newly formed cell is 
 * See Nägeli, 'Zeitschrift f. Botauik.,' Heft 3 and 4, p. 143. 
 
280 HOFMEISTER, ON 
 
 followed by division by means of septa parallel to the basal 
 surface, and perpendicular to the longitudinal axis of the 
 root. The outer cells of the group formed by the miüti- 
 plication of those cells of the second degree wliich are 
 directed upwards (those which adjoin the daughter-cells of 
 the second degree which are directed downwards) continue 
 to multiply for some time by division by means of septa 
 alternately radial and parallel to the periphery. But the 
 succession of these divisions is twice interrupted by the 
 formation of horizontal septa in the entire mass of cells pro- 
 duced by the mnltiplication of the cell of the second degree 
 which is directed upwards. 
 
 The adventitious roots like the adventitious buds are 
 capable of remaining dormant for a long time. When they 
 burst forth and become elongated, the central string of cells 
 is transformed into avascular bundle. The tissue immedi- 
 ately enclosing the latter becomes disintegrated, dries up, 
 and ultimately disappears. Thus a hollow cylindrical air 
 cavity is produced beneath the bark of the adventitious 
 root. The upper surface of the root becomes covered with 
 long papilla} Avhich become brown in age. In very old 
 rhizomes the cortical layer of the root usually disappears 
 entirely; the central vascular bundles only, (whose tissue 
 is very firm) are persistent, and have the appearance of 
 tough, thick, deep-brown fibres. 
 
 Fruit is usually developed only on the vigorous shoots 
 produced from the lowest internodes of a shoot of the 
 previous year. The transition from the form of the ordinary 
 sheathing leaves, to that of the lowest circle of sporangia is 
 very rapid and sudden, even in those species which (like 
 Equisefum arveme) have special fructifying shoots. The 
 sheathing leaf immediately underneath the fruit is shorter 
 and more fleshy than the others ; there is no other inter- 
 mediate condition. The fructification is morphologically 
 unlimited ; owing to its mode of origin its longitudinal 
 development is not confined within bounds, any more than 
 that of the vegetative shoots, which (at least those above 
 ground) nevertheless do not become elongated beyond a 
 certain extent. Each circle of sporangia makes its appear- 
 ance in the form of an annular cushion underneath the 
 
THE HIGHER CRYPTOGAMIA. 281 
 
 terminal bud,* like the first mdiment of the vegetative 
 leaf, but more massive and much less elevated. 
 
 Definite points in this very flat annular wall become 
 prominent, after the manner in which the leaf tips 
 project above the (originally) smooth margin of the 
 sheathing leaf. A ring of hemispherical protuberances is 
 thus produced aroinul the stem, which, in the growing- 
 fruit, is clearly perceptible in the third rudimentary 
 sporangial circle, reckoning from the terminal l)ud down- 
 wards (PI. XXXVI, figs. 3, 6). The normal cell-multipli- 
 cation of these hemispherical celhilar masses — the rudiments 
 of the stalks of the sporangia — is similar to that of the 
 fruit-rudiment of Pellia (PI. XXXVI, figs. 4, 5). The 
 development of their upper part soon exceeds that of the 
 lower ; by the pressure of their apices against one another 
 they assume the form of hexagonal shields. On the under- 
 side, where they pass into the stalk, these shields soon 
 exhibit at five or six points a rapid cell-multiplication pro- 
 duced by the division of one of the cells of the under surface 
 of the shield. This division takes place by septa inclined 
 in different directions, and is repeated continually in the 
 apical ceU (PI. XXXVI, fig. 7). Prom five to six blunt 
 warts of cellular tissue are thus produced on the under side 
 of the shield : these are the first rudiments of the sporangia. 
 Shortly after their first appearance the growth of one of the 
 inner cells considerably surpasses that of its neighbours. 
 The cell in question is at this time only separated from the 
 apex of the young sporangium l)y a simple layer consisting 
 of a few cells. It is the primaiy mother-cell of tlie spores ; 
 the cells surrounding it become the wall of the sporan- 
 gium. 
 
 The first division of the primary mother-cell takes place 
 by a horizontal septum (PI, XXXVI, fig. 8). By repeated 
 bi-partition of the primary mother-cell the number of cells 
 destined for spore-formation is increased (PI. XXXVI, 
 figs. 9, 10). In the mean time the number of the cells of 
 the wall increases much more rapidly : the latter soon con- 
 sists of a double layer produced by the division of its 
 
 * The structure and mode of cell-multiplication of the terminal bud exactly 
 correspond with that of the terminal bud of vegetative shoots. 
 
283 HOFMEISTER, ON 
 
 cells by septa parallel to the outer surface (PI. XXXVI, 
 fig. 9). A previous division takes place by septa which 
 cross one another in different directions, and are perpen- 
 dicular to the outer surface, and by such division the cir- 
 cumference of the wall is increased, keeping pace with the 
 increase in volume of the group of mother-cells. In the 
 mean time the division by septa parallel to the outer surface 
 occurs once more, so that now the wall of the sporagium 
 consists of three layers of cells (PI. XXXM, fig. 10). 
 
 The inner one of these layers and the middle one be- 
 come dissolved, and are displaced by the group of mother- 
 cells, the size of which increases continually. The inner layer 
 is dissolved at an early period, and the middle one shortly 
 before the time when the mother-cells are individualised 
 (PI. XXXA^I, fig. 13). The connexion between the mother- 
 cells is not broken up all at once. Small groups, consisting 
 normally of four cells, usually hang together for some time 
 (PI. XXXVI, figs. 11, 12). This process corresponds ex- 
 actly with what takes place in the formation of tiie pollen 
 of phsenogams. 
 
 Each of the spore-mother-cells when free exhibits a large 
 central nucleus, as is the case at all periods of their deve- 
 lopment, except immediately before the division of a gene- 
 ration of mother-cells. This nucleus, which usually has 
 only one moderate-sized spherical nucleolus, is a globular 
 empty cavity, having a vesicular appearance, and is filled 
 with fluid which is less highly refractive than the thickly 
 mucilaginous contents of the cell, Mdiich are rendered turbid 
 by numerous fine yellowish granules. In the further 
 progress of the development of the fruit the membrane 
 of this nucleus is slowly dissolved : its fluid contents do 
 not intermingle with that of the cell (PI. XXXVI, fig. 12; 
 PI. XXXVIl, fig. 1). In its place two large flatly ellip- 
 soidal nuclei suddenly appear occupying almost half the 
 mother-cell. These latter nuclei at first exhibit no nu- 
 cleoli, but at a later period they contain several (PI. 
 XXXVI, fig. 3). In the equator of the cell, between 
 the two nucleoli, a ring or plate of protoplasmic granules 
 is formed near the cell-wall (PL XXXVIl, figs. 4, 5). 
 The outlines of the two flattened nuclei then become more 
 
THE HIGHER CRYPTOGAMIA. 283 
 
 and more indistinct, and soon disappear altogether. The 
 granules which compose the above-mentioned ring or plate, 
 distribute themselves in the fluid contents of the mother- 
 cell, and four smaller globular nuclei are now seen in the 
 latter, whose appearance is as sudden as that of the two 
 larger flattened nuclei, which took place a short time pre- 
 viously (PI. XXXV II, fig. 6). They are arranged in the 
 angles of a tetrahedron, and a septum is visible between 
 each two of them. Introductory stages of the development 
 of the septum may be seen in the form of thick indistinct 
 flattened agglomerations of yellowish protoplasm. Thus 
 the mother- cell is divided into four tetrahedral cells which 
 are the special-mother- cells (PI. XXXVII, figs. 7, 8). 
 
 Hitherto the development of the spores, from the separa- 
 tion of the mother-cell down to the minutest details, re- 
 sembles that of the pollen of the Abietinese.'^ This renders 
 their further history so much the more peculiar. 
 
 The four tetrahedral cells into which the mother-cell 
 divides, very soon become disunited, doubtless on account 
 of the dissolution of the primary wall of the mother-cell, 
 and of the outer layer of the walls of the four daughter- 
 cells. They then appear in the form of perfectly spherical 
 very thin-walled cells. A layer of granular mucilage covers 
 the inner wall, leaving in the centre a free globular cavity 
 filled with a thin fluid. The' very flat nucleus is embedded 
 in the protoplasmic layer. The globular cell, when lying 
 in water, soon appears surrounded bj' a bright halo, formed 
 of a layer of apparently gelatinous matter, which when 
 treated with iodine exhibits no colour. (PL XXXA'^II, 
 fig. 9). A very delicate membrane forms the outer boun- 
 dary of this covering layer. In somewhat older sporangia 
 this membrane appears more firm, and more distinctly 
 separated from the inner part of the layer surrounding the 
 globiüar cell, which now consists of a fluid coloured pale 
 yellow by iodine. These stages of development of the 
 spore-mother-cell are passed through in a very short time. 
 In the same sporagium of J^q.pa/mfre there may be found 
 mother-cells with the primary nucleus in the act of disso- 
 lution, others with two flattened nuclei, and others with 
 * 'Bot. Zeit.,' 1848, p. 670, 
 
284 HOFMEISTER, ON 
 
 four globular daughter-nuclei ; there may also be found 
 sets of four tetrahedral daughter- cells, individual daughter- 
 cells, of a globular form, and lastly, others which already 
 exhibit the transparent halo slightly developed. The ap- 
 pearance of the latter is not accompanied ])y any percepti- 
 ble contraction of the contents of the globular cell. If the 
 cells which, when treated with water, exhibit the above- 
 mentioned halo, are examined in the fluid contents of the 
 sporangium, their membrane appears thin and (piite homo- 
 geneous even under the best microscopes. But in sporangia 
 a little more advanced, the membrane in question under 
 similar circumstances appears to be composed of two layers, 
 the inner one of which is thicker and more highly re- 
 fractive than the outer one. The outer layer, when treated 
 with alcohol, contracts so as to be hardly distinguishable 
 from the inner one. At the same time the cell-contents con- 
 tract, sometimes into a globular shape, sometimes irre- 
 gularly. If water is applied the outer layer swells con- 
 siderably, and forms a thick, gelatinous, almost fluid cover- 
 ing, round the inner one, w^hich remains unaltered. Under 
 the further action of water this gelatinous layer is dissipated 
 in the surrounding fluids. The effect of alcohol upon the 
 fresh cell is to lessen considerably this power of distension. 
 After treatment with alcohol the outer layer only swells up 
 to a definite extent (to about three times its original size), 
 in distilled water. If the preparation is now crushed, the 
 swollen layer is pressed out over a wide space, and is then 
 clearly seen to consist entirely of a homogeneous hyaline 
 gelatinous substance, and that the granular aspect of its 
 outer surface is owing to the attachment of small extrane- 
 ous bodies. A longer exposure to the eft'ect of alcohol 
 often entirely destroys the capacity for distension. 
 
 Iodized solution of chloride of zinc imparts a pale blue 
 colour to the entire mass of the outer membrane, and 
 renders the inner one yeflow. After the cells have lain in 
 alcohol the same solution renders the outer layer pale yellow, 
 and the inner one brown. The addition of water brings 
 out the blue colouring in the outer layer. Ammoniated 
 oxide of copper applied to the fresh cell causes only a slight 
 distension of the outer layer, and hardens it so that it no 
 
THE HIGHER CRYPTOGAMIA. 285 
 
 longer spreads out under pressure. Sulphuric acid dissolves 
 the outer layer ; the inner one withstands its action but 
 assumes a broAvn colour. At this period of development 
 the diameter of the cell is from 20-24 to 23-60 m. m. m. 
 and no trace of any third inuer membrane is perceptible, 
 even when the cell is ruptured after lying in alcohol. 
 
 But when the cell has attained a diameter of from 30-3 
 to 37 m, m. m. a third internal covering of theceU-contenls 
 soon makes its appearance. Such a cell when placed in 
 diluted alcohol exhibits three perfectly distinct membraucs. 
 Each of the three globular vesicles is situated excentrically 
 in the interior of the next outer one. If the fresh cell is 
 placed in alcohol the three membranes swell up but in dif- 
 ferent degrees : the outer one swells the most, the middle 
 one to a less extent than the outer, and the inner one least 
 of all. The cell-contents swell up at the same time ; they 
 always remain closely attached to the inner membrane, and 
 cannot be brought to contract into a smaller space than 
 the cavity of the latter. In a cell for instance whose diameter 
 in alcohol was 30*2 m. m. m. the membrane immediately 
 enclosing the cell contents measm-ed (after treatment with 
 water) 32 m. m. m.; the middle one 37-04 m. m. m., and 
 the outer one 68'84 m. m. m. 
 
 At this stage of development the iodized solution of 
 chloride of zinc colours all three membranes blue ; the 
 middle one changes colour first, and its colour is the most 
 intense. If such cells, after lying in alcohol, are ruptured 
 by pressure, the membranes, which have previously been 
 closely attached to one another, separate ; the middle one 
 contracts to a smaller space than the outer one, and the 
 inner one more than the middle one. After contrac- 
 tion they still retain the form of tense globular vesicles, 
 and exhibit a greater thickness of wall than before. If 
 cells fresh from the sporangium are treated with water, the 
 outer and middle membranes often swell up to some extent : 
 they separate from the inner layer, remaining at the same 
 in close connexion with one another. The distended mem- 
 branes are easily separable from one another by pressure, 
 and they exhibit a scarcely perceptible increase in thickness. 
 At this period no trace is yet visible of the course of the 
 
286 HOFMEISTER, ON 
 
 spiral bands into which the outer membrane shortly after- 
 wards divides.* 
 
 In those sporangia however in which some cells of the 
 outer membrane exhibit traces of elater-formation and others 
 do not, the capacity for distension of the middle membrane 
 is far behind that of the outer one. Even in the fluid con- 
 tents of the sporangium itself the outer membrane, in 
 Equisetum limomm, is at a considerable distance from the 
 middle one. Upon treatment M'ith alcohol the middle and 
 the inner membrane are drawn far away from the outer one 
 whilst tliey remain in close contact with one another, and 
 with the cell-contents. Upon the subsequent addition of water 
 the inner membrane remains still in close contact at every 
 point with the cell contents; the middle one becomes some- 
 what detached and often irregularly folded; and the outer 
 layer is far removed from the middle one. With this dis- 
 tension of the outer membrane it becomes manifest that 
 the latter is traversed by two left handed, parallel, spiral 
 lines, in the course of which the membrane is thinner than 
 in its other parts. In profile, i. e., in an optical longitu- 
 dinal section of the cell, I see with the best microscopes 
 that the thicker portions of the membrane protrude uiwarch 
 over the thinner parts (PI. XXXVII I, fig. 10), not out- 
 warcUy^ as Sanio says (' Bot. Zeit.,' 1857, p. 661). AVhen 
 
 * In the ' Vcrgleiclieiide Untersuchuugeii,' p. 99, I spoke of the processes 
 above described as consisting of the formation of a free cell (the spore) around 
 the primary nucleus of the special mother-cell. In opposition to this, Sanio 
 iias shown ('Bot. Zeit.,' 1856, p. 181, 1857, p. 657) that loithiii the spoi-angium. 
 tlie two membranes always lie close to one another, and that therefore a free 
 cell-formation cannot be admitted. This is quite correct. Sanio further 
 attempted to show that tlierc could be no such thing as a centripetal spiral 
 thickening of the outer cell-membrane, which membrane at a later period splits 
 to form the elaters. The reasons brought forward to prove this are however 
 not convincing. During the development of the spores of the Equisetaeefe 
 some phenomena occur which have an important bearing upon the study of the 
 cell-membrane, and 1 therefore give here in some detail the result of recent 
 investigations of this subject. Some of Sanio's o1)jeetions to my views as to 
 the diyisions of the mother-cell (1. c, 1856, p. 170) have since been abandoned 
 by himself (I. c, 1857, p. 658). With regard to his observations on the 
 abnormal development of certain mother-cells and the division of the primary 
 nucleus by constriction, I will oidy remark that there is no analogy between 
 such cases and the cases where the process of development is normal. 
 
 ■\ I contend that my representation ('Vergl. Unters.,' t. xx, f. 18) is quite 
 correct, irrespective of the fact that in this figure the thin portions of the 
 membrane have come out disproportionately thick, 
 
THE HIGHER CRYPTOGAMIA. 287 
 
 ill water the outer membrane, wliicli is in the process of 
 being transformed into elaters, is coloured pale blue by 
 iodized solution of chloride of zinc ; in the middle layer the 
 blue is more intense. 
 
 In sporangia a little more advanced the thin parts of the 
 outer membrane disappear : the delicate pelHcle which held 
 together the coils of the elaters is no longer present. Presh 
 elaters are coloured a greyish-blue by the above-mentioned 
 solution, with the exception of a thin outer layer which 
 assumes a yellowish colour. By adding a quantity of 
 water the colom- of the main portion of the elaters becomes 
 a more pure blue. After the separation of the elaters the 
 middle spore membrane exhibits a very different reaction 
 with iodine ; it remains yellow under all circumstances, 
 under the iodized solution of chloride of zinc, as well as 
 under iodine and sulphuric acid. Animoniated oxide of 
 copper if applied to the outer membrane just after it has 
 split to form the elaters, is very rapid in its effects. The 
 membrane becomes distended and is gradually dissolved. 
 Under the action of the same fluid the next inner membrane 
 swells up into a large vesicle, without diminishing per- 
 ceptibly in thickness. Its substance is then softer; by 
 rolling it under a covering glass it is easily wrinkled. The 
 third membrane is tightly stretched upon the cell-contents. 
 The further action of animoniated oxide of copper gives it 
 a yellowish colour, but in other respects it remains un- 
 changed. 
 
 A little later, whilst the elaters are continually increasing 
 in breadth and thickness, the rudiment of a final innermost 
 membrane of the spore becomes visible. If a young spore 
 ill this stage of development is detached from its elaters, 
 and placed in alcohol, and if water be then added, the 
 membrane next to the elaters becomes detached from the 
 third membrane, and from the cell-contents which are 
 closely embraced by the latter, and in which chlorophyll 
 now begins to appear. If the spore be iioav ruptured by 
 pressure, the membrane next to the elaters remains folded 
 without changing its volume. The next inner one remains 
 after the rupture tense as before, whilst it contracts upon 
 a much smaller space, and now appears considerably thicker 
 
288 HOFMEISTER, ON 
 
 than it previously was. It has Ijonie a strong pressure 
 from the expanding cell-contents, and possesses a high 
 degree of elasticity. Its hitherto smooth outer surface 
 now exhibits very small protuberances which give it a 
 finely granular appearance. Its inner surface is covered 
 by a tolerably thick layer of semi-fluid hyaline matter, 
 which by hard pressure is partly driven out from the 
 fissure of the ruptured membrane. If a spore in the 
 above stage of development be taken fresh from the sporan- 
 gium and treated Avith caustic potash, the elaters swell 
 up ; the adjoining membrane is distended into a vesicle, 
 and usually becomes wrinkled. The third granular mem- 
 brane assumes a brown colour, but in other respects re- 
 mains unchanged. The fourth membrane, which is still 
 delicate, contracts round the cell-contents, and exhibits a 
 double outline.* The peripheral portion of the cell-con- 
 tents then assumes a red colour, which never extends so 
 far as the middle point of the cell, and which depends 
 upon the presence of tannin. f Sometimes in spores taken 
 from the same sporangium, like those just mentioned, the 
 innermost layer swells up under caustic potash, and remains 
 in contact with the granular layer. The latter may then 
 be stripped off from the inner layer by friction with the 
 covering glass, and will be seen to be a closed vesicle sur- 
 rounding the cell-contents. Sulphuric acid innnediately 
 destroys the elaters of such spores ; the next inner mem- 
 brane, like the third granular layer, thereupon expands 
 into a capacious vesicle, but resists the acid. The fourth 
 innermost layer swells, and becomes converted into gela- 
 tine, which after the rupture of the cell is innnediately dis- 
 persed in the surrounding fluid. 
 
 After the bursthig of the ripe sporangiaj the elaters, when 
 dry, are stretched out, remaining attached to the spore by 
 then- median portion. When moistened tlu^y roll together 
 
 * Sanio, 1. c, p. 6G5, who from its contractility, draws the couclusiou that it 
 is a primordial utricle. 
 
 t Sachs, ' Sitziingsb. AViener. Acad.,' xxxvi, (ISoO) p. 21. Sauio has observed 
 that the red colour only afTccts the cell-contents, 1. c, p. GGG. 
 
 X The wall of the sporangia, which consists of one layer of cells, is trans- 
 formed into spiral cells. Compare Henderson, 'Trans. Linn. Soc.,' v, xviii, 
 p. 507. 
 
THE HIGHER CRYPTOGAMIA, 289 
 
 in a spiral manner, covering the spore entirely as at first. 
 It may easily be seen by the examination of detached 
 fragments of elaters that the rolling inwards is not accom- 
 panied by any contraction of the concave side. It folloAvs 
 from this that the extension of the elaters depends upon a 
 relatively greater contraction of the outer layers of their 
 tissue, a contraction which is completely balanced by 
 moistening the elaters. By moistening the ripe dry spores 
 the elaters are rapidly rolled inw^ards ; almost immediately 
 afterwards they become unrolled. Sulphuric acid and Avater 
 also causes a rolling inwards of the elaters : when concen- 
 trated to a certain extent it destroys only the inner layers. 
 The thin outermost layer, which during the formation of 
 the inner layer was coloured yellow by iodized chloride of 
 zinc (Pringsheim's ' Elater-cuticle,' Bot. Zeit., 1853, p. 
 244), remains behind in the form of a loose band. The 
 second (now the outermost) membrane of the spore, be- 
 comes distended and detached from the middle layer by 
 the action of sulphuric acid, whether concentrated 'or 
 diluted. The inner spore-membrane is largely distended 
 by concentrated sulphuric acid, so that it soon ruptures 
 both the outer membranes, and emerges with the spore- 
 contents in the form of a gelatinous globule (PI. XXXVIII, 
 iig. 11). The two outer membranes are not affected by 
 heated sulphmic acid, not even by remaining in the acid 
 for ten days. The outer layer under such circumstances 
 remains at first as clear as glass, and afterwards only ex- 
 hibits a smoky-grey colour and a granular consistency of 
 the outer surface. The inner layer which is finely granular 
 is coloured deep brown. After the rupture of the spore 
 all its membranes contract considerably, so that the diameter 
 of their inner cavity is only about half the previous size. If 
 the rupture of the spore is effected by treatment with sul- 
 phuric acid the contraction of the middle (third) mem- 
 brane, and consequently the elasticity upon which this 
 contraction rests, appears to be altogether unaffected, and 
 that of the outer membrane is but slightly acted on. After 
 the bursting, by pressure, of the fresh, ripe, detached spore, 
 the outer boundary only of the innermost (fourth) mem- 
 brane is sharply defined ; the inner side of the latter mem- 
 
 19 
 
290 HOFMEISTEE, OX 
 
 brane becomes by degrees a half solid gelatinous layer. 
 It is not until germination that this membrane becomes 
 smooth and firm on both sides. The expansion of the 
 cell-contents and of the innermost membrane which takes 
 place when the spore is sown upon moist ground, very 
 soon ruptures the outermost of the three membranes, and 
 shortly afterwards the middle one also, and both are stripped 
 off. The substance which is coloured red by caustic 
 potash remains attached to the inner wall of the innermost 
 membrane after the latter has become free, and even for 
 some time after its division into two cells. This substance 
 has the form of a layer composed of very minute particles, 
 and it may be detached by pressure from the cell-mem- 
 brane. 
 
 Two facts in the process of development of the spores of 
 the Equisetacese are of general interest. The spore-mem- 
 brane is here seen to increase in thickness after two differ- 
 ent modes of growth occm'ring side by side. There is 
 growth by apposition and growth by intussusception. To 
 the former is to be attributed the orioin of the third and 
 fourth membranes, which are evidently produced from the 
 gradual hardening of layers of gelatinous matter spread 
 over the inner surface of the previously existing membranes. 
 To the latter belongs the centripetal groAvth of the claters, 
 after their separation from one another, and the centrifugal 
 growth of the second and third membrane during and after 
 the formation of the fourth ; a growth which exhibits itself 
 in the granulation of the outer surfaces of both these mem- 
 branes. The second point, however, is the more important one, 
 viz., the remarkable modifications of the physical properties 
 and chemical reactions which each of the four membranes 
 of the spore imdergoes during the process of development. 
 Each of them exhibits during a certain period of its exist- 
 ence the assumed characteristic relation between cellulose 
 and iodine and sulphuric acid ; but this relation is never 
 seen in the earliest states of development, nor is it constant. 
 The outer layer of the first membrane (/. e., the elaters), 
 and of the fourth membrane (even after the commencement 
 of germination), assume in the course of development the 
 character of a cuticle ; the second and third maintain that 
 
THE HIGHER CRYPTOGAMIA. 291 
 
 character tlirougliout. The three outer membranes when 
 young are far more capable of distension than at a later 
 period, and during this condition the second and third 
 membranes are not without a high degree of elasticity, 
 which diminishes as the capacity of distension becomes less, 
 or even disappears altogether. 
 
 Sanio* has made some interesting observations upon the 
 abnormal formation of elaters out of the membranes of 
 mother-cells in which the division into four daughter- 
 cells has been suppressed. Since these observations it can 
 hardly be doubted that the outermost membrane, which is 
 transformed into elaters, must be looked upon as their 
 special-mother-cell. The Ec|uisetace3e, therefore, exhibit 
 the rare circumstance of the persistence of the membrane 
 of the special-mother-cell, a fact which, as far as I know, 
 occurs in phaen ogams only in Maranta Zehrina. During the 
 transformation of the membrane of the special-mother-cell 
 into elaters a change in the substance of the membrane 
 appears to take place. Spiral strips of the membrane be- 
 come thinner and ultimately disappear, whilst other strips 
 parallel to these increase in thickness. The differentiation 
 of the membrane in a superficial direction into strips of 
 different characters, may be compared with its differentiation 
 in the direction of the thickness into two layers of different 
 properties. 
 
 In the ripe spores the central globular nucleus is very 
 clearly visible floating in the yellowish oleaginous fluid 
 contents, in which, even before the shedding of the spores, 
 numerous chlorophyll granules are seen. The number of 
 the latter increases rapidly when the spores are sown on 
 moist ground. After a few hours the primary nucleus 
 vanishes. In its place two new ones make their appearance, 
 the position of which can often only be made out by means 
 of the agglomeration of chlorophyll-granules in theii* 
 neighbourhood (PI. XXXVIII, fig. 12). Between the two 
 a septum is formed, dividing the spore into two very un- 
 equal parts (PL XXXVII, fig. 13). One of these, the 
 larger one, contains almost all the chlorophyll-granules of 
 the cell : the other has hardly anything but finely-granular 
 
 * «Bot. Zeit.,' 1857, p. 667. 
 
292 HOFMEISTER, ON 
 
 mucilage. This latter cell usually constitutes the first 
 radicular hair of the growing prothallium (PI. XXXVII, 
 figs. 14—16). 
 
 In Equisetum Umosiim and ^^alustre the upper chlorophyll- 
 bearing cell divides inunediately by a vertical or strongly 
 inclined septum (PL XXXVIIl, figs. 15, 10). In Equi- 
 setum arvense the cell often expands to a very considerable 
 extent before it di^'ides, especially Avhen the spore is sown 
 in a very moist shady place (PI. XXXVIII, fig. 19). The 
 formative matter — protoplasm mixed with numerous chlo- 
 rophyll-granules — is accumulated at the apex of the upper 
 cell, which is turned away from the rooting end of the 
 growing prothallium. This uuicilaginous mass usually, but 
 not ahvays, surrounds the nucleus. The latter dissolves 
 gradually and two new ones take its place (PI. XXXVIII, 
 fig. 19). A transverse septum, wdiicli makes its appearance 
 between the two, divides the large chlorophyll-bearing cell 
 into an upper, smaller cell, destined for further active division, 
 and a lower, distended, permanent cell (Pl.XXXA'II, fig. 20). 
 The basal cell often grows into a tubular root after the 
 previous growth of one or more capillary roots from the 
 free outer wall of the vounger cells. Prequently, however, 
 this does not take place (PL XXXVII, fig. 20).' 
 
 The further development of the prothallium is very 
 various. There is hardly any organ of the higher plants 
 in which there is so little regularity of cell-nuiltiplication. 
 Usually there is a tendency to longitudinal gro^^'tll by the 
 repeated division of one or more apical cells by means of 
 transverse septa, and also to the division of the cells of the 
 second degree by longitudinal septa. Lateral shoots are 
 very often formed. They are produced by the protrusion 
 of the wall of a somewhat older cell, and the subsequent 
 separation of the protuberarice from the primary cell-ca^•ity 
 by means of a transverse septum (PL XXXA^II, fig. 20). 
 These adventitious shoots exhibit the like forms of cell- 
 multiplication as the ])rimary shoots, which they often sur- 
 pass in vigour (PL XXXVII, fig. 22). In other cases there 
 is a manifest bifurcation of the fore-end of the prothallium 
 produced by the parting asunder and development of two 
 apical cells (PL XXXVII, figs. 17, 21). AVhen the cells 
 
THE HIGHER CRYPTOGAMIA. 293 
 
 of the protliallimn have reached the stage at which the 
 protoplasm of their contents clothes the inner wall in the 
 form of a thin layer, they have a manifestly vesicnlar ap- 
 pearance. I have often clearly observed their mnltiphcation 
 by division (PI. XXXVII, fig. 20). Mucilaginous threads 
 radiate from the nucleus. 
 
 However various the ramifications of the prothallium 
 may be at first, the final result is always the same. One 
 or more (five at the most) of the numerous shoots develope 
 themselves much more vigorously than the others in length, 
 breadth, and thickness. Their outline resembles to some 
 extent that of the prothallia of the ferns. The subse- 
 quently formed capillary roots of the prothallium are pro- 
 duced almost exclusively from their under side. Sexual 
 organs are mainly produced from these principal lobes ; 
 they seldom occur on other parts of the prothallium. 
 
 The prothallia of .Equischivi arvense, ijrateme, and 
 palmtre, are distinctly disecious. The individuals wdiich 
 bear antheridia produce them very plentifully, but yield 
 archegonia only in the rarest instances, and then upon late 
 shoots of the base of the prothallium. These may be con- 
 sidered as new individuals, by analogy to the processes 
 which spring from the marginal cells of old fern-proth al- 
 ba. The male prothallia do not attain the full size 
 of the females. They consist normally of only one or two 
 thickly fleshy expansions of cellular tissue, wdiose margins 
 bear the antheridia, and also some thin membraneous 
 barren shoots. Their chlorophyll contrasts with that of 
 the female prothallia by a manifest tendency to a yelloAv 
 colour. The deep-brown colour which is assumed by 
 empty antheridia, imparts a diseased appearance to the 
 male prothallia at an early period. 
 
 The production of an antheridium is preceded by fre- 
 quently repeated division of one of the marginal cells by 
 means of septa inclined alternately in two directions (PI. 
 XXXVIII, fig. 24). The cells of the second degree divide 
 by radial longitudinal septa, and each of the three-sided 
 cells thus formed divide into inner and outer cells by septa 
 parallel to the axis of the organ. The latter become the 
 covering layer of the antheridium, and numerous chloro- 
 
394 HOFMEISTER, ON 
 
 pliyll vesicles are spread over tlieii' inner wall. The me- 
 dian cavity of the cell is filled with a watery fluid. The 
 axile cells of the young anthcridium form an oval group, 
 composed of four longitudinal rows of cells, and contain 
 finely-granular mucilage (PI. XXXVII, fig. 24). By 
 rapidly repeated division in all three dii'ections of space 
 they are transformed into a mass of small tessellated cells, 
 which at first are in very close connexion with one another. 
 In each of them a flattened ellipsoidal cellule is formed 
 (PI. XXXVII, fig. 25), in the interior of which a small 
 vesicle with less highly refractive fluid contents is some- 
 times visible (PL XXXVII, fig. 26). The waUs of the 
 firmly adherent cubical cells are now dissolved, and the 
 eflipsoidal cellules become free. A gelatinous mass, spread 
 over their inner wall, soon begins to be visible ; it forms 
 an imperfect ring parallel to the major axis of the ellipsoidal 
 cell. This is the first indication of the nascent sperma- 
 tozoa (PI. XXXVII, fig. 27). Numerous mucilaginous 
 granules remain for a long period in the middle point 
 of the cellule, even until the ripening of the antheridium. 
 
 The apical cells of the covering layer of the antheri- 
 dium, which are usually eight in number, contain little or 
 no chlorophyll. In the elongated antheridia of Eq. Hmosmn 
 the cells adjoining these apical cells have also very little 
 chlorophyn'(Pl. XXXVII, fig. 24). When the organ is 
 ripe the apical cells part asunder, and the cellules enclosnig 
 the spermatozoa ooze slowly out. 
 
 These cellules are larger in Equisetum than in any other 
 known plant. In Eq. arvense their diameter attains y^". 
 When the vesicle is ripe the spermatozoon soon becomes 
 partly free, apparently by the distension and. dissolution of 
 parts of the wall of the enveloping cell. The numerous cilia 
 on its thick fore-end commence their active oscillating motion, 
 by means of which the spermatozoon with the attached 
 vesicle moves rapidly about in the water on the slide. The 
 spermatozoon seldom becomes entirely free from its mother- 
 cell. When it does so, it has the form of a spiral vermiform 
 body, consisting of a mucflagino-gelatinous substance be- 
 coming dark-brown under iodine. Its fore-end, which is 
 the thicker of the two and slightly compressed laterally, 
 
THE HIGHER CRYPTOGAMIA. 295 
 
 forms tAYO narrow closely approximated turns of a (iisnally) 
 left-handed spiral. Tliese turns alone bear the cilia. 
 During the rapid motion of the spermatozoon m water its 
 wider, final turn, upon which the cilia are wanting, ap- 
 pears to be someAvhat reduced in size (PI. XXXVIII, fig. 
 38), but Avhen the spermatozoon is killed with iodine, it ap- 
 pears on the contrary considerably enlarged (PI. XXXVIII, 
 tigs. 30 — 3-3). This remarkable phenomenon depends upon 
 an organization hitherto (as far as is known) unique in 
 the vegetable kingdom. The end of the spermatozoon bears 
 on the inner side of its ultimate turn a wide fin-like 
 process, consisting of a delicate membrane, which during 
 the motion of the spermatozoon glistens like the undulating- 
 membranes of the spermatozoa of toads and Tritons. 
 When the motion becomes more active the membranous 
 margin becomes invisible like the cilia ; it is only clearly 
 \isible when the vital activity of the spermatozoon is on 
 the decline (PL XXXVII, figs. 30—33). The undula- 
 tions of the fin last longer than the oscillations of the 
 cilia. The hinder end of the spermatozoon appears still 
 somewhat pointed when the quiescent cilia of the fore-end 
 are already visible. The hinder end of the spermatozoon is 
 of a very delicate half-fluid consistence ; it attaches itself 
 easily to any object, and is then drawn out into long threads. 
 It often happens that a spermatozoon drags after it the 
 empty membrane of the mother-cell attached to one of 
 such threads, or that it fastens itself to a capillary root of a 
 prothallium (PI. XXXVIII, fig. 28*). Spermatozoa whose 
 motion, after many hours continuance, ends spontane- 
 ously, always exhibit a thin caudal appendage often of 
 very considerable length. The substance of their hinder 
 end has doubtless been drawn out into such threads, in 
 consequence of the spermatozoon having attached itself to 
 some liody during its motion, and then torn itself away. 
 The sulDstance of such spermatozoa exhibits, by the pre- 
 sence in it of vacuoles, manifest traces of a state of disten- 
 sion.* If the spermatozoa are killed with iodine they 
 
 * 111 tlie 'Veigleich. Uuters.,' p. 301, I treated the whip-sliaped elongated 
 form of the hinder end as a peculiarity common to the spermatozoa of Equisetum, 
 an assumption which was grounded upon the frequent occurrence of such 
 peculiarity. 
 
296 HOFMEISTER, ON 
 
 usually uurol themselves like a suail (PL XXXVII, figs. 
 31 — 33) ; it is but rarely that the individual turns remain 
 at a distance from one another, as is the case during the 
 motion. The motile cilia appear stiff and extended when 
 the spermatozoon is quiescent ; their direction is not radial 
 to the axis of the spiral of the spermatozoon, but is turned 
 backwards. 
 
 The mode in which portions of the spermatozoon remain 
 attached to the mother-vesicle is very various. Very fre- 
 quently the thick fore-end remains inside the spherical 
 vesicle, the lower turns protruding out of the fissure, and 
 causing by the oscillation of their cilia a restless reeling 
 motion of the organ and its mother-cell. More rarely the 
 fore-end is free and the hinder-end enclosed in the vesicle. 
 In such cases the motion is more regular and more rapid. 
 It more often happens that the cilia of the thickest end of 
 the spermatozoon protrude out of a fissure in the vesicle. 
 The continual rolling motion of such spermatozoa very much 
 resembles that of many infusoria. 
 
 I have seen the motion of the spermatozoa of Eqinsetuw 
 arvense last for five hours. The sensitiveness of the sper- 
 matozoa to external influences appeared to me much less 
 than that of ferns. Water containing much gypsum, Avhich 
 acted in a decidedly injurious manner upon the spermatozoa 
 of Aspleniiim septentrio/iale, had not the slightest effect upon 
 those of Eq. arvense, palustre, and Uviosum. 
 
 In Eq. limosi/m I found the first ripe antheridia five 
 weeks after the soAving of the spores (on the 1st of July), 
 in Eq. arvense thirteen weeks after (at the end of July) ; 
 in one case four weeks only after the sowing (at the end of 
 May). The number of the antheridia upon one prothallium 
 is sometimes as many as sixteen in Eq. arvense. The inner 
 wall of the cavity of antheridia which liave discharged 
 their contents assumes a deep brown colour. The escape 
 of the cells enclosing the spermatozoa certainly takes place 
 spontaneously ; heaps of agglomerated dried mother-cells 
 of spermatozoa are often found at the apex of empty anthe- 
 ridia. 
 
 Numerous obstacles seem to interfere with the natm'al ger- 
 mination of the Equisetaceae. Although I have often searched 
 
THE HIGHER CRYPTOGAMIA. 297 
 
 for them, I have never found the prothallia of any species in 
 their natural state. Even under culture, the greater number 
 of the prothallia decay before the development of antheridia, 
 or are destroyed by insects, or by an overgrowth of 
 Vaucherise, Oscillatorieae, or proerabryos of mosses. Before 
 1852 very few of the prothallia of Eqidseiinn arveuse which 
 I had cultivated lived beyond the fifth month after the 
 sowing. They were all of the male sex. In some I ob- 
 served the formation of a short, flat, lateral shoot, which 
 produced the rudiments of archegonia. This was the only 
 instance of departure from the disecious character which 
 ever occurred to me in the prothallia of Equiseta. 
 
 Those prothallia of Eq. arvense, variegatum, and palustre, 
 which produce archegonia never produce antheridia.* 
 They ramify to a much greater extent and become far more 
 vigorous than the male prothallia. A female prothalliura 
 is normally a circular combination of from three to six 
 fleshy masses of cellidar tissue, which bear very numerous 
 green crisp shoots of more delicate texture, and from a 
 quarter to half an inch in diameter. The form very much 
 resembles that of young plants oi Anfhoceros j^utidafus. 
 
 When male and female prothallia are produced from 
 spores sown contemporaneously, the archegonia of the 
 female prothallia appear much later than the antheridia of the 
 male ones ; the younger female prothallium would seem to be 
 sterile. The spores from which female and male prothallia 
 originate are exactly of the same size and quality. Exter- 
 nal circumstances seem to have an influence upon the 
 germinating prothallia. A dry place exposed to light 
 seems decidedly to favour the development of male pro- 
 thallia of Eqicisetum arvense. The spores of Equisehim 
 arvense and j^Tate/ise when sown artificially produced prin- 
 cipally male prothallia,t and those of Equisetum palustre 
 
 * On the ot,ber hand Bischoff has found the prothallium of JEq. sylvcdium 
 bearing archegonia on its older portions and antheridia on its younger slioots. 
 ('Bot. Zeit.,' 1S53). 
 
 f In 1849, 50, and 51, I obtained only male prothallia, upon which rudi- 
 ments of archegonia appeared only at a late period, and then only upon f.dven- 
 titious shoots. In the summer of 1852 the number of male prothallia was 
 greater by about one half than that of the female ones. That summer seems to 
 have been especially favorable to the germination of Equisetum. Cultivated 
 specimens of Equisetum tariegatuni shed spores at the beginning of May. 
 About the middle of July female prothallia, which were present in great 
 numbers, developed small leafy plants. 
 
298 HOFMEISTER, ON 
 
 (accorcliiig to repeated experiments) only female pro- 
 thallia. 
 
 The archegonia are produced by the multiplication of 
 individual cells of the fore-edge of the thick, fleshy lobes 
 of the prothalhum. After the commencement of the form- 
 ation of the archegonium the mass of cellular tissue to 
 Avhich the organ is attached usually continues to grow 
 underneath it, so that the archegonia, like those of Pcllia, 
 are afterwards situated on the surface of the prothalhum. 
 A small, thin, membranous shoot of the prothalhum is 
 usually formed near each archegonium (PI. XL, fig. 1). 
 
 The mother-cell of an archegonium which, like its neigh- 
 bom\s, contains chlorophyll, only diff'ers from the latter by 
 its greater abundance of protoplasm. After its free upper 
 AA^all has become consideral)ly curved, its first division takes 
 place by a horizontal membrane. The lower of the two 
 halves, which is entirely sunk into the tissue of the pro- 
 thallium, becomes the central cell of the archegonium, the 
 aperture of the latter being formed by repeated bi-parti- 
 tions of the upper half. 
 
 The first of these partitions takes place by a vertical 
 longitudinal septum. Another septum, also vertical and at 
 right angles to that just formed, appears immediately in 
 each of the two newly formed cells. The four cells sur- 
 rounding the central cell, which in the mean time has be- 
 come remarkably curved above, grow uniformly upwards, 
 and are at the same time divided by horizontal transverse 
 septa — exactly in the same manner as the four vertical-cells 
 of the fruit rudiment of a Jungermannia.* Thus a cylinder 
 is formed projecting above the central cell of the archego- 
 nium, composed of four longitudinal rows of cells (PI. 
 XXXVII, figs. 35 — 37). The upper pair of cells undergoes 
 considerable elongation, which afterwards takes place also 
 in the next adjoining pair, though in a less considerable 
 degree. The two lower pairs of cells of the neck of the 
 archegonium become elongated upwards, but hardly per- 
 ceptibly so ; however, the incipient multiplication of the 
 cells adjoining the central cell extends to the two lower 
 pairs of cells, or at least to the lowest of them, the division 
 taking place by means of septa alternately perpendicular 
 * 'Vergl. UuteiVpp. 18, 38. 
 
THE HIGHER CRYPTOGAMIA. 299 
 
 and parallel to the walls of the central cell. In consequence 
 of these divisions the central cell of the archegonium, when 
 fnllv developed, appears to be surrounded by one or two 
 epithelioid layers of cells (PI. XXXVIII, figs. 1—4). 
 
 Inside the central cell, during the first stage of develop- 
 ment of the archegonium, there is formed a daughter-cell, 
 — i\\e germinal vesicle. It originates round a secondary 
 nucleus, which makes its appearance in the apical arch of 
 the cell (PL XXXVII, figs. 35, 36), sometimes as early as 
 the commencement of the formation of the transverse 
 septa of the two pairs of cells which form the neck of the 
 archegonium (PI. XXXVII, fig. 35). It grows gradually, 
 and during the formation of the archegonium displaces 
 more and more the contents of the central cell, especially 
 the second nucleus of the latter, wdiich exists during its 
 formation (PI. XXXVIII, fig. 1). AVhen the archegonium 
 opens, some graniüar mucilage, the last remnants of so 
 much of the contents of the central cell as has not been 
 absorbed in the formation of the germinal vesicle, seems to 
 be usually spread over the outer wall of the free spherical 
 cell (PL XXXVIII, fig. 2). 
 
 The four longitudinal rows of cells Avhich form the neck 
 of the archegonium now become disconnected at their edges. 
 An open canal is formed leading to the central cell and 
 traversing the longitudinal axis of the cylindrical neck. 
 This canal is the entrance to the archegonium. The four 
 elongated cells of its mouth bend semicircularly backwards 
 by which means the archegonium assumes a very strange 
 appearance ; it resembles an anchor with four flukes or arms 
 (PL XXXVIII, figs. 2, 3, 4, 6). The arched cells of the 
 mouth when they part asunder contain no solid matter ; the 
 few chlorophyll vesicles as well as the nucleus of the cell 
 have disappeared. The same is the case with the four cells 
 which support those last mentioned. The free neck of the 
 archegonium is transparent like glass. 
 
 There is far less difference betAveen the structure of the 
 archegonia of the Equisetacese and those of ferns than there 
 is between the antheridia of the same plants. The former 
 ao-ree in all essential features with those archcQ-onia of the 
 
 o ^ o 
 
 Polypodiacese in which the neck consists only of four longi- 
 
300 HOFMEISTER, ON 
 
 tudinal rows of cells. It may be asserted that the Equise- 
 taceae on account of the dicEcioiis nature of theh' prothallia, 
 and the constant similarity of the structure of their arche- 
 gonia with that of the archegonia of the Rhizocarpeae, 
 especially of Pikdaria, form the transition from ferns to the 
 Rhizocarpea?. 
 
 Male and female prothallia grow in the closest proximity, 
 their shoots often intermingling with one another. The 
 access to the archegonia, which is afforded to the sperma- 
 tozoa not only by every rain but also by every heavy dew, 
 is rendered still easier by the force with which, on tlie 
 spontaneousopeiiing of over ripe antheridia,*the spermatozoa 
 still enclosed in their mother-cells — are ejected. I found 
 in the canal of a recently impregnated archegonium mucila- 
 ginous masses closelv resembhng defunct spermatozoa 
 (PL XXXVIII, fig. 4). 
 
 The first visible change in an impregnated archegonium 
 is the closino- of the lower end of the canal, caused by the 
 horizontal expansion of the cells of its walls (PL XXXIX, 
 fig. 4, PL XL, figs. I — 8). This closing is accompanied by 
 the further multiplication of the cells of the tissue surround- 
 ing the central cell. These cells divide repeatedly by lon- 
 gitudinal and transverse septa ; the division is particularly 
 active in the cells of the epithelium-like layer which adjoins 
 the central cell. The impregnated germinal vesicle has in 
 the mean time become somewhat larger. Its nucleus has 
 disappeared, and a layer of finely granular protoplasm 
 lines its inner wall (PL XXXVIII, fig. 4). Now for the 
 first time — after tlie obliteration of the lower end of the 
 canal — the series of divisions couunences by which the 
 embryo is produced. 
 
 The germinal vesicle is first divided by a septum inclined 
 to the longitudinal axis of the archegonium. The two 
 halves are again immediately divided l)y transverse septa 
 at right angles to those just formed. Sometimes the upper 
 and sometimes the lower of the two first cells of the rudi- 
 mentary embryo takes the lead in this division (PL XXXVIII, 
 figs. 5, 6). 
 
 * It, is at this time only that the small delicate crown represented by Thuret 
 ('Ann. d. Sc. nat.,' iii S.,'vol. xvi, pi. 16, f. 1) is formed. 
 
THE HIGHER CllYPTOGAMIA. 301 
 
 At this time or a little later the recurved cells of the 
 aperture of the archegonium shrivel and fall otf. 'J'he four 
 elongated cells of the neck of the archegonium upon which 
 they are borne also lose their vitality. Their walls, so far 
 as they form the canal of the archegonium, assume a dark 
 brown colour. 
 
 The number of the archegonia of a vigorously developed 
 prothallium varies from twenty to thirty ; it exceeds there- 
 fore that of the antheridia of even the largest male prothallia. 
 Usually more than one archegonium is impregnated. I 
 counted as many as seven embryos in one and the same 
 prothallium. The brown colour of the unimpregnated 
 archegonia extends not only over the walls of the whole 
 canal — which remains open — l3ut also over the central cell 
 and its contents (PL XXXVIII, fig. 8). 
 
 The first axis of the embryo (which remains undeveloped) 
 has its origin in a series of repeated divisions of the terminal 
 cell commencing in the three-sided cell which includes the 
 lower end of the embryo rudiment (PI. XXXVIII, 
 figs. 7—10 ; PL XL, figs. 1—3). The cells of the second 
 degree divide at first only by longitudinal and transverse 
 septa perpendicular to the free outer surfaces (PL XXXVIII, 
 figs. 7,8; PL XXXIX, fig. 1) ; at a later period septa, 
 parallel to these surfaces make their appearance and form 
 inner cells. A similar cell-multiplication commences in the 
 one lateral cell of the 4-cellular-embryo-rudiment. The 
 lines in which the first septa of the lateral cell intersect are 
 parallel to the longitudinal axis of the archegonium (PL 
 XXXVIII, figs. 7 — 10). A side shoot of the embryo is 
 thereby formed — the second axis of the germ plant, its 
 first leaf-bearhig shoot. By the considerable growth in 
 thickness of the primary axis below the place of origin 
 of the secondary one, and still more by the upward ciu'va- 
 tiu'e of the latter during its development, the rudiment of 
 the secondary shoot is soon brought almost to the 
 apex of the globular cellular mass which now constitutes 
 the embryo — to within a small distance from the locus of 
 the lower end of the canal of the archegonium which is now 
 entirely obliterated (PL XXXIX, figs. 4, 5). 
 
 Up to this stage the rudiment of the embryo may be 
 
303 HOFMEISTER, ON 
 
 detached without much difficulty. From this time however 
 the cells of the surftice of its primary axis become more and 
 more closely connected with the neighbouring cells of the 
 prothallium, whilst the latter — in some of which multiplica- 
 tion is continually going on — are more and more com- 
 pressed and at last entirely absorbed by the rapid increase 
 in size of the new plant. 
 
 The end of the secondary axis of the embrj'o resembles 
 at an early period both in its form and in the mode of nuil- 
 tiplication of its cells the terminal bud of a shoot of a 
 developed Equisetum. The comparatively large apical cell 
 and the ladder-like arrangement of the cells of the second 
 degree are clearly distinguishable in the sharply conical 
 wart of cellular tissue (PL XXXIX, fig. 4). As soon as 
 the bud has assumed this form, it produces its first leaf, 
 which like those of the developed plant is a closed, annular 
 sheath of uniform height {a, fig. 4, PL XXXIX). The 
 margin of this sheath is elongated upwards by contempo- 
 raneous division of its cells by means of septa inclined 
 alternately inwards and outwards, and after some time it 
 forms three lobes, which at first are blunt, but soon become 
 pointed (PL XXXIX, fig. 5). 
 
 Contemporaneously with these three pointed processes of 
 the first sheathing leaf the first adventitious root of the 
 germ plant 1)ecomes visible. Originating in the multipli- 
 cation of a cell of the inner tissue of the primary axis, it 
 appears at first in the shape of a small, semicircular knob on 
 that side of the embryo wdiicli is turned away from the 
 secondary leafy shoot (PL XXXIX, fig. 5). The root 
 grows in length by the multiplication of a cell of the interior 
 of its apex like the root of the developed plant, and pene- 
 trates vertically downwards into the tissue of the prothallium 
 (PL XL, figs. 2, 3). At last it breaks through the latter and 
 makes its way for some depth into the soil. A short time 
 afterwards the upward growing leafy shoot is sent forth from 
 the prothallium. It consists of a small number, from ten 
 to fifteen, of elongated intcrnodes. All its sheathing leaves 
 have three teeth, a rule Avhich applies to Equisetum arvense, 
 E.j^ratensc, and U. variefjatum. 
 
 After the prothallium has sent forth the root and the 
 
THE HIGHER CRYPTOGAMIA. 303 
 
 leafy shoot, vascular bundles are formed in the interior of 
 the two organs : in the stem there are three arranged in a 
 narrow circle ; in the root one single axile bundle. In the 
 first node of the germ -plant, at the place where the first 
 leafy branch and the first adventitious root branch off from 
 the primary axis, all the cells into which the vascular 
 bundles of both unite, are transformed into short annular 
 and spiral cells, forming a closed ligneous mass without 
 pith (PI. XXXIX, fig. 6). The primary axis of the embryo, 
 Avhicli is far less developed in the Equisetacea? than in the 
 ferns and Rhizocarpeae, and which now stands at the side of 
 the germ-plant, remains devoid of vessels. Its cells, which 
 now contain much chlorophyll, become elongated upwards. 
 
 When the first leafy branch has reached a certain stage 
 of development, an adventitious bud is produced in the in- 
 terior of its cortical tissue by the multiplication of a cambial 
 cell of its base, at the elevation of the sohd ligneous 
 mass of the first node. This bud is situated on that side 
 of the leafy shoot which is turned away from the primary 
 axis of the germ plant and below the depression formed by 
 the two lobes of the first sheath (PL XXXIX, fig. 6). In 
 its position as well as in its mode of development it corres- 
 ponds entirely Avith the adventitious buds, by which all the 
 ramification of the developed Equisetum is effected. It 
 grows rapidly and vigorously and breaks through the bark 
 of its mother-shoot into the open air. It is distinguished 
 from the first leafy axis by having sheathing leaves with 
 four teeth, and at first also by its pale yellow, ivory-like 
 colour. The new shoot, which is far more vigorously 
 developed than the first shoot, is the second link in the 
 series of shoots originathig from the adventitious buds of 
 the lowest sheaths. It is by means of these latter shoots 
 that the vigorous shoots with many-toothed sheaths and more 
 ample ramifications are produced from the delicate primary 
 stem which bears leaves with three teeth. The basal ad- 
 ventitious buds of the above vigorous shoots at last become 
 fruit-l3earing stems. 
 
 Sometimes the third, and if not the third, one or more 
 of the subsequent principal adventitious buds (by which 
 the duration of the germ-plant is secm-ed) assume in the 
 
304 HOFMEISTER, ON 
 
 course of their development a lateral, or downward direc- 
 tion, passing into the soil, and thus forming the first hori- 
 zontal subterranean rhizome of the Equisetum. The 
 sheathing leaves of this subterranean axis— which produces 
 a large quantity of adventitious roots — have also four teeth. 
 The shoots however which proceed from the bases of their 
 sheaths, of which some grow up to the light, and others 
 pierce vertically downwards to a great depth in the soil, are 
 considerably more vigorous than all the previous ones and 
 bear sheaths with five teeth. 
 
 Adventitious buds are produced at the bases of the 
 upper sheathing leaves of the first shoots of the germ 
 plant. In I^qiii^etioii arvense one or two only and these 
 rarely and irregularly break through the bark of the 
 mother-shoot, and when developed form leafy branches of 
 very limited longitudinal growth. The limited number of 
 whorls (amounting on the first axis to barely three, and on 
 the succeeding axes to not more than four), forms a 
 striking contrast with the rich ramification of the \ege- 
 tative shoots of old individuals. The formation of dwarf 
 shoots occurs only rarely and exceptionally on those 
 branches. 
 
 The development of the germ-plant under favorable 
 circumstances is very rapid and vigorous. Germ-plants of 
 Eq/dsetum arvense, produced from the prothallium in the 
 first week in June, formed by the beginning of August 
 seven generations of shoots, the last of them being then a 
 foot high, and 1 J'" in diameter, though bearing only four- 
 toothed sheaths. The strong side-shoots of subterranean 
 rhizomes became visible about the end of August. 
 
 The reproduction of the Equisetacea3 from spores long 
 remained a mystery. A'aucher'''' in the spring of 1822 
 first brought forward the results of experimental sowing 
 of the spores, and he was followed by J. G. Agardh.f 
 They both saAv only the first stages of development of 
 the prothallia, which Agardh described as cotyledons on 
 account of their two-lobed form. In the following year 
 Vaucher published some observations which gave a full 
 
 * 'Mem. Soc. de Geneve,' i, (1S17) p. 329. 
 •j* 'Mem. du Musee d'Histoire Nat.,' vol. ix. 
 
THE HIGHER CRYPTOüAMIA. 305 
 
 account of the external phenomena of the germmation. 
 Vaucher found* that spores of Bq. Telmatela and palustre, 
 when sown in flower-pots, became swollen, and divided at 
 the apex first into two, and then into several lobes. These 
 lobes sent forth rootlets which affixed themselves to the 
 ground, and ultimately formed bright green patches some- 
 times as much as a line in diameter, and resembling a 
 small Aneura. They remained in this condition for about 
 two months without growing perceptibly. At last a 
 green point grew out from the middle of the patch, which 
 point, as it became larger, exhibited a frill at its base, then 
 a second, and then a third frill, from the apex of which the 
 young stem arose. Vaucher distinguished the two kinds 
 of roots of the prothallium and of the embryo ; he stated 
 that the first formed roots were numerous, although thin 
 and stunted ; but that a vigorous root was produced from 
 the stem of the young Equisetum, and penetrated perpen- 
 dicularly into the ground. 
 
 Vaucher's observations remained for some time quite 
 unsupported. In 1826 Bischoff's experiments only re- 
 sulted in the production of prothallia, all of which after- 
 wards decayed. He showed, however, clearly,! that the 
 processes described by Agardh and Vaucher as cotyledons, 
 were only an imperfect, or intermediate germ-growth (a 
 proembryo or prothallium), which, as in most other cryp- 
 togamic plants, afterwards became transformed into a 
 true embryo. In the autumn of the same year Bischoff 
 supplemented his observations by publishing the result of 
 his examination of some germ-plants of Bq. palmtre, found 
 in the autumn of 1827, in their native habitats. | He 
 observed that the young germ-plants burst forth from the 
 interior of the prothallium, and he disproved Vaucher's 
 statement, — viz., that the root which penetrates into the 
 earth is afterwards transformed into the rhizome — by show- 
 ing that at a very early period the germ-plant produces 
 lateral shoots, whose growth from the commencement fol- 
 lows a horizontal or downward direction. He noticed also 
 
 * 'Mem. d. Musec.,' vol. x, 1823, p. 429. 
 
 t ' Kryptog. Gewächse,' i. Nürnberg, 1828, p. 43. 
 
 % See 'N. A. A. C. L.,' vol. xiv, p. 785. 
 
 20 
 
306 HOFMEISTER, ON TUE HIGHER CRYPTOGAMIA. 
 
 the development of more than one germ-plant out of the 
 same prothallium. At that time he quite overlooked the 
 sexual organs. Thm-et {' Ann. d. So.,' iii ser., 1849, vol. v, 
 p. 5,) gives the first account of the antheridia of Equi- 
 setmn, and the discovery of the archegonia seems to be 
 due to Bischofi". Mettenius mentions (' Beiträge zur Bot.' 
 Heidelberg, 1850, p. 22), that archegonia resembling the 
 defunct archegonia of ferns were found upon a small piece 
 of a prothallium which he saw in Bischofi"s possession. Milde 
 in 1850 ('Linnaea,' xxiii, p. 545), gave a more complete 
 account of the structure of the antherida and spermatozoa. 
 A little later I myself explained the development of the anthe- 
 ridia and spermatozoa, and figured the first stages of deve- 
 lopment of the archegonia (' Vergl. Unters.' Leipz., 1851, p. 
 102, PL XX, fig. 62). Soon afterwards, Milde also observed 
 the neck of the archegonium, but without knowing what it 
 was ON. A. A. C. K,' xxiii, 641). In 1852 I observed 
 the development of the embryo (' Plora,' 1852, p. 385), 
 and almost at the same time Milde discovered arche- 
 gonia, and he published his observations soon after mine 
 (' Flora,' 1852, p. 497). I made some further remarks 
 upon my previous observations in the fourth volume of the 
 ' Transactions of the Royal Society of Saxony,' p. 168. 
 
CHAPTER IX. 
 
 OPHIOGLOSSE^. 
 
 The germination and development of Botri/chium Lunaria Sw. 
 
 The Moonwort germinates imderground. Germ-plants* 
 are sometnnes found in the neighbourhood of full-grown 
 individuals in places where the plant is common. They 
 are not unlike torn fragments of bj-anched roots of the 
 plant itself (PI. XLII, figs. 2 — 5), but upon careful exami- 
 nation they are found to be organically closed at all ends. 
 At the point of junction of the roots, a prominent knob 
 is found (PI. XLII, figs. 4, 5). A microscopical analysis 
 of the latter leads to the discovery of a bud buried in 
 a deep, almost closed depression. In September, 1854, 
 Irmisch and I discovered at a depth of from one to three 
 inches under the surface of the earth, not only a series 
 of productions undoubtedly transitional between germ- 
 plants and full-grown Botrychia, but also germ-plants, to 
 which the prothallium was still attached. The prothallium 
 of Botrychium (PI. XLI, fig. 5), is an oval mass of firm 
 celkilar tissue, whose larger diameter does not exceed half 
 a line, and is often less. It is hght brown on the outside, 
 yellowish-white on the inside, and furnished on all sides 
 with scattered, rather long, capillary roots. The cells, 
 whose size diminishes from the middle of the prothallium 
 towards the periphery, are filled with large and small lumps 
 
 * The germ-plants upon wliicli these observations were made came from the 
 iieiglibourliood of Sondershauseu. I am indebted to my friend Professor 
 Irmisch for them. 
 
308 HOt'MKISTER, ON 
 
 of a semi-transparent substance, which is not rendered 
 blue by iodine. On the side turned towards the surface 
 of the earth the prothalHuni mostly produces antheridia, 
 and on the opposite side archegonia. The former have the 
 appearance of cavities in the mass of the prothallium, which 
 open outwards wdth a very narrow mouth (PL XLI, figs. 
 5, 6, 10*.) The spennatozoa are hardly distinguishable 
 from those of the Polypodiaceae, except in being half as 
 large again as the latter. The walls of empty antheridia arc 
 coloured light brown, and are covered w'ith a granular sub- 
 stance. The archegonia (PL XLI, figs. 5, 10''), are en- 
 tirely buried in the prothallium, but agree in other respects 
 w ith those of the ferns. Spores sown artificially swelled to 
 twice their natural size, but underwent no further change. 
 The membrane of a spore thus swollen was found attached 
 to a prothallium, and was recognisable by the three promi- 
 nent ridges of the outer surface, which meet at angles of 
 120° (PL XLI, fig. 7). 
 
 The position of the embryo with regard to the prothal- 
 lium differs widely from what occurs in the Polypodiaceae 
 and Rhizocarpea?. Botrychium in this respect is allied to 
 those vascular cryptogams, whose prothallium, like that of 
 the Ophioglosseae, is devoid of chlorophyll (Isoetes, Selagi- 
 nella). The punctum vegetationis of the embryo lies near 
 the apex of the central cell of the archegonium. The first 
 roots originate underneath it near the base of the archego- 
 nium (PL XLI, fig. 6*; PI. XLII, fig. 1*). In con- 
 sequence of the downward direction of the mouth of the 
 archegonia, the embryo has to turn half round in order to 
 give its bud an upward direction, so that the prothallium 
 is found attached to it laterally. The youngest germ- 
 plants found attached to prothallia, exhibited at least 
 two roots, and also near the punctum vegetationis, a more 
 or less developed hemispherical or oval knob (PL XLI, figs. 
 8 — 10). The outside of the latter (on account of the 
 colour) bears only a distant resemblance to the roots : its 
 internal structure differs widely from theirs : the hemi- 
 spherical body consists of wide parenchymatal cells, which 
 become gradually smaller and fiatter towards the outer 
 surface : a rudimentary vascular bundle consisting, with 
 
THE HIGHEH CRYPTOGAMlA. 309 
 
 the exception of vessels, only of thin-walled prosenchymatal 
 cells, extends from the nearest vascnlar bundle of the root 
 for a short distance into the mass of cellular tissue. This 
 structure, and also the position of the knob on the germ- 
 plant, correspond exactly with the structure and position of 
 the organ found on the embryo of the Polypodiacese and 
 of other vascular cryptogams, which I have treated, as the 
 continuously developing primary axis of the embryo — with 
 the primordial tissue of the embryo, which bears on its lateral 
 surface the formative cells for further development.*^ 
 
 In Botrychium this primary axis, if nnusually developed 
 in thickness, may protrude laterally out of a fissure of the 
 prothallium. The roots originate above the knob, the 
 oldest and longest of them beino; the nearest to it. The 
 direction of the roots is usually opposite to that of the 
 knob. The punctum vegetationis — the growing end of the 
 secondary axis of the embryo — occupies the highest point 
 of the germ-plant (PL XLT, fig. 10*; PL XLII, fig. 1'). 
 This bud, which consists of a flatly-conical group of thin- 
 walled cells, is situated at the base of a narrow, short, trans- 
 verse fissure in the blunt apex of the germ-plant, i. e., the 
 narrow opening of the vaginated scale-like first frond 
 of the latter (PL XLII, fig. 1*). Germ-plants less deve- 
 loped than those above described were also found in quan- 
 tities (PL XLII, figs. 2, 3). They consisted only of the 
 globular knob, and the first or the first and an incipient 
 second root. The punctum vegetationis lay immediately 
 on the upper surface of the knob. In these plants no 
 trace of the prothallium could be perceived. They were 
 probably of the same age as those above mentioned, but 
 stunted and arrested in their development. 
 
 The nature of the punctum vegetationis of the germ-plant 
 of Botrychium is a matter of special interest, inasmuch as it 
 must afford material assistance in deciding which of two 
 opposite opinions is the correct one. Röperf assumed that 
 the true stem rises vertically, but owing to the non-deve- 
 lopment of the internodes, imperceptibly ; that it produces 
 two leaves or fronds every year, whose stalks grow together 
 
 * 'Griesebacb Jahresber.,' 1852, p. 40J;. 
 
 t 'Linrisea/ vol. i, p. 460; 'Flora Mecklenbergs,' vol. i, p. 110. 
 
310 HOFMEISTER, ON 
 
 upwards for some distance, and consequently enclose the 
 true apex of the stem, together with the bud which consists 
 of tAVo leaves corresponding with the former in every 
 respect. Presl (' Tent, pterid,' suppl., p. 41) has modified 
 this view. He considers the fertile and the sterile frond as 
 only segments of one and the same leaf, the under segment 
 of which becomes fruitful, whilst the upper remains leaf- 
 like. Mettenius (' Farrne des botan. Gartens zu Leipzig,' 
 1856, p. 119) and Roper also quite lately ('Bot. Zeit.,' 
 1859, p. 244) have arrived at the same opinion. Braun,* 
 on the other hand, asserts that " the cellular body from 
 which in Ophioglossuni the leaves are produced cannot be a 
 special sheathing leaf, nor even of the nature of a stipule or 
 ligule, but it is a cellular body which smTOunds the centre 
 of growth, and inside which the leaves are formed in suc- 
 cessive spirals, and there remain. Within this body each 
 leaf forms its own cell, which enlarges with the growth of 
 the leaf, and becomes gradually elevated in a conical form, 
 and ultimately pierced in a sheath-like manner. The fruc- 
 tification of Ophioglossuni is axillary ; it is the only leaf 
 which comes to perfection from, a bud in the axil of a sterile 
 leaf. .... Botryclnum does not possess the enve- 
 loping cellular body, but on the other hand, in this genus, 
 the leaves form their own sheaths." I have myself at- 
 tempted to show that the most striking feature sug- 
 gested by Braun exists also in Botryclnum, for I assumed 
 that each of the contemporaneously developed pairs of 
 fronds originated in an entirely closed cavity, being the base 
 of the next older i)air of fronds. According to this the 
 stem of Botrychium would be a sympodium of the basal 
 portions of successive yearly shoots. f Schacht also agreed 
 in this view when he asserted that Botrychium was repro- 
 duced only by adventitious buds.i 
 
 These notions, however, are founded in an error, easily 
 accounted for by the want of transparency of the tissue. 
 This eiTor consists in omitting to observe the very narrow 
 points of junction of the cavities of the pairs of fronds as 
 
 * 'Flora,'] 839, p. 301. 
 t 'Vergl. Unters.,' p. 88. 
 ?^ 'Dio rflnnzeuzelle,' p. 30 i. 
 
THE HIGHER CRYPTOGAMIA. 311 
 
 well inter se as with the atmosphere, and with the (hitherto 
 entirely unobserved)* depressed empty space above the 
 vegetative centre or terminal bud of the stem. 
 
 The second and the third frond also of the germinating 
 Botr}' chium are scale-Uke, of a whitish colour, and composed 
 of elono-ated cells containino- very little solid matter : never- 
 theless the second frond soii/efimcs, the third cdwai/s, have a 
 greenish tip (PI. XLII, fig. 9), which is the first indication 
 of the lamina of the frond. In the foarth frond this green 
 portion is more fully formed : it contains on either side two 
 or three feathery flaps, between the lowest of which the 
 rudiment of the fertile frond makes its first appearance in 
 the form of a hemispherical protuberance. It produces only 
 a few, usually two, simple ramifications. This pair of 
 fronds, after breaking through the sheathing portion which 
 forms the principal mass of the third frond, rises above the 
 surface of the earth during the next vegetative period, and 
 represents a diminutive moon-wort, not differing essentially 
 from the older ones. It is not yet ascertained whether, 
 during the subterranean growth of the germ-plant, one only 
 of the scale-like fronds is developed yearly, as is the case 
 with full-grown plants. It is very unlikely that such should 
 be the case : the formation of the first, second, and third 
 fronds probably takes place in the first vegetative period of 
 the germ-plant, which consequently would develope in the 
 second year the first green frond, and at the same time the 
 first spore-bearing frond. 
 
 Each new pair of fronds makes its appearance near the 
 almost smooth end of the stem of the full-grown plant in 
 the form of a minute flatly-conical protuberance. The 
 basal sheathing portion is first developed by active multi- 
 plication of the cells, especially in the direction of a plane 
 passing through the median line of the organ and radial to 
 the longitudinal axis of the stem, so that the rudiment of 
 the pair of fronds destined to be developed in the third fol- 
 lowing spring covers the terminal bud of the stem, like the 
 cotyledons of a liliaceous plant. The apex of the frond- 
 
 * This circumstance was not noticed by Presl and IMettcnius, but was ob- 
 served by Roper in a paper -nliicli appeared after the publicatiou of the above 
 observations. (See ' Bot. Zeit.,' 1859, p. 242.) 
 
312 HOFMEISTER, ON 
 
 rudiment is at this time almost hemispherical, witliout a 
 trace of a division. The fore-edge of the base of a frond is 
 not in organic connexion with the tissue of the end of 
 the stem upon which it rests ; at this place there is a low 
 but tolerably wide fissure (PI. XLII, figs. 10^ 11). In the 
 second summer a flat cellular mass first makes its appear- 
 ance out of the rounded apex of the frond-rudiment : this 
 is the rudiment of the sterile frond, upon which the lowest 
 pinnae of the lamina first make their appearance. Whilst 
 the next four, five, or six segments of the sterile frond are 
 making their appearance on the continually-elongating end 
 of the cellular body, (and frequently also at an earlier period), 
 a button-shaped cellular protuberance becomes visible close 
 underneath, and almost between, the oldest pinnae of the 
 sterile frond ; this is the rudiment of the fertile frond (PL 
 XLII, fig. 2). So far the pair of fronds is developed up to 
 midsummer of the second year. The further development 
 remains dormant until the following spring. During this 
 time the transverse fissure which divides the fore edge of 
 the sheathing base of the frond from the underlying tissue 
 continues still open for a short space ; it forms a direct 
 communication between the hollow spaces which enclose 
 the pairs of fronds for the second and third following years 
 and the terminal bud. The transverse fissure first disap- 
 pears during the vegetative period in which all the parts 
 of the pair of fronds are completed, — twelve months be- 
 fore the final appearance above ground, — whilst the rami- 
 fications of the fertile frond proceed from the protuberance 
 in front of the points of insertion of the lowest segments of 
 the barren frond. The development, as in the barren frond 
 and in the fronds of ferns, is centrifugal.* 
 
 Dcvelojjme/d of the vegetative or(/ans of Ophiofjlossum 
 vid(/atum. — The thick covering of cellular tissue which sur- 
 
 * Roper has made an interesting observation (' Bot. Zeit.,' 1859, p. 257), 
 viz., tliat jjlanls of Botrychium Lunaria growing in loose sandy ground sometimes 
 exhibit lateral ramifications on the subterranean stem, originating, it would 
 seem, from the formation of adventitious buds underneath the base of the frond. 
 The growth of these lateral branches resembles to a great extent that of germ- 
 plants, inasmuch as at first they form scaly leaves only, and ultimately, when a 
 leaf first appears above ground, fertile and barren segments are formed contem- 
 poraneously. 
 
THE HIGHER CRYPTOGAMIA. 313 
 
 rounds the young undeveloped frond of Opliioglossnm is 
 not entirely closed. On tliat side of it which is tiu'ned to- 
 wards the next older frond (which has broken out of its 
 covering) it exhibits a narrow opening surrounded by a 
 tuft of jointed hairs constituting in this plant the only 
 appendicular organs of the epidermis (PI. XLI, fig. 1). On 
 the inside also the hollow space which covers the oldest of 
 the enveloped fronds is not closed. A narrow cylindrical 
 passage leads from its fore-side into the cavity which en- 
 closes the next younger frond, and from this in like manner 
 into the cavity in which the frond destined for development 
 in the third following year is produced ; and lastly the 
 latter is in open communication with the narrow space 
 above the flat end of the stem (PL XLI, figs. 1, 2). 
 
 The fi'onds surround the end of the stem in a | left 
 handed spiral, as may be clearly seen in transverse sections 
 of the stem at the place where the vascular bundle which 
 passes from the cylinder of vasciüar bundles obliquely up- 
 wards to the fronds, traverses the cortical parenchyma 
 (PI. XLI, figs. 3, 3*). The young frond makes its appear- 
 ance near the depressed, almost flat end of the stem, in the 
 form of a slender conical knob, from the fore side of which 
 a fleshy flat stipule-like excrescence, as in Marattia, is pro- 
 duced (PI. XLI, fig. 2*). This cellular mass developes in 
 breadth more vigorously than the part of the frond which 
 is situated above its place of attachment. It embraces 
 about two fifths, and the frond about one third, of the zone 
 of the stem upon which they both stand. The axile stipule 
 attaches itself by its fore edge to the front surface of the 
 stipule of the obliquely-opposed next older frond and at 
 its lateral edges it amalgamates immediately with the 
 stipules of the adjoining older fronds to the right and left,* 
 which stipules have already amalgamated inter se, and pro- 
 trude considerably beyond the youngest frond behind which 
 they stand. By this means the hollow space is formed 
 which encloses the young frond. The walls of the cavity 
 are derived from four different sources. The wall which is 
 turned towards the front surface of the enclosed frond con- 
 
 * The second and third, reckoned backwards from the frond of which we 
 are speaking. 
 
314 HOFMEISTER, ON 
 
 sists, in its lower portion, of the hinder side of its own par- 
 ticular stipnle, and in its upper portion, of the stipule of 
 the next older frond. The greater part of the wall which 
 is turned towards the hinder side of the frond, is composed 
 of the front surface of the stipule of the third youngest 
 frond, and the remainder of the latter wall is formed of 
 the front surface of the stipnle of the second youngest frond. 
 The different stipules amalgamate at all points of contact 
 with the exception of those points which are coincident 
 with a line perpendicular to the apical cell of the stem. 
 Consequently there remains a very narrow open canal 
 leading to the apex of the stem into which the different 
 cavities enclosing the fronds debouch by a small opening 
 (PI. XLI, figs. 1, 2). 
 
 If a careful section be made through that part of the 
 stem in which the punctum vegetationis lies, the three- 
 sided apical cell of the stem is seen at the base of the 
 canal* leading to the punctum vegetationis, smTounded by 
 the youngest secondary cells (PI. XLI, fig. 4j. Longitu- 
 dinal sections through the terminal bud (PL XLI, fig. 2'0- 
 exhibit most distinctly the deep depression of the apex of 
 the stem into the prematurely developed peripheral tissue ; 
 a phenomenon which, here as elsewhere, depends upon an 
 early vigorous diametral cell-multiplication accompanied 
 by a very slight almost obsolete longitudinal ceU-multipli- 
 cation. 
 
 The course of the vascular bundles of Ophior/Jossum is 
 simple ; they form a cylindrical net, one of the meshes of 
 which corresponds with each frond, and sends out to the 
 frond a vascular bundle from its apical angle. Frequently, 
 however, all the cellular tissue which fills up the 
 meshes is transformed into scalariform vessels, so thai the 
 stem then, for considerable distances, exhibits a closed 
 cylinder of vessels. Sometimes this condition is found only 
 in one longitudinal moiety of the stem, whilst in the 
 other the distribution of the meshes of the vascular bundles 
 is the same as in the neighbourhood of buds. Roots — re- 
 markable for the slight development of the root-cap — spring 
 
 * The canal is somewhat enlarged above the punctum vegetationis. 
 
THE HIGHER CRYPTOGAMIA. 315 
 
 from the bundles adjoining the sides 'of the meshes of the 
 reticulated vascular bundles of the stem ; their position 
 with, regard to the fronds is not a definite one. Op/no- 
 r/Iossum vidgatum (like 0. 2^Gdunculosum'), is often repro- 
 duced by root-buds. The new plant is reproduced by 
 the multiplication of a camlual cell of the vascular bundle 
 which traverses the longitudinal axis of the widely-creeping 
 adventitious root, and is at first concealed in i\\Q cortical 
 parenchyma of the root. However, this mode of repro- 
 duction is not so essential for the economy of the plant as in 
 0. pedimciilosicm, a species which may be called mono- 
 corpous, inasmuch as its shoots usually die off when they 
 have brought fortli sporangia : its perennial duration rests, 
 it may be said, exclusively upon the adventitious shoots of 
 the roots.* 
 
 The appearance of fertile fronds on the front surface of 
 the sterile ones is the same in Ophioglossum as in Botry- 
 chium, and justifies the same conclusion, viz., that the 
 fertile frond is a shoot of the sterile one. 
 
 Mettenius has published some observations upon the 
 germination of Ophioglossum (^ Farrne des Leipz. Botan. 
 Gartens,' Leipzig, 1856,' p. 119). He found the sub- 
 terranean prothallia and germ-plants of Oßhio^Iossum 
 peiulunciilomm growing in the neighbourhood of the 
 mother-plants. Artificial sowings of the sjDores were un- 
 successful. The youngest prothallia which he found con- 
 sisted of a small globular knob, of from \' to 1|- lines 
 in diameter, from which a conical prolongation of about 
 two lines in length proceeded. The delicate-walled cells of 
 the parenchymatal tissue of this knob were filled with 
 amyloid granules : the superficial cells, and the capillar}'^ 
 roots proceeding from them, were already dead. The 
 formation of the knob was thus already ended, and the 
 growth of the prothallium limited to the prolongation, 
 whose cells filled with thick protoplasm, were in an active 
 state of division. In older prothallia the prolongation 
 attains a considerable length, as much as two inches. Its 
 growth arises from the repeated division of a single apical 
 cell by means of oljlique septa. The daughter-cells ap- 
 * Like Tyrola uniflora. See Irmiscli in 'Bot. Zeit.,' 1856. 
 
316 HOFMEISTER, ON 
 
 peared in some prothallia to be arranged in three rows. 
 Slender prothallia consist throughont, even in the cylin- 
 drical poi'tion, of tissue homogeneous with that of the knob. 
 In thicker prothallia a string of cells in the axis of the 
 cylinder attains to double the length of the cells of the 
 peripheral tissue. The former contain only a few 
 amyloid granules ; the latter are quite filled Avitli them. 
 Dichotomous prothallia were but rarely seen, and a repe- 
 tition of the division of one of the branches was of still rarer 
 occurrence. When in a normal position the apex of the 
 prothallium tends to grow to the surface of the ground. As 
 soon as it reaches the light it assumes a green colour, the 
 amyloid granules receiving a covering of chlorophyll. 
 The effect of light seems to be to limit the further growth 
 of the prothallium : the protruding apex either dies, or 
 becomes flattened, or divides into two or three small lobes, 
 which develope themselves no further. Antheridia and 
 archegonia are met with on the same prothallium without 
 any definite number or arrangement. They are either 
 altogether wanting on the knob, or are present in small 
 numbers at the base of the prolongation. They are always 
 plentiful upon the latter. Slender prothallia produce more 
 antheridia than archegonia : in vigorous prothallia the 
 archegonia are most numerous. The development of the 
 sexual organs progresses from the base of the prothallium 
 towards its apex. Their structure entirely resembles that 
 of the same organs in Botrychium. The youngest ob- 
 served embryos are ellipsoidal bodies consisting of few cells. 
 That end of the rudiment of the embryo which is turned 
 towards the apex of the prothallium forms the first leaf; the 
 opposite end forms the first adventitious ]-oot. Both cause 
 an expansion of the surrounding tissue ; the leaf makes itself 
 a passage for a longer or shorter distance into this tissue, 
 sometimes penetrating, with a turn downwards, as far as the 
 knob, and growing through it. After its egress the leaf is 
 enclosed by the drawn-out portion of the prothallium. Its 
 fore-surface is turned towards the apex of the central cell of 
 the archegonium, a circumstance in Avhich it agrees with 
 Botrychium, and differs from the Polypodiaceae and Rhizo- 
 carpeae. The first root, as soon as it is formed, bends out- 
 
THE HIGHER CRYPTOGAMIA. 317 
 
 wards, and pierces through the prothallium. Towards the 
 base of the central cell of the archegonium the rudiment of 
 the embryo is developed into a rounded inconspicuous 
 swelling, consisting of wide cells filled with amylum. 
 This swelling is the continuously-developing primary axis 
 of the embryo. 
 
CHAPTER X. 
 
 PTLULARIA GLOBULIFERA AND MINUTA ; MARSILEA 
 PUBESCENS. 
 
 The fruit of Pilularia is the transformed end of a furcate 
 brancli, wliicli is apparently produced in the axil situated 
 between one of the long thin fronds and tliejprincipal axis, 
 and which in Pilularia mimita is usually a lateral bud 
 situated in one of the normal bifurcations of the stem. In 
 P. miuuta it forms when in the very young state, a globular 
 mass of delicate homogeneous cellular tissue flattened at the 
 apex. An outer layer of celliüar tissue, composed of four 
 layers of cells, surrounds two lenticular cavities which are 
 separated fi'om one another by a thick septum. The inner 
 side of the outer wall bears the rudiments of sporangia. In 
 this species, even at this early period of development, no 
 traces of the junction of the amalgamated parts are visible 
 at the apex of the fruit (PI. XLIV, fig. S). In the young 
 fruit of Pilularia glohulifera the commissures of the fom* 
 delicate cross septa of the divided chambers exhibit very 
 manifest lines of junction, which, in the half developed fruit 
 (upon the outer wall of which numerous hairs are formed) 
 are still unclosed. Here also clavate masses of cellular 
 tissue, the first rudiments of the sporangia, spring out of 
 the inner wall of the outer surfaces of these chambers. In 
 Pilularia mimita there are only two or three of these masses, 
 in other species as many as eight Aertically one over the 
 other. The wider end of the very young sporangia, which 
 is borne by a short thick stem, exhibits a large central cell 
 surrounded by a double layer of smaller cells (PI. XLIV, fig. 3). 
 
HOFMEISTER, ON THE HIGHER CRYPTOGAMIA. 319 
 
 The central cell divides into two (PI. XLIV, fig. 4), 
 and each of the cells thus formed divides repeatedly 
 into two cells turned towards all three directions of space. 
 The cells of the two enveloping layers meanwhile divide only 
 by septa perpendicular to the outer surface. The sporan- 
 gium thus becomes a globular mass of large cells enclosed 
 by a double layer of smaller tubular cells, and borne upon 
 a very short cylindrical stem. The larger cells — the 
 mother-cells of the spores — isolate themselves during the 
 further growth of the fruit ; the cells of the inner layer of 
 the covering produce in the mean time numerous free small 
 cells in their interior, which, as the membranes of their 
 mother-cells divide, escape from the latter into the inner 
 cavity of the sporangium (PI. XLIV, fig. 5) : at a later 
 period they are absorbed. Each spore-mother-cell when it 
 has become free divides contemporaneously into four 
 daughter-cells which are the special mother-cells of the 
 spores. This stage of development is attained at an earlier 
 period by the lower sporangia than by the upper ones. 
 After the walls of the special mother-cells have increased 
 considerably in thickness, a spore is produced in each of 
 them (PL XLIV, figs. 6, 10, 11). Up to this point all 
 the sporangia behave alike. From this time however the 
 further development of the lowermost sporangium of each 
 compartment of the fruit differs very materially from that 
 of the others. In the sporangium in question the special 
 mother-cells and spore- cells (which are arranged in sets of 
 four) all die slowly off" except one (or two). The spores of 
 the one set which remains soon become free by the absorp- 
 tion of the walls of the inother-and special-mother-cells, and 
 assume a globular form. At first all four increase rapidly 
 ill size (PI. XLIV, fig. 7); their walls then become much 
 thickened but unequal-sided, so that the globular inner 
 cavity of the young spore becomes excentric (PI. XLIV, 
 figs. 6, II). The growth of one of the spores soon exceeds 
 that of the others. The former alone continues to develope 
 itself, whilst the growth of the others is arrested, and ])eing 
 puslied aside — like the remains of the mass of special 
 mother-cells — by the one growing spore, they are soon dis- 
 solved. When the fruit is ripe the large spore occupies the 
 
3^0 HOFMEISTER, OX 
 
 entire cavity of the sporangium, whicli in the mean time 
 has become much enlarged. The shape of the spore changes 
 during its growtli from that of a globe into a short pear- 
 like form (PI. XLIV, %s. 12, 13, U), and from the latter 
 into that of an oval, slightly constricted at the equator 
 (PI. XLIII, fig. 1). In its narrow end, which is turned 
 towards the apex of the sporangium, its nucleus is found 
 embedded in a mucilaginous layer which clothes the w^all. 
 
 By the time the spore has become globular a transparent 
 outer membrane is distinguishable, differing from the deli- 
 cate inner w^all. Afterwards a second membrane, composed 
 of prismatic closely appressed columnar cells, is formed 
 upon this inner layer of the outer membrane. These 
 columnar cells are very short at the base of the spore, much 
 longer in its upper third part, but altogether Avanting at 
 the apical point of the spore. The ripe spore is clothed by 
 a thick gelatinous layer, the component parts of which are 
 also prism-shaped. This layer also does not cover the apex 
 of the spore, to which there is access Ijy a funnel-shaped 
 passage through the gelatinous layer (PI. XLIII, figs. 1, 7). 
 The glassy inner layer of the outer membrane extends 
 beyond the apex of the ripe spore in the form of a 
 conical arch, open at the tip. It appears torn into nu- 
 merous — in Filidaria f/Ioht/Iifera as many as eight — three- 
 sided shreds. 
 
 The spores which originated in the upper sporangia 
 are transformed jointly and severally into much smaller 
 globular spores, exhibiting at their apices three fissm-es 
 of the exosporium, meeting at angles of 120°. These 
 fissures point out the edges of contact of four spores 
 inside a set of special mother-cells. In Pihdaria minaia 
 the small spores also are clothed with a gelatinous layer, 
 which is w^inting in those of P. ylohulifera. No trace 
 of a nucleus is visible either in the large or small spores 
 when ripe. The contents of both consist of a mass of 
 albuminous fluid containing numerous firm granules of a 
 substance rendered brown by iodine, as well as oil-drops 
 and starch-grains. In the large spores the starch-grains, 
 Avhich are of a great size, exhibit manifest lamination, and 
 a central cavity with fissures proceeding from it. In the 
 
THE HIGHER CRYPTOGAMIA. 331 
 
 small spores the starch grams are exceedingly small and 
 exhibit no strncture. 
 
 The ripe fruit of PiMaria glohulifei-a splits into four 
 valves. The sporangia burst by the vast expansion of the 
 internal jelly produced by the dissolution of the special 
 mother-cells ; the jelly becoming distended by the absorp- 
 tion of water. Numbers of large and small spores thus 
 become fi'ee. 
 
 A few hours after this process the germination of the 
 large spores commences. The first indication of this is the 
 appearance of a lenticular agglomeration of finely granidar 
 protoplasm on the inner side of the apex of the spore, 
 underneath the pyramidal arch formed by the triangular 
 lobes of the inner membrane. This mass of protoplasm is 
 soon clothed with a membrane, and then constitutes a very 
 flat cell with a circular outline (PI. XLIII, fig. 2). Shortly 
 afterwards, before the expiration of twenty-four hours, the 
 conical cavity formed by the lobes of the glassy layer of 
 the outer spore-membrane appears to be filled by a cellular 
 body, consisting of a large central cell surrounded by a 
 simple layer consisting of a few tabular cells (PI. XLIII, 
 figs. 3, 3*, 5). I did not succeed in finding the intenne- 
 diate stages between this condition and the one previously 
 described, but I do not doubt that this cellular body is pro- 
 duced by repeated bi-partition of the lenticular cell which is 
 arched above. The lenticular cell may be first divided into 
 four, by the production of septa cutting one another at right 
 angles. It is probably one of these four cells, which — 
 being divided by a diagonal septum inclined inwards — gives 
 i-ise to the formation of the central cell, which latter cell 
 growing more vigorously than the rest, soon occupies the 
 middle point of the cellular body, and is covered by the 
 other four cells which in the mean time have divided by 
 septa perpendicular to the outer surface (PI. XLIII, fig. 3). 
 The central cell afterwards divides into a lower, flat, tabular 
 cell, and an upper, spherical one. The lower tabular cell 
 soon divides by repeated bi-partition into fom' (PL XLIII, 
 fig. 5), then into eight, and afterwards into twelve cells. In 
 the lower part of the prothallium thus formed, the cells 
 which surround the sides of the larger central cell ultimately 
 ^ 21 
 
322 HOFMEISTER, ON 
 
 divide by septa parallel to tlie outer surface (PL XLlil, 
 figs. 7 — 9). The four cells which project beyond the apex 
 of the larger cell expand above in a papillate manner 
 (PI. XLIII, fig. 5), after which each of them divides by a 
 transverse septmn (PL XLIII, fig. 4). All the cells of the 
 prothallium, Avith the exception of these papillate cells and 
 the large central one, form chlorophyll granules in their 
 interior. 
 
 The increase in the circumference of the pro-embryo causes 
 a bending back of the smTounding pointed shreds of the inner 
 layer of the outer spore-membrane. The pro-embryo be- 
 comes visible in the form of an emerald-green wart at the 
 apex of the germinating spore. The four papillate cells at 
 the apex of the pro-embryo, and their four basal cells, now 
 part asunder at the commissm'C, and thus an open canal, 
 leading to the large central cell of the pro-embryo, is pro- 
 duced (PL XLIII, figs. 8, 9). Some of the papillate cells 
 sometimes divide now by a second transverse septum 
 (PL XLIII, fig. 9). A daughter- cell is in the mean time 
 formed within the large central cell, the contents of which 
 latter cell are finely granular and mucilaginous. This 
 daughter-cell soon after its formation almost entirely fills 
 the mother-cell (PL XLIII, figs. 8, 9). The central cell of 
 the prothallium, and the four projecting cells, constitute the 
 archegonium. The prothallium of Pilularia ne^er produces 
 more than one archegonium. 
 
 The development and structure of the prothallium of 
 F. viinuta entirely resemble those of F. (jlobulifera as far 
 as my observations extend, with the single exception that 
 the base of the prothallium in the former is somewhat more 
 strongly constricted than in the latter, so that the prothal- 
 lium appears more spherical. 
 
 The small spores swell slightly after becoming free. The 
 outer spore-membrane splits at the apex, forming three 
 fissures, the direction of which corresponds to the edges of 
 contact of the spore with the three sister-spores produced 
 in the same mother-cell. The inner spore-membrane 
 bursts, and some small spherical cells escape from the 
 inner cavity of the spore ; these cells contain small starch- 
 grains and a lenticular vesicle attached to the wall (PL 
 
THE HIGHER CRYPTOGAMIA. 323 
 
 XLIII, ng. 6). The lenticular vesicle encloses a very thin 
 spermatozoon rolled up in three or four coils, which soon 
 exhibits a rotatory motion in the interior of the enveloping 
 cell. By rupture of the cell- wall it ultimately becomes 
 free (PL XLIII, fig. 6*), and moves about in the water 
 with helicoid contortions. Its fore-end, which is hardly 
 thicker than the othe]', carries a few oscillating cilia (PI. 
 XLIII, tig. 6, c — -f). I have observed the actual entrance 
 of the motile spermatozoa into the mouth of the archego- 
 nium (PL XLIII, fig. 7). 
 
 A short time after the appearance of the spermatozoa in 
 the neighbourhood of the large germinating spore, the large 
 cell produced in the central cell of the prothallium appears 
 divided into a few cells. The arrangement of these cells 
 shows that their formation results from repeated division 
 of the mother-cell by means of septa at right angles to a 
 plane passing through the longitudinal axis of the archego- 
 nium (PL XLIII, figs. 10, li). The cells of the prothal- 
 Hum, with the exception of the four papillate cells, multiply 
 in the mean time actively in all three directions of space, 
 especially the cells of the lower portion. Repeated divi- 
 sion also occurs in the cells of the few-celled body enclosed 
 in the prothallium, which body is the rudiment of the 
 new plant, or embryo ; and the result is, that the latter 
 soon becomes a body composed of very small cubical cells, 
 and having the form shown in PL XLIII, figs. 12, 13. 
 
 That end of the embryo which is turned away from the 
 cavity of the large spore, and which points obhquely up- 
 wards, soon exhibits a more active development than is 
 seen in its other parts. It is transformed into a cone which 
 becomes continually more pointed as its development pro- 
 gresses. The multiplication of the cells is caused by con- 
 tinual division of the apical cell by difi'erently inclined septa, 
 and by the division of the cells of the second degree thus 
 produced, by radial septa, and then by septa parallel to the 
 longitudinal axis of the cone. The mode of cell-multiplica- 
 tion resembles in its essential features that of the first frond 
 of the Polypodiacese (PL XLIII, fig. 15). A similar cell- 
 multiplication, which at first, however, is very slow, takes 
 place immediately underneath the place of origin of the 
 
324 HOFMEISTER, ON 
 
 cone just mentioned (the first frond). Near it, at the oppo- 
 site end of the embryo, a similar but shorter mass of cel- 
 hilar tissue soon begins to protrude (PL XLIII, fig. 15). 
 This is the first root, an adventitious root, differing in no 
 respect from those which afterwards appear in numbers. It 
 grows, like the adventitious roots of the Polypodiaceae and 
 Equisetaccae, by division of a cell in the interior of the 
 tissue nearly imderneath the apex of the organ. Tiiis divi- 
 sion is produced partly by septa almost parallel to the 
 basal surface, which is tm-ned towards the apex of the root, 
 and partly by septa parallel to the lateral surfaces which 
 converge at an obtuse angle. The cells of the second 
 degree which lie towards the apex of the root have tlie 
 form of a meniscus ; their first division takes place by a 
 vertical septum bisecting the cell, after which a septum is 
 formed cutting the one last formed at right angles. The 
 four cells thus formed divide several times by longitudinal 
 septa, but not by transverse septa (PI. XLIV, lig. 2"). 
 The part of the root underneath the punctum vegetationis 
 grows much slower than tlie part above it. Close above 
 the punctum vegetationis the four outer cellular layers of 
 the root separate from the two axile ones, and an annular 
 air-cavity is produced. A similar air-cavity is formed in 
 the first frond, even in its early youth (PI. XLIV, fig. 1). 
 The cells of the protliallium enclose the embryo on all sides 
 even during the development of the first frond and the first 
 root ; they are nuicli extended in the direction of the 
 length of this organ, and gradually compressed and ab- 
 sorbed even up to the outermost layer. Contem])orane- 
 ously with the first appearance of the root, the part of the 
 embryo which is turned towards the large cavity of the 
 spore, and separated froni the latter by a simple cellular 
 layer, becomes strongly concave (Plate XLIV, fig. 1). 
 During the further development of the embryo it becomes 
 more and more arched, until at last it has assumed the form 
 of a short conical cellidar mass enclosing an elongated pear- 
 shaped cavity in connexion with the interior of the spore 
 (PI. XLIV, fig. 2). The cellular layer of the prothalluun 
 which encloses this cavity is afterwards dissolved. The 
 distended portions of the proembryo which enclose the 
 
THK HIGHER CRYPTOGAMIA. 325 
 
 first frond and the first root as it Avere with a sheath, are 
 ultimately unable to keep pace with the growth of the 
 latter. These portions are ruptured, and the apices of the 
 frond and of the root become free. Almost at the same 
 time the second frond appears near the place of origin of 
 the first frond, and separated from it by the blunt end of 
 the future principal axis : it has the form of a conical wart 
 (PI. XLIV, fig. 2), which by continual multiplication of the 
 cells of its apex grows rapidly in length. 
 
 As the plant becomes further developed the joints of the 
 stem elongate considerably : the terminal bud remains 
 rather sharply conical. From the underside of the stem, 
 in the immediate neighbourhood of the terminal bud, 
 numerous bicellular hairs enclosing the latter are pro- 
 duced, and fiu'ther backw^ards, close underneath the place 
 of origin of each frond, adventitious roots make their 
 appearance. Tlie basal cell of the hairs which are situ- 
 ated on the outer wall of the fruit, divides repeatedly, at 
 a late period and after the complete formation of the 
 apical cell, by transverse septa ; in this respect these hairs 
 bring to mind the scales of the Polypodiacese. 
 
 The large oval ripe spore of Marsilea puhescens, at the 
 time when it is discharged from the ruptured capsule, is of 
 a similar nature to that of Pilularia glohulifera. The 
 inner cavity of the spore is clothed with a very delicate 
 membrane, which becomes somewhat more manifest by 
 distension, upon the application of caustic potash. In 
 contact with this membrane there is found at first a tole- 
 rably thick glassy layer of a yellowish coloiu'. Except 
 at the apex of the spore — the spot, that is to say, Avhich 
 answers to the place of contact of the spore with its 
 three sister -spores produced by the same cell — this 
 glassy membrane is surrounded by an outer membrane, 
 the component parts of which are prism-shaped, and 
 ari^anged in a radial manner. Out of this outer membrane, 
 and upon the apex of the spore, a portion of the middle 
 membrane protrudes in the form of a blunt wart. The 
 spore is enclosed in a thick layer of clear transparent homo- 
 geneous firm jelly, which extends beyond the apex of the 
 spore almost throughout its entire length. An enlarged 
 
326 HOFMEISTER, ON 
 
 passage leads tliroiigli tliis gelatinous mass to tlie pro- 
 truding portion of the inner spore-membrane. At the Ijase 
 of this passage are found the debris of the three sister- 
 cells, v.'hich were produced in the same mother-cell with the 
 spore. These are small shrivelled tetrahedral cells, which 
 are attached by one of their points to the Avart-like protru- 
 sion of the inner layer of the outer membrane of the spore 
 (PLXLIV, fig. 16)^ 
 
 The inner cavity of the spore is filled Avitli a fluid con- 
 sisting of albuminous matter and yellow oil, and containing 
 numerous large and small starch granules. The larger 
 granules exliil)it manifest lamination, and sometimes also 
 indications of tv/in-granules. The protruding portion of the 
 apex of the spore is separated from the rest of the cavity of 
 the spore by a very delicate septum. It forms a distinct 
 cell filled with a finely granular mucilage. When treated 
 with caustic potash it exhibits in its middle point a nucleus 
 of an ellipsoid shape (PI. XLIV, fig. IS). This cell is the 
 mother-cell of the prothallium. 
 
 Germination begins a few liom's after the escape of the 
 spore from the opening fruit. In the primary cell of the 
 prothallium two new nuclei appear in the place of the pri- 
 mary nucleus which disappears (PI. XLIV, fig. 17), and 
 shortly afterwards the cell is divided into two longitudinal 
 halves by a vertical septum. The longitudinal division is 
 repeated in each half by a septum at right angles to the 
 former one (PL XLIV, fig. 19). In the mean time an 
 orange-red coloiuing matter appears in the mucilaginous 
 fluid contents of the two or the four cells, in the form of 
 small vesicles (or drops ?) By a series of bipartitions the 
 prothallium is transformed into a hemispherical cellular 
 mass (PI. XLIV, figs. 20 — 24), consisting of a central cell 
 with mucilagmous contents, supported upon a double layer 
 sm-rounded by a triple layer of narrow cells. The four 
 longitudinal rows of cells which extend beyond the apex of 
 the central cell, part asunder at their edges of contact, and 
 an open narrow passage leading to that cell is formed (PI. 
 XLIV, fig. 22). 
 
 The structure of the prothallium of ]\Iarsilea consequently 
 agrees in its essential featm-es with that of Pilularia, except 
 
THE HIGHER, CRYPTOGAMIA. 327 
 
 that it is more massive, and differs from Pilularia in the 
 snbordinate point that the cells which form the mouth of 
 the passage leading to the central cell do not become papil- 
 late. Here, as there, the entire prothallium is devoted to 
 the formation of one archegonium. 
 
 The spores of Marsilea which came under mv observation 
 did not become further developed. The small spores pro- 
 cured contemporaneously from the same fruit, '^ which was 
 8^ years old, exhibited no change : it would seem that these 
 latter lose their povrer of germination sooner than the large 
 spores. The prothallia died when they had attained the 
 stage of development necessary for impregnation, inasmuch 
 as the small spores mingled in the surrounding fluid de- 
 veloped no spermatozoa. I observed the same phenomenon 
 in Pilularia minuta. 
 
 * Eor which I was indebted to the kindness of Alexander Braun. They 
 were part of the same gatliering which yielded the materials for his and Mette- 
 nius's observations, and were found at ilontpelier in 1S42. 
 
CHAPTER XI. 
 
 SALVINIA NATANS. 
 
 At the latter end of autumn the large ripe spores of 
 Salvinia form ellipsoidal cells whose longitudinal diameter 
 is from \"' to ^"', clothed with a thick outer membrane in 
 which two layers are visible, the inner one being horny, and 
 the outer one granular and of a looser texture. At the apex 
 of the spore — that pole of it which is turned away from the 
 stalk of the sporangium — the outer membrane exhibits a 
 division into three lobes, the boundaries of which answer to 
 the edges of contact of the young spore Avith the three sister- 
 cells which were produced contemporaneously in the same 
 mother-cell. 
 
 The contents of the spore look like a quantity of oil and 
 albumen. Spherical drops, both large and small, of a half 
 fluid substance, swimming in a thinner fluid, fill the inte- 
 rior of the spore. The apical portion of it is occupied by a 
 larger accumulation of the like mucilage. The history of 
 the development of the spore, which when half ripe appears 
 filled with delicate round vesicles, as well as the behaviour 
 of the above spherical masses during germination, render it 
 not improbable that some at least of those large drops are 
 cellular formations filled with nutritive matter destined for 
 the germ -plant. 
 
 During the winter the walls of the fruit perish. The 
 sporangia — as well those which contain one large spore each, 
 as those which contain small spores — fall from their stalks, 
 
HOFMEISTER, ON THE HIGHER CRYPTOGAMIA. 329 
 
 and are carried up to the surface of the water in the early 
 spring by the surrounding growing masses of confervas. In 
 the last weeks of March a short three-edged cellular body 
 of a beautiful emerald-green coloiu' is seen at the apex of 
 the spore, between the three separated lobes of the outer 
 spore-membrane. This body is the prothallium. 
 
 Tlie prothallium is produced by continued bi-partition of 
 the agglomeration of granular mucilage which was spread 
 over the arched apex of the interior of the spore, and has 
 become transformed into a flattened cell (PI. XLV, fig. 1). 
 The prothallium whilst still very young is already multicel- 
 lular, and exhibits a simple cellular layer, spread over the 
 inner arcuate cavity of the macrospore (PI. XLV, fig. 3). 
 When seen from above it appears to have a bluntly trian- 
 gular form (PL XLV, fig. 4). Prom the arrangement of 
 the cells it may be concluded, that when the primary mother- 
 cell was first divided by septa perpendicular to the mem- 
 brane of the macrospore, a three-sided and a four-sided 
 moiety Avere normally formed upon each division. As soon 
 as the middle of the prothallium, by transverse division of 
 its cells, has attained a thickness of three cellular layers, the 
 first archegonium is formed at its apex. The position of the 
 cells of the prothallium — which at this time is still entirely 
 enclosed by the lobes of the spore-membrane and is devoid 
 of chlorophyll — when seen in longitudinal section, shows 
 clearly that this first archegonium was formed by transverse 
 division occurring twice in the middle cell of the prothallium. 
 The middle of the three daughter-cells becomes the central 
 cell of the archegonium. At first it is much drawn out in 
 width and is almost tabular (PI. XLV, fig. 5). The upper 
 cell first divides twice by longitudinal septa arranged cross- 
 wise. The four daughter-cells are afterwards, and after 
 their free outer surface has become arched, divided by trans- 
 verse septa (PL XLV, fig. 6). By parting asunder at their 
 edges of contact they form the canal leading to the central 
 cell. In the lower one of the three cells which are derived 
 from the middle cell of the prothallium, the cell-multiplica- 
 tion which prevails in the entire mass of the prothallium is 
 continued, and by this means the circumference of the latter 
 is considerably enlarged, and thus — some time after the 
 
330 HOFMEISTER, ON 
 
 formation of the first arcliegonium — tlic three lobes of the 
 outer spore-membrane'-'^ are bent back. 
 
 The formation of the subsequent archegonia, which appear 
 in numbers upon tlie prothaUiuui, takes place in a similar 
 manner by transverse division of one of the cells of the outer 
 surface of the prothallium. The central cell is formed from 
 the inner of the daughter-cells, whilst from the outer ones 
 are produced tlie boundary cells of the canal leading to the 
 central cell. After the formation of those archegonia, which 
 are situated near the highest of the three blunt angles of 
 the three-sided, cushion-shaped prothallium, transverse divi- 
 sion is sometimes several times repeated in the covering 
 cells of the archegonia, and in the tissue surrounding them. 
 The canal leading to the central cell of these latter arche- 
 gonia is of considerable length, and has a bent course (PI. 
 XLV, fig. 10). 
 
 At the commencement of the formation of the arcliego- 
 nium the central cell is quite filled with granular nuicilage, 
 and a nucleus with more transparent contents floats in the 
 middle of it (PI. XLV, fig. 5). Afterwards, as the central 
 cell increases in size, the granular protoplasm accumulates 
 so as to cover the wall, and the nucleus is imbedded in it. 
 One or two oval or pear-shaped cells, in contact with the 
 inner wall, are now visible in the upper arch of the cell : 
 these are the germinal vesicles (PL XLV, figs. 6 — 9). They 
 not unfrequently occur in pairs, a fact not hitherto observed 
 in any other vascular cryptogam. 
 
 During these changes in the large spores, the sporangia 
 v/hich contain small spores are also carried up to the surface 
 of the water, either in groups or singly. Li autunm, when 
 the mother-plant dies, the small spores contained in each 
 ripe sporangium are firmly attached to one another and not 
 capable of isolation, their outlines being hardly distinguish- 
 able. This has been observed by Mettenius,t and the same 
 is the case even in early spring. If however such a spo- 
 rangium be subjected at this time to gentle pressure under 
 
 * The two glassy inner layers remain during this process, as during the 
 entire act of germination, quite unchanged (PI. XLV, fig. 2). The notion of 
 their conversion into an ap|iarently cellular mass is erroneous. (Mettcnius 
 ' Beitr. z. K. d. llhizocarpeen,' p. 17.) 
 
 t 'Beitr. zur K, der Ilhizocarpeaj.' Frankfort, a. M., 1810, p. 19. 
 
THE HIGHER CRYPTOGAMIA. 331 
 
 the microscope, spherical or elongated ellipsoidal cells may 
 be seen to escape from the fissures between the cells of the 
 wall as they part asmider. These spherical or ellipsoidal 
 cells are divided by delicate septa into from tAvo to six com- 
 partments, filled with finely granular mucilage, in which 
 one or several nuclei float. Afterwards each compartment 
 contains from one to four free roundish cellules. Each of 
 these cellules encloses a spiral thread, a spermatozoon, which 
 after its escape by the rupture of the wall of the cellule 
 moves about actively in the water. Many of these cellules 
 — those namely which are less developed — contain, instead 
 of the spiral thread, a transparent vesicle (or nucleus?) in 
 the centre, in the interior of which dark spherical lumps of 
 mucilage (nucleoli ?) are sometimes visible. By careful 
 dissection of microsporangia under the microscope at the 
 beginning of ]\Iarch, I succeeded in separating entire the 
 inner cell membranes of the microspores from the glutinous 
 contents of the microsporangia, which consisted of the de- 
 tached and agglomerated exosporia of the microspores. 
 When isolated they appeared in the shape of cellules already 
 extended to an oval form, having a major axis of 17*5 
 m.m.m., with turbid granular contents, and a spherical trans- 
 parent nucleus (PI. XLIV, fig. 26). In the latter half of 
 March the contents of the microsporangia are pultaceous : 
 the celhües lie free in the granular mucilage of the interior, 
 which is brownish green imder transmitted light. By this 
 time the contents of the cellules are transparent, and most 
 of them are divided transversely (PI. XLIV, fig. 5). Purther 
 divisions lead to the formation of a multicellular oval body, 
 the antheridium, in the compartments of which the sperma- 
 tozoa are formed in the interior of spherical vesicles (PI. 
 XLIV, figs. 27 — 30). By using higher powers of the 
 microscope, it may be seen that the cilia of the spermatozoa, 
 which are less numerous than in the Polypodiacese, are of 
 unusual length (PI. XLIV, figs. 31, 32). The movements 
 of the spermatozoa are exactly like those of the spermatozoa 
 of the Polypodiacese, so far as regards the direction and the 
 rapidity of the motion. 
 
 I have several times in diff'erent years found spermatozoa 
 of this kind swimming about in the water in which Salvinia 
 
332 HOFMEISTER, ON 
 
 had germinated. There can be no doubt that in the regular 
 course of nature, they are set free from the microsporangia 
 by gradual decay of the walls of the latter. 
 
 In archegonia which die without being impregnated and 
 become brown, the remains of the germinal vesicle are still 
 visible, and of their original size. Those archegonia how- 
 ever which by the widening of the central cell and the 
 multiplication of the cells adjoining to the latter give 
 evidence of impregnation, exhibit a considerable increase in 
 size of the germinal vesicle, which now almost fills the 
 central cell (PI. XLV, fig, 9).* As soon as it quite fills 
 the central cell, the first division of the impregnated ger- 
 minal vesicle takes place, by means of a transverse septum 
 slightly inclined to the longitudinal axis of the archegonium. 
 Cross longitudinal septa are produced in each of the two 
 halves, and then again slightly inclined transverse septa 
 are formed. The succession of these divisions is not 
 subject to any definite rule (PI. XLV, figs. 11 — 14): 
 the final result however is always the same, viz. the forma- 
 tion of an oval cellular body having its longitudinal axis at 
 right angles to that of the archegonium, and having one of 
 its apices, the blunter one, composed of four cells placed 
 crosswise (PI. XLV, fig. 14''), whilst the other apex only 
 exhibits a single top cell (PI. XLV, figs. 13, 14'', 150. I 
 will call the latter the fore-end, and the former the hinder 
 end of the embryo. 
 
 At the hinder end the number of the cells increases 
 almost uniformly in all directions (PI. XLV, figs, 19, 21, 23). 
 At the fore-end on the other hand a particularly active cell- 
 multiplication occurs, which commences in the growing cell 
 adjoining the original apical cell of the pointed end of the 
 embryo. This cell-multiplication is produced by septa 
 inclined alternately forwards and backwards, and at right 
 angles to a plane passing through the longitudinal axis of 
 the archegonium and of the oval embryo. In this way an 
 excrescence originates which is directed upwards (PI. XLV, 
 
 * I did not succeed in observing spermatozoa in the interior of tliese arche- 
 gonia. A phenomenon which lias been observed in dilTerent mosses and iu 
 Fleris aqialhia occurs, as an irregularity, also in Salvinia, viz , that the interior 
 of the archegonium enlarges more rapidly than the imperfectly developing 
 embryo, which is thus surrounded by a wider cavity (PI. XLV, fig. 12). 
 
THK HIGHER CRYPTOGAMIA. 333 
 
 ligs. 21 — 23,) and which becomes rapidly wider by longitu- 
 dinal divisions,* first of the apical cell, and then of the 
 other cells of the fore-edge (PL XLV, figs. 20, 24,) of the 
 flat and leaf-like structure. This excrescence is the first 
 leaf. 
 
 Soon after its appearance, a shoot of the fore-end of the 
 embryo is observable underneath its place of attachment 
 and before its median line. This shoot appears at first as 
 a hemispherical, slighty protuberant, cellular excrescence. 
 The arrangement of the cells of the embryo, especially if 
 observed in a louQ-itudinal section throuo-h the median line 
 of the first leaf (PI. XLV, fig. 21), leads to the conclusion 
 that the excrescence w^as formed by the division of the 
 apical cell of the fore-end, first by a septum inclined towards 
 the first leaf, and then by a septum inclined in the opposite 
 direction. t These divisions are repeated in regular suc- 
 cession in the terminal cell for the time being, which cell 
 has the form of a segment of a sphere. This excrescence 
 is the principal axis of the germ plant. On the right and 
 left of it the margin of the lamina of the first leaf is deve- 
 loped into ear shaped appendages (PI. XLV, figs. 24, 25""'). 
 Whilst these — extending beyond the end of the principal 
 mass — approximate more and more nearly to one another, 
 the still leafless apex of the leafy shoot ramifies twice, 
 sending out the more slender ramification (normally) first 
 to the right and then to the leftj (PI. XLV, fig. 25^'-^). 
 Li the mean time the cells of the hinder end of the embryo 
 only multiply to a small extent. That end is now attached 
 at right angles in the form of a stalk-like prolonga- 
 tion, to the fiat, proportionably thick, first leaf, which forms 
 the principal mass of the embryo (PL XLV, figs. 22, 2(5, 
 25"'*''). Its cehs are now thronghout almost cubical. 
 
 This groW'tli of the first leaf ruptures the prothallium 
 (PL XLV, fig. 26). By the expansion of the cells of the 
 hinder end of the pro-embryo, — w^hich expansion takes 
 
 * These divisions are interpolated between the divisions produced by septa 
 inclined to the outer surfaces. 
 
 f The succession of the division may be inverted (PI. XLV, fig. 19). 
 
 X The observer is su]iposed to look frum above upon the fore-surface of tlie 
 first leaf. 
 
334- HOFMEISTER, ON 
 
 place suddenly and at right angles * to the surface of the 
 first leaf — the first leaf and the prhicipal bud are carried 
 upwards out of the fissure (PI. XLV, fig. 27). The stalk- 
 Kke organ which bears the first scutiform leaf is therefore 
 not formed exclusively, or even mainly, by the longitudinal 
 extension of either the lower end of the embryo which lies 
 opposite to the entrance to the archegonium, or of the 
 primary axis, Avhich in Salvinia is only very slightly deve- 
 loped. The hinder end of the embryo plays the principal 
 part in the formation of the above-mentioned stalk. 
 
 The vascular bundles originate from the stalk. Never- 
 theless, the interior of the latter does not produce any 
 spiral vessels which pass imiuediately into the first leaf and 
 the stem above it (PL XLV, fig. 28) ; here all the cells of 
 the bundle remain thin-walled. The second and the third 
 leaf are formed behind the ramifications of the principal 
 bud, without the occurrence of any new ramifications 
 (PL XLV, fig. 28, 29). Then, hoAvever, the less vigorous 
 branches become elongated (usually ramifying again at the 
 same time), and form the leafless branches, of limited 
 growth, which hang down into the water, and which have 
 been generally considered by the earlier waiters as adven- 
 titious roots. f bliese branches grow by the repeated divi- 
 sion of an apical cell by mecius of septa, inchned alter- 
 nately in two directions, and by the division of the cells of 
 the second degree by a radial longitudinal septum, and 
 then by a transverse septum perpendicular to the axis. 
 Afterwards the cells divide, by septa parallel to the axis, 
 into inner and outer cells, and this latter division is several 
 times repeated in the cells of the circumference. 
 
 I observed myself — what Savi had previously noticed — 
 that microspores wdiich had been carefully kept apart from 
 microsporangia developed a prothallium, but no embryos. 
 It is but rarely that two embryos are produced in the same 
 prothallium. I have only observed the occurrence twice. 
 
 The Rhizocarpese have always attracted a considerable 
 
 * This direction i'onns au angle of about 30" with the longitudinal axis of 
 the embryo. 
 
 t Mettcnius has correctly described them, 'Beitr. zur Botanik.,' Heft i, 
 (Heidelberg, 1850) p. 15. 
 
THE HIGHER CRYPTOGAMIA. 335 
 
 amount of attention from botanists, especially their ger- 
 mination."* The knowledge of them had progressed 
 considerably when Schleiden's well-knowai work threw the 
 w^hole sidjject into confusion. f Schleiden alleged that the 
 small spores (pollen- grains, as he called them) emit a tube, 
 which penetrates into the prothalliuni developed from the 
 large spores, and is there transformed into the embryo. 
 Schleiden made these statements with a positiveness which 
 would have admitted of no contradiction, had it not been 
 for some almost unaccountable errors of observation. 
 IMettenius, in his beautiful and accurate w^ork, ' Beiträge 
 zm* Kenntniss der Rhizocarpea?,' did not venture to attack 
 this theory of Schleiden, although he was unable to verify 
 any one of Schleiden's observations. Nageli | never saw 
 the small spores of Pilularia emit tubes, but he made the 
 important discovery that the mother-cellules of the Sperma- 
 tozoa originate in them. He pointed out anew that the 
 four papillate cells of the mouth of the archegonium — 
 w'hich Schleiden, strange to say, described as " pollen 
 grains seated upon the nucleus, and wdiich had developed 
 tubes " — could not be pollen-grains, but that they rather 
 originated from the prothallinm. I published the outlines 
 of the account given above many years ago.§ Älettenius, 
 in a subsequent work, adopted my views. {| 
 
 "'^' The earlier literature is fully treated of in Llettenius's vrork * Beiträge 
 zur Keuntiiess der llliizocarpcen,' Frankfurt a. M., ISiG, p. 1. 
 f 'Grundzü^e,' 2nd edition, p. 101. 
 
 X 'Zeitschrift f. Botanik.,' lieft 3 and 4, (Zurich, 1S46,) p. ISS. 
 § 'Bot. Zeit.,' 1819, No. 45. 
 11 'Beitr. zur Botanik.,' 1 Heft, Heidelberg, 1S50. 
 
CHAPTER XII. 
 
 ISOETES LACUSTRIS. 
 
 The development of the Isoetese is a subject of great 
 importance in botanical morphology. They are the only 
 known family in which the principal axis never ramifies. 
 As far as present observations extend, they alone, in the 
 vegetable kingdom, are distinguished by the entire sup- 
 pression of a supplementary cell-multiplication in the joints 
 of the stem. In other stems, however little their inter- 
 nodes may be developed, an active multiplication of the 
 cells in a longitudinal direction takes place (after the for- 
 mation of the youngest internode) in the second youngest, 
 or even in the adjoinhig internodcs. In Isoetes, after the 
 formation of one internode, the longitudinal growth ter- 
 minates absolutely. The features by which the Isoetese 
 are clearly distinguishable from the plants nearest allied to 
 them in their mode of reproduction are as follows : — the 
 development of adventitious roots (apparently in a descend- 
 ing series), the form of the ligneous mass, and especially 
 the existence of a mantle of cambium surrounding the 
 \vood and retaining its activity during the Avhole life of the 
 plant. The processes of impregnation are seen in Isoetes 
 with greater facility and clearness than in any other diae- 
 cious cryptogams. 
 
 Hugo von Mohl pointed out the peculiar phenomena of 
 growth of the Isoetese,* viz., the development of the adven- 
 titious roots in an apparently descending order on both 
 sides of a furrow traversins; the under surface of the 
 
 * 'Liunaa,' ISiO. 'Vermischte Schriften,' p. 122. 
 
HOFMEISTER, ON THE HIGHER CRYPTOGAMIA. ' 337 
 
 flattened stem — the peculiar form of the wood — and the 
 annual renewal of the bark by the vitality of a cambium 
 layer surrounding the wood. Since Von Mohl's disco- 
 veries the special attention of botanists has been almost 
 constantly directed to this interesting family. Alexander 
 Braun * pointed out the connexion between the « or |- 
 arrangement of the fronds of young plants, and the two or 
 three-lobed form of the stem; he discovered the true 
 nature of the regular bifurcation of the roots, which had 
 been taken by earlier observers f for accidental lateral 
 ramification. He endeavom-ed to explain the remarkable 
 relation of the roots to the stem by the assumption that 
 " the roots in Isoetes, instead of breaking forth outwardly 
 from the vascular cylinder, penetrate, on the contrary, in 
 an inward direction." Mettenius,| about the same time, 
 gave a very accurate account of the structure of the ripe 
 spore, and suggested that the germination of Isoetes, might 
 agree with that of Selaginella, as to which, '§1 at the same 
 time, he published the first correct microscopical obser- 
 vations. A year afterwards, Karl jMüller gave an account 
 of the germination of Isoetes lacustris. \ He describes the 
 large spore (of which he had only advanced specimens 
 before him) as a cellular sac, enclosed by an exosporium, 
 and in whose cavity the rudiment of the embryo appeared 
 in the form of a free cell, which w^as gradually transformed 
 into the cellular body. Mettenius forthwith corrected the 
 most essential errors of this account.^ He proved anew, 
 in a striking manner,** the similarity of the germination of 
 Isoetes and the other vascular cryptogams, by the discovery 
 of the formation of spermatozoa in the small spores, and 
 the description of the origin of the archegonia upon the 
 prothallium developed by the large spores. 
 
 The following observations will afford some facts 
 supplementary to those noticed by Mettenius and Müller, 
 
 * 'Flora,' 1847, p. 32. 
 
 f BiscliofF, 'Krypt. Gewächse,' Nürnberg, 1828, p. 10. 
 
 % 'Limifea,' 1847, p. 269, ou AzoUa. 
 
 I 1. c, p. 270, note. 
 
 II 'Bot. Zeit.,' 1848. 
 
 ^ 'Bot. Zeit.,' ]848,' p. 688. 
 ** ' Beitrage zur Botanik.,' Heft 1, Heidelberg, 1850. 
 
 22 
 
338 HOFMEISTER, ON 
 
 and will be found in accordance with those reported by 
 Mold. I am indebted to the kindness of Mettenius,* 
 Alexander Braun, and Gustav Reichenbachjf for the abun- 
 dant materials upon which my observations are founded. 
 
 The large spores of Isoetes lacustris are at first tctra- 
 hedral with a convex basal surface. As they ripen, their 
 remaining surfaces also become gradually arched, and 
 assume almost a spherical form. The delicate primary cell- 
 membrane is clothed with a thick exosporium, which, 
 when cut through, exhibits three principal layers. The 
 innermost is a glassy membrane, of a brown colour and 
 moderate thickness, upon which ridges of different lengths, 
 and converging towards the pole of the spore, are seated. 
 Three of the longer and more prominent of such ridges, 
 answering to the edges of contact of the spore with its 
 three sister-spores, unite at the apex at angles of 120°. 
 They reach to the equator of the cell, and there intersect a 
 somewhat less prominent annular ridge, which surrounds 
 the spore. This innermost layer of the exosporium is 
 succeeded by a thinner layer, of a granular consistence 
 and yellowish colour, over Avhicli the thick outermost 
 covering, consisting of a transparent gelatinous mass, is 
 spread. Like the former one, it covers all the ridge-like 
 pi'otuberances of the innermost glassy layer of the exos- 
 porium, and it is especially fully developed over the four 
 principal ridges (PL XLVI, fig. 1). 
 
 The matter composing the exosporium behaves towards 
 reagents like the exine of pollen-grains. Sulphuric acid 
 imparts a reddish colour to the inner layers, v.hicli are soft- 
 ened by boiling in alkaline leys. The gelatinous layer is 
 rapidly destroyed by mineral acids and caustic alkalis. As 
 Röperj has observed, the exosporium does not contain 
 carbonate of lime, although Schleiden§ suspected its pre- 
 sence from the appearance of the dry spores. The contents 
 of the ripe spore in its optical and chemical characters 
 
 * I received living specimens of Isoefes lacustris from the lake in (be Black 
 Eorcst, the same habitat whicli afforded the materials for the observations of 
 Bisciioff, Mold, Braun, and Mcttcnius. 
 
 t Dried specimens of species of tlie Mediterranean Flora. 
 
 % 'Zur riorä Mecklenburg's/ vol. i, p. 135. 
 
 § 'Gi-undziige,' 2nd edit., vol. ii, p. 84. 
 
THE HIGHER CRYPTOGAMIA, 339 
 
 resemble a mixture of oil and albumen. If a spore be 
 crushed upon thin paper, it leaves behind a transparent stain. 
 
 A few weeks after the spore has become free by the decay 
 of the walls of the sporangia, its interior begins to be filled 
 with cellular tissue. Sections afford no explanation as to 
 the nature of this cell-formation. If a spore which is not 
 yet entirely filled with closed parenchyma be crushed, its 
 contents become a formless pultaceous mass. If however 
 the exosporium be immersed for half an horn* in a saturated 
 solution of glycerine, it becomes sufficiently transparent to 
 expose to view flatly-spherical accumulations of a granular 
 sulDstance spread over the inner wall of the spore (PI. XL VI, 
 fig. 1). There can be no doubt that these masses of granu- 
 lar mucilage, which become confluent when the spore is 
 submitted to pressure, are newly-formed primordial cells, 
 /. <?., naked primordial utricles ; and therefore that the for- 
 mation of the cellular tissue which fills the spore, i. e., of 
 the prothallium, is the result of free cell-formation. This 
 accords with the mode of origin of the endosperm of the 
 greater number of pheenogams, and especially with the de- 
 velopment of the albumen of the Coniferse. The formation 
 of rigid cell-membranes appears to commence for the first 
 time when the accumulated contents of the spore-cell have 
 become transformed into dauo-hter-cells. 
 
 This cell-formation probably commences in the apical 
 arch of the spore-cavity. When the parenchyma of the 
 spore is sufficiently firm to admit of longitudinal sections, 
 the cells of the apex of the prothallium are far smaller and 
 more numerous than those of its base. This leads to the 
 conclusion that a miütiplication of the cells has commenced 
 at the apex some time previously, which multiplication does 
 not take place at the base until a much later period, and 
 then with far less activity. The contents of the cells of the 
 prothallium are not distinguishable from those of the ripe 
 spore. No nuclei are visible in the thick turbid fluid.* 
 
 During the formation of the prothallium the inner mem- 
 
 * The want of transparency of the milky cell-contenfs is so great, that even 
 in very thin sections it prevents tlie recognition of the boundaries of the cells 
 as long as the preparation lies in clean water. The addition of concentrated 
 solution of glycerine produces with greater rapidity a far more perfect trans- 
 parency than the chloride of calcium recommended by Mettenius, ('Beitr. zur 
 Bot.,' Heft i, p. 1].) 
 
340 HOFMEISTER, ON 
 
 braue of the spore changes considerably, especially in its 
 upper portion. It increases in thickness, and when a section 
 is made, several layers are distinguishable. It can with 
 difficulty be stripped off from the prothallium.* When 
 viewed superficially the mcmlu-ane which Avas previously 
 homogeneous appears finely granular — all which phenomena 
 are found to occur in a remarkably similar manner in the 
 embryo-sac of the Conifera?. 
 
 The spherical prothallium increases in size by multiplica- 
 tion and expansion of its cells, and ruptures the upper half 
 of the exosporium, dividing it into three lobes, each of the 
 three ridges which unite at the apex of the spore separating 
 into two longitudinal halves. A small portion of the apex 
 of the prothallium — three very pointed triangles meeting at 
 auswies of 120° — is thus made free. 
 
 Archegonia are produced by the nndtiplication of indivi- 
 dual cells of the upper surface of these exposed portions. 
 The first of these archegonia is produced exactly at the apex 
 of the prothalhum (PL XLVI, fig. 2). If this first one 
 remains imimpregnated several others are formed in deycend- 
 ing order, I have never counted more than eight. 
 
 The mother-cell of an archegoniuui divides by a septum 
 parallel to the free outer surface, and a similar division 
 takes place in the outer of the two newly-formed cells. 
 Vertical longitudhial septa then divide each of the two 
 upper cells into longitudinal moieties (PI. XLVI, fig. Sa), 
 in each of which a longitudinal septum at right angles to 
 the one last formed is immediately produced. The under- 
 most cell of the archegonium increases somewhat in size 
 and becomes the central cell. Division by transverse septa 
 usually occurs once more in the lower of the two double 
 pairs of (four times smaller) cells Avhicli project beyond the 
 central cell (PI. XLVIj fig. 3, a^). Exceptions to this are rare. 
 
 During these processes the part of the inner membrane 
 of the spore-cell which is not covered by the exosporium 
 peels off gradually, swelling up in front.f By the parting 
 asunder of the four longitudinal rows of cells which cover 
 
 » Compare Metteuius, 'Bot. Zeit./ ISIS, p. 690. 
 
 ■\ The mode of i;ro\vlli of tlie adventitious roots of some grasses, especially 
 of Aveua saliva, affords a very remarkable instance of the peeling off of whole 
 masses of cellular tissue by the casting off of the primary membrane and the 
 thickening layers of the epidermal cells. 
 
THK HIGIIKR ORYPTOGAAIIA. 341 
 
 the central cell of the archegonium, an open passage is 
 formed leadmg to the latter cell (PI. XL VI, fig. 5). Before 
 the formation of tliis passage a free spherical danghter-cell 
 is produced in the central cell, almost filling the cavity of 
 the latter (PI. XLVI, figs. 4 — 6). It is the primary cell of 
 the new generation — the germinal vesicle — capable, after 
 impregnation by the spermatozoa produced in the small 
 spores, of forming a new frond and spore-bearing plant of 
 Isoetes. 
 
 All the ripe macrospores of Isoetes lacustris form pro- 
 thallia and produce archegonia. The further development 
 Avhich results in the formation of the embryos of a leaf- 
 loearing plant is attained only by those macrospores which 
 come in communication with microspores. This is analo- 
 gous to what occurs in Selaginella and the Rhizocarpese. 
 Prothallia when kept quite apart from microspores live for 
 a long time ; according to my experiments from the begin- 
 ning of September to the middle of March. Some of these 
 even then brought forth new archegonia of the normal form 
 apparently fitted for impregnation. 
 
 The small spores of Isoetes lacustris when ripe have the 
 form of the quadrant of a sphere ; in rare instances they are 
 tetrahedral. The sharp edges and angles of the spore are 
 formed of exine, those of the inner spore-membrane are 
 bluntly rounded off. At both the upper and lower ends of 
 the spore the exosporium forms a wart-like tip (PI. XLV, 
 figs. 8, 9) ; all along the edges of contact of the spore with 
 the three sister-spores it forms a prominent fold (PI. XLVI, 
 fig. 7). The outer surface of the cxine is very finely granu- 
 lated, almost smooth. Its colour is a light yellowish grey. 
 
 The fully-developed small spore contains a finely granu- 
 lar protoplasm mixed with many small oil-drops. When 
 viewed with transmitted light the mass of differently refrac- 
 tive fluids appears almost opaque. A sharp-outlined sphe- 
 rical nucleus with transparent fluid contents floats in the 
 middle point of the spore (PI. XLVI, fig. 7). 
 
 About four weeks after the microspores have become free 
 by the decay of the wall of the sporangia, the primordial utricle 
 of the cell divides into from two to fom- portions which be- 
 come individuahsed into daughter-cells (PL XLVI, fig. 8). 
 
312 HOFMEISTER, ON 
 
 Sometimes tlie moieties of the primordial utricle fill the 
 mother-cell entirely ; the cell-walls secreted by them then 
 appear — so far as they correspond with the surfaces of 
 contact of two halves of the primordial utricle — like septa 
 seated upon the inner wall of the spore (PL XLVI, fig. 9).* 
 ^More frequently however the division of the cell-contents is 
 accompanied by a contractionf of them into a smaller space ; 
 the daughter- cells, which are of a flatly ellipsoidal form, lie 
 free in the interior of the spore. Numerous very small 
 amyloid granules now appear in the fluid contents of the 
 daughter-cells. Each of these cellules produces in its inte- 
 rior one or two lenticular vesicles, in each of which is pro- 
 duced a thread, rolled up in a right-handed spiral, and 
 consisting of a substance rendered brown by iodine (PI. 
 XLVI, fig. 11). One of its ends is somewhat thickened, 
 the other is drawn out into a thread-like termination. 
 When perfect, the spore and its daughter-cells are ruptured 
 by the swelling of the contents ; the lenticular mother- 
 vesicles of the spermatozoa become free in the opened cavity 
 of the spore. Soon the membrane of the vesicle itself — 
 which is rendei-ed blue by iodine — is ruptured ; one end of 
 the spermatozoon ])rotrudes from the fissure, and immediately 
 commences an active oscillatory motion, which causes a rapid 
 revolution of the mother-vesicle (PI. XLVI, fig. 12). Ulti- 
 mately the spermatozoon frees itself entirely from the vesicle, 
 and the turns of the spiral separate somewhat from one 
 another. It slips out of the ruptured spore, maintaining a 
 constant revolution round the axis of its spiral, and moves 
 about in the water with the thick end in front, dragging the 
 thinner one after it (PI. XLVI, figs. 13 — 15). Its motions 
 are slightly more rapid than those of the spermatozoa of 
 mosses. J 
 
 If the spermatazoon be killed with iodine, a small number 
 
 * Spores ilius divided are exactly like the small ellipsoidal cellular bodies 
 which burst forth in the spring from those sporangia of Sahinia nutans whicli 
 produce microspores, i.e., the cellules in whose chambers the mother-vesicles 
 of the s]:)ermatozoa originate. 
 
 i" Analogous to the process occurring in the spore-formation of liverworts 
 and mosses (Pellia and Phascum). 
 
 X Mettcnius, who discovered the spermatozoa of Isoetcs, remarks upon the 
 slowness of their motion compared with the rapid motion of the spermatozoa of 
 ferns. 
 
THE HIGHER CRYPTOGAMIA. 343 
 
 of very fine cilia attached to tlie t\YO front coils of the spiral 
 may be distinguished under favorable illumination (PI. 
 XLVI, figs. 16, 17). The addition of colouring matter to 
 the water in which the spermatozoa are moving, shows that 
 during the life of tlie latter these cilia oscillate actively. 
 The duration of the motion of the spermatozoa of Isoetes 
 never exceeds three hours according to my observations. 
 
 Microspores sown at the end of August produced the 
 first spermatozoa in the middle of September. The pro- 
 duction of spermatozoa lasted until January. The water 
 of the vessels in which I sowed the large and small spores, 
 swarmed with spermatozoa on some days in the middle 
 of October, At this time the thinly-fluid mucilage which 
 fills the canal of the mouth of ripe archegonia, often con- 
 tained thread-like bodies of a firm mucilaginous substance, 
 which might be the remains of spermatozoa, whose motion 
 had ceased. 
 
 The first indication of the commencement of the develop- 
 ment of an embryo in an archegonium, is the division of 
 the impregnated germinal vesicle by a transverse septum, 
 somewhat inclined to the longitudinal axis of the archego- 
 nium (PI. XLVI, figs. 18, 20). During the formation of 
 this septum the germinal vesicle expands, often to some 
 extent, in a direction at right angles to the longitudinal 
 axis of the archegonium. After the disappearance of the 
 primary nucleus of the cell and the appearance of two new 
 nuclei, the lower of the two halves of the impregnated 
 germinal vesicle, and afterwards the upper half also, is 
 divided by a septum cutting the first formed septum at a 
 right angle (PI. XLVI, fig. 21). The rudiment of the embryo 
 of the new generation, when consisting of from two to four 
 cells, has the form of a procumbent oval ; when viewed in the 
 dii'ection of its longitudinal axis (Plate XLVI, figs. 18, 19), 
 it appears not longer than the unimpregnated germinal 
 vesicle. But owing to its longitudinal expansion, it has 
 already began to penetrate destructively into the tissue of 
 the prothallium. 
 
 As in many similar cases, the cells of the prothallium 
 which immediately adjoin the rudimentary embryo, exhibit 
 a somewhat active multiplication before they become 
 
344 HOFMEISTER, ON 
 
 loosened and pushed aside by the developing germ-plant, 
 and ultimately dissolved.* The embryo in its first stages 
 appears surrounded by a tissue of very narrow cells (PL 
 XLYI, fig. 21). As early as during the occurrence of 
 the first divisions of the impregnated germinal vesicle, the 
 cells of the mouth of its archegonium die ; their fluid con- 
 tents become as clear as water, and their Avails assume the 
 deep-brown colour so common in the dead cell -membranes 
 of vascular cryptogams. Similar changes sometimes occur 
 in those cells of the upper surface of the prothallium which 
 adjoin the mouth of the archegonium (PL XLYI, figs. 21, 
 23). 
 
 It very rarely happens that more than one archegonium 
 of the same prothallium is impregnated. The rest wither ; 
 the contents of their central cells shrivel up into an irregu- 
 larly shaped ball of dark-brown matter, and all the cell- 
 membranes of the archegonium become brown. 
 
 The rudiment of the embryo when 4 -celled grows to- 
 wards the middle point of the spherical prothallium by 
 repeated division of the cells turned away from the canal of 
 the archegonium. At the same time an active multiplica- 
 tion commences in the one lateral cell which occupies the 
 more pointed end of the oval embryo-rudiment. It Vlivides 
 by a vertical septum forming an acute angle with one of 
 the axes of the embryo. The outer of the newly-formed 
 cells is immediately divided again by a septum at right 
 angles to the last-formed septum. In the apical cell for 
 the time being of the excrescence (of the embryo) thus 
 produced, the division is repeated for a long time by septa 
 inclined alternately in two different directions (PL XLVI, 
 figs. 22, 23). This lateral shoot of the young rudimentary 
 plant — which shoot up to a certain point is continually 
 elongating — is the first leaf. 
 
 The cells of the second degree produced by the division 
 of the (primary) apical cell of the leaf, are divided by radial 
 longitudinal septa. Each of the tertiary cells divides — 
 
 * Instances of this occur in the development, whilst within the prothallium, 
 of the germ-plant of ferns — iu the penetration of the lower end of the moss- 
 fruit into tiie incipient vaginula — and in the displacement of the endosperm of 
 many phseuogams by the growing embryo. 
 
GLASGOW 
 ßUBUC LIBRARIES 
 
 THE HIGHER CRYPTOGAMIA. ^ 345 
 
 by septa parallel to the chords of the arched free outer 
 surfaces — into an inner and an outer cell. In the latter a 
 septum is produced at right angles to the one immediately 
 preceding it, and radial to the longitudinal axis of the leaf; 
 close under the growing tip of the leaf eight perij)heral 
 cells enclose four axile ones. The form of the leaf, which 
 at first is flattened above and below, is gradually changed 
 by this cell-multiplication into a conical one (PL XLVI, 
 fig. 24). The leaf increases in thickness by repeated divi- 
 sion of the cells of its circumference, produced by radial 
 longitudinal septa alternating with septa parallel to the 
 tangents of the free outer walls. When it has attained a 
 certain stage of development its longitudinal growth is 
 much accelerated by the occurrence of transverse division 
 in most of its cells. This multiplication commences close 
 miderneath the apex of the leaf, and progresses from 
 thence, on the one side towards the base, and on the other 
 side towards the apex, so far at least as it extends into those 
 cells of the apex of the leaf which have been formed since 
 its commencement. The cells of the circumference divide 
 first ; from the latter the multiplication proceeds towards 
 the longitudinal axis, without reaching the four rows of 
 cells adjoining the latter. The latter remain twice as long 
 as the cells of the peripheral layer ; they are destined at a 
 later period, by repeated longitudinal divisions, to become 
 transformed into vascular bundles (PI. XLVII, fig. 1). 
 
 The first leaf either shoots out at right angles from 
 the longitudinal axis of the archegonium and embryo, or 
 it trends upwards, often at such an acute angle that its 
 apex penetrates into the upper arch of the central cell of 
 the archegonium. The latter case is the most frequent ; it 
 very rarely happens on the other hand that the leaf takes a 
 downward direction tow^ards the centre of the prothal- 
 lium. 
 
 As early as the time when the number of the cells of the 
 leaf, counted in a longitudinal direction, amounts to from four 
 to six only, the free outer wall of the cell which occupies 
 the middle of the base of the upper surface of the leaf — that 
 surface which is turned towards the apex of the prothal- 
 lium — begins to swell in a vesicular manner (PL XLVI, 
 
346 HOFMEISTER; ON 
 
 fig. 23). The protuberance has the form of an ellipsoid flat- 
 tened on the upper and under side, and is separated from 
 the original cavity of the mother-cell by a septum (PI. 
 XLVI, fig. 24). The roundish cell, not unlike a knobby 
 hair, which is now seated at the base of the fore side of the 
 leaf, is the primary cell of the single scale which it produces. 
 Its first divisions exactly resemble those of the cell of the 
 first degree of one of the gemmae of JMarchantia or Lunu- 
 laria. The cell is divided two or three times by transverse 
 septa, which are at right angles to the future longitudinal 
 axis of the scale, and pei*iDendicular to its surfaces (PI. 
 XLVII, fig. 1). The apical cell then divides, and after it 
 the lower cells also, by a longitudinal septum at right angles 
 to the one previously formed. The halves increase — after 
 new transverse septa have been formed in each of the two 
 upper cells — by the growth of septa parallel to the free 
 outer edges of the scale, followed by septa produced in the 
 outer of the newly formed cells at right angles to the outer 
 margin. The organ which has now the shape of a blunt 
 spatula (PL XLIX, fig. 4), continues to increase the number 
 of its cells by the division of those of its circumference by 
 means of longitudinal and transverse septa which alternate 
 with tolerable regularity. This activity of the cells terminates 
 much sooner at the apex of the leaf than at its base, wehere 
 an intercalary nudtiplication of the cells occurs, mainly in 
 a longitudinal direction, some time after the cells of the apex 
 of the leaf have lost their power of division. The scale be- 
 comes pointed and heart-shaped (PI. XLIX, fig. 5). 
 
 All these septa are perpendicular to the surfaces of the 
 scale. Soon, however, septa parallel to its surfaces appear 
 in its middle cells (PI. XLVII, fig. 2). Thence the divi- 
 sion advances towards the cells of the base of the leaf, 
 which are engaged in intercalary multiplication in length 
 and breadth. In the cells nearest to the base the divi- 
 sion is sometimes repeated, so that this part of the scale 
 consists of three layers. The remainder of it has two 
 layers, with the exception of the margin and the top, 
 which always exhibit a single layer of cells. Individual 
 cells of the margin grow out into rather long pointed 
 papillae. 
 
THE HIGHER CRYPTOGAMIA. 347 
 
 111 all the principal features the development of the scale 
 of Isoetes accords with that of the scales of ferns. The 
 first commencement of the multiplication of the single 
 primary cell is essentially the same in both, i. c, it rests 
 upon the alternation of rectangular, longitudinal, and 
 transverse divisions ; besides this, both exhibit the subse- 
 quent intercalary basal cell-multiplication, and the same 
 kind of miütiplication of the median cellular layers ; and 
 lastly, in both cases the development of the scales rapidly 
 gets ahead of that of the organ to which they form appen- 
 dages, and they soon die. 
 
 Immediately after the commencement of the formation 
 of the scale, a sheath begins to be formed at the base of the 
 leaf, enclosing the scale and some of the cells underneath 
 it. A horse-shoe-shaped, cushion-like protuberance, open 
 towards the front surface of the leaf, is first formed by the 
 arching outwards of the free outer wall of a girdle of cells 
 surrounding those parts (PI. XLVII, fig. 24). When the 
 intercalary cell-multiplication of the base of the leaf takes 
 place, this protuberance grows up into a tolerably high 
 annular sheath, by repeated division of the apical cell for 
 the time being by means of horizontal septa (PL XLVII, 
 fig. 2). 
 
 The leaf grows in thickness at the point of origin of the 
 scale ; its fore-side appears bent obhquely inwards (PI. 
 XLVII, figs. 2, 3), close above the base (PI. XLVII, figs. 
 2, 3). In its lower part, the vascular bundle which tra- 
 verses it is excentrical, being nearer to the front surface. 
 
 The primary axis of the germ-plant, which at the time of 
 the appearance of the first leaf consisted of only a fcAV 
 cells, increases considerably in length and circumference 
 dming the development of the leaf and the formation of 
 its scale. This increase is caused more by expansion than 
 by multiplication of its cells. The axis now projects 
 consideraljly from the embryo, in a hemispherical form, 
 and is directed towards the middle point of the pro- 
 thallium ; the leaf is seated upon one of the lateral sur- 
 faces of the embryo (Pl.XLVI,fig. 24; PL XLVII,figs.l-3). 
 
 A process of cell-multiplication has now commenced 
 upon its opposite lateral sm*face also : this is the beginning 
 
348 HOFMEISTER, ON 
 
 of the formation of the first root, an adventitious one, like 
 all the roots of the vascular cryptogams. Its development 
 commences with tlic nuiltiplication of a cell of the inner 
 tissue of the embryo, viz., the cell Avliich hes opposite to 
 the primary cell of the first leaf, and is separated by a 
 cellular layer from the upper surface of the germ-plant 
 (PI. XLYII, fig. 1). This cell divides, in repeated succes- 
 sion, by transverse septa opposite to one another, forming 
 cells of the second degree, lying alternately above and 
 below the primary cell. The lower ones are produced by 
 the formation of a septum slightly convex below ; their 
 form is that of a meniscus. Their multiplication takes 
 place in two directions only ; all the septa which are 
 formed in them are perpendicular to the arched upper and 
 under surface of the cell whose derivative cells constitute 
 one of the cap-shaped cellular layers — enclosed one Avithin 
 the other — which cover the outermost apex of the root, and 
 which, during the growth of the latter, gradually peel off 
 outwardly (PL XLA^II, fig. 3). After the formation of a 
 lower secondary cell, and before the division of the cell of 
 the first degree by a septum opposite to the last-formed 
 septum, septa parallel to the longitudinal axis of the root 
 are produced in the latter cell three times in succession. 
 One of these septa is turned towards the outer side of the 
 root — that side which is turned away from the punctum 
 vegetationis of the germ-plant. The two other septa are 
 at right angles to this one. Thus three lateral cells of the 
 second degree are formed, which arc followed by the pro- 
 duction of a shorter upper cell by the division of the 
 primary cell by means of a transverse septum (PI. XLVII, 
 fig. 3). I will call the first three the outer, the second the 
 inner of the upper secondary cells. Both kinds of upper 
 cells of the second degree, the lateral cells as well as those 
 which follow them, multiply in all three directions. Their 
 divisions are offener repeated and last longer than those of 
 the lower secondary cell which belongs to the same period 
 of division of the primary cell. 
 
 The formation of lateral cells of the second degree 
 causes a very considerable unilateral thickening of the root. 
 The diameter of the latter increases much more rapidly on 
 
THE HIGHER ORYPTOGAMIA. 349 
 
 that side wliicli is turned away from the futiu-e place of 
 origin of the second root, than on the opposite side. The 
 consequence of tliis is that eacli new cap-shaped covering 
 Kiyer of the tip of the root appears to be attached more 
 obHquely than the preceding one, and reaches higher up on 
 that side of the root Avhich is turned towards the punctum 
 vegetationis than it does on the opposite side. 
 
 Each newly-formed inner cell of the upper cells of the 
 second degree is first divided into unequal longitudinal por- 
 tions by a septum inclined inwards to the axis of the root, 
 the inner portion, that, namely, which is turned tow^ards the 
 punctum vegetationis of the germ-plant, being the smaller 
 one. Both portions multiply immediately in all three direc- 
 tions. The two innermost cells which adjoin the longitu- 
 tlinal axis of the root, and are turned towards one another, 
 lemain about one step behind all the others in the process 
 of division by transverse septa, i. e., by septa at right 
 angles to the lono-itudinal axis of the root. Instead of 
 that division they each divide twice by longitudinal septa 
 at right angles to one another. Thus there is produced 
 v^ithin the root a string of sixteen longitudinal rows of 
 extended cells, situated excentrically, being nearer to the 
 inner side. This is the rudiment of the vascular bundle 
 (PL XLA' II, fig. 3). The cells of the outer surface of that 
 portion of the root, which, — as opposed to the root-cap 
 which peels off little by little — may be called the persistent 
 portion, divide by radial longitudinal septa and by trans- 
 verse septa once oftener than those of the inner surface ; 
 the epidermis of the root consists of tabular cells four 
 times smaller than those adjoining them on the inside. 
 These divisions of the cells of the outer surface occur even 
 within the region which is protected by the transient cap- 
 shaped covering layers of the tip of the root ; they occur 
 on the outer side of the root, where these coverings do not 
 extend so high up, earlier (/. e., nearer to the tip of the 
 root) than on the inner side (PI. XLVII, fig. 3). 
 
 Some of these circumstances attract but little attention 
 in the first root of the germ plant which is hardly as thick 
 as a bristle, in consequence of the inferior development of 
 the tissue destined to form the bark of the root. In order 
 
350 HOFMEISTER, ON 
 
 to explain them I must speak, in anticipation, of the process 
 of development of vigorous roots of plants some years old 
 (PL LII, figs. 2—5). 
 
 The one cell which is situated underneath the place of 
 insertion of the scale of the first frond, and is surrounded 
 by its sheath- like base, is the punctum vegetationis of the 
 (secondary) principal axis of the plant; the terminal bud 
 of the embryo is at this time limited to this one cell. As 
 the bud is developed the cell divides by septa inclined 
 alternately in opposite directions. The lines in which these 
 septa cut one another are at right angles to the front surface 
 of the first leaf. 
 
 Until the plant is fully formed the growth of the stem is 
 caused by the constantly repeated uniform division of the 
 apical cell. The direction of the septa produced in it re- 
 mains always the same, viz., at right angles to the major 
 axis of the ellipsoidal transverse section of the stem, and 
 parallel to the furrows of its under side. 
 
 The mode of miütiplication of the cells of the second de- 
 gree which are thus produced, resembles in general that of 
 the same cells of the first leaf above described. After the for- 
 mation of the second secondary cell, the second leaf is pro- 
 duced on that side of the end of the principal axis which is 
 turned away from the first leaf, by the multiplication of the 
 youngest cell of the second degree of the stem-bud. The 
 mode of its development corresponds entirely with that of 
 the first (PI. XLVII, figs. 2, 3). Its formation commences 
 immediately after the first root becomes visible ; during its 
 development the upward growth of the surrounding sheath 
 of the first leaf ceases for some time. When the second 
 leaf has attained a height of from three to four cells, a re- 
 markable elongation of the cells of the first leaf — which now 
 contain chlorophyll — commences at the apex of the latter. 
 In consequence of the multiplication of its cells in a longi- 
 tudinal direction, the first leaf has by this time advanced 
 almost to the periphery of the prothallium. The leaf breaks 
 through the prothallium and ajDpears in the form of a green 
 point outside the latter : it elongates itself very rapidly by 
 the longitudinal expansion of its cells, which proceeds from 
 the apex of the leaf towards its l)ase, where cell-multiplica- 
 
THE HIGHER CRYPTOGAMIA. 351 
 
 tion is still in progress. In my experiments the first 
 leaves broke out from the ends of the prothallia at the end 
 of September, six weeks after the spores were sown. From 
 that time leaves continued to make their appearance singly 
 until the middle of January, when their number suddenly 
 diminished in a remarkable manner. From the beginning 
 of February until towards the end of March no new germ- 
 plants became visible ; at the commencement of spring 
 however they began to appear again, becoming continually 
 more numerous until the middle of April. Even in the 
 middle of May almost all the prothallia which I examined 
 contained embryos in different stages of development. These 
 prothallia were surrounded by the episporiura, and had 
 been produced from a sowing made in the middle of the 
 preceding August. Such was the result of chamber culture. 
 It is probable that in the natural condition the embryos 
 which break through the prothallium in winter do not 
 survive, and that those germ-plants only which are produced 
 in spring attain to a fm'ther development. 
 
 Soon after the appearance of the first leaf, the first root 
 also breaks through the prothallium. It bends itself down- 
 wards and penetrates into the mud, the leaf having a vertical 
 direction, inasmuch as being specifically the lighter portion 
 of the plant it stands erect in the water. The prothallium 
 is now attached laterally to the embryo. The thin mass of 
 cellular tissue at its apex forms a ring round that portion 
 of the germ-plant between the root and the front surface of 
 the leaf. The large-celled blunt end of the primary axis of 
 the young plant extends into the principal portion of the 
 prothallium, Avhose cell-contents, like those of the cells of 
 the first axis of the plant, henceforth become gradually 
 transformed into a transparent fluid. 
 
 After the breaking through of the leaf and the root, the 
 further development of the germ-plant ceases for about a ' 
 month. Expansion and multiplication of the cells of the 
 first leaf and of the first root still continue, taking place in 
 the former by intercalary multiplication of the cells of the 
 base of the leaf, in the latter by the growth of the apex. 
 But the formation of new leaves and new roots goes on only 
 slowly and gradually. 
 
352 HOFMEISTER, ON 
 
 The above-iiieiitioned two-fold lonoitudinal division of the 
 strino; of eloiiu;ated cells which hecoiiie dift'erentiated in the 
 interior of the leaf and root does not occur until after the lat- 
 ter have emerged from the prothalhum. The divisions appear 
 to take place contcmporaneouslj throughout the entire 
 length of both the cellular strings which unite underneath 
 the terminal bud. The division by transverse septa of the 
 basal cells of the leaf, continues even after the conunence- 
 nient of the formation of the vascular bundle, although in 
 a less degree ; and the cells of the string Avhich goes to 
 form the vascular bundles take part from time to time in 
 the division. One single longitudinal row of cells is en- 
 tirely exempt from it. This row originates in the middle 
 of the! fore side of the vascular bundle, by supplementary 
 longitudinal division of a row of carabial cells. In the 
 cells of this row, wdiose length — owing to the entire sup- 
 pression of all transverse division — far exceeds that of all 
 the neighbouring cells, thickened annular threads soon 
 make their appearance, passing here and there into spiral 
 threads (PI. XLVII, fig. 3). The continual longitudinal 
 growth of the surrounding tissue stretches and distorts the 
 young vessel, and removes the annular threads to a consi- 
 dei'able distance from one another. 
 
 In like manner there appears on the inner side of the 
 rudimentary vascular bundle of the root a row of elongated 
 spiral and annular cells of a prosenchymatal form like the 
 vessels of the leaf. In the first node of the plants, at the 
 place where the precursors* of the vascular bundles of the 
 leaf and root unite underneath the rudiment of the second 
 leaf, more than one of the longitudinal rows of cambial 
 cells assume a prosenchymatal form, and thickenings of the 
 walls are formed in all of them (PI. XLVIII, fig. 1). 
 These cells, which are the first rudiments of the wood, are 
 short and spindle-shaped, t and already bear some resem- 
 blance in form to the cells of which the principal mass of 
 the wood of the mature plant will consist. 
 
 Many of the cells of the tissue which adjoins the vascular 
 
 * Precurseurs Mirhel. 
 
 t The intercalary transverse division has not extended to the cells adjoining 
 these. 
 
THE HIGHER CRYPTOGAMIA. 353 
 
 biindles of the leaf and of the root separate at their edges, 
 and the intercelhilar cavities become filled with air. The 
 tissue which is filled with air soon dries up ; at last it 
 disappears altogether, and large air-cavities are formed ; — 
 four cylindrical cavities parallel to the axis are formed iu 
 the leaf, and are divided into a series of compartments by 
 persistent cellular surfaces ; in the root one large air-cavity 
 is formed in front of, and near to the excentrical vas- 
 cular bundle. 
 
 Whilst the base of the second leaf beo-ins to form a 
 sheath round the terminal bud, the latter produces the 
 third leaf at a point opposite to the second, and above the 
 first (PL XLVTI, fig. 3). At the same time the forma- 
 tion of the second root commences. It originates under 
 the second leaf, opposite to the first root, very near to the 
 first node, and is produced by the multiplication of a cell 
 adjoining the string of cells which goes to form the vascular 
 bundle. It is formed in precisely the same manner as the 
 first root, with which it makes an angle of about 30° open- 
 ing downwards. A plane passing through the longitudinal 
 axis of the first and second leaves and of the first root, 
 usually bisects the second root also ; small lateral deviations 
 are however not unconunon. The root in its longitudinal 
 development stretches the outermost cellular layer of the 
 rudimentary stem of the germ-plant to a considerable ex- 
 tent before it breaks through it (PI. XLVII, fig. 3). 
 
 The rudiment of the third root, like that of the first and 
 second, only becomes visible when the third leaf has 
 already attained a certain degree of longitudinal develop- 
 ment. It is produced, like the second, by the multiplica- 
 tion of a cell adjacent to the lower end of the precursor of 
 the vascular bundle, and to the rudimentary ligneous body 
 of the germ-plant, and originates consequently on the left 
 hand, close above the place of origin of the first root. In 
 its development it turns itself at once somewhat side- 
 ways ; it makes its way through the cortical tissue of the 
 stem of the germ-plant in a direction which diverges about 
 30° laterally from that of the first root. 
 
 The fourth and the following leaves, at least as far as the 
 
 23 
 
35 i HOFMEISTER, ON 
 
 eip:litli, exhibit the ^ arrangement.* The commence- 
 ment of the formation of each new leaf takes place some 
 time before the cessation of the growth {i. e., the cell-mul- 
 tiplication of the base) of the next preceding one. The 
 lowest part of the back of the leaves enters into the forma- 
 tion of the bark of the stem, like the base of the underside 
 of the leaf of the Equiseta, the Lycopodiaceae, and the phse- 
 noü'ams. The A arrano-emeiit of the leaves causes an 
 excessive increase in the mass of the cortical tissue at two 
 points of the circumference of the stem lying opposite to 
 one another, and corresponding with the dorsal surfaces of 
 the leaves. Here the bark is develo^Ded so as to form two 
 fleshy bodies widened at the base,t and spreading obliquely 
 do^vnwards from the ligneous body of the stem. These 
 bodies are separated from one another by a flat indentation 
 which is at right angles to the large horizontal axis 
 of the stem, and is the first rudiment of the characteristic 
 furrow of the unc^erside of the stem. 
 
 The development of each young leaf, and the growth in 
 thickness of its base, -^VQCQQiX pari jjassuwiWi the cell-multi- 
 plication in circumference and diameter, of the older 
 portion of the end of the stem, as well as of the base of the 
 preceding leaf by which the young leaf is sheathed. The 
 active increase in the number of the cells round the upper 
 end of the longitudinal axis, pushes the previously formed 
 portions of the circumference of the stem continually 
 fm'ther outwards. The latter are able to bear this pressure 
 for a long time by the expansion of their cells in a tangen- 
 tial direction. But in the plane which passes through the 
 small horizontal axis of the stem this expansion is ahnost 
 entirely suppressed. At this part the cortical parenchyma 
 splits from the outside (sideways and from below), at an 
 early period, by which means the furrow of the under side 
 of the stem is made much deeper. 
 
 Shortly after the commencement of the formation of each 
 new leaf, a new root is produced laterally beneath it ; the 
 
 * As Alex. Braun remarked in 1847 (' Flora,' p. 135), and which he pointed 
 out as the immediate cause of the bipartite arrangement of the stem of Isoetcs. 
 t This widening is due to the greater vigour of each new leaf. 
 
THE HIGHER CKVPXOGAMIA. 355 
 
 fourth being near to the second, and obhquely o])po.sitc to the 
 thh'd. The primary cell of the fifth root lies near the first, 
 exactly opposite to the third. The sixth originates near the 
 second obliquely opposite to the fifth. The places of origin of 
 the roots of the first year — as well as of all the successive 
 periods of vegetation — consequently all lie in a plane 
 passing through the indentation of the underside and the 
 terminal bud of the stem. The roots are developed in 
 ascending order. Each new root originates somewhat 
 higher up, and farther from the longitudinal axis of the 
 stem than the second preceding one, /. c, its next neigh- 
 bour underneath. The points of origin of the roots of the 
 first vegetative period form together an arc slightly convex 
 below (PI. XLIX, figs. 1, 1'')- During the development 
 and the penetration through the bark of the roots sub- 
 sequent to the third root, the former are compelled (like 
 the third root itself), to bend downwards towards the 
 furrow* of the stem, in order to avoid the vascular bundles 
 of the preceding roots. If the third root diverges to the 
 right of the longitudinal axis of the elliptical transverse 
 section of the stem, then the fourth will turn to the left of 
 it, the fifth also to the left, the sixth to the right, and so 
 forth. Each new root converges at a more acute angle 
 to the small horizontal axis of the stem ; the last roots of 
 the first year are almost parallel to that axis and to the 
 furrow of the underside of the stem (PI. XLVIII, fig. 5). 
 
 The roots as they break through the bark bend sharply 
 downwards, and appear on the underside of the stem 
 arranged in two rows almost parallel to the indentation of 
 the latter. The locus of the points of penetration of the 
 roots may be considered as forming an elongated ellipse. f 
 The roots which are nearest to the centre of the stem and 
 the lowest down, are the oldest, those which spring from 
 the wide lateral margins and are the highest up, are the 
 youngest. The vascular bundles of the third and following 
 roots, which are excentrical like those of the first and 
 second, are brought near to that side of the root which is 
 turned towards the furrow of the stem ; the excentricity 
 
 * This furrow becomes contiuuiiUy more and more clearly defined, 
 ■'f Von Moll!, 'Vermischte Schriften,' p. 137. 
 
356 HOFMEISTER, ON 
 
 is reckoned not with reference to the longitudinal axis of the 
 stem, but to a plane passing through this axis and the in- 
 dentation of the stem, in which plane the points of origin of 
 the roots are situated. 
 
 The tissue of the region of the stem in which the 
 closely crowded horizontal places of origin of the vascular 
 bundles of the leaves meet together, goes to form the 
 upward-growing portion of the proportionably slight woody 
 mass which occupies the longitudinal axis of the stem, but 
 encloses no pith. 
 
 In the germ-plant, as long as the Ä arrangement of 
 the leaves lasts, this upper half of the woody mass has a 
 two edged form. Its usually spindle-shaped cells — reti- 
 culated and spiral cells mixed with a few delicate walled 
 cells — have almost all the same direction ; they are parallel 
 to the larger transverse diameter of the woodv mass (PI. 
 XLVIII, figs. 2, 3 ; PI. XLIX, fig. 1*). A longitudinal sec- 
 tion through the furrow of the stem cuts all the wood-cells 
 transversely. As the arrangement of the leaves passes 
 through the g into the |, |, jl, and rfj arrangements, the 
 upper part of the woody mass becomes round, and the di- 
 rection and form of its cells very various, appearing at first 
 sight to have no regularity, owing more particularly to the 
 fact that now many other cells besides the primary cells of 
 the vascular bundles take part in the wood-formation. 
 Spiral cells are also formed which are situated between the 
 converging rudimentary portions of the vascular bundles ; 
 by this means the woody mass is closed up to the form of 
 a cylinder. 
 
 The closely crowded points of origin of the roots repre- 
 sent the under half of the woody mass : a row of spiral 
 cells concave above, at light angles to the larger horizontal 
 axis of the upper mass of wood, which latter in the first 
 vear is two-edged. 
 
 At the close of the first vegetative period of the germ- 
 plant the cells of the bark are filled with amyloid granules, 
 mixed with a few oil-drops. The cells, however, which 
 immediately surround the mass of wood retain their capa- 
 city for multiplication. Some time before the commence- 
 ment of the first period of winter-rest they have divided 
 
THE HIGHER CRYPTOGAMIA. 357 
 
 once, twice, or three times Iw septa parallel to the longitu- 
 dinal axis of the wood. Thus there is formed a mantle of 
 cambium surrounding the mass of wood on the sides and 
 from below, and passing above into the growing cellular 
 tissue of the end of the bud. 
 
 At the recommencement of vegetation in the second year 
 an active multiplication of the cells of this cambial layer 
 begins. The increase in size keeps pace with the growth 
 in thickness of the new portion of the stem produced by the 
 development of the terminal bud. The multiplication of 
 the cambial cells is most remarkable at the sides of the 
 mass of Avood ; it is less vigorous in that half of the cam- 
 bium which surrounds the lower, half-moon-shaped portion 
 of the woody mass. 
 
 The development of the cambium has pushed outwards 
 the cortical tissue which is filled with assimilated matter. 
 The vascular bundles are thereby nuich stretched, but not 
 so as to destroy them. The vitality of the cells of the 
 vascular bundles manifestly still exists ; by the expansion 
 of their own walls they follow the change of position of the 
 surrounding tissue. The thickenings of the walls of the 
 vessels are alone materially changed dm'ing these processes, 
 being loosened here and there and in other places distorted, 
 so that every trace of regular arrangement disappears (PI. 
 LXI, fig. 3). The function also of the vascular bundle does 
 not seem to have come to an end at the time of the com- 
 mencement of the vegetative period which succeeds its 
 formation. The starch and oil contained in the cells of the 
 bark of the previous year — which bark has been pushed 
 outAvards — are gradually sucked up and carried to the grow- 
 ing portions of the plant. At the end of each vegetative 
 year the cells of the bark of the preceding year contain only 
 a transparent fluid. 
 
 The old bark which is pushed outwards, gradually dies 
 from the periphery inwards ; its cell- walls assume a deep 
 brown colour, and ultimately the bark perishes. The new 
 bark behaves similarly to the old bark, in the fact that the 
 cells of the portion which clothes the furrow of the stem 
 only expand slightly in breadth. The indentation of the 
 stem already appears deeper than in the preceding year, on 
 
358 HOFMEISTER, ON 
 
 account of the less active development of tlie corresponding 
 region of the bark-forming cambium, and it becomes deeper 
 still by the regular tearing away of the tissue of the bark 
 from the sides, that tissue not being stretched transversel}'. 
 
 The roots of the previous year arc pushed for some dis- 
 tance outwards and downwards with the bark through 
 which they have penetrated. Like the latter they assume 
 n deep brown colour and die. 
 
 The new roots destined for the support of the plant 
 during the current period of vegetation originate on the 
 convex edge of the lower, half-moon-shaped portion of the 
 mass of wood, by the multiplication of some of the cambial 
 cells adjoining the wood. The nature of their cell-mvütipli- 
 cation corresponds in ahnost every respect with the account 
 given above of the first root. The only difference is that 
 during the passage through the bark the transient cellular 
 layers of the root-caps are inordinately developed, and the 
 permanent cortical layer of the root, on the other hand, very 
 slightly so. 
 
 The first root of the second year is formed close under 
 the place of origin of the first root of the germ-plant, at the 
 spot where the development of the cambium has torn oft' 
 the vascular bundle of the root about to be cast off — /. c, at 
 the place of attachment of the latter root. The second root 
 originates underneath the place of insertion of the second 
 root of the previous year, the third imder that of the third 
 root of the previous year, and so forth. In their direction 
 also the new roots agree entirely with the older ones. The 
 two first originate opposite to one another, trending away 
 from the lateral surfaces of the lower growth of wood, and 
 bent in different directions inter se. They break forth op- 
 posite to one another in a perpendicular direction imdcrncath 
 the terminal bud, on both sides of the furrow of the stem. 
 The third and following roots bend more and more side- 
 ways. The two last pairs of roots of one period of vegeta- 
 tion traverse the bark almost parallel to the furrov»' of the 
 stem. All the roots as they grow through the bark describe 
 a flattened are concave to the indentation of the stem. A 
 lons;itudinal section taken through that indentation lays 
 bare within each half of the stem onlv the rudiments and 
 
THE HIGHER CRYPTOGAMIA. 359 
 
 the tip of tlie older of the roots which are still hidden 
 within the bark : the middle portion of the root is bent 
 away from the plane of the section (PI. LI, fig. 1). 
 
 As in the first year so also in the following ones the bark 
 is pierced by the new roots close under the deepest part of 
 the indentation. The brown roots of the previous year 
 stand far outside those of the current year. Inasmuch as 
 many of them last for two, three, or four years before they 
 become quite decayed, the result is that in some plants, 
 especially the older ones, the peculiarity obsei'ved by Von 
 Mohl makes its appeai'ance with the greatest distinctness. 
 This peculiarity is, that the oldest roots are the outermost 
 and apparently the highest, the youngest the innermost and 
 apparently the lowest. As appears from what has been 
 said above, this is only an apparent irregularity, depending 
 upon the unusually vigorous development of the bark, and 
 its yearly reno^T.tion from within outwards. 
 
 It is a rule Avithout exception that the middle ones of 
 each series of generations of roots are the oldest, that those 
 which are nearer to the lateral terminal points of the furrow 
 of the stem break forth at a later period than those in its 
 middle point. This circumstance however is not unfre- 
 quently less striking, owing to the fact that the duration of 
 each root is far less strictly liuTjited to any definite period 
 than that of the leaves. The outermost roots of the pre- 
 ceding series are almost always in a state of vitality when 
 the first innermost ones of the next series begin to appear. 
 Old vigorous individuals which form a large number (as 
 many as twenty) of leaves in the com'se of one year, develope 
 during this period tioo complete series of generations of 
 roots ; the whole cycle, commencing with the lowest inner- 
 most roots and progressing to the outermost, is formed 
 twice in saccession (PI. LI, fig. 1). In the Isoetes from 
 South Europe and North Africa, which produce an abund- 
 ance of roots, as many as six generations of roots are pro- 
 duced in the same vegetative period. With the close of 
 each cycle of roots a double pair is added to the number of 
 the roots of the previous year, which double pair originates 
 at the horns of the half-moon-shaped lower portion of the 
 mass of wopd (PI. LI, fig. 1). 
 
860 JIOKMEISTETJ, ON 
 
 The position of the vasc-ular bundles of the roots remains 
 throughout the whole life of the plant the same as in the 
 first year : they are always brought close to that side of the 
 root \Ahich is turned towards the indentation of the stem. 
 The cambial cells bctAveen the places of origin of those 
 vascular bundles which pass to the new roots become for 
 the most part woody : individual cells only, situated between 
 the transformed annular and spiral cells, remain thin-walled 
 (PI. LI I, fig. 6). Thus the latterally compressed lower half 
 of the woody mass grows downwards at its convex edge, at 
 the same time increasing in diameter. 
 
 The roots of Isoetes usually ramify in a furcate manner 
 repeatedly — as many as four times — diuing their longitudi- 
 nal development.* Judging from the arrangement of the 
 cells of roots which have only just become forked, it would 
 seem that the furcation commences with the longitudinal 
 division of the cell of the first degree of the apex of the root, 
 by means of a septum at right angles to the larger trans- 
 verse diameter of the downward- growing wood (PI. LII, fig. 
 2). The forks of the roots separate from one another at an 
 angle of about 30°; the two first are parallel to the furrow 
 of the stem. The direction of the next ramifications differs 
 by about 90° from the former. The excentrical vascular 
 bundles of the forks of the root are always removed to that 
 side which is turned towards the sister-fork of the root 
 (PI. LII, fig. 3). 
 
 Every year the same processes are repeated. The old 
 bark is thrown off and replaced by new. The upper cylin- 
 drical portion of the wood grows upwards by the lignification 
 of those cells of the terminal bud which overlie its summit, 
 and by the addition of the rudiments of vascular bundles 
 intended for the new roots. Its lialf-moon-shaped lower 
 portion increases in circumference on the convex edge, by 
 the addition of the bases of the vascular bundles which 
 pass to the new roots. Thus the plant becomes continually 
 more vigorous ; the number of the leaves and roots increases 
 in each new vegetative period. 
 
 The abundant development of leaves, in connexion with 
 
 * Discovered by Alexandei- Brauu iu 1847. ' Flora,' p. 33. 
 
THE HIGHER CRYPTOGAMIA. 361 
 
 tlie entire suppression of intercalary cell-multiplication in 
 the joints of the principal axis, leads necessarily to the result 
 that the younger portion of the bark formed out of the con- 
 fluent basal portions of the leaves projects far beyond the 
 punctum vegetationis of the principal axis. The top of old 
 plants exhibits a remarkable funnel-shaped depression, upon 
 whose inwardly-inclined slope the younger leaves which 
 sheath one another are seated (PI. LI, fig. 1; PI. LII, fig. 1). 
 The terminal bud occupies the base of the crateriform de- 
 pression, exhibiting a blunt cone of cellular tissue (PI. L, 
 figs. 1, 2), surrounded at moderate distances by the rudi- 
 ments of the youngest leaves, which in plants of from five to 
 eight years old have the /j arrangement. 
 
 The nature of the cell-nmltiplication of the terminal bud 
 remains (as has been said) the same throughout the entire 
 life of the plant. The alternately oblique septa by which 
 the apical cell divides in repeated succession, are inclined to 
 the large lobes of the bark ; a plane passing through the 
 furrow of the stem cuts those septa at right angles. The 
 daughter-cells of the cells of the second degree soon divide 
 by transverse septa, and become cells of the third or fourth 
 degree (PL LT, figs. 1,2). Close under the apex of the termi- 
 nal bud the arrangement of the cells, which at first was 
 ladder-like, is changed into a concentrical scale-like arrange- 
 ment. The inner cells — those nearest to the axis of the 
 stem — of the derivatives of the third- and fourth-youngest 
 cell of the second degree, expand remarkably in width in a 
 direction radial to the longitudinal axis of the wood. By 
 this means the terminal bud, even above the place of origin 
 of the youngest leaf, is quite flattened (PI. L, figs. 1,2). 
 
 The effect of the yearly renovation of the cambial layer is 
 not only to increase and renew the cortical tissue, but ncAV 
 spiral cells also become added, although only sparingly, to 
 the wood of old vigorous plants. Lidividual cells of the 
 cambium, separated by two or three cambial cells from the 
 older principal mass of the wood, often exhibit thickenings 
 of the walls, Avhich by their delicacy and want of colour 
 betray their undoubtedly recent origin (PI. LI, fig. 2). 
 New elementary organs are never added to the oldest por- 
 tions of the wood, those namely which are formed in the one 
 
362 HOFMEISTER, ON 
 
 and two-year old germ-plant : the two-edged lower end of its 
 upper part retains its form unclianged during the entire life of 
 the plant (PI. LI, fig. 1 ; PI. Lll, lig. 1). The formation of 
 new wood around that already present seems only to last 
 during a few vegetative cycles. All longitudinal sections of 
 plants from three to eight years old exhibit a somewhat 
 exuberant enlarged growth of the wood close under the 
 upper end. This locus of the greatest thickness of the w^ood 
 consequently moves continually upwards during the develop- 
 ment of the plant. 
 
 The primary portions of the vascular bundles which 
 passed off into the leaves and roots formed many years pre- 
 viously, and which portions are attached to the wood, are 
 compressed by the cand)ium surrounding their sides, which 
 is always in a state of active vitality. Ultimately these 
 portions are torn off and pushed outwards, and the stump 
 Avhich adjoins the mass of the wood is grown over by the 
 cambium just in the same manner as the stem of a tree gets 
 rid of the boughs of its lower portion. 
 
 The vigorous leaves of plants of many years' growth ex- 
 hibit in their earliest stages, when viewed in front, the 
 ladder-like arrangement of their cells (PI. LII, fig. 7) which 
 is the necessary result of the mode of multiplication of the 
 cell of the first degree. This however soon becomes indis- 
 tinct by the rapid and vigorous development of the leaf in 
 thickness. Tlie form, when viewed from above, of leaves 
 which are somewhat more developed (PI. LI, fig. 5) leads to 
 the conclusion that now, after each two divisions by septa 
 at right angles to the fore and hind surfaces of the leaf, septa 
 are formed in the terminal cell at right angles to the lateral 
 surfaces of the leaf and turned towards its front or hind side. 
 
 Isoetes lacn-stris exhibits a manifest periodicity in the 
 interchange of sterile and fertile leaves. "^ Li the terrestrial 
 species this interchange is very striking. Microscopical 
 investigation shows that the rudiments of the leaves are 
 formed a full year before they are developed ; the fruit- 
 bearing ones being produced late in summer and in autumn, 
 and the sterile ones in spring and early summer. During 
 
 * Described by Alexander Brauu in tlie Tlora,' lSi7, p. o'l But see 
 BisclioO", 'Ki\vpt. Gewächse,' p. 84.. 
 
THE HIGHER CRYPTOGAMIA. 363 
 
 the winter tlie development of the leaves is considerably 
 retarded, but does not entirely cease. Those leaves which 
 are first formed in winter and make their appearance at the 
 end of the next autumn, are very imperfect. In the scanty 
 development of the leafy portion, and the vigorous develop- 
 ment of the base, they form the transition to the stipule-like 
 organ which in the terrestrial Isoetes, especially /. Durieui 
 and Hi/sfricV, appear at the commencement and the close of 
 every vegetative period.* In the semi-terrestrial species 
 such as /. velata and achj^ersa, the last leaves of the year 
 exhibit — in a more marked manner than /. lacusfris — a dis- 
 toi'ted leafy portion and an overgrown sheathing portion 
 whose cells are quite filled with starch and oil. 
 
 The scales of the first leaves only of the germ-plant origi- 
 nate immediately above the place of attachment of the leaf. 
 With the second leaf frequently, Avith the third and following 
 ones always, the case is different. Here the cell which by 
 the vesicular protrusion of its outer wall lays the foimdation 
 of the scale, is removed by at least one cell from the base 
 of the leaf (PL XLVII, fig. 8; PI. XLIX, fig. 1'). The 
 intercalary cell-multiplication of the base of the leaf takes 
 place with remarkable activity in tliis one cell and in those 
 cells which lie in the same horizontal plane. By this means 
 the scale is carried upwards to some height on the leaf (PI. 
 L, figs. 1, 2 ; PL LIII, figs. 2, 3). A flat three-sided cellu- 
 lar mass then sprouts forth from the leaf close under the 
 scale and covering the base of the latter (PL LIII, figs. 2, 3). 
 Beyond and over the sides of this cellular mass the two 
 lower angles of the triangular scale are developed in a down- 
 ward direction ; the base of the scale becomes heart-shaped 
 like the scales of the Polypodiaceas (PL XLIX, fig. 5), The 
 cells of the base, which are inserted in the tissue of the leaf, 
 exhibit a vitality which forms a marked contrast to the early 
 cessation of the growth of its free portion. The horizontal 
 row of cells produced by the multiplication of the first cell 
 of the second degree belono'ino- to the scale — vvliich cell is en- 
 closed by the substance of the leaf — is transformed by a 
 series of rapidly repeated divisions into a transversely-ex- 
 tended ellipsoidal cellular body, the two ends of which, by 
 
 * Alex. Braun, in ' Exploration Scientiüque de I'Algerie,' PI. 36, fig. 1*, 2i. 
 
364 HOFMEISTEH, ON 
 
 repeated multiplication of the cells, ultimately grow upwards 
 in such a manner that the base of the scale becomes a fleshy 
 mass of very small cells with turbid contents, having the 
 form of a horse-shoe opening upwards, and inclined inwards 
 to the longitudinal axis of the leaf. Underneath also the 
 exuberant growth of the base of the scale extends into the 
 three-sided slioot of the front surface of the leaf, partly 
 pushing forward the existing cellular tissue (PI. LIII, fig. 5). 
 As the longitudinal development of the leaf draws to a close, 
 those of its cells which adjoin the highly-developed base of 
 the scale become ligneous by spiral thickenings of the walls. 
 Almost all the cells of the interior of the ligule-like shoot of 
 the fore-side of the leaf take part in this wood-formation* 
 (PI. XLIX, fig. 1). In an upward direction it is only the 
 one cellular layer adjoining the place of insertion of the 
 scale which is transformed into spiral cells ; on the other 
 hand the whole of the tissue enclosed by the two horns of 
 the half-moon-shaped base of the scale becomes woody. 
 The middle of the lower end of the woody mass which is 
 produced at a late period reaches close to the axile vascular 
 bundle of the leaf. 
 
 The leaves of Isoefes lacustris which are formed in the 
 third year after germination, and are developed in the 
 fourth year, produce the first fruit. The rudiment of the 
 sporangium f is formed in the earliest youth of the leaf, at 
 the time of the commencement of the intercalary multipli- 
 cation of its base. Of the two cells into which — by a 
 tranverse septum — the cell underneath the place of inser- 
 tion of the scale is divided, the upper one becomes the 
 
 * First observed by Melteiiius, ' Liuusca,' ISl-Z. 
 
 f Schleiden, out of love for some supposed analoE^ies with the lower crypto- 
 gams, will ouly ajiply tlie term " sporangia" to the sporc-motlier-cells of the 
 mosses and vascular cryptogams. Like most other botanists, I use the term 
 "sporangia" for tiic fruit containing the spore-motlier-ccUs and spores, for 
 the capsules of mosses and liverworts, for the fruit of ferns and Lyeopods, and 
 for those portions of the fructification of the Equisetace:« and Riiizocarpese 
 which immediately enclose the spores. 1 do so because the term "sporangium" 
 was first applied to the fruit of ferns. It appears neitiier necessary nor advisa- 
 ble to use the same tirm for the Fungi, Lichens, and Algae, as is used for the 
 Characeaj, mosses and vascular cryptogams. Moreover the expression " spo- 
 rangium " is quite unnecessary in the case of the lower cryptogams. De- 
 script.ive botany already possesses a more than suDScieut number of suitable 
 names for the organs iu question. 
 
THE HIGHER CllYPTOGAMIA. 365 
 
 primary cell of tlie ligulate process which covers the base 
 of the scale, and the lower one becomes the primary 
 mother-cell of the sporangium (PL LIII, fig. 1). By 
 repeated divisions in all three directions, especially in a 
 longitudinal direction, the latter is soon changed into 
 an oval hillock of cellular tissue, whose longitudinal axis 
 coincides with that of the leaf (PI. LIII, figs. 2, 3). The 
 longitudinal and transverse divisions produced by septa 
 perpendicular to the front surface of the leaf, are more 
 active in each of the new outer cellular layers of the rudi- 
 ment of the fruit, which are formed by septa parallel to 
 the free outer walls of the cells of the upjDer surface. The 
 young sporangium soon becomes an oval cellular mass at- 
 tached to the leaf by a proportionably small basal surface. 
 The tissue of the leaf which adjoins the place of attach- 
 ment of the sporangium afterwards — when spore-formation 
 begins — overgrows the fruit on all sides, principally above ; 
 it forms a membranous border, reaching; far above the 
 sporangium, and is the veil of descriptive botanists (PI. 
 LIII, fig. 5). 
 
 Until shortly before the appearance of this last 
 growth of the base of the leaf, the sporangium con- 
 sists throughout of homogeneous delicate walled cells, 
 which now begin to be differentiated into three difierent 
 sorts of tissue. The two outermost cellular layers assume 
 more and more a tabular shape, and become the capsule 
 wall. The interior divides into groups of delicate-walled 
 cells in close connexion with one another — the primary 
 mother-cells of the spores — and into plates separating 
 these groups of cells from one another, and formed each of 
 two layers of cells whose intercellular cavities contain air. 
 The cells of the wall of the sporangium, as also those of 
 the tissue destined to produce the reproductive cells, con- 
 tinue to multiply by division for some time longer. The 
 cells of the plates which divide the portions of that tissue 
 from one another keep pace with the increase in size of the 
 sporangium by expansion of their walls (PI. LIII, fig. 4). 
 
 At last the spore-mother-cells separate from one another, 
 and assume a globular form (PI. LIII, figs. 6, 7, 8). In 
 the sporangia intended to form small spores, more generations 
 
366 HÜt'MElSTER, OxN 
 
 of spore-mothei'-cells are produced than in those which 
 form niacrosporcs ; the spore-niotlier-cells of the latter are 
 considerably larger. The spore-mother- cells, botli after 
 and before their individualization, exhibit a very distinct 
 large nucleus. By degrees the outline of the latter becomes 
 fainter ; at last the nucleus vanishes after tAvo flatly-spherical 
 accumulations of granular matter have made their appear- 
 ance between its periphery and the inner wall of the cell (PL 
 LIII, fig. 9). After the disappearance of the membrane of 
 the primary imcleus the above accumulations of mucilage 
 immediately assume an ellipsoidal shape, and appear as two 
 secondary nuclei (PL LIII, fig. 11). Sometimes the spore- 
 motlier-cell now divides by a transverse septum, after the 
 constriction of its contents at the equator (PL LIII, tigs. 
 10, 12), and each of the two halves— after the dissolution of 
 their ellipsoidal nucleus, and the appearance of two globular 
 daughter-nuclei — is divided into two daughter-cells having 
 the form of quadrants of a sphere (PL LIII, figs. 15 — 17). 
 Sometimes, however, the two secondary nuclei of the mother- 
 cell are dissolved before the commencement of the division 
 of the cell ; four tertiary spherical nuclei appear (PL LIII, 
 figs. 13, 14), and the cell divides at once into four daughter- 
 cells. This latter case is by far the most luiconnnon one. 
 At their first appearance the four nuclei usually lie in one 
 plane, and the four daughter-cells of the mother- cell (the 
 special-mother-cells) retain, as in the first case, the form of 
 quadrants of a sphere. It is only very rarely that the 
 special-mother-cells are arranged in the angles of a tetra- 
 hedron. The septa by which the special-mother-cells arc 
 separated are of a gelatinous nature. They swell up easily 
 and quickly in water. If their contents are made to contract 
 by the application of diluted acids, the cell walls swell up 
 into a mass similar to that into which the contents contract. 
 The special-mother-cells of the small spores separate very 
 shortly after their formation. AVhen separate they retain 
 their three-edged (rarely six-edged) form. Now, for the 
 first time — by analogy to the similar phenomenon in Equi- 
 setum — there is produced in each special-mother- celt a 
 daughter -cell, whose form exactly corresponds with that 
 of the special-mother-cell. The daughter-cell becomes 
 
THE HIGHER CRYPTOGAMIA. 367 
 
 clothed with an episporium (PL LIII, fig. 18), of the nature 
 described at the commencement of this chapter, and be- 
 comes free by the dissolution of the special-mother-cell, 
 some time before the rupture of the walls of the sporangium 
 permits the escape of the spores, whose outward ap- 
 pearance, when ripe, exhibits no farther change. The 
 special-mother-cells of the large spores, which have always a 
 tetrahedral arrangement, remain for a longer time united in 
 fours — even until after the formation of the exosporium.* 
 
 Alexander Braun's observations have shown that amongst 
 the species of Isoetes, those at least of the old world, 
 Isoetes lacustris is the only one which has only one furrow 
 on the underside of the stem. All others, the South-West 
 European and the North African species, have three, in 
 exceptional cases, four, deep indentations of the under 
 surface of the principal axis. The new roots break forth 
 from the base of the deep furrow ; ni the species which 
 inhabit dry localities these roots are far more numerous than 
 in Isoetes lacustris. Even in the three-furrowed species 
 the form and structure of the wood always corresponds 
 exactly with the number and position of the furrows of the 
 bark. The lower portion of the wood is three-armed : it 
 consists of three laterally-flattened arched masses of wood, 
 meeting at angles of 120°, and formed out of the closely 
 crow^ded rudiments of the vascular bundles of the roots, 
 and of the tissue between these vascular bundles, part of 
 which tissue is changed into spiral cells, and part remains 
 thin-walled. Where the number of roots is much greater 
 than in Isoetes lacustris, as is the case especially with 
 /. liystrix and /. Durieui, the development of the lower 
 part of the wood also is unequal. Each of the three arms 
 of the lower half of the wood meets one of the deep cortical 
 furrows (PI. LIII, fig. 20). The newly formed roots originate 
 the lower arched margin of the plate of wood ; they bend 
 in an arcuate manner, and breaking through the side-walls 
 of the furrow, make their appearance at the deejjest part 
 of the latter. Many cycles of roots are developed in each 
 vegative period ; I have seen as many as eight in old strong 
 plants of Isoetes Uystrix. In the greater number of the 
 
 * Wahlenberg, 'Flora Lapponica,' PI. xxvi, fig. 1, K. 
 
368 HOFMEISTER, ON 
 
 roots of such plants it is manifest that the uppermost roots 
 of the individual rows are the youngest, a fact which is 
 not so easily seen in Isoetes lacustris. In the three-furrowed 
 Tsoetes also the vascular bundles of the roots are excen- 
 trical ; they are pushed towards that side of the root which 
 is turned towards the cortical furrow in which the root 
 breaks forth. The yearly renewal of the bark by the de- 
 velopment of the mantle of cambium which also surrounds 
 the lower three-armed portion of the wood, causes the 
 removal of the older roots in a lateral direction away from 
 the indentation of the stem in which they first appeared, 
 and pushes them downwards and outwards. In the three- 
 furrowed species however this change of position is less 
 remarkable than in Isoetes lacusfris. 
 
 In the three-furrowed species the stem occasionally ex- 
 liibits a fourfold division ; this appears to happen most 
 frequently in Isoetes ienulssima, I found it to occur in 
 two specimens out of seven. In stems of this sort the 
 lower portion of the woody mass is four-armed. 
 
 The terminal bud of most of the three-furrowed Isoetes 
 is far more deeply buried than even in Isoetes lacustris 
 (PL LIII, hg. 21). This partly arises from the propor- 
 tionably greater number of the leaves, and the consequently 
 more rapid increase of the cortical tissue. One essential 
 cause of the phenomenon is, however, the circumstance that 
 the cambium-layer — which clothes the cylindrical portion 
 of the woody mass, and which becoming prominent at 
 three places, as in Isoetes lacustris, reaches to the outeruiost 
 ends of the upwardly- curved arms of the lower portion of 
 the wood — has far greater vigour, on account of the much 
 more considerable radius of the lower portion of the woody 
 mass. The activity of the numerous layers of cambial 
 cells, which are almost convex above, nmst necessarily in- 
 crease the mass of the bark more rapidly than is the case in 
 Isoetes lacustris. 
 
 The leaves of the three-furrowed species, the multiplica- 
 tion of whose cells usually agrees with that of Isoetes 
 lacustris, exhibit a far greater variety in their morphology 
 and anatomy. The stipule-formation mentioned in a previ- 
 ous part of this chapter is an example of this. The most 
 
THE HlGUEll CllYPTüGAMIA. 369 
 
 remarkable })lieiiomenoii, however, is that exhibited by 
 Isoeies Ifysfrid', and Duriciii, in the hgnification of the 
 masses of ceUular tissue of the bases of their leaves,* which 
 varies in the different varieties of these species. The 
 cells remain in the closest connexion, and are thickened in 
 a porous manner by the superposition of dark-brown layers 
 upon the inner walls, so that, as in Niphoholus cJiinensis, a 
 stony, closed bark is formed round the stem. By the 
 development of new leaves the lignified portions of the 
 bases of the leaves are pushed more and more outwards 
 and — after the death of the herbaceous parts of the leaves — 
 form a close spiny covering to the stem which can hardly 
 be cut with the sharpest knife, and is a sad hindrance in 
 the examination of these parts. 
 
 In the three -furrowed species of Isoetes, the end of the 
 stem, which occupies the base of the deep and steep depres- 
 sion of the top of the stem, is a wart of cellular tissue of 
 a much flatter form than in Isoetes lacustris. It grows 
 like that of /. lacustris, by continually repeated division 
 of the single apical cell. The nature of the cell-multiplica- 
 tion is, however, essentially different. The septa, an end- 
 less series of which appear in the apical cell, are turned 
 in three different directions. The apical cell has the form 
 of a three-sided pyramid, with the top timied downwards ; 
 the cells of the second degree are produced by the forma- 
 tion of septa successively parallel to each one of the lateral 
 surfaces (PI. LIII, fig. 22). The cells of the second 
 degree form a spiral, winding round the middle point of 
 the primary cell, which spiral, as far as observations have 
 hitherto gone, is always a right-handed one, and becomes a 
 snail-shell-spiral, in consequence of the fact, that the cells 
 of the second degree from the time of their formation 
 grow by expansion and multiplication in all three direc- 
 tions. 
 
 As far as observations have hitherto gone, all the septa 
 formed in the apical cell and turned in one of the 
 three directions, are at right angles to a plane passing 
 through that indentation of the stem which is nearest 
 to them. Consequently, in one of the most essential 
 
 * A. Brauu, 1. c, pp. 35, 30. 
 
 24 
 
370 HOEMEISTER, ON 
 
 features, the mode of groAvtli of the terminal bud of the 
 three-fiuTOwed species of Isoetes agrees with tliat of 
 Isoetes lacustris : the septa which appear in the apical cell 
 are tm-ned towards the furrows of the stem. 
 
 Isoetes lacustris — as is well known* — exhibits occa- 
 sionally, but rarely, a three-furrowed stem. Transverse sec- 
 tions of the stems of plants of this kindt exactly resemble 
 those oi Isoetes setacea. The lower part of the woody mass 
 has three short arms (PI. XLVIII, figs. 6, 7). The mode of 
 multiplication of the apical cell of the terminal bud is ex- 
 actly the same (PI. XLVIII, fig. 8). 
 
 Like the Selaginellse amongst the Lycopods, Isoetes, in its 
 mode of reproduction, resembles — more indeed than any 
 other cryptogam — that group of phgenogams wliich comes 
 nearest to the cryptogams, viz., the Coniferfe. The pro- 
 thallium, which consists of cells devoid of chlorophyll, 
 occupies a space not much greater than the maci'osporc 
 itself. It originates by free cell-formation in the interior 
 of the spore-cell. In both respects it comports itself in a 
 manner precisely similar to that of the albuminous body of 
 the Coniferse. The archeoonia of Isoetes in the most 
 essential features of their development and structure ex- 
 actly resemble the corpuscula of the Conifcra3. 
 
 Amongst the dioecious cryptogams — the cryptogams 
 with spores of two different sizes, of which the larger pro- 
 duce the germs of the second, spore-bearing generation, 
 and the smaller produce the spermatozoa by which the 
 germs are impregnated — Isoetes exhibits more clearly than 
 any other the necessity for the operation of both kinds* 
 of spores in the process of reproduction . In Pihdaria and 
 Marsilea the reproductive cells are surrounded by an 
 abundance of mucilage, which hinders the examination of 
 the spermatozoa, a state of things which occurs in many 
 of the lower ])lants and animals of the most different kinds. 
 In Salvinia observation is impeded by the firm adhesion 
 of the small spores, and by the difference in the time of 
 development of the microspores and macrospores when sown 
 contemporaneously. In Isoetes, on the other hand, the 
 
 * A. Brauu, ' Flora,' lSi7, p. 3i, 
 
 t Amongst more than 100 specimens I found only one of this kind. 
 
THE HIGHER CRYPTOGAMIA. 371 
 
 mode of appearance, and the abundance, of both kinds of 
 reproductive cells, are favorable to the observation of the 
 origin of spermatozoa in the smaller archegonial prothallia, 
 ancl not less so to the observation of the separate develop- 
 ment of the microspores and macrospores. 
 
 The germination of Isoetes, like that of the Ophioglossese, 
 is distinguished from that of the vascular cryptogams Avhich 
 have green prothalha in one essential point. In these the 
 lateral cell of the limited primary axis of the embryo, from 
 whose multiplication the (secondary) principal axis pro- 
 ceeds, lies in the apical region of the former. The leaf- 
 bearing principal axis developes the first leaf on the side 
 which is turned away from the apex of the primary axis ancl 
 towards the exit of the archegonium. The first leaf lies 
 above the principal biul, between it and the mouth of the 
 archegonium, as is the case with the Ferns and the Rhizo- 
 carpege. In Isoetes, on the other hand, the bud of un- 
 limited growth lies near the first adventitious root, close 
 under the canal of the archegonium, and the first leaf lies 
 under that bud. Judging from the position of the first 
 root on the germ-plant, Selaginella would exhibit a similar 
 state of affairs, were it not for the fact, that here the secondary 
 principal axis of the plant, instead of producing a leaf 
 close above its point of origin, divides into two branches, 
 having previously grown considerably in length, and having 
 produced a pair of opposite leaves. 
 
 In its vegetative development as well as in its fructifica- 
 tion and germination, Isoetes exhibits a remarkable agree- 
 ment Avith the Lycopods, in the fact that the wood-forming 
 tissue has no parenchymatous pith in the centre, but 
 occupies the whole of the longitudinal axis in the form of 
 a homogeneous woody body. Nägeli's investigations* have 
 shown that in Lycopodium a circle of vascidar bundles is 
 visible at first, but that after the differentiation of the 
 circularly-arranged longitudinal strings of a delicate cam- 
 bium, the whole of the axile tissue of the stem enclosed by 
 the latter enters into the formation of the wood, and is 
 afterwards changed from parenchymatal into prosenchy- 
 matal cells of various kinds. Thus in nearly allied plants, 
 
 * ' Zeitschrift für Botanik,' H. 3 and i, p. 140. 
 
372 HOI'MEISTEH, ON TilK HIGHEll CllYPTOGAMlA. 
 
 wliicli exhibit a considerable suppleiiientaiy longitudinal 
 development of the internodes, there is found the most 
 decided tendency to form an axile woody body, similar to that 
 whose production in Isoetes might — by the omission to 
 notice the analogous phenomena in the stem of Lycopodium 
 — be attempted to be brought into causal connexion with 
 the complete suppression of an intercalary multiplication of 
 the joints of the stem. 
 
 As far as om* knowledge extends, Isoetes alone of all the 
 vascular cryptogams possesses a cambium layer, which is 
 renewed yearly, and a stem which grows in length both at 
 the upper and lower ends ; peculiarities of which the one is 
 rendered necessary by the existence of the other. By the 
 organization of its stem, especially that of the downward- 
 growing portion of the wood, Isoetes approaches nearer to 
 Dicotyledons, — such as Cyclamen and Beta, — which have 
 undeveloped stem-joints and a stem which does not die from 
 below, than to the few Monocotyledons with diametrically- 
 increasing stems, such as Dracaena, Cordyline, and Tamus. 
 The mode of arrangement of the roots which spring from 
 the lower portion of the wood of Isoetes answers to that of 
 the adventitious roots which break forth in vertical rows 
 from the main root of dicotyledons, a phenomenon which 
 Schimper and Sachs* have stated and proved to be of uni- 
 versal occurrence. Some of the commonest plants in culti- 
 vation, such as turnips and radishes, exhibit such a manifest 
 regularity in the position and mode of succession of the 
 adventitious roots, that more certain general results may in 
 all probability be attained. 
 
 * ' Silzungsber. Wicucr Akad.,' 13. xxvi (1S5S), p. 331. 
 
CHAPTER XIV. 
 
 Selaginella. 
 
 In the species of Selaginella whose leaves have the 2J 
 arrangement and stand in pairs opposite to one another in 
 fonr longitudinal rows, the form of the growing end of the 
 stem is that of a cone much flattened laterall}^ It projects 
 far beyond the place of origin of the youngest pairs of leaves 
 (PL LIV, figs. 3, 5, 7"). The miütiphcation of the cells of 
 the end of the stem goes on in the young shoot of jS. horterms, 
 Metten, {denticidata hortul.) until the commencement of 
 the formation of the third pair of leaves, and in /S'. Galeoitii 
 until that of the sixth pair. The multiphcation is first pro- 
 duced by continual division of a single cell occupying the 
 apex of the blunt cone, by means of septa inclined alter- 
 nately to the right and to the left, always towards one of 
 the small sides of the terminal bud. The form of this cell 
 is that of a segment of an ellipsoid (PI. LIV, fig. 8 ; PI. LVI, 
 figs. 1, 3). The formation of the above septa, like all the 
 divisions of the cells of the end of the stem, is preceded by 
 the disappearance of the primary nucleus of the cell,* the 
 formation of two new smaller nuclei, and the appearance of 
 a dark line between the two newly-formed nuclei (PI. LIV, 
 fig. 9). This line is easily o1)literated, even by the continued 
 action of pure water; its direction indicates that of the 
 future septum. It is the side-view of the surface of contact 
 of the two halves of the contents of the mother-cell. 
 
 Contemporaneously with the commencement of a new 
 
 * This primary nucleus is a globular vesicle floatinp: freely in the fluid con- 
 tents of the cell which are rendered turbid by numerous granules. 
 
374 HOFMEISTER, ON 
 
 division in tlic apical cell, the second yonngest cell of the 
 stem which adjoins the apical cell divides into two halves 
 by a longitudinal septum cutting the narrow side of the 
 terminal Inid, and inclined towards one of the wide sides of 
 the end of the stem (PI. LVI, figs. 1*, l^. Each of the two 
 halves is divided by a longitudinal septum which is concave 
 towards the septum last formed, and cuts the boundary wall 
 of the adjoining cell, which latter cell was produced by the 
 multiplication of the next younger cell of the second degree. 
 Of the two cells into which each half is thus divided one is 
 turned towards the narrow, and the other towards the wide 
 side of the stem. The former is a four-sided prism, the 
 latter a three-sided one with curved lateral surfaces. The 
 four-sided daughter-cell then divides, by a septum parallel 
 to the longitudinal axis of the stem, into an inner and an 
 outer cell. Frequently in Seluf/inella Galeottii, less often in 
 other species, this latter cell-duplication is preceded by the 
 production of a septum which cuts the upper and the free 
 outer wall of the cell of the third degree at a very acute 
 angle (PL LVI, fig. 3). This mode of cell-multiplication 
 differs from what takes place in Selac/inella denficu/ata, 
 helvetica, viticulosa, Martensi, and others, where the more 
 ordinary cell-succession occurs, and the result of the differ- 
 ence is, that a half-girdle of wedge-shaped cells is interpo- 
 lated between each two of the groups of cells produced by 
 the multiphcation of a cell of the second degree. In this 
 case the division into an inner and an outer cell by a sejDtum 
 parallel to the axis of the stem, takes place only in the larger, 
 loAver half of the four-sided cell of the third degree. 
 
 The three-sided cell of the third degree of the stem of 
 Selaginella Jiorfensis, helvetica, kc. is divided into two un- 
 equal parts by the formation of a longitudinal septum 
 which is attached in a radial direction to the free outer 
 surface of the cell, very near to the original side-wall of the 
 cell of the second degree. The cells produced by the mul- 
 tiplication of the cell of the second degree are now all 
 divided transversely by membranes which are parallel to the 
 former boundary wall between the cell of the second degree 
 and the apical cell (PI. IÄY, figs. 8, 9). This latter divi- 
 sion usually occurs somewhat later in the inner cells than in 
 
OR OTHERWISE INJURE 
 THIS BOOK 
 THE HIGHER CRYPTOGAMIA. 375 
 
 the outer cells. In Sdag India Gal cot til the like divisions 
 are produced — by longitudinal septa cutting the free outer 
 surface of the cells — in both parts of the cell of the third de- 
 gree adjoining the periphery of the terminal bud, i. e. in the 
 upper wedge-shaped five-surfaced moiety, as well as in the 
 lower Avhich has six sm'faces. Division by a horizontal 
 transverse septum however only takes place in the inner cell. 
 By this means the difference in the mode of cell-multiplica- 
 tion from that which occurs in Selac/wella horten sis is re- 
 moved (PL LVI, fig.3).* 
 
 When the end of the stem is about to become forked 
 there occur — in addition to the divisions of the apical cell 
 by septa turned towards the narrow sides of the stem — 
 divisions by septa inclined alternately towards the wide 
 sides of the stem. The top surface of the terminal cell 
 assumes, in consequence, the form of a parallelogram. The 
 divisions of the apical cell in the four different directions 
 follow one another in a left-handed spiral, as far at least as 
 observations go. This second form of the divisions of the 
 apical cell commences at a very early period in Selaginella 
 hortensis — as early as the commencement of the formation 
 of the fourth pair of leaves of a segment of a shoot (PI. LIV, 
 figs. 11, 12); in Selaginella Galeottii and Martensi they 
 occur much later (PI. LVI, fig. 4). In Selac/inetla hortensis 
 the forking of the stem commences at a very early period. 
 A transverse section through the end of the stem imme- 
 diately underneath the apex, exhibits four axile cells, in 
 which no one of the three directions of space preponderates. 
 These cells are surrounded by a simple wreath of twelve 
 cells somewhat stretched in a radial direction. Each two 
 of them form one of the small sides, each four of them one 
 of the wide sides of the terminal buds. The laterally com- 
 pressed form of the stem is visible close under the apex of 
 its growing end (PI. LIV, fig. T). 
 
 At first the portion of the axis above the youngest leaf 
 increases considerably in thickness. The number of the 
 
 * My former notice of the succession of tlie divisions was (' Yergl. Unters.' 
 p. 112), that the division of each of the lialvcs into an inner and an enter cell 
 followed immediately after the ßrst division of the cell of the second degree, 
 llepeated investigations have proved to me that the former division is preceded 
 by a division produced by an almost radial longitudinal septum. 
 
37ß HOFMEISTER, ON 
 
 cells of its diiiiiieter and circimifcrenct^ is increased by re- 
 peated division of the two outermost cellular layers of its 
 lower part, by means of radial septa, and of septa parallel 
 to the longitudinal axis of the stem. Near the place of 
 origin of the youngest leaf the longitudinal growth of the end 
 of the stem of ^elafjlnella denticidata experiences a remark- 
 able acceleration, by the division of the cells of its outer 
 surface bv means of horizontal transverse septa (PL LIV'^, 
 fig. 8). 
 
 The formation of the two youngest leaves commences at 
 a distance of from eight to ten cells — reckoning down- 
 wards — from the apical cell of the terminal bud. Two 
 horizontal opposite rows of cells, each of which occupies a 
 fourth part of the circumference of the stem, become arched 
 outwards, and divide contemporaneously by septa inclined 
 downwards (PL LV, fig. 21). In the outer three-sided 
 prismatic ones of the newly-formed cells, division then 
 ensues by septa inclined in opposite directions (PL LV, figs. 
 22, 23). The young leaf, viewed from above, now appears 
 as a narrow seam surrounding a fourth part of the circum- 
 ference of the stem (PL LIV, fig. T). It grows rapidly in 
 length by continual division of the cells of its fore-edge by 
 means of septa inclined alternately towards the upper or 
 the under surface of the leaf (PL LV, fig. 23 ; PL LVI, fig. 
 12). This multiplication of the cells is far more active in 
 the middle of the fore-edge than at its sides. The form of 
 the leaf would sooner become pointed were it not for the 
 fact, that the two middle cells of the fore-edge frequently 
 divide by longitudinal septa perpendicular to the surfaces 
 of the leaf and slightly diverging from its longitudinal axis. 
 In the young state of the leaf one such division ahnost 
 always occurs after each two divisions by septa inclined to 
 the surfaces of the leaf. Similar divisions occur from time 
 to time in the outer of the cellular grou[)s near the middle 
 of the fore-edge of the leaf (PL LV, figs. 24, 25 ; PL LVI, 
 figs. 5, G). By this means the originally parallel arrange- 
 ment of the cells of the leaf becomes radiating and fan- 
 shaped. By the repeated division of all the marginal cells 
 of the leaf its base also becomes considerably widened. 
 The newly-formed basal cells do not amalgamate with the 
 
TUR HIGHER CRYPTOGAMTA. 377 
 
 neighbouring cells of the circumference of the stem, but 
 are developed independently, and form — when the leaf is 
 perfected — the basal appendages which are especially em- 
 ployed in the determination of the species. In the greater 
 part of its area the X^^ioiSelagineUaMartensi and /S'. Galeottii 
 continues as a double layer of cells ; only the cells of a wide 
 longitudinal strip adjoining the median line on both sides 
 divide repeatedly by septa parallel to the surfaces of the 
 leaf, alternating from time to time with septa perpendicular 
 to the sm'face. Both divisions occur oftener in the inner 
 than in the outer cells of the longitudinal ribs which are 
 thus formed, and which project on the underside of the 
 leaf. The string of narrowei' cells wliicli thus originates in 
 the longitudinal axis of the mid- rib is afterwards trans- 
 formed into a vascular bundle (PL LVI, fig. 11). 
 
 Contemporaneously with the commencement of the thick- 
 ening of the mid-rib, a longitudinal expansion of the apex 
 of the leaf begins, an expansion, that is, of the middle cells 
 of the fore-edge, which by their more frequent divisions 
 have in the mean time shot ahead of the neighbouring cells. 
 The walls of these become thickened ; in the place of the 
 faintly-green mucilage which has hitherto filled the cells, 
 sharply defined chlorophyll granules make their appearance 
 in the fluid contents, which have become transparent. 
 After the commencement of these processes a multiplica- 
 tion of the superficial cells of the base of the leaf ensues, by 
 the division of such cells, once at least, by longitudinal 
 and transverse septa perpendicular to the surfaces of the 
 leaf. The cells of the under-side divide once oftener than 
 those of the upper-side, such division being produced by 
 septa at right angles to the longitudinal axis of the leaf. 
 In the perfect leaf the cells of the under-side are always about 
 one half shorter than those of the upper-side, which latter, 
 instead, divide once oftener by longitudinal septa, so that 
 they are only half as wide as those of the under-side (PL 
 LVII, fig. 8). 
 
 The double row of cells of the upper surface of the leaf, 
 which lies in the angle between the leaf and the stem, and 
 inunediately adjoins the circumference of the stem takes 
 no part in these divisions. These cells remain consider- 
 
378 HOFxMEISTER, ON 
 
 ably larger than their neighbours (PI. LVI, fig. 12). Their 
 free wall becomes arched upwards ; the cell farthest from 
 the stem then divides by a septum inclined away from the 
 longitudinal axis of the stem. The double layer of cells 
 which rises in the form of a wall thus receives an addition 
 of a row of top cells. These continue to divide by septa 
 inclined alternately in two directions ; the result is that a 
 flat membranous cellular body is produced from the upper 
 side of the base of the leaf (PI. LV, figs. 26, 27 ; PI. LVI, 
 figs. 11, 12). This body was first observed by R. Müller,* 
 and is a kind of ligulate formation, most nearly resembling, 
 on the one hand the coronet of the perigone of the Narcissi 
 and the ligule of the grasses, and on the other hand the 
 scale in Isoetes. I shall merely call it a stipule. 
 
 The cells of the stipule which are raised above the 
 surface of the leaf very soon divide by longitudinal septa 
 perpendicular to the upper and under side of the stipule 
 (PI. LVI, fig. 9), and afterwards also by transverse septa 
 at right angles to the surfaces of the organ. This multi- 
 plication continues in the base of the stipule for some time 
 after the multiplication of the apical cells has ceased (PI. 
 LVI, fig. 11). 
 
 At a later period the number of the cells of the organ in 
 the direction of the thickness, is increased by the division 
 of the cells of its lower portion parallel to the surface (PI. LV, 
 fig. 27 ; PL LVI, figs. 11, 12). The double row of basal 
 cells sunk in the substance of the leaf does not increase in 
 number, but the cells increase considerably in size. As 
 the longitudinal growth of the stipule draws to a close, its 
 apical cells, in Selapnella Galeoftii and others, divide 
 only by transverse septa perpendicular to the surface. Tlie 
 upper end of the stipule becomes a simple cellular layer. 
 The margin, in all species, exhibits a delicate fringe, caused 
 by tlie pa])illate outgrowth of individual cells (PL LV, 
 fig. 28). The cells of the stipule contain granular mucilage 
 which is colourless or grey or — under transmitted light — 
 of a reddish colour. They never contain chlorophyll. 
 Like the stipules of the greater number of those phsenogams 
 in which stipules occur, the development of the stipule of 
 
 • 'Bot. Zeit.,' 1846. 
 
THE HIGHER CllYPTOGAMIA. 379 
 
 Selaginella terminates long before that of the leaf to which 
 it belongs. It is only to be fonnd in full vitality amongst 
 the closely crowded leaves of the bud ; in the axils of 
 those leaves betAveen which the last longitudinal expansion 
 of the stem began it is always shrivelled and inconspicuous. 
 Spring, who has written a monograph of the family, has 
 not himself seen the organ. 
 
 That region of the young leaf which, by repeated division 
 parallel to the surface of the cells of the underside, becomes 
 transformed into the mid-rib, corresponds exactly in breadth 
 with the place of attachment of the leaf. This breadth in 
 the youngest state of the leaf, and up to the time when the 
 formation of the mid-rib begins, is equal to one fourth part 
 of the circumference of the stem. It is afterwards much 
 less, inasmuch as after the commencement of the formation 
 of the leaf the number of the cells of the circumference 
 of the stem continues to increase. Each of the transverse 
 rows of cells of the circumference of the stem — by whose 
 multiplication a leaf is produced belonging to one of the 
 four longitudinal rows in which the leaves of the greater 
 number of the species of Selaginella are arranged — stands 
 immediately above the place of insertion of the next lower 
 leaf (PI. LV, figs. 11, 12). The circumference of the stem 
 becomes thickened as in the Equisetacepe by the growth in 
 thickness of the bases of the leaves, which originate close above 
 each other, and by the often repeated division, parallel 
 to the longitudinal axis of the leaf, of the cells of the base 
 of its under-side. Its periphery appears to be formed of a 
 number of cellular layers produced by the multiplication of 
 the cells of the yomig rudiment of the leaf (PL LV, 
 fig. 11). The axile cells of the stem which correspond 
 with the naked end of the bud — which naked end projects 
 above the rudiment of the youngest leaf — enter for the 
 most part into the formation of the vascular bundles and 
 the parenchyma between them. 
 
 AVhen the leaf is almost fully formed every otlier one of 
 
 its marginal cells expands laterally into a blunt papilla, 
 
 whili becomes rapidly elongated, often to a very consider - 
 
 able extent, as for instance at the base of the upper leaves* 
 
 * Tlie " lutermediären Blatter " of Spring. 
 
380 HOFMEISTER, ON 
 
 of Selaginella Martensi. The papilla assumes a conical form. 
 The sharp apex of these unicellular hairs, which represent 
 the teeth of the margin of the leaf, are soon entirely filled 
 by rapid thickening of the walls. The conical mass of cel- 
 lulose often bears a deceptive resemblance to a small cell, 
 owing to the seam of light which its edges exhibit when 
 seen with transmitted light (PI. LYI, fig. 7). The two 
 rows of cells of the upper side of the leaf which immediately 
 adjoin the marginal cells, exhibit in many species definite 
 appendages of the outer wall. Yox instance, S. Galeoftii 
 has two longitudinal rows of bluntish warts, similar to those 
 on the outer side of the hairs of many Boraginese (PL LVI, 
 fig. 7). 
 
 Numerous chlorophyll-granules are formed in the narrow 
 cells of the upper surface of the leaf In >S'. Galeottn and 
 Martensi they have a distinctly vesicular appearance, and 
 contain some very small starch granules. In the square 
 cells of the underside of the leaf the green mucilage 
 coagulates into a single large spherical ball, as is the case 
 in Anthoceros (PI. LVI, fig. 8). At the places where the 
 cells of the under-siu-face of the leaf adjoin those of the 
 upper, a connected net-work of air-cavities is produced by 
 the parting asunder of the edges of contact of the cells of 
 the under side from the closely connected cells of the upper 
 side of the leaf. The place of contact of each cell of the 
 under surface of the leaf with the cells of the upper surface 
 is surrounded by an air-cavity which is usually six-sided. 
 Towards the outside the cells of the under-side of the leaf 
 are in close connexion. 
 
 The Lycopodiacese in general, and especially the 
 species of Selaginella, whose stems are elliptical in a trans- 
 verse section, aff'ord some of the most marked instances of 
 true forking of the apex of the stem, which are to be found 
 in the whole of the vegetable kingdom. In all species 
 of Selaginella, whose leaves have the 1\ arrangement, 
 a forking of the stem occurs, almost without excep- 
 tion,* after each four circuits of leaves ; and the same 
 thing occm'S also in those species whose shoots are appa- 
 rently quite simple and undivided for a considerable dis- 
 
 * The only exceptions I know are seen now and tlien in S, helvetica. 
 
THE HIGHER CilYPTOGAMIA. 381 
 
 tance. In /S. viiiculosa and cordifolia also, a iiidinientary few- 
 leaved axis may be found on the lower part of the upright 
 shoots of the second order which spring from the creeping 
 stem : it is situated between each fourth upper and under 
 leaf, and is hidden alternately in the right and left edge 
 of the stem. If the upright shoot is broken off, these 
 buds, which otherwise remain dormant, arc developed into 
 upright shoots. 
 
 When the end of the stem is about to fork, the apical 
 cell divides by a vertical septum, instead of by a septaui 
 inclined in the opposite direction to the septum last 
 formed. In both the newly-formed cells this division is 
 usually repeated once or several times (PI. LVI, figs. 1', 9, 
 10), Avhilst the number of cells of the next lower portion of 
 the stem in the direction of the largest transverse measure- 
 ment of the two edged stem is correspondingly increased by 
 repeated longitudinal divisions. In the two outermost cells 
 of the row of cells thus formed which crowns the apex of 
 the end of the stem, a division ensues by a septum 
 strongly diverging from the axis of the shoot. The wedge- 
 shaped one of the tAvo newly formed cells is immediately 
 divided by a septum inclhied in the opposite direction. 
 Thus the development of two new shoots^ in the manner 
 pointed out in a previous part of this chapter, is brought 
 about (PL LV, fig. 10). This happens normally imme- 
 diately after the commencement of the formation of the 
 last leaf of the forking shoot, even before these leaves are 
 clearly visible above the circumference of the stem. 
 
 JMany species, for instance S. Martensl, Galeotfii, and 
 viticulosa, exhibit a feature which is found in the Aneurse. 
 Either the right or the left fork of the stem, alternately, 
 developes itself more vigorously than the other, and soon 
 pushes the latter entirely on one side. These species seem 
 to be furnished with a principal shoot, which sends forth 
 adventitious shoots to the right and to the left. On the 
 other hand, in S. hortensis, helvetica, Sj'c, the forks of the 
 terminal bud are developed quite equally in length and 
 thickness. The forking end of the stem here assumes at 
 first the shape of a spatula (PI. LIV, figs. 7", 10) ; in con- 
 sequence of the rapid development of the forked shoots con- 
 
382 HOFMEISTER, ON 
 
 stitutiiig the edges of the spatula-like fiat cellular mass, 
 the fore-edge of the latter soon appears deeply indented 
 (PL LIV, figs. 3, 5). In one respect, however, even here 
 there is a preponderance of the development of one branch 
 of the fork ; the right or left fork, alternately, forms 
 a primary \eai* before its sister-shoot, even before the divi- 
 sion of the end of the stem is manifest. This leaf, there- 
 fore, appears to be situated on the middle of the underside 
 of the forking end of the stem (PI. LIV, figs. 5). By the 
 subsequent growth of the shoot it is pushed more on one 
 side. 
 
 Each shoot of Selaginella is traversed in its upper portion 
 by two thin cylindrical woody bundles, whose position 
 corresponds with the foci of the ellipse represented by the 
 transverse section of the stem. Towards the base of the 
 shoot, near the points of junction with the other branch of 
 the fork, the two bundles unite to form one (PL LIV, fig. 3). 
 The differentiation of these vasciuar bundles from the 
 surrounding tissue of the stem first takes place in Selaginella 
 Galeottii underneath the second youngest pair of leaves. 
 The cells destined to form the vascular bundle lag beliind 
 the neighbouring cells in transverse division, and divide 
 repeatedly by longitudinal septa radial to the axis of the 
 stem and parallel to it. This takes place even later in 
 S. horteusif^, some time after the commencement of the 
 forking of the naked end of the shoot in question. In 
 this species the remarkably regular fm'cation of the vascnlar 
 bundle of each shoot f is manifestly in connexion with the 
 succession of the forkings of the stem. 
 
 The cells immediately adjoining the vascidar bundles 
 take no part in the remarkable longitudinal expansion of 
 the cells of the stem by which the leaves are removed far 
 from one another, and the first clear distinction between 
 stem and leaves is produced. The stretching of the neigli- 
 boming cells of the bark and of the pith, as well as of the 
 vascidar bundle itself, soon removes those cells from one 
 another, so that they have the appearance of proportionably 
 thin threads, which unite the vascular bundle — which is 
 
 * Feuille primaire. Spring. 
 
 t See ' Kaulfuss Wesen der Tarrnkräuter,' p. 25. 
 
THE HIGHER CRYPTOGAMIA. 383 
 
 placed in the middle of a hollow cylindrical air-cavity — 
 with the remaining tissue of the stem (PI. LVII, fig. 11). 
 These cells afterwards divide by a transverse septum, once 
 at least in those species in which the air-cavities have a 
 proportionably narrow diameter, and several times in those 
 species where the air-cavities attain a considerable develop- 
 ment, as in SelaginelJa helvetica. 
 
 A string of cells passing from the vascular bundles of 
 the stem through the thickened longitudinal axis of each of 
 the neio-hbourino; leaves, becomes transformed into a vas- 
 cular bundle whose nature and structure resembles in its 
 essential features those of the stem. The formation of the 
 vascular bundles always commences earlier in the stem 
 than in the leaves ; it progresses from the former towards 
 the latter (PI. LVI, fig. 11). 
 
 Adventitious roots spring from the forks of the stem ; in 
 8. denticulata and helvetica they spring from each fork, after 
 the commencement of the final longitudinal expansion of 
 the stem. In S. Martensi and Galeotfit, and still more so 
 in S. viticulosa the upper ramifications of the upright 
 shoots, which have a tendency to produce fruit, are apt to 
 be devoid of roots. The root is always situated in the 
 angle of the primary leaf, which in the bud apparently 
 occupies the middle of the forking end of the stem. It 
 originates on the outer side of the transverse junction which 
 in the fork of the stem unites the two vascular bundles 
 (PL LIV, fig. 3). The mode of cell-multiplication in the 
 growing tip of the root exactly resembles that in the Equi- 
 setaceae and Polypodiacese ; the examination of it is much 
 more difficult than in the latter plants on account of the 
 smallness of the cells. The roots of the Selaginellae, like 
 those of the Lycopodiacese in general, are usually several 
 times branched ; they exhibit the most regular furcations 
 in two directions diverging from one another at about 90°. 
 The first fork of a root is usually parallel to the surfaces 
 of the leaf in whose axil it has originated, and the second 
 at right angles to those surfaces.^' The outer side of the 
 root-cap is often clothed with long papillae, which, as the 
 
 * The relation is very manifest in the roots of S. Galeottii, and Martensi 
 wliich ramify frequently high above the ground. 
 
384 HOFMEISTER, ON 
 
 organ becomes fmtlier developed, arc thrown off with the 
 cells which bear them. The adventitious roots of the larger 
 species fork frequenth'^ even long before they reach the 
 ground. Those of S. hortensis usually ramify for the first 
 time after they have penetrated into the ground. TliCv 
 foundation for the first ramification is however here also 
 laid at an earlier period. The aerial roots as soon as they 
 have reached a certain stage of development exhibit a 
 spherical enlargement of the end.* This thickening of the 
 tip of the root is formed by the commencement of fm'cation : 
 the lenticular cell of the first degree of the root has divided 
 by a longitudinal septum into halves, each of which com- 
 mences an independent multiplication in a direction away 
 from the other. The two rudimentary branches thus formed, 
 surrounded l)y the outer cellular layers of the root, which 
 were formed before the commencement of the forking, con- 
 stitute the almost spherical mass of the end of the root. 
 
 It is a known fact that the smallest fragment of the stem 
 of Selaginella when properly treated — that is, kept moist 
 and warm upon loose earth — will produce a new plant. 
 This depends upon the production of adventitious roots in 
 definite positions : in the angles formed by the vascular 
 bundles w^hich branch off into the leaves with the vascular 
 bundles of the stem. The adventitious shoot breaks through 
 the cortical layer of the stem and is developed into a new- 
 plant by a succession of shoots, in the same manner as 
 an embryo is produced by impregnation of an archeog- 
 nium, after an adventitious root has grown out close to its 
 place of origin (PI. LVI, fig. 10). 
 
 Fruit is formed in Selaginella only on particular shoots 
 differing greatly in their habit from the vegetative shoots. 
 The branch destined to develope sporangia is, like the 
 vegetative branches, a fork of the naked end of the shoot 
 of the preceding order. It is distinguished from the vege- 
 tative shoots even in its earliest condition by a far less rapid 
 increase in length, so that, even in Selaginella denilculaia, 
 it is soon pushed to the side of the vegetative shoot — whose 
 direction is the same as that of the shoot of the preceding 
 order — and might be taken for an immediate prolongation 
 
 * Kaulfuss, Wesen der rarrnkräuter,' p. 64. 
 
THE HIGHER CRYPTOGAMIA. 385 
 
 of it (PL LIV, fig. 3). The mode of cell-multiplication in 
 the growing end of the fruit-branch resembles that of the 
 terminal bud of vegetative shoots (PL LV, fig. 29), with 
 this difference only, that the growth in thickness is uniform 
 on all sides. The transverse section of the fruit-branch is 
 circular not elliptical. 
 
 A sporangium is produced in the axil of each of the 
 equal-sized leaves of the fruit-branch — which leaves have 
 the 2^ arrangement — with the exception of the two or three 
 first, lowest leaves. The first rudiment of the sporangium 
 is produced by the division, by means of a septum almost 
 perpendicular to the outer sm^face of the terminal bud, of one 
 of the cells of the circumference of the stem close above the 
 middle point of the place of attachment of the youngest 
 leaf. This is followed by the production of septa at right 
 angles to that surface in the sporangia! cells of the second 
 degree, and of septa parallel to it in the sporangial cells of 
 the third degree (PI. LV, figs. 1, 2). As soon as 
 the organ has the appearance of a hemispherical lateral 
 outgrowth of the end of the stem, a central cell may 
 be seen, surrounded by a simple layer of cells, and borne 
 upon a short stalk consisting of a few cells. In SeJar/ineUa 
 helvetica this central cell iö much larger than its neighbours 
 (PL LIV, fig. 2). In 8. horfensis the cells which bear it 
 divide for the first time at a late period by septa paraUel to 
 the longitudinal axis of the sporangium. In this species 
 the cell in question appears as the uppermost of a string 
 of cells traversing the axis of the rudimentary sporangium- 
 (PL LV, fig. 3). 
 
 The enveloping cells divide repeatedly by septa perpen- 
 dicular to the outer surface of the young fruit, alternating 
 twice with septa parallel to that sm-face. The wall of the 
 sporangium soon becomes a double cellular layer and ulti- 
 mately a triple one (PL LV, figs. 4 — 6). The cells of the 
 stalk also divide repeatedly by septa parallel to the longitu- 
 dinal axis and perpendicular to it ; the stalk of the sporan- 
 gium rapidly becomes both longer and thicker. In the 
 mean time the central cell also multiplies, although more 
 slowly, by repeated bipartitions in all three directions 
 (PL LX, figs. 4, 5). In a mass of fruit of Selaginella 
 
 25 
 
38G HOFMEISTER, ON 
 
 even tlie fifth-youngest sporangia have the appearance of a 
 central group of larger cells (the mother-cells of the spores) 
 Avith grumous contents and large nuclei, surrounded innne- 
 diately by a layer of delicate, mucilaginous, radially- 
 extended cells, similar to those which surround the string 
 of mother-cells of the anthers of phaenogams. This layer 
 is followed by a layer of tabular, thick-walled, chlorophyll- 
 bearing cells, which supports the epidermis of the sporan- 
 gium : these chlorophyll-bearing cells are radially-extended 
 prismatic cells with watery fluid contents ; in the young 
 fruit they are four times smaller than the chlorophyll- 
 bearing cells immediately below : when the fruit is 
 almost ripe they are — in consequence of repeated divisions 
 — almost sixteen times smaller than the same cells (PI. 
 LV, figs. 5, 6, 16). 
 
 This multiplication of the cells of the young sporangium 
 takes place mainly in the direction of the breadth ; the 
 organ assumes the form of a laterally-flattened ellipsoid, 
 which in the macrosporangia passes by degrees into the 
 shape of a kidney, and in the microsporangia becomes 
 more elongated. The leaf in whose axil the sporangium 
 originates, does not begin to develop its stipule until a 
 later period, when the young fruit has attained a con- 
 siderable size, and the central group of spore-mother- 
 cells has almost completed its Ml number (PI. LIV, 
 figs. 3, 4). 
 
 The mode of development of the sporangium shows 
 most distinctly that the latter cannot be considered as a 
 transformed portion of a leaf, unless * the group of cells 
 which is formed close above the place of insertion of the 
 stipule, above the apex of the angle between the latter and 
 the stem, is considered as belonging to the leaf and not to 
 the stem. This supposition is only difficult to reconcile 
 with the observed youngest conditions of the leaf and spo- 
 rangium. The young rudiment of the fruit, wdien consist- 
 ing of only very few cells, is generally situated on the 
 outer surface of the end of the stem (which outer surface is 
 turned towards the leaf,) even in those species, like Sela- 
 ginella helvetica and spinulosa, whose sporangia, when only 
 
 * See voii Molil ' Vermischte Schriften,' p. 106. 
 
THE HIGHER CRYPTOGAMIA. 387 
 
 slight!}^ developed, are pushed so far upwards on the upper 
 surface of the next lower leaf that they appear to form a 
 portion of it (PL LIV, fig. 1 ; PI. LVI, fig. 30). In the 
 vascular cryptogams there are the like difficulties in obtain- 
 ing a clear idea of the relation of the sporangium to the 
 leaf, as are met with in observing the relations between the 
 placenta and ovules of phsenogams, and the carpels. The same 
 considerations must find a place here, and on this account 
 I would withdraw my former assent to the explanation * of 
 the sporangium of Selaginella given by Bischoff*, who 
 described it as a metamorphosed axillary bud, and adopt 
 von Mohl's view, the probability of the correctness of 
 which is supported by the relation between the sporangium 
 of Isoetes and its leaf and leaf-scale, the latter being the 
 manifest analogue of the stipules of Selaginella. 
 
 As the sporangium becomes older the spore-mother-cells 
 become individualised, after a moderate thickening of their 
 walls. They then form spherical cells with turbid mucila- 
 ginous contents and a rather large nucleus. They are 
 closely crowded together and fill the cavity of the fruit 
 (PI. LV, fig. 6). 
 
 Up to this point the history of the development of all 
 sporangia is the same. Henceforth however, as in all the 
 Rhizocarpeae, the subsequent development exhibits essen- 
 tial differences, according as the sporangia are destined to 
 become microsporangia or macrosporangia, i. e. to produce 
 small or large spores. In Selaginella hortensis the lowest 
 sporangium only of each mass of fruit becomes a macro- 
 sporangium ; that one, namely, which is formed in the axil 
 of the lowest one of that longitudinal row of aristate 
 leaves which is situated vertically over the last primary leaf 
 on the right or left side of the shoot of the preceding 
 order. By the rapid and remarkable increase in size of the 
 fruit the latter grows beyond the lateral margins of its own 
 covering leaf, so that the two next lower ones also, which 
 are sterile leaves belonging to other longitudinal rows of 
 the fruit-ear, have to take part in covering the fruit. 
 
 Of the many free spherical cells of the interior of the 
 young macrosporangium, one single cell only, not distin- 
 * ' Vergl. Unters.,' p. 119. 
 
388 HOrMElSTER, ON 
 
 guislied in any respect from the others,* JDecomes slightly 
 increased in diameter, its primary nucleus becomes dis- 
 solved, and foiu- new nuclei are formed. This cell then 
 divides into four tetrahedral daughter-cells, the special- 
 mother-cells of the spores, by six septa cutting one another 
 at angles of 120° (PI. LA^ fig. 7). Almost immediately 
 afterAvards there is formed in each of the special-mother- 
 cells a cell almost filling the latter, and having at first very 
 delicate wahs. This cell is the spore. The four spores 
 innnediately begin to become individualised by the gradual 
 dissolution of the wall of the special-mother-cells (PL LV, 
 figs. 8, 9, 10), and they assume a spherical form. The 
 loci of the commissures of the special-mother-cells are 
 indicated by very shghtly prominent ridges (PL LV, figs. 
 11*, 12*). The product of the dissolution of the special- 
 mother-cells (which cannot be seen by direct observation) 
 appears to retain the spores for some time longer in some- 
 what close proximity. 
 
 Soon after the separation of the spores the formation of 
 the outer spore- membrane commences. The inner trans- 
 parent layer t is first visible (PL LV, fig. 11*), and soon 
 afterwards the outer one also, which is composed of a quan- 
 tity of two different substances varying in their refractive 
 power. Both layers take part in the composition of the 
 long spines of the exosporium, which are united by reti- 
 culate ridges (PL LV, tig. 17). During their formation 
 the three converging ridges at the top of the spore become 
 somewhat more conspicuous ; each of them now appears 
 to be traversed by a fine longitudinal fissure. The spines 
 appear as slight projections of the inner glassy layer 
 (PI. LV, fig. 18), and gradually increase in length. AVhen 
 quite ripe they appear considerably shorter than when 
 half-developed. It would seem that the pressure which 
 the rapidly -growing spores exert upon one another breaks 
 
 * In some cases I was convinced that this cell floated almost in the middle 
 of the macrosporangium. At the time when one of the free spherical cells be- 
 comes (by division into four) the mother-cell of the spores, tlie free spherical 
 cells no longer entirely fill the inner cavity of the macrosporangium ; a space 
 filled with watery fluid is found above the place at which the stalk is attached 
 to the capsule. 
 
 f Under transmitted light this layer is at first as clear as glass, then straw- 
 coloured, and ultimately brown. 
 
THE HIGHER CRYPTOGAMIA. 389 
 
 off the points of the spines. Shortly before the sponta- 
 neous rupture of the macrosporangium the spores adhere 
 rather firmly to its inner wall by means of their spines. 
 
 During the formation of the large spores the macro- 
 sporangium changes its form very considerably. By a 
 vigorous local multiplication and expansion of the cells of 
 the wall, two hemispherical protuberances of the latter are 
 formed in the middle of the two lateral surfaces of the reni- 
 form sporangium which are turned towards the stem and 
 the covering leaf. This occurs even long before any one of 
 the four spores has touched the inner wall of the sporan- 
 gium (PI. LV, fig. 11"). The top of the organ also becomes 
 more steeply arched. At this time the spores still float 
 freely in the watery contents of the macrosporangium, in 
 company with the numerous unchanged sister-cells of the 
 one spherical cell, which, by its division, becomes the mother- 
 cell of the spores. Four or more of those small delicate- 
 walled cells are often found still loosely adhering to one 
 another, a remnant of the innate connexion which in the 
 earlier stages of development of the sporangium subsisted 
 amongst the mother-cells. The layer of radially-extended, 
 mucilaginous, actively-multiplying cells which clothes the 
 inner wall of the capsule exists up to this time. It disap- 
 pears with the further development of the spores, and the 
 wall of the sporangium when almost ripe consists of only 
 two layers of cells (PL XLI, fig. 16). 
 
 The development of the large spores of many other 
 species, especially of ScJaginella Martensi, Iielvetica, and 
 spinulosa, differs from that above described, especially in 
 the fact that the special-mother-cells last much longer than 
 in S. horfensis. The spore has therefore (even when fully 
 developed) a somewhat sharply defined tetrahedral form 
 (PI. LV, fig. 13 ; PL LVII, figs. 6, 7), at least its apex ex- 
 hibits three very distinct ridges, meeting at angles of 120°, 
 and extending downwards for a considerable distance ; this is 
 the case in S. liclvetica. The species in which this occurred 
 are all species in which the macrosporangia and microspo- 
 rangia, differing little if at all in their external form, are 
 intermixed apparently without regularity. In Selacjinella 
 Galeottii even the very young large sj)ores have a regular 
 spherical form. In S. Martensi a considerable increase in 
 
390 HOFMEISTER, ON 
 
 size takes place in that one of the many free spherical cells 
 in the interior of the young capsule which is destined to 
 become the mother-cell of the large spores (PI. LVII, figs. 
 1 — 5). Four new spherical nuclei (PI. LVII, fig. 3) are 
 formed on the outside of its primary nucleus, which becomes 
 more and more indistinct. Soon afterwards the primary 
 nucleus disappears (PL LVII, figs. 4, 4*), and six septa 
 meeting at angles of 120° suddenly appear in the mother- 
 cell (one between each two of the secondary nuclei), which 
 represent four tetrahedral special-mother-cells. In each of 
 the latter a spore is formed after a previous consideral)le 
 thickening of the wall, and during the very remarkable 
 increase in size of the special-mother-cells which follows this 
 thickening. The brown exosporium is in this species very 
 thick. In the perfect state three layers are distinguishable, 
 the middle one of which is of a glassy nature. The thick- 
 ened special-mother-cells are still in a good state of preser- 
 vation. The lines of division between each two are here 
 far more clearly distinguishable than in any phaenogamous 
 plant except the Malvaceao (PI. LVII, fig. 7). At this stage 
 of development a slight pressure separates the special- 
 mother-cells, each of which contains a spore (PI. LVII, fig. 
 7*). In a manifestly diseased state of iS. Mariensi I have 
 seen the disproportionately thick exosporium composed of 
 prismatic (or, to speak more accurately, of truncate-pyramidal) 
 fragments ; the spore had remained much smaller than usual 
 (PL LVII, fig. 8). 
 
 During the formation of the outer membrane of the large 
 spores of all the species which I have examined, the spheri- 
 cal nucleus usually lies close under the place at which the 
 three prominent ridges of the exosporium unite (PL LVII, 
 fig. 7).* It increases rapidly in size, and its nucleolus 
 disappears. Afterwards mnnerous vesicular bodies appear 
 within it (PL LV, figs. 13, 14). As the spore approaches 
 maturity it appears to be dissolved : I was never able to 
 find it in those spores which entirely fill the macrospo- 
 rangium.f 
 
 * If the young spore lies for some time in water, the nucleus disappears. 
 
 t Mcttenius appears to assume that the nucleus of the spore gradually expands 
 until it attaches itself at all poiuts to the inner wall of the si)ore-cell (' Beitr. 
 zur Botanik,' H. i, p. 7). I have never seen anything indicative of such a 
 process. 
 
THE HIGHER CRYPTOGAMIA. 391 
 
 111 the microsporangia all the free spherical cells of the 
 interior divide at a somewhat early period into four tetra- 
 hedral special- mother-cells. The process is similar to that 
 \Yhich takes place in the division of the mother-cells of the 
 large spores of SeJaginella Martensi. Fom* new smaller 
 nuclei are formed outside the primary nucleus of the cell, 
 apparently by the double bipartition of a spherical accumu- 
 lation of formative matter. Between each two of them the 
 six double walls appear which separate the individual special- 
 mother-cells from one another. The commissure of the 
 septa of each two special-mother-cells is often very percep- 
 tible even in the mother-cells of the small spores, notwith- 
 standing the minuteness of the object (PI. LVII, fig. 10^). 
 In each of the special-mother-cells a spore is formed, wdiich 
 in many species (for instance in S. Martensi) produces 
 w^onderfully long spines on the outside of the exosporium 
 after the absorption of the special-mother- cells. On the 
 other hand the outer membrane of other species, such as S. 
 helvetica, appears only slightly granulated. All small spores 
 of Selaginella exhibit at the apex three converging ridges 
 of the outer spore-membrane. In the microsporangia of 
 cultivated tropical species of Selaginella, malformations are 
 not uncommon. Thus in S. Martensi it frequently happens 
 that a mother-cell divides into two or three special-mother- 
 cells only,* of which three, two only produce spores (PI. 
 LVII, fig. 11); or sometimes, out of a mass of special- 
 mother-cells, two or even three become shrivelled, whilst 
 the rest retain their vitality. In one case I saw the follow- 
 ing singular phenomenon. In one sporangium, containing 
 several abortive and several apparently healthy sets of 
 mother-cells, eight oval cells occurred, more than three 
 times as large as the largest special-mother-cells, and having 
 a disproportionately thick, glassy, transparent wall, which 
 exhibited manifest lamination : the cell-contents consisted 
 of concentrated granidar mucilage and a rather large nucleus 
 (PI. LVII, fig. 12). 
 
 The large spores only of the SelagineJlse produce pro- 
 thallia. The first rudiments of the latter are formed before 
 
 * As iu R. Brown's Trijjosporium. 
 
392 HOrMEISTER, ON 
 
 the biu'sting of the macrosporangia. A circular simple 
 cellular layer appears spread over the inner side of the pri- 
 mary spore-membrane, underneath the point in which the 
 foiu- special-mother-cells of the spores touch one another. 
 Those cells are of the greatest height which are situated in 
 the middle of the cellular layer underneath the point of 
 junction of the three projecting ridges of the outer spore- 
 membrane; they divide very soon by transverse septa. 
 Towards the periphery the cells gradually diminish in height ; 
 the outermost have the form of a procumbent wedge (PI. 
 LVII, fig. IG). In many species, especially JS. hortetms 
 and helvetica, the rudiment of the prothallium when seen 
 from above appears to have no distinct boundary, inasmuch 
 as the outermost edge of the marginal cells formed by the 
 convergence, at a very acute angle, of the upper and under 
 wall of the cell, does not refract transmitted light much 
 more powerfully than the primary wall of the spore itself. 
 The marginal cells of the prothallium when seen from above 
 appear open towards the outer side (PL LVII, fig. 17).* 
 The prothallia of other species, for instance of S. Martensi, 
 exhibit nothing of the sort (PI. LVII, fig. 18). 
 
 I have not yet made out the first stages of development 
 of the rudiment of the prothallium. It is uncertain 
 whether it is formed, like the prothallium of Marsilea, by 
 repeated bipartition of a single cell, or whether, like 
 
 * I believe that the above explanation is sufficient to explain tlie peculiar 
 plienonieuon. Mettenius ('Beitr. zur Botanik,' Part 1, p. 10), deduces from 
 it a mode of development of the cells of tlic prothallium, which would differ very 
 widely from all other phenomena hitherto observed in the vepjetable kingdom. 
 He believes that the prothallium originates between two lamellae of the wall of 
 the spore, which separate from one another; that it increases gradu- 
 ally in circumference whilst those lanu^lla? become further se])arated from one 
 another, and that new cells are added to the circumference of the prothallium 
 in a manner Mhieh — even if it is not yet fully investigated — offers no points of 
 resemblance with ihe hitherto better known forms of cell-formation. 1 consider 
 Mettenius's conclusions to be incorrect, especially because the small-celled por- 
 tion of the prothallium from which the arehegonia are produced occupies wiien 
 fully developed (I'l. LVIII, figs. 1, 4), no relatively greater portion of the cir- 
 cumference of the s])orc than it does when it first becomes visible. I consider 
 it mucli more probable that the empty cells figured by Mettenius in fig. 10 of 
 the first plate of his work, should be cells, which, by the development of the 
 large-celled inner portion of the prothallium have been pressed against the 
 outer spore-membrane, and squeezed together so as to obliterate the cavity, 
 than that they should be cells in a formative condition. 
 
THE HIGHER CRYPTOGAMIA. 393 
 
 the endosperm of the Coniferae — which in so many- 
 respects resembles the prothalHmn of Selaginella — it is 
 formed by the attachment of originahy free cells to the 
 inner wall of the large spherical firm-walled cell (the spore 
 or embryo-sac) in which it originated. 
 
 In the above state the large spores are discharged from 
 the ruptured macrosporangium. In S. hortensis and hel- 
 vetica their further development is preceded by a dormant 
 condition which lasts for several months. During the latter, 
 the walls of those cehs of the prothallium which adjoin the 
 spherical inner cavity of the spore become thickened. Thick- 
 ening layers are formed on both their sides, leaving, in some 
 cells, w^ide circular pits free (PI. LVIII, figs. 1, 2). By 
 taking longitudinal sections of these pits it is seen that the 
 thickening of the walls is most considerable on that surface 
 which is turned towards the interior of the spore. The 
 contents of this large spherical cell secrete cellulose and 
 cause a thickening not only of tlie septa which separate the 
 contents from the cells which have attached themselves to the 
 inner wall of the apex of the spore, but also of the free 
 portion of the inner surface of the primary spore-membrane, 
 so that the latter becomes a very compact glassy membrane 
 ikd" thick. The contents of the large cavity of the spore 
 consist during this period of a mixture of albuminous and 
 oily matter. These phenomena are most remarkable in S. 
 hortensis, less so in S. helvetica. In S. Martensi and other 
 tropical species the large spores germinate a few wrecks after 
 being sown, and the above thickenings of the walls are 
 hardly perceptible (PL LVII, fig. 19). 
 
 when the further development of the prothallium com- 
 mences, its cells divide repeatedly by longitudinal septa 
 perpendicular to the outer surface, and by transverse septa 
 parallel to that surface. This cell-multiplication begins 
 in the middle point of the prothallium, proceeds from 
 thence towards the periphery, and ceases long before it 
 reaches the latter (PI. LVII, fig. 6). Before the repeti- 
 tion of the division by transverse septa archegonia are 
 formed. 
 
 The first archegonium appears exactly at the apex of the 
 prothallium ; those which are lower down are of later origin. 
 
394 HOFMEISTER, ON 
 
 The formation of the archegonium commences by the division 
 by means of a transverse septum of one of the cells of the 
 upper side of the prothallium. This is followed by the 
 division of the npper cell by a longitudinal septum, and the 
 division of the two halves by a septum at right angles to 
 the one last formed and perpendicular to the free outer 
 surface. Each of the four narrow tall cells which are situ- 
 ated above the larger basal cell, is divided by a horizontal 
 septum into two parts of which the under half is usually 
 the lower in height (PL LVIII, fig. 1). The four apical 
 cells of the archegonium generally arch out into short 
 papilla? (PL LVIII, fig. 2). By the parting asunder at 
 their edges of contact of the four parallel pairs of cells, a 
 narrow passage is formed, leading to the basal cell (PL 
 LVIII, figs. 1*, 4). In the latter a spherical cell is pro- 
 duced almost fining the mother-cell and rich in finely 
 granular protoplasm. All the narrow cells of the pro- 
 thallium now exhibit distinct nuclei if sufficiently fine sec-; 
 tions be taken. The outer walls of the cells of the upper 
 side, especially those of the apical cells of the archegonia 
 appear at this time remarkably thickened (PL LVIII, 
 
 fig. 2). 
 
 Contemporaneously with the development of the arche- 
 gonia a tissue of wider cells becomes visible spread over 
 the under side of the small-celled portion of the prothallium 
 (PL LVIII, fig. 1). The middle of this cellular mass pro- 
 jects into the unoccupied portion of the inner cavity ; it 
 hangs downwards from the inner Avail of the primary spore- 
 membrane for some distance beyond the first-formed por- 
 tion of the prothallium. Its marginal cells repeat the form 
 of that of the older cellular layers ; they are wedge-shaped, 
 and their underside forms a very acute angle with the inner 
 wall of the spore. In S. Martensi a similar large-celled 
 tissue fills the entire cavity of the spore-cell. 
 
 There is only one species, viz. S. helvetica, in which I have 
 been able to ascertain the behaviour of the small spores 
 after they are set free. In this case however there was no 
 doubt. Pive months after the beginning of March, at 
 which time they were sown upon earth mixed with fine 
 sand and kept continually moist, a large number of very 
 
THE HIGHER CRYPTOGAMIA. 395 
 
 small * spherical cells were formed in almost every small 
 spore, and nearly filled its cavity (PI. LVII, fig. 18). By 
 careful pressure these cellules escaped through the fissures 
 of the ruptured spore-membranes. They contained either 
 a finely granular protoplasm,! or a very fine, thin sperma- 
 tozoon, rolled up spirally, Avhich when free moved slowly 
 (PI. LVII, fig. 15). 
 
 The production of spermatozoa in the small spores termi- 
 nates long before the complete formation of the prothallium. 
 In S. helvetica, as has been said, it ceases five months after 
 the sowing of the spores, whilst the first archegonia on the 
 prothallia of large spores sown at the same time, did not 
 appear until six weeks later. This is no doubt the reason 
 Avhy all experiments with the large spores yield no result — 
 whether sown separately or mixed with the small spores — 
 where the possibility of the subsequent access to the pro- 
 thallia of small spores of the same species, is precluded. | 
 The young plant or embryo is formed by the repeated 
 bipartition of the one daughter-cell produced in the basal 
 cell of the archegonium. It does not often happen that 
 more than one archegonium of the same prothallium is im- 
 pregnated. The abortive archegonia, especially those low 
 dov/n on the prothallium, often exhibit a peculiar luxuriant 
 growth of their apical cells § (PI. LVIII, figs. 4, 5). The 
 first division of the mother-cell of the embryo (the germinal 
 vesicle) takes place by a transverse septum (PI. LVIII, 
 fig. 3).1| 
 
 It happens occasionally but rarely that the embryo origi- 
 nates immediately from the lower of the two cells, and that 
 all its daughter-cells take part in the formation of the 
 massive portion of its first axis (PI. LVIII, fig. 6). The 
 
 * Diameter gjj'" or less. 
 
 t See PI. LVII, fifj. 13. I consider these cellules as not fully developed. 
 
 % Wlien I sowed the large and small spores together, and covered them with 
 a hand-glass, all the sowing failed. Spring \;^i, similarly unsuccessful ('Mono- 
 graphie de la famille des Lycopodiacees,' extraite des tomes xv et xxiv des ' Me- 
 nioires de 1' Academic Royal de Belgique,' Bruxelles, ]84:2 et '49, p. 316, note). 
 On tlie other hand when richly-fruiting specimens of the same Selagiuella were 
 brought under the hand-glass, embryos soon appeared. 
 
 § Tlie process is very accurately explahied by Metteuius, 'Beiträge,' Part 1, 
 p. 12. 
 
 II See the note to this figure in the explanation of the plates. 
 
396 HOFMEISTER, ON 
 
 commencement of the formation of the first axis — wliich 
 takes place by division of the terminal cell of the short pro- 
 embryo by alternately inclined septa — is usually preceded 
 by the division (from once to three times) of the terminal 
 cell of the bicellular pro-embryo (embryo-bearer) by tnms- 
 verse septa. During this process a very considerable 
 longitudinal expansion of the upper cells of the pro-embryo 
 takes j)lace, in consequence of which its lower end is pushed 
 deep down into the tissue of wider cells, which tissue in 
 iS. /iortensis now fills about a third part (PL LVIII, fig. 4), 
 and in )S. M arte n si the whole of the cavity of the spore. 
 
 By the multiplication in manner above mentioned of the 
 terminal cell of the pro-embryo, the first axis of the embryo 
 is formed. In S. horfensis, after a very short longitudinal 
 development, the number of the cells of this axis increases 
 no further ; on the other hand an adventitious axis shoots 
 out from one of its sides destined to break forth from the 
 prothallium and to produce the first pair of leaves of the 
 embryo (PI. LVIII, figs. 7 — 10). The form of the growing 
 end of this shoot, as well as the mode of its cell-multiplica- 
 tion, is exactly that of the subsequent vegetative axes above 
 described. Its growth is directed obliquely upwards. 
 During its longitudinal development, the end of the primary 
 axis of the young plant, which in S. hortensis is hitherto 
 hardly perceptible, increases somewhat in size, more by the 
 expansion of its cells than by their multiplication (PI. LVIII, 
 figs. 7, 10). 
 
 Before the shoot of the second order has pierced through 
 the low^er, wide-celled layer of the prothallium, it produces 
 two opposite leaves, by the contemporaneous division of 
 horizontal rows of cells of its wide lateral surfaces. After 
 the shoot has emerged to the light these leaves arc developed 
 and produce chlorophyll in their cells. The arrangement 
 of their cells exactly corresponds in all stages of develop- 
 ment with that of the prihiary leaves of vegetative shoots. 
 In the germ-plants of all the species which I have seen, 
 these leaves bear appendages on both sides of their base. 
 In their axils adventitious leaves are formed, precisely 
 similar to those produced at a later period (PI. LVII, 
 fig. 22). Not long after the appearance of the first pair of 
 
THE HIGHER CRYPTOGAMIA. 397 
 
 leaves the naked terminal bud above them becomes forked 
 (PL LVII, fig. 22). Now, or soon afterwards, the cells of 
 the lower j)ortion of the axis of the second order undergo a 
 sudden and considerable longitndinal expansion, and thus 
 break through the small-celled upper half of the prothallium. 
 The two leaves spread out expand in length and breadth, 
 and become green. 
 
 At the same time the two axes of the third order, into 
 which the end of the axis of the second order has divided, 
 commence their further development. Their cells multiply 
 rapidly in a longitudinal direction, and produce leaves. 
 The four longitudinal rows of leaves do not appear con- 
 temporaneously upon the shoots of the third order. A 
 lower first leaf appears without an opposite upper leaf. The 
 next leaf which is a lower leaf of another longitudinal row, 
 is also often without an opposite upper leaf. From thence 
 upwards the arrangement of the leaves is regularly 
 2^. The longitudinal expansion of the two shoots of 
 the third order (like that of the subsequent vegetative 
 shoots) commences, in Selaginella hortensis, for the first 
 time, when their ends begin to fork for the formation of 
 the axis of the fourth order, and the result is that these 
 leaves of the shoots of the third order are for some time so 
 closely crowded, as to appear upon a cursory examination 
 to belong to the axis of the second order, with whose two 
 leaves they seem to form angles of different divergence. 
 
 The first adventitious root springs out of that side of the 
 axis of the first order which lies opposite to the place of 
 origin of the shoot of the second order. It corresponds in 
 development and structure most completely with those after- 
 wards produced. In Selaginella liortensis it is usually 
 first developed at a very late period, at the time of the 
 commencement of the longitudinal development of the 
 axes of the third order. Exceptions to this are of 
 rare occurrence. It appears much earlier on the germ- 
 plant of S. Martensi ; even whilst the embryo remains 
 within the lower layer of the prothallium (PI. LVII, 
 fig. 20). In the latter species the end of the primary axis 
 is far more fully developed than in the former. 
 
398 HOFMEISTER, ON 
 
 In the mode of cell-multiplication, the succession of the 
 shoots, and the development of the leaves, Lycopodium* comes 
 much nearer to the Polypodiaceae (for instance to Aspidivm 
 ßlix-mas) than to Selaginella. The terminal bud which is a 
 conical wart, extends somewhat beyond the place of origin of 
 the youngest leaf. The division of its apical cell, as well as 
 the multiplication of the cells of the second degree, resembles 
 the same process in Aspidium. The leaf appears to be 
 formed by the multiplication of a single cell of the circum- 
 ference of the terminal bud. It grows in length by divi- 
 sion of an apical cell by septa inclined alternately towards 
 the upper and the under surface of the leaf. Here also it 
 is easily seen that the cells of the base continue to divide 
 long after the multiplication of the cells of the tip of the 
 leaf has ceased. Ramifications of the stem occur by the 
 forking of the terminal bud above the place of origin of 
 the youngest leaf.f The growth of the roots exactly re- 
 sembles that of the adventitious roots of the Polypodiaceae, 
 the Equisetaceae, and the Pilularise. 
 
 Psilotum friquetriim is exactly like the Selaginellae in the 
 mode of forking its terminal buds. This plant also re- 
 sembles Selaginella viticulosa, and still more so S. conlifolia, 
 in the relation of the annual shoots to the buried perennial 
 stem. 
 
 The growth of the stem of Psilotum results from the 
 repeated division of a single apical cell by means of septa 
 inclined alternately in different directions. The growth of 
 the leaves in the first stages of development resembles that 
 of Lycopodium. Afterwards a forking of the tip of the 
 leaf takes place. 
 
 The reproduction of those Lycopodiaceae which bear 
 powdery spores of one kind only is still a mystery. Re- 
 peated sowings of the spores of Lycopodium clavatiim, 
 L. inundatum, and of Selago, have yielded me no results, but 
 I have lately often observed that in spores of Li/cojwdium 
 SelagOy which had been sown for from three to five months, 
 numerous small spherical cells had been formed, similar to 
 
 * I have particularly examined Lycopodium iimndahcm. 
 
 t Compare Ncägeli, ' Zeitschr. f. Botanik,' Parts 3 & 4, PL v, fig. 1. 
 
THE HIGHER CRTPTOGAMIA. f( ^ : ^g;»?' '^hee 
 
 the mother-cells of the spermatozoa of Selag'mella helvetica, 
 I have not yet found spermatozoa inside these vesicles. De 
 Bary has lately discovered (' Berichte der naturf. Gesellsch. 
 zu Freiburg,' 1858, p. 467), that the spores of Lijcopo- 
 dium inundatum produce a body composed of a few cells, 
 whose structure is not unlike that of the archegonium of a 
 fern. It is probable from these observations that the 
 similarly formed spores of Lycopodium, Psilotum, &c., are 
 of different sexes, and as in Equisetuvi arvense produce 
 partly archegonia and partly spermatozoa. 
 
 Of late years the Lycopodiacese have received less atten- 
 tion from vegetable anatomists than any other of the 
 higher cryptogams. Since the appearance of those parts 
 of BischofF's ' Cryptogamische Gewachse,' which relate to 
 these plants, few papers on the subject have been pub- 
 lished. Karl Müller's observations (which however are full 
 of errors), are to be found in the ' Botanische Zeitung' for 
 1846, besides which we have Nägeli's work cited above, and 
 Mettenius's history of the origin of the embryo of S. invol- 
 vens. Spring's monograph is devoted principally to the 
 limitation of the species. 
 
CHAPTER XV. 
 
 CONIFERS. 
 
 The ovules of the Coniferse, however much they may differ 
 in their position and mode of attachment, exhibit the greatest 
 uniformity in their internal structure. A simple, some- 
 what fleshy integument, surrounds a short and thick nu- 
 cleus formed of delicate cellular tissue, leaving open a 
 wide micropyle-canal. In the anatropal ovules of the 
 Abietineae the division between nucleus and integument 
 extends downwards only for a short distance (PI. LIX, 
 fig. 10) ; the mouth of the ovule widens considerably above 
 the apex of the nucleus, parallel to the spermophorc, and 
 appears as a transverse fissure. In Pimts sj/Ivesfris and 
 JP. sfrobiis the nucleus exhibits a very remarkable depression 
 of its apex; in Finns balsamea (PI. LIX, figs. 10, 11), 
 the depression is less manifest. The nucleus in Juniperus 
 and Tluija increases in diameter towards the apex : in 
 both, the apex exhibits a depression, which however in Juni- 
 perus is but sHght (PI. LXIV, fig. 5). Lastly, the nucleus 
 of Taxus, which is far larger than that of any other indi- 
 genous Conifer, is quite like that of most phaenogams, 
 in its oval form, and in the separation between its nucleus 
 and integument, which extends to the base of the ovule 
 (PI. LXIII, fig. 1). 
 
 The nucleus at the time of the shedding of the poUen 
 consists of delicate-walled cells filled with granular muci- 
 lage. Deep in its interior — in the Abietinea) and in Juni- 
 perus, underneath the place where the integuments and 
 the nucleus amalgamate; higher up in Thuja, and still 
 
HOFMEISTER, ON THE HIGHER CRYPTOGAMIA. 401 
 
 liiglier in 'J'axus. — certain of the cells (in the Abietinesc 
 and in Juniperus rarely more than one)* of the middle 
 lono-itudinal strino; of the cellular tissue of the ovule become 
 the embryo-sacs (PI. LIX, figs. 10 — 12). In the ovule of 
 Taxus a short row of cells, usually consisting of three cells 
 of the axile cellular string of the nucleus, is distinguished 
 from the neighbouring cells by their size, and by their 
 containing an abundance of granular mucilage mixed with 
 small starch-granules (PL LXIII, fig. 2). Of these cells 
 sometimes one, sometimes each one of the three is deve- 
 loped into a perfect embiyo-sac ; Taxus, at first, always 
 exhibits more than one. The cellular layers immediately 
 surrounding the embryo sac are strikingly distinguish- 
 able f]-om the rest of the tissue of the ovule by their more 
 delicate cell-walls, and by the greater concentration of the 
 mucilaginous contents. 
 
 The first stages of development of the pollen of the 
 Coniferae, from the individualization of the mother-cells up 
 to that of the pollen-cells, correspond exactly with the 
 ordinary type of phsenogams. The young anther of Pinus f 
 appears at the end of the autunni preceding the flowering 
 season as a short, spatula-shaped scale, convex below. 
 On its under-side, near the base, two oval protuberances 
 are to be seen : these are the lobes of the anthers. Each 
 lobe is filled with a firmly-connected tissue of rather large, 
 delicate-wafled cells, the mother-cells of the pollen. Each 
 of these cells contains a spherical nucleus, occupying about 
 one half of the cell-cavity, and having rather transparent 
 fluid contents, and several very small nucleoli. The rest of 
 the cell-cavity is occupied by a gelatinous mucilage in 
 which numerous very small starch-granules are embedded. 
 Tincture of iodine colours this mucilage a pale yellow, and 
 the coagulating fluid contents of the nucleus a deep brown. 
 Two layers of tabidar cells form the entire outer covering 
 of the mass of mother- cells ; the layer of horizontally 
 
 * There are trees of Finns s^lves/ri.s (one for instance in a marsliy spot in the 
 Botanical Garden at Leipzig) which, like the yew, develope two embryo-sacs in 
 most of their ovules. 
 
 f The species which 1 examined were P. sylvestris, maritima, Larix, and 
 balsamea. 
 
 26 
 
402 HOFMEISTER, ON 
 
 expanded cells -which occurs in so many monocotyledons 
 and dicotyledons is altogether wanting in the Coniferae. 
 
 The mother-cells remain during the winter in the state 
 described. At the commencement of the warmer season 
 the connexion between the mother-cells is dissolved. This 
 occurs in Piniis sylvestris at the beginning, and in 
 F. maritima in the middle of April. The membranes of 
 these cells become thickened, and one or two of the 
 nucleoli have increased in size. In Finns balsamea this 
 growth is far more considerable than in Finns sylvestris, 
 where sometimes all traces of the nucleoli have already 
 disappeared. The fluid substance of the nucleus coagu- 
 lates very easily under the action of water, even more 
 rapidly than in Tradescantia. The viscid fluid contents of 
 the cell then appear most clearly distinct from the spherical 
 cavity, which was filled by the nucleus before the latter 
 became coagulated and contracted into a spherical ball. 
 In Pinus Larix the slight tendency of the cell-fluid to 
 absorb water and become swollen — which is the cause 
 of the appearances above mentioned in F, balsamea — 
 exhibits itself in a different manner. The membrane of 
 the mother-cell swells rapidly in w^ater, and is lifted away 
 from the cell-contents, the original volume of which is not 
 increased. 
 
 The dissolution of the nucleolus or nucleoli soon ensues, 
 as well as that of the nucleus, just in the same way as in 
 Tradescantia, Lilium, Iris, Passiflora, &c. In the homo- 
 geneous fluid contents of the cell, two large flattened 
 elliptical nuclei are next formed. The fluid substance of 
 the latter refracts light in almost exactly the same manner 
 as the fluid contents of the cell, from which it can only be 
 distinguished with much ditticulty. At their first appear- 
 ance these nuclei never contain nucleoli (PL LIX, figs. 2 — 4). 
 Nucleoli — especially in Finus balsamea — are first produced 
 at a later period, contemporaneously with the distinct defi- 
 nition of the limits of the cell-fluid. These nucleoli are 
 always very numerous, sometimes there are as many as twenty. 
 The nucleoli produced from the nucleus of a ruptured 
 mother-cell of F. balsamea were coloured blue by diluted 
 tincture of iodine, proving themselves to be starch- granules. 
 
THE HIGHER CRYPTOGAMIA. 403 
 
 The numerous amyloid granules of the cell-sap, accumu- 
 late, aFter the production of two secondary nuclei, in the 
 form of an annular girdle in the equator of the cell. This 
 girdle soon divides into two, parallel to one another 
 (PL LIX, fig. 3). The division of the cell-contents into 
 two halves appears thus to be indicated. These conditions 
 are so frequent that I do not doubt they must occur in all 
 mother-cells. The further formation, however, takes place 
 in two different ways. The case of least frequent occur- 
 rence is as follows : — A delicate line suddenly appears in 
 the equator of the cell between the two girdles of granules, 
 which line immediately disappears under the action of 
 strong reagents. I believe the line to indicate the surface 
 of contact of the two membraneless halves of the cell- 
 contents produced by the division of the contents of the 
 mother-cell. Shortly afterwards a circular ridge makes its 
 appearance, seated upon the inner wall of the mother-cell 
 and traversing its equator, and forming as it w^ere a frame to 
 the septum of the two special-mother-cells of the first degree 
 which are in course of formation. The other case above 
 alluded to, and which is the one of ordinary occurrence, is 
 the following: — The division of the primordial utricle is in- 
 terrupted by the fact that the membranes of the secondary 
 nuclei are absorbed, and in the place of each one of them, 
 two — making four altogether — perfectly spherical nuclei are 
 formed, which either lie in one plane, or are arranged at the 
 angles of a tetrahedron. Between each two of these, 
 flattened accumulations of granules are produced, in each 
 of which a delicate line suddenly becomes visible, which is 
 the first indication of the septum dividing the two special- 
 mother-cells. 
 
 After the formation of two special-mother-cells of the 
 first degree, two cells are formed in each of them, so that 
 then each set of special-mother-cells consists of four. 
 
 Pinus Larix differs somewhat fi'om other Coniferse in the 
 circumstance that in one Avay or another more than four 
 special-mother-cells and pollen-cells are frequently, in fact 
 almost always, formed in one mother-cell. The usual 
 nimiber is six, and the occurrence of seven or eight is 
 not unusual (PI. LIX, fig. 6). 
 
404 HOFMEISTER, ON 
 
 In Juniperus and Thuja occidenfaJis the phenomena of 
 cell -division arc exactly the same as in the above-named 
 plants. In the former, however, on account of the small- 
 ness of all the parts, and in the latter, owing to the abun- 
 dance of starch- granules in the cell-contents, the obser- 
 vations are rendered much more difficult. 
 
 In each special-mother-cell a pollen-cell is formed, which, 
 when its membrane first becomes visible, entirely fills the 
 cavity of the former. The two layers of the membrane of 
 the pollen-cell, the intine and the extine, are clearly distin- 
 guishable whilst the pollen-cell is still enclosed in the 
 special-mother-cells. The rudiments of the two hemi- 
 spherical appendages of the extine which are characteristic 
 of Abies pecfinata, Picea vulgaris, and Pinus sylvestris, are 
 formed whilst the pollen-cell is still within the special- 
 mother-cell. These appendages consist, when in the young 
 state, of a soft inner substance, which passes on the outside 
 into a firmer cortical layer composed of reticulate ridge-like 
 protuberances. By the use of any fluid which attracts 
 water, such as a solution of sugar, the inner substance is 
 contracted into a smaller space, and the cortical layer of 
 that portion of the appendages which is furthest from the 
 middle point of the pollen-cell is made to turn inwards. 
 
 After the pollen-cells have become free by the dissolution 
 of the walls of the mother- and special-mother-cells, a cell- 
 multiplication commences in them which is quite peculiar 
 to the gymnosperms, and is not seen in any other phseno- 
 gams. Two nuclei suddenly appear in the cell — a spherical 
 one, similar in all respects to the original nucleus of the 
 pollen-cell, and one somewhat smaller of a very flatly- 
 lenticular form (PL LIX, fig. 7). It is hardly a matter of 
 doubt that the latter is newly formed by the side of the 
 primary nucleus of the poUen-cell. Soon afterwards the 
 two nuclei appear separated by a membrane, convex towards 
 the larger one, having the form of a segment of a spherical 
 surface, and which divides the pollen-cell into two unequal 
 parts. That part which contains the flattened nucleus is 
 the smaller one. The disproportion in size of the two 
 parts is inconsiderable in Pinus Larix (PI. LIX, fig. 8), 
 but very remarkable in Picea vulgaris and Pinus sylvestris. 
 
THE HIGHER CllYPTOGAMIA. 405 
 
 In the Abietineaß the lenticular daughter-cell of the 
 pollen-grain increases rapidly in size, and divides twice by 
 septa convex towards the middle point of the pollen-cell. 
 When the pollen-grain is ripe a cellular body is found 
 at one end,* projecting far into the cavity of the pollen- 
 grain, and consisting of a large vesicle borne upon a stalk 
 consisting of two low meniscoid cells. In Finns Larix 
 this body fills more than half the cavity, and in Picea vul- 
 garis and Finns sylvestris it fills the latter almost entirely 
 (PL LIX, fig. 9). 
 
 The inner membrane of the pollen-cell exhibits, even in 
 the young state, a great capacity for distension, so that 
 when placed in water the intine swells into a Avide layer, 
 which stretches the extine and compresses the cell- contents. 
 After the pollen-grain is ripe this peculiarity is intensified ; 
 thus, for instance, Avhen the detached pollen of Finns syl- 
 vestris is moistened with water, the extine is immediately 
 ruptured, and frequently entirely stripped ofF.f 
 
 The development of the pollen of Juniperus, Taxus, and 
 Thuja appears to be similar in all respects to that of the 
 Abietineae, but the smallness of all the parts, and the want 
 of transparency of the cell-contents interferes very much 
 with the examination in these plants. The perfect pollen- 
 grain of Juniperus, Thuja, and Taxus appears to be divided 
 
 * That end which corresponds with the point of contact of the pollen-cell 
 with its sister-cell. In Pinus Larix the daughter-cell lies in the more pointed 
 end of the oval pollen-cell : in Finns sylvestris and Abies pectinata it lies on the 
 longest edge of the pollen-grain, in the middle part of that side which lies oppo- 
 site to the side which bears the two hemispherical appendages of tiie extine. 
 
 f The structure of the pollen of the Abietineaj was correctly understood and 
 described by Fritzsche ('Mem. Acad. St. Petersbourg p. divers savants,' III 
 (1837), p. 693). He states that at the one pole of the somewhat ellipsoidal 
 pollen-grain of Finns Larix, the outer one of the two layers which conipose the 
 inner membrane encloses a cavity flUed with granular matter, underneath which, 
 in a depi-ession of the inner layers of the intine, a second similar but more sphe- 
 rical cavity is found ; to the latter is attached a closed vesicle, filled with 
 fovilla, which projects into the interior of the pollen-grain. Tritzsche in like 
 manner ascertained the structure of the pollen of Finns sylvestris — a more diffi- 
 cult matter — only here the central vesicle appeared to him to be altogether 
 wanting. Schacht ('das Mikrosko]),' 2nd edition, Berlin, 1855, p. 148) ex- 
 plained that in P. sylvestris the vesicle in question entirely fills the cavity ; he 
 pointed out also that in the Coniferse it is not the inner membrane of the pollen- 
 grain, but the above vesicle — the terminal cell of the short row of cells which is 
 attached to one pole of the pollen-grain — which grows out and forms the 
 pollen-tube. 
 
406 HOFMEISTER, ON 
 
 into only two uneqnal cells ; it is probable that the larger 
 of the two is the terminal cell — expanded so as entirely to 
 fill the pollen-cell — of the short roAV produced by the 
 multiplication of the smaller portion of the pollen-grain.* 
 
 The cell-multiplication in the interior of the pollen-grain 
 of the Coniferae takes place very rapidly ; in the space of a 
 few days ; I observed it, for instance, in Pimis Larix, 
 in the year 1855, to last from the 27th of March to the 
 10th of April. 
 
 The pollen of the Coniferse passes through the Avide 
 micropyle directly on to the nucleus. Each pollen-grain 
 sends out into the tissue of the latter — at first only for a 
 short distance — a tube formed by the prolongation of the 
 terminal cell of the short row of ceUs attached to its inner 
 waU. In Taxus and Juniperus this tube is emitted shortly 
 after the shedding of the pollen, in the Abietinese not until 
 after remaining dormant for many weeks. The formation 
 of poUen-tubes takes {)lace in Pinus sylvestris, Miiglius, and 
 austriaca at the beginning of June, in P. Strohus somewhat 
 later. In a few days they penetrate at the utmost not 
 farther than near to the place where the integument sepa- 
 rates itself from the nucleus (PL LIX, fig. 14); then, and 
 not unfrequently even sooner, their longitudinal growth 
 ends for the first time (PI. LIX, fig. 17). Up to this point 
 the embryo sac remains a simple cell, whose large nucleus 
 is gradually dissolved (PL LIX, fig. 14). Some days later 
 however numerous free nuclei appear in its interior 
 (PL LIX, fig. 15), and immediately thereupon it appears 
 filled by a large number of radially-elongated cells arranged 
 in a concentrical layer (PL LIX, figs. 1 6, 1 6*), which mul- 
 tiply actively in all three directions until the commence- 
 ment of the winter rest. The primary wall of the embryo- 
 sac has in the mean time become so thin and delicate that 
 it almost disappears from observation. At the same time 
 a considerable multiplication of all the cells of the nucleus 
 
 * The pollen of Ephedra behaves exactly like that of Larix. (see Schacht, 
 'das Mikroskop/ 2ud ed., 1S55, p. US); the pollen of the Cvcadeje on the 
 other hand appears unicellular when ripe. Possibly stages of development 
 similar to those of the Couiferaj are gone through in these plants, but are 
 entirely obliterated at an early period. 
 
THE HIGHER CRYPTOGAMIA. 407 
 
 takes place in length, breadth, and thickness. With the 
 commencement of the cold season the walls of the endo- 
 sperm which fills the embryo-sac become much thick- 
 ened, and exhibit lamination of the gelatinous substance of 
 the thickened portions (PL LIX, fig. 13). If dehcate 
 sections of the endosperm are placed in water, the gela- 
 tinous matter of the thickening layers of the cell- walls 
 becomes rapidly and easily dispersed in the fluid ; the pri- 
 mordial utricles of the cells then lie free in the cell-cavity 
 (PI. LIX, fig. 17). The thickened walls of the central 
 cells of the endosperm are the most sensitive to the action 
 of w^ater. This peculiar natm-e of the cells of the transitory 
 endosperm of the first year renders the observation of their 
 walls especially difficult.* 
 
 At the beginning of ]\Iarch the dissolution of the 
 thickened ceU-walls of the endosperm commences. Each 
 of the primordial cells thus made free exhibits a large 
 central spherical nucleus filled with brighter fluid (PI. LX, 
 fig. I). About April this nucleus is dissolved; cells 
 whose nuclei have been just absorbed contain numerous 
 spherical drops of a highly refractive substance, which 
 nearly fill the cell. Fm^ther developed cells contain two 
 (PL LX, fig. 1*), others four, many only three nuclei. 
 Around each such nucleus a free daughter-cell is formed, 
 originally of a spherical shape, lying free in the mother- cell. 
 By absorption of the wall of the mother-cell the daughter- 
 cells become free ; the same process is repeated in their 
 interior (PL LX, fig. 3). Thus the number of the cells 
 enclosed by the embryo sac increases very rapidly in geome- 
 trical progression. The embryo-sac itself grows in a re- 
 markable manner to more than twenty times its previous 
 volume by pushing aside the loosened cells of the adjoining 
 portions of the nucleus of the ovule ; its wall, hitherto very 
 tender, becomes thick and glassy, and ultimately granulated 
 on the outer surface. At the same time a very active mul- 
 
 * The earlier observers considered the embryo-sac filled with cellular tissue 
 to be a cavity in the tissue of the nucleus {Ilcniig, ' Naturgeschichte der Forst- 
 culturpflanzen,' see the explanation to fig. 17 of Plate xxv. Gottsclie, 'Bot. 
 Zeit.,' 1845, p. 380). Quite lately Pineau pointed out its true nature ('Ann. d. 
 Sc. Nat.,' iii ser. vol. ii, p. 85). 
 
408 HOFMEISTER, ON 
 
 tiplication recommences in the cells of the ovnle, with the 
 exception of the upper portion of it which has been tra- 
 versed by the pollen-tubes and which remains stationary ; 
 the ovule grows from one third of a line to two lines and 
 a half. 
 
 In the middle of May a simple layer of cells begins to 
 spread itself on the inner wall of the embryo-sac (PL LX, 
 fig. 2). The side-walls of these cells do not yet touch one 
 another at all points (PL LX, fig. 2*) ; if the embryo-sac is 
 ruptured by gradually increased pressure, the cells within 
 it and those also which are spread over its wall are driven 
 out throngh the fissure in the form of spherical vesicles 
 (PL LX, fig. 3). The firm adhesion inter se of the above 
 cells does not take place until after several layers of them 
 have been formed (PL LX, fig. 4). The cell-midtiplication 
 at the same time goes on continually, both in the free cells 
 of the centre, and in those forming the parenchymatal 
 mass of the periphery. Thus at last there is again formed 
 an endosperm entirely filling the inner cavity of the 
 embryo-sac, a body far longer in its circumference and 
 composed of a far greater number of cells than the one 
 which existed at the commencement of the winter rest. The 
 development of the endospei'm of Juniperus much re- 
 sembles that of the species of Pinus whose seeds take two 
 years to ripen. Li the lower part of the nucleus before 
 the shedding of the pollen there is found a cell surrounded 
 by concentrical layers of smaller cells : this cell is the 
 embryo-sac. It becomes filled with a few cells (PL LXIV, 
 fig. 5), shortly after those pollen-grains which have reached 
 the nucleus have begun to emit tubes. In this condition 
 the ovule remains through the first summer and winter. 
 At the commencement of the next vegetative period the 
 ovule and embryo- sac increase rapidly and remarkably in 
 size, and the primordial utricles of the cells which fill the 
 embryo-sac become individualised. By active multiplication 
 of these primordial cells, numerous cells are produced 
 floating freely in the fluid contents of the embryo-sac. They 
 soon * clothe the inner wall of the embryo-sac in the form 
 of a compound cellular layer (PL LXIV, fig. 6); by division 
 
 * At the begiuumg of May iu the second year. 
 
THE HIGHER, CllYPTOGAMIA. 409 
 
 of the cells of the latter, coupled with the deposition of new 
 celhilar layers on the inner side of those first formed, the 
 embryo-sac is soon (within the space of a week) filled for 
 the second time with closed cellular tissue. 
 
 The development of the endosperm of Taxus is far 
 more simple. The rudiments of the embryo-sacs are here 
 represented (as has been already mentioned) by several 
 larger cells situated in the middle of the lower portion of 
 the nucleus of the ovule, surrounded by cellular tissue 
 arranged in scale-like layers (PI. LXIII, fig. 2). Soon after 
 the shedding of the pollen the tissue surrounding those 
 cells becomes loosened (PI. LXIII, fig. 4). The growing 
 embryo-sacs begin to increase considerably in size ; this 
 increase in many instances continues to go on in one only 
 of the embryo- sacs ; the growth of the others is arrested, 
 they become shrivelled, and at last, like the loosened cells 
 of the surrounding tissue, they are dissolved and displaced 
 by the one embryo-sac (PI. LXIII, figs. 5 — 8). Often 
 however two of these larger cells grow and form embryo- 
 sacs. The nucleus of the cell destined to form the embryo- 
 sac is soon absorbed, and the cell then usually assumes the 
 shape of a flask (PL LXIII, fig. 5). Two new nuclei soon 
 appear contemporaneously in its upper part, embedded in 
 the mucilaginous layer which clothes the inner wall. More 
 and more nuclei soon make their appearance in the lower 
 part also of the young embryo-sac in a similar position 
 (PI. LXIII, figs. 6, 7). At first they often have no nucleoh, 
 but at a more advanced period of growth the latter are 
 never wanting. A cell is formed around each of the nuclei 
 which are deposited upon the inner wall of the embryo-sac 
 (PI. LXIII, fig. 8). The walls of the young cells soon close 
 upon one another, and thus the embryo-sac is filled with 
 closed cellular tissue, except at its young upper end, where 
 nuclei are found which for a long time continue to float 
 freely (PI. LXIII, fig. 9), until at last, at this end also, the 
 formation of parenchyma proceeds. In those Abie tineas 
 whose seeds ripen the first year, the embryo-sac is filled, a 
 few days after the shedding of the pollen, with a closed 
 tissue of large cells (PI. LXII, fig. 11), by whose con- 
 tinual miütiplication in all three directions the endosperm 
 
410 HOFMEISTER, ON 
 
 increases in size. Thuja and Cupressus behave in just the 
 same manner. 
 
 In all the Coniferae, after the embryo-sac has become 
 entirely filled with cellular tissue, a considerable growth 
 commences in certain cells situated close under the mi- 
 cropylar end of the endosperm, which growth sets in 
 even long before the cell-multiplication in the neighbouring 
 cells has ceased (PI. LX, figs. 5 — 7). Thus the essential 
 part — viz., the large spherical cell— of the so-called cor- 
 puscala is differentiated from the surrounding tissue. In the 
 Abietineae each corpusculum is separated from the next by 
 at least one, often by several cellular layers (PI. LX, figs. 6, 7 ; 
 PI. LXII, fig. 3). The corpuscula of Juniperus (PL LXV, 
 figs. 1 — 3, 9), Thuja and Cupressus, immediately adjoin 
 one another. In Taxus two corpuscula are sometimes in 
 contact ; most of them are separated from one another by 
 thick layers of cellular tissue (PL LXIV, figs. 1, 2). 
 
 The corpuscula of Taxus are shortly ellipsoidal, those of 
 the Abietineae are ellipsoidal and elongated ; those of Juni- 
 perus and Cupi'essus are long and prismatic, with blunt 
 edges and small ends. The formation of corpuscula is not 
 always limited to the micropylar end of the albuminous 
 body. In Juniperus especially, numerous irregularities 
 occur : sometimes there is only a remarkable increase in 
 size of the deeply seated cells of the endosperm, some- 
 times a corpusciüum is formed complete in all its parts and 
 opening in the middle of one of the lateral sm'faces of the 
 endosperm. 
 
 The apex of each corpusculum is at first only separated 
 by a single cell from the inner wall of the upper arch of the 
 embryo-sac. In most of the Coniferae this cell divides twice, 
 and produces four cells lying in one plane which are distin- 
 guished from the neighbouring cells by their contents 
 being thickly mucilaginous and having many granules ; this 
 is the case in Finns sylvestris (PL LX, fig. 8), Pinus Strobus, 
 austriaca, maritimus and Muglms ; in Abies Larix and bal- 
 samea ; in Taxus baccata (PL LXIII, fig. 11), and ca?ia- 
 densis (PL LXIV, fig. 1) ; in Juniperus sibirica (PL LXV, 
 figs. 2, 9) Siwdi . communis ; in Cupressus pi/ramidalis and 
 Thuja orieyitalis. In Pinus Fraseri I found the four apical 
 
THE HIGPIER CRYPTOGAMIA. 411 
 
 cells often divided transversely, so that the rosette consisted 
 of eight cells lying in two planes. Pinus canadensis and 
 Picea L. are remarkable exceptions. Here the one cell 
 which covers the top of the corpuscula does not divide by 
 longitudinal septa crossing one another, but by repeated 
 transverse septa (PL LXII, figs. 1, 2). It thus keeps pace 
 with the multiplication of the cells of the top of the endo- 
 sperm, which multiplication in the other Abietinese and in 
 Juniperus continues after the formation of the corpuscula, 
 whilst in the above species the double pairs of cells which 
 cover the upper arch of the corpuscula are sunk in depres- 
 sions of the upper side of the endosperm, over which the 
 primary membrane of the embryo-sac extends. In Juni- 
 perus, Thuja, and Cupressus the top cells of all the corpus- 
 cula, with rare exceptions, are closely crowded together at 
 the base of a wide depression of the top of the endosperm 
 (PL LXV, figs. 2, 9). The upper end of the endosperm of 
 Pinus exhibits as many funnel-shaped depressions as there 
 are corpuscula; each of these short passages leads to a 
 single corpusculum. In like maimer, in Juniperus, Thuja, 
 and Cupressus, the parenchyma of the endosperm grows 
 over the covering cells of the corpuscula. At the top of 
 the endosperm there is found a rather deep depression 
 whose base is occupied by the closely-crowded four-celled 
 rosettes of the elongated corpuscula, which latter are in 
 contact wil-h one another. 
 
 The cells of the endosperm which adjoin the corpusculum 
 on the sides and below, divide repeatedly by septa at right 
 angles to the surface of the latter. A layer is thus formed 
 which surrounds the corjDusculum, and consists of small 
 cells filled with granular mucilage. This layer is very 
 striking in the Abietineae. 
 
 In Pinus sylvestris and austriaca the number of corpus- 
 cula is from three to five ; in Abies halsamea and pectinata 
 usually three ; in Pinus canadensis very regularly four (rarely 
 five) ; in Taxus baccata and Juniperus from five to eight. 
 
 The primary nucleus of the cell which becomes the cor- 
 pusculum lasts for some time ; in Pinus sylvestris (PL LX, 
 figs. 5, 6) until the corpusculum has attained half its full 
 
412 HOFMEISTER, ON 
 
 size ; in Juniperus (PL LXV, fig. 2) until the full size is 
 attained. In Pinus it usually lies at the upper end of the 
 corpusculum — that end which is turned towards the micro- 
 pyle — rarely at the opposite end ; it is embedded in a muci- 
 laginous layer, which clothes the inner wall of the organ, and 
 which in Pinus is thin, and rendered turbid by numerous 
 granules (PL LXV, figs. 5, 6), and in Juniperus and Cu- 
 pressus* firm and transparent ; in the centre of the corpus- 
 culum there is only a small ellipsoidal cavity filled with 
 watery fluid. At last the nucleus is dissolved ; in Pinus 
 sylvestris this is often preceded by the formation of a free 
 spherical cell around this nucleusf (PL LX, fig. 5). At 
 last it disappears from observation, and at the same time, in 
 the Abietineee, several vacuoles make their appearance : the 
 latter are so numerous and so close together in Tiims sylves- 
 tris and Strobus, that they impart a frothy aspect to the 
 whole contents of the corpusculum ; in Finns Larix and 
 canadensis they are less numerous and of very unequal 
 size. Diu^ing the further development of the corpuscula 
 the number of these vacuoles diminishes. Nuclei and free 
 nucleolate spherical cells now appear amongst them, the 
 latter at first being only small and few in number. Their 
 number however soon increases, whilst that of the vacuoles 
 diminishes more and more. In Pinus sylvestris and Strobus, 
 and in Abies Larix, the latter disappear entirely before the 
 arrival of the pollen-tube at the corpusculum, whilst in 
 Pinus canadensis, Picea Larix, and in Larix, one or two of 
 the vacuoles in the middle of the corpusculum usually last 
 until the moment of impregnation. In Pinus canadensis. 
 Picea Larix, and Larix, the free cells which float in the in- 
 terior of the corpuscula, i. e., the germinal vesicles, appear 
 almost all undivided until impregnation (PL LXII, fig. 1) ; 
 in a few cases only in Pinus canadensis and Larix, indivi- 
 dual germinal vesicles are found more or less entirely filled 
 
 * In the later stages of development of the corpusculum ; in the earlier con- 
 dition strings of granular mucilage radiate from the nucleus. 
 
 f As is the case round the primary nucleus of the embryo-sac of Asphodelus 
 luteus and Fioikia ccerulea. Sec pp. 10 and 13 of my 'Entstehung des Embryo 
 der Phauerogamen.' 
 
THE HIGHER CRYPTOGAMIA. 413 
 
 by two, very rarely three or four, endogenous daugliter-cells. 
 In Pinus si/lvestris on the other hand very many of the 
 germinal vesicles, and in Pinus Slrobus almost all of them, 
 contain, even before impregnation, several — sometimes as 
 many as six, usually four — nucleolate daughter- cells. The 
 membranes of the germinal vesicles, as well as those 
 of the daughter-cells formed before their impregnation, 
 dissolve in water. The germinal vesicles of Pinus cana- 
 densis contain small amyloid granules which are not found 
 in other species. The phenomena which may be ob- 
 served in the formation of the germinal vesicles, resemble 
 generally those which appear in the formation of the cells 
 of the endosperm of phsenogams in the restricted sense 
 of the word. The free cell- formation in the impregnated 
 embryo-sac of the Iridese* offers the most points of 
 resemblance. As in that case the first organized forma- 
 tions have the form of vesicles of moderate size. They 
 either possess fluid contents only, or in more rare instances 
 they have one or two spherical bodies (nucleoli) of a 
 strongly refractive substance, floating in the fluid contents. 
 These formations according to current notions must be 
 considered as nuclei. The larger of these vesicles exhibit 
 in their interior a small spherical, celliüar formation — the 
 nucleus around which the cell originated — situated some- 
 what excentrically, and exactly similar to the above-men- 
 tioned freely -floating bodies. There is only one circum- 
 stance which does not entirely accord with these explana- 
 tions of the observations, and that is, that sometimes 
 (although not often), cells are found whose single nucleus 
 is decidedly smaller than any one of the freely-floating 
 nuclei observed contemporaneously in the same corpus- 
 ciüum. This may however very probably depend upon 
 individual peculiarities. It may well be, that the moment 
 at wdiich a cell is formed round a nucleus, is determined 
 by circumstances quite unconnected with the fact whether 
 or not the nucleus has attained its greatest size. A 
 nucleus might, long before it was fidl-grown, become the 
 middle point of a cell in process of formation. If it be 
 
 * ' Eutsteliuug des Embryo,' p. 27. 
 
414- HOFxMEISTER, ON 
 
 assumed that its growth then ceased, the above pheno- 
 menon would be sufficiently explained.* 
 
 The refractive power of the substance of the nuclei of 
 the freely-floating cells of ihe corpuscula of Pi7ius sylvestris, 
 austriaca, and Strobus, is so exactly the same as that of 
 the contents of the cells, that the nuclei do not become 
 visible until by the prolonged action of water, or of tincture 
 of iodine, the contents of the cell and of the nucleus 
 are changed, and the albuminous matter coagulated. In 
 the corpuscula of Pinus canadensis the refractive power of 
 the nuclei upon transmitted light is greater than that of the 
 contents of the cells. 
 
 The number of the freely-floating cells in the corpuscula 
 of the Abietinese is so great that they quite fill the latter. 
 This is the ground of the statement made by Mirbel and 
 Spach that the corpuscula are filled " par un tissu fin et 
 jaunätre." In Taxus, Juniperus, and Cupressus, the 
 numlBer of these cells is usually less, but yet cases occur 
 here also in which they entirely fill the corpuscula (PL 
 LXIII, fig. U ; PI. LXIV, fig. 1 ; PI. LXV, fig. 9). 
 
 Of the many delicate-walled daughter-cells of the 
 corpusculum, those which occupy its upper and lower 
 end often appear to be pressed against it, in like 
 manner as the germinal vesicles of the phaenogams and 
 the cells antipodal to them press against the two ends of 
 the embryo-sac. In the upper end of the corpusculum 
 they are only found when the arch of the latter is particu- 
 larly steep, and then several usually occur (PL LXI, 
 fig. 1) ; in the lower end one only is found, and that not 
 often ; when present it is much flattened above. 
 
 The development of the endosperm in the embryo-sac of 
 the Coniferae does not appear to be absolutely dependent 
 upon the contact with pollen of the same species, although 
 
 * It is undeniable that many cases of free cell-formation, especially tliose 
 occurring in the embryo-sac of phaenogams, when considered by themselves, 
 agree better with the theory of the identity of the cell and the nucleus, than 
 witii the opposite one propounded by Schleiden. It is not so however with all ; 
 in some cases {Asphodelus albus, Staphjlea pbuiala') the diameters of I he cells in 
 process of formation are always at least half as large again as those of the largest 
 of the freely-floating nuclei. The undoubted analogy however with the fully- 
 observed cases of the so-called cell-division, suggests the necessary explanation 
 even of those more obscure phenomena. 
 
TUE HIGHER CRYTTOGAMIA. 415 
 
 it is undeniably favoured by such contact. I have known 
 flowers of female specimens of Juniperus sibirica, which 
 had been completely separated from male ones, to produce 
 normal fruit, and to develope endosperm with fully formed 
 corpuscula. Female flowers of young trees of Pinus cana- 
 densis, Avhich w^ere three miles distant in a straight line 
 from the nearest other trees of the same species, produced, 
 for two years successively, only female flowers, but no male 
 ones. Microscopical examination showed that in both cases 
 no pollen-grains were present upon the nucleus. In both, 
 the formation of embryos was entirely suppressed. 
 
 After the interval which occurs in the growth of the 
 pollen-tubes — and which takes place even in those Coniferae 
 whose seeds ripen the first year — the latter begin again to 
 penetrate towards the embryo-sac. This happens almost 
 at the time when the differentiation of the corpuscula from 
 the surrounding tissue commences. After the tubes are 
 completely formed they reach the endosperm : in Pimis 
 sylvestris and Juniperus sibirica this happens at the be- 
 ginning of June, in Pinus Strobus and Juniperus communis 
 at the end of June of the second year ; in Abies excelsa and 
 Taxus canadensis in the middle of May, in Taxus baccata 
 at the end of May, and in Pinus canadensis at the end of 
 June, of the first year. The deeper the pollen-grains pene- 
 trate into the luicleus the thicker they become, a pheno- 
 menon which is most manifest in Taxus, and least so in the 
 Abietinege. The growth in thickness of the lower part of 
 the pollen-tube of Taxus is so remarkable, that the organ 
 assumes the form of a conical sac (PI. LXIII, fig. 11; 
 PI. LXIV, figs. 1,2). The great transverse increase does 
 not commence until the completion of the longitudinal 
 growth. 
 
 About the time when the pollen-tube reaches the endo- 
 sperm, the very thick, hitherto leathery and tough primary 
 w'all of the embryo-sac w^hich encloses the endosperm, is 
 softened at the top. The pollen-tube breaks through this 
 wall, apparently after some resistance, (a constriction or 
 sudden narrowing of the tube is often visible at this place), 
 and reaches the double pairs of cells which cover the tops 
 of the corpusciüa. Sometimes it makes its w^ay sideways to 
 the corpusculura, piercing through and destroying the 
 
416 HOFMEISTER, ON 
 
 tissue of the endosperm. This has been often observed in 
 T?inus canadensis. In Taxus it often destroys the entire 
 uppermost part of the endosperm ; on the other hand the 
 four cells which close up the corpusculum which is about 
 to be impregnated, are at first only slightly pushed apart 
 from one another, by the protrusion by the pollen-tube of 
 a short prolongation which passes between their detached 
 edges and up to the outer wall of the corpusculum (PL 
 LXIV, figs. 1,2). These cells do not disappear until a later 
 period, after the formation of the pro-embryo ; they often last 
 for a very long time (PL LXIII, fig. 13). Juniperus and 
 Thuja (PL LXV, figs. 2, 8, 9, 10,) behave in 'a similar 
 manner. In the Abietinese, on the other hand, the cells above 
 the corpuscula are destroyed immediately after the pollen- 
 tube has reached them (PL LX, fig. 9 ; PL LXI, fig. 1 ; 
 PL LXII, figs. 2, 3). Its end attaches itself to the outer 
 wall of the corpusculum ; in Pin us canadensis it then 
 often expands considerably in breadth (PL LXII, fig. 3). 
 With this process in most cases, its penetration terminates ; 
 more rarely it breaks through the wall of the corpusculum 
 and grows into it for a short distance. This happens 
 regularly in Pinus Larix, and tolerably frequently in Piniis 
 canadensis (PL LXI, figs. 13, 14; PL LXII, fig. 2).* _ 
 
 Free spherical cells are often developed in the interior of 
 the ends of those pollen-tubes of the Coniferae which 
 penetrate up to, or into the corpusculum. In the Abietinese 
 the observation of them is often rendered difiiciüt by the 
 large number of co-existent starch-granules, but even here 
 undoubted instances of the presence of cellular formations 
 in the pollen- tubes may easily be seen. The pollen-tube of 
 Pinus canadensis when it has penetrated into the corpus- 
 culum usually contains — ^in addition to granules of starch 
 and mucilage — several (2, 4, or even 8) sharply defined 
 spherical balls of finely granular protoplasm floating freely 
 in the interior of the tube (PL LXIII, fig. 2). In some of 
 these corpuscula I saw, close under the end of the pollen- 
 tube but not in contact with it, a free oval cell diftering 
 from the germinal vesicles which — still in the same state as 
 before the arrival of the pollen-tube — filled the rest of the 
 
 * Many sucli cases are figured by Pinean, 'Ann. d. So.' iii. ser., vol. xi, 
 pi. vi, fig. 4; aud by Schacht, 'Eutw. des Pfianzen-enibryou,' pi. xi, fig. 5 — 7. 
 
THE HIGHER CRYPTüGAMIA. 417 
 
 cavity of the corpusculiim, by beinp; somewhat larger, and 
 especially by its containing a considerable quantity of 
 granules of protoplasm of a larger size (PI. LXII, fig. 2). 
 The nucleus of these cells differs from those of the neigh- 
 bouring germinal vesicles by the more considi^rable size of 
 the nucleoli. In other corpuscula which were taken partly 
 from ovules of the same cone I found a similar cell, 
 but without a nucleus, at the base of the corpusculum. In 
 other corpuscula, again, from the same inflorescence, a cell 
 of the same kind furnished with a firm membrane * was 
 firmly pressed into the lower end of the coi'puscnlum. It 
 can now be recognised beyond a doubt as the primary cell 
 of the compound pro-embryo (PL LXII, fig. 4). In an 
 impregnated corpusculum of Pinus canadensis which 
 already contained a multicellular pro-embryo, I once saw a 
 large free cell, situated above the latter and containing two 
 nuclei, and very similar to an impregnated germinal vesicle 
 on the point of dividing (PI. LXil, fig. 5). This observa- 
 tion is the only one of tJie kind which occurred in the 
 course of my very numerous investigations, and it indicates 
 that more than one germinal vesicle of the same corpus- 
 culum may be impregnated. 
 
 The pollen-tube of Pinus sylvestris, after penetrating the 
 rosette of the corpusculum, usually passes only for a short 
 distance into the interior of the latter, so that the end of 
 the tube projects into the end of the cavity in a hemi- 
 spherical form ; a farther penetration is of rare occurrence. 
 In the earliest observed conditions in which a change in the 
 contents of the corpusculum was perceptible, an oval, capa- 
 cious, sharply defined cell, was visible near the base of the 
 corpusculum ; in the more pointed lower end of this cell a 
 lenticular nucleus was embedded in a considerable accumu- 
 lation of granular protoplasm (PI. LX, fig. 9). The walls 
 of the upper part of the cell are clothed with a thin layer 
 of plasma ; a flattened layer of protoplasm passes through 
 the entire length of the upper cavity of the cell. In other 
 corpuscula the lower end of this cell almost touched the 
 base of the corpusculum. In these cases the nucleus, and 
 the accumidation of protoplasm enclosing it, appeared sur- 
 
 * In the couditions previously meutioued this inembraiie was wanting. 
 
 27 
 
418 HOFMEISTER, ON 
 
 rounded by a firm cell-wall, and separated from the upper, 
 very dclicate-vvallcd, larger nn-nucleated portion of the cell. 
 Corpnscula from the same tree examined one or two days 
 later, exhibited this small loAver daughter-cell attached to 
 the lower part of the corpusculum, to whose walls the 
 lateral surfaces also of the upper, un-nucleated, larger 
 portion of the cell adhere, whilst the boundary in the 
 direction of the apex of the corpusculum becomes in- 
 distinct (El. LX, fig. 10). As in Pimis canadensis the end 
 of the pollen-tube during these processes exhibits no 
 opening ; its contents are of the same nature as in the 
 species just mentioned. The unimpregnated germinal vesi- 
 cles which fill the cavity of the corpusculum remain at 
 first unaltered, which is also in accordance with Finns 
 canadensis. A difference, however, exists in Finns sf/Iveslris, 
 viz., that very often one or two of the germinal vesicles 
 which lie in the micropylar end of the corpusculum and 
 touch the end of the pollen-tube, have firm membranes 
 composed of cellulose, a fact which has never been observed 
 in Pinus canadensis. After the cell which is pressed into 
 the lower end of the corpusculum has become changed by 
 repeated divisions into the compound pro-embryo, the tip 
 of the pollen-tube of Pinus sylvestris often appears to be 
 open, and its contents to be discharged into the cavity of 
 the corpusculum ; this is plainly the result of mechanical 
 rupture. The cells of the endosperm which surround the 
 funnel-shaped depression leading to the corpusculum 
 expand considerably in width after impregnation, and 
 compress the pollen-tube, frequently to such an extent as 
 to obliterate the cavity of the latter. Its contents thus 
 undergo a strong pressure, which must ultimately lead to 
 the rupture of the free end. 
 
 In Pinus abies, L. [Abies excelsa, B. C), I obsei-ved 
 phenomena similar to those in Pinus sylvestris. In 
 some cases I saw the daughter-cell of the corpusculum 
 — after the former had grown to a large size, and its 
 contents had increased and become firmer — in inmiediate 
 contact with the end of the pollen-tube (PI. LXI, fig. 1). 
 In others I found a similar but very large cell half way 
 towards the base of the corpusculiun divided into four 
 
THE HIGHER CRYPTOGAMIA. 419 
 
 cells, forming two larger upper ones and two smaller termi- 
 nal cells (PI. LX, figs. 2, 2*.) The identity of this cellular 
 body with the compomid pro-embryo which is afterwards 
 firmly inserted into the lower part of tlie corpusculum is 
 beyond all doubt. In Fi?nfs Abies the germinal vesicles, 
 which remain in contact with the end of the pollen-tube, 
 regularly become clothed with firm elastic cell-membranes. 
 
 The pollen-tube of Finus Lance usually swells out in a 
 vesicular manner within the funnel-shaped depression of 
 the endosperm above the corpusculum, and then sends 
 forth a pointed prolongation, which pierces through the 
 covering cells of the latter. The membrane of the tube is 
 incomparably more tenacious than in the above-mentioned 
 species. In the latter when the endosperm is detached 
 from the nucleus the pollen-tube regularly tears off at the 
 place where it emerges from the tissues of the nucleus, 
 whilst in Finns Larix the apex of the pollen-tube may often 
 be drawn out from the corpusculum, so as to hang freely 
 down for a considerable distance. 
 
 The end of the pollen-tube even before it reaches the 
 corpusculum exhibits an accumulation of protoplasm which 
 is often sharply defined like a cell, and further upwards in 
 its interior numerous starch-granides are seen partly com- 
 bined in groups of twos or fours. Immediately after reach- 
 ing the corpusculum the apex of the pollen-tube, when 
 drawn out from the latter, appears rather thin-walled and 
 without appendages. In cones somewhat more developed 
 a cell is found fastened to the end of the pollen-tube when 
 the latter is detached. The diameter of this cell seldom 
 equals that of the end of the pollen-tube, and often re- 
 mains considerably less. It resembles in all its parts one 
 of the smaller germinal vesicles which float in the interior 
 of the corpusculum. Like these vesicles it exhibits a 
 nucleus of lighter substance, and is devoid of the firm cell- 
 membrane.* No further change is at this time perceptible 
 in the remaining portion of the corpusculum. 
 
 * At the place where this cell is attached, the pollen-tube exhibits no trace 
 of an opening, and there is nothing to show that the cell, which differs so 
 remarkably from the poUeu-tube by the absence of a firm membrane, has grown 
 out of the latter. 
 
420 HOFMEISTER, ON 
 
 In corpuscula which are about two days more advanced a 
 larger cell is seen near the end of the pollen-tube which now 
 reaches down into the corpnsculuni ; this larger cell differs 
 from the neighbouring unaltered germinal vesicles in its 
 circumference — which is more than double that of the latter 
 ■ — in its more transparent fluid contents, and in its firmer 
 membrane. Its upper end not unfrequently protrudes 
 above the spot at which the before- mentioned small cell is 
 attached to the apex of the pollen-tube. The large free cell 
 never exhiljited any connexion with the small cell. In other 
 corpuscula of the same cone a larger cell of the same kind 
 occurs at the base of the corpusculum. Its circumference 
 is more considerable, and its contents of the same kind, as 
 in the above-described impregnated germinal vesicles of 
 Pi Ulis SI/1 vest ris. The more pointed lower end of the oval 
 cell is filled by an oval daughter-cell with turbid contents 
 and a firmer membrane. The larger upper part of the cell 
 is devoid of a nucleus ; a thin protoplasmic layer covers 
 the inner wall, and a similar flattened layer traverses the 
 inner cavity longitudinally (PL LXI, fig. 13). A short 
 time afterwards the lower cell, which is rich in granular 
 protoplasm, appears pressed into the base of the corpuscu- 
 lum (PI. LXI, fig. 14). It is now drawn out bread tlnvise ; 
 its upper wall, which is turned towards the inner cavity of 
 the corpusculum, is only slightly arched. Observation 
 shows that it is the rudimentary cell of the compound pro- 
 embryo. The upper unnucleated portion of the large cell 
 becomes attached laterally to the arch of the corpusculum, 
 but is soon dissolved. 
 
 The free germinal vesicles in the upper part of the cor- 
 pusculimi continue in the mean time without any observable 
 alteration (PI. LXI, fig. 14). On the other hand, the cell 
 attached to the tip of the pollen-tube becomes clothed with 
 a firmer membrane of cellulose at the time when the large 
 transparent cell appears near the tip of the pollen-tube ; 
 sometimes also it increases in size so that its transverse 
 diameter becomes three times that of the pollen-tube 
 (PI. LXI, figs. 12—14). The inner wall of the pollen- 
 tube exhibits, exactly at the point where the cell is attached 
 to it, a narrow pit traversing the thickening layers which 
 
THE HIGHER CRYPTO GAM! A. 421 
 
 in the mean time have been deposited upon its wall (PL LXT, 
 fig. 12). Tliis pit always appeared to be closed on the out- 
 side by the primary membrane of the pollen-tube ; no open 
 communication between the pollen -tube and the cell could 
 be ascertained. The nucleus of this cell has by this time 
 disappeared ; its contents, which are tolerably transparent, 
 are only rendered turbid to a certain extent by a few fine 
 granules. Sometimes it contains some larger bodies, equal 
 in size to the starch granules in the pollen -tube, and com- 
 posed of a substance rendered brown by iodine. The 
 relations of position between the cell and the pollen -tube 
 are of two kinds: either the upper part of the cell is 
 attached to the terminal point of the extended conical tip 
 of the pollen-tube, and thus hangs down freelj into the 
 cavity of the corpusculum (PI. LXI, figs. 13, 14), or else 
 the end of the pollen-tube is lifted up round the cell — so 
 as to form an annular cushion — and grows round the larger 
 part of the cell so as only to leave the hemispherical lower 
 end protrucUng out of the introverted end of the pollen- 
 tube (PI. LXI, fig. 11). This process has been observed 
 in its different stages. If a moderate pressure is applied to 
 the upper end of a pollen-tube having the attached cell 
 enclosed in the introversion of its apex (PI. LXI, fig. 1 1), 
 the introverted membrane often becomes exserted, and the 
 exserted portion then appears to be conical, and bears the 
 cell in question at its outermost tip (PI. LXI, fig. II), just 
 as in the first case above described. The two forms of the 
 end of the pollen -tube are equally common in longitudinal 
 sections of corpuscula. In isolated instances two such cells 
 are attached to the tip of the pollen-tube. 
 
 Prom these observations on the Abietinese I think the 
 following conclusions may be drawn as to the development 
 of the embryo. After the arrival of the end of the pollen- 
 tube at or into the upper end of the corpusculum, one of 
 the germinal vesicles lying near the end of the pollen-tube 
 is impregnated. It increases in size, and glides through the 
 mass — consisting of protoplasm and unimpregnated germi- 
 nal vesicles — which fills the corpusculum, down to the base 
 of the latter, into which it presses itself. At this time (in 
 Finns canadensis) or, (in P. sylvestris and Larix) even 
 
432 HOFMEISTER, ON 
 
 during its dowiiAA-ard progress, a daugliter-cell is formed in 
 its lower end, hy tlie repeated bipartition of Avliicli, the 
 compound pro-embryo originates. It always happens in 
 Piiuis Lariv, and frequently in P. sylvestris, that one or 
 more of the germinal vesicles which are in contact with the 
 pollen-tube, but which remain unimpregnated, acquire firm 
 membranes of cellulose, and attach themselves to the tube, 
 but this phenomenon is not essentially connected with im- 
 pregnation.* 
 
 The swelling which the pollen-tube of Ta.xus baccafa 
 forms above the top of the endosperm often attains di- 
 mensions equalling that of the latter. Where much pollen 
 has fallen, several pollen-tubes almost always penetrate into 
 the ovules. These tubes swell and press against one another, 
 so that they not only fill the entire cavity above the en- 
 dosperm, but pass beyond it, sending forth prolongations 
 of different forms. Cases occur in which the swollen ends 
 of numerous pollen-tubes grow round the endosperm on 
 all sides, and meet underneath it, thus smothering it by 
 cuttino; off the access of nutriment. Even before the cor- 
 puscules are fully developed one, or more rarely two, large 
 spherical cells are formed in each pollen-tube. These cells 
 have no firm membranes, and are filled with a thickly- 
 fluid finely- granidar protoplasm which encloses a central 
 nucleus. These cells at first float quite freely in the in- 
 terior of the pollen-tube. They are often surrounded by a 
 
 * Schacht (' Beiträge zur Anatomie,' &c., Berh'n, 1S54, p. 287, 'Das Mikro- 
 skop,' 2nd edit., Berlin, 1855, p. 151, 'Tlora,' 1855) arrived at a conclusion to 
 some extent in accordance with the above, inasmuch as it assumed the descent 
 of the rudiment of the pro-embryo from the upper end of the corpusculum to 
 the lower. In the 'Flora' for 185 5 I have attempted to show that Schacht'» 
 conclusions arc incorrect. The objects which he took for the rudiments of the 
 pro-embryo cannot in the nature of things be what he supposed. 
 
 Geleznoff's statements as to the formation of the embryo of Larix are more 
 opposed to mine. He considers that tlic cell attached to the pollen-tube grows 
 by degrees out of the apex of the latter, and he assumes that ihe two communi- 
 cate by an open pore, and that the first cell of the pro-embryo originates in the 
 lower end of this cell. In all these points my observations gave a negative 
 result. I believe that I may j)lace great reliance upon them, not only on account 
 of my investigations having been carried on for three years, but because my 
 numerous observations were repeated and verified dining a sojourn in the Alps,^ 
 where, from the opportunities which existed for collecting cones at places of 
 diU'ercut altitudes, the various stages could be followed out niucii more easily 
 and with greater certainty than could be done in a flat country. 
 
THE HIGHER CRYPTOGAMIA. 423 
 
 tliin layer of granular mucilage, from which fine strings 
 radiate to the walls of the tube. In more advanced ovules 
 these cells appear to be situated nearer to the lower wall 
 of the pollen-tube, and to be fastened to the latter by an 
 accumulation of viscid protoplasm ; their earlier spherical 
 form has passed into a flatly-ellipsoidal one. Instead of 
 the central nucleus, Avliich has now disappeared, two newly- 
 formed nuclei make their appearance, one in eacli focus of 
 the cell (PI. LXIII, fig. II). 
 
 The unimpregnated corpuscula usually contain only a 
 few (from six to ten) free germinal vesicles, amongst which 
 one in particular, whicli floats in the middle part of the 
 corpusculum is distinguished by its size, by the sharpness 
 of its outline, and by the richness of its granular contents 
 (PI. LXIII, fig. II).* 
 
 The prolongation of the pollen-tube which penetrates 
 between the cells of the rosette of the corpusculum is fre- 
 quently, but not always, filled by four cells placed cross- 
 wise, manifestly produced by the twice-repeated division by 
 means of longitudinal septa of the (originally) free spheri- 
 cal cell which is now adherent to the inner wall of the 
 tube (PL XLIV, fig. 2). One of the germinal vesicles in 
 the interior of the corpusculum, apparently the central one, 
 now appears swollen, as well as more rich in granular 
 contents, and in many instances situated nearer to the base 
 of the corpusculum (PL LXIV, fig. 2). The membrane of 
 the pollen-tube when uninjured appears completely closed. 
 The openings which are sometimes seen in it after its 
 separation from the corpusculum are almost certainly acci- 
 dental ruptures. The contents of the four cells which fill 
 the pollen-tube, or of the one cell which is sometimes 
 found there, consist of very small motionless bodies, partly 
 spherical and partly spindle-shaped, which fill the cell in 
 great numbers. The next condition of the impregnated 
 corpuscula exhibits the impregnated germinal vesicle at the 
 base of the latter, firmly pressed into the lower end of the 
 
 * In the ' Vergl. Uuters.,' p. 129, I took this formation to be tlie primary 
 nucleus of the corpusculum. This I thiuk. was an error, because in the Abie- 
 tineae and Juuiperiuefe the nucleus of the corpusculum docs not last until im- 
 preguation. 
 
424 HOFMEISTER, ON 
 
 corpusculum (PI. LXIV, fig. 1). The miimprcgnaled 
 germinal vesicles remain still nnchanged in the upper 
 part of the corpuscukmi.* Sometimes one or two of the 
 impregnated germinal vesicles which are in contact with 
 the pollen-tube become clothed wäth firm cellulose mem- 
 branes, and adhere to the apex of the tube. 
 
 The side-waUs of the upper end of the corpuscula of 
 Thuja Orientalis, Juniperus communis, and -/. sabina are 
 considerably thickened, and fm-nished with delicate an- 
 nular ridges, which are often very clearly visible in the 
 form of transverse stripes. At the beginning of July the 
 contents of the corpuscula consist, as has been mentioned, 
 of very finely granular almost glass-like transparent pro- 
 toplasm in the middle of which a large vacuole occurs. 
 Above this vacuole the primary spherical nucleus of the 
 corpusculum lies embedded in the protoplasm. This nu- 
 cleus afterwards disappears, and in its place some new free 
 nuclei make their appearance, around which, in a short 
 time, spherical cells are formed, which are the germinal 
 vesicles. Whilst the latter continue to grow, the central 
 vacuole becomes perpetually smaller and smaller : at last 
 it disappears altogether, and the corpusculum is filled with 
 a uniform mass of protoplasm having the germinal vesi- 
 cles floating in it. Amongst the latter, one or more near 
 the upper end of the corpusculum are distinguished by 
 their great size (PI. LXV, fig. 9 on the right). 
 
 The pollen-tube breaks through the softened membrane 
 of the embryo-sac — which membrane extends over the 
 depression at the top of the endosperm — and becomes 
 swollen so as to entirely fill the depression. In the regular 
 course of things a large spherical cell now appears in the 
 interior of the pollen- tube, filled W'ith granular mucilage 
 which surrounds a central transparent nucleus (PL LXV, 
 fig. 9). In certain conditions which must doubtless be 
 looked upon as more advanced, this cell has the form 
 of an ellipsoid, and is furnished with two nuclei, one in 
 each focus : other conditions ao-ain exhibit the cavitv of 
 the cell traversed by a septum passing between the two 
 
 * A decisive proof that tlie pollen-tube docs not, as Schacht supposes, eu- 
 tirely fill the corpusculum ('Flora,' 1S55). 
 
THE HIGHER CKYPTOGAMIA. 425 
 
 nuclei. Ultimately, and shortly before the pollen-tubes 
 penetrate into the rosettes of the corpuscula, two spherical 
 cells of the kind above mentioned (PI. LXV, fig. 9 on the 
 left) are often found in the tube, which in all probability 
 are produced by the division of the original single cell. 
 The increasing pollen-tube now presses together the ro- 
 settes of the corpuscula, and sends a short, very delicate- 
 walled prolongation through the line of contact of the four 
 cells which are in process of dissolution, into each corpus- 
 culum which is to be impregnated (PI. LXV, figs. 3, 10). 
 In some cases the free cells contained in the pollen-tube 
 now appear to be much flattened, attached to the w^all of 
 the tube, and divided into a larger number, normally six- 
 teen, of small cells lying in one plane (PI. LXV, fig. 4) ; 
 in other cases the pollen-tube contains four middle-sized, 
 or eight smaller, roundish cells, without any firm mem- 
 brane (PI. LXIV, fig, 3), and wdiicli probably have arisen 
 from repeated division of one of the large originally spheri- 
 cal cells. The protruded portion of the pollen-tube breaks 
 through the compact membrane of the upper end of the 
 corpusculum, forming a fissure which is very visible in the 
 apical aspect of the latter. Even after impregnation, the 
 ends of the tubes if carefully extracted appear quite 
 closed (PL LXV, fig. 10). In an object so delicate as the 
 membranes of these tubes, a small opening might easily be 
 overlooked. The following observation, however, is de- 
 cisive as to the non-existence of any such opening : the 
 contents of the corpuscula, especially of those of Juni- 
 2ierus sahina and communis, when just impregnated, swell 
 up after imbibing water, and rupture the w^all of the cor- 
 pusculum. If a longitudinal section of the endosperm of a 
 germinal vesicle which has just been impregnated, is 
 placed under the microscope, it will be seen that as the 
 contents of the corpusculum sw^ell, the delicate-walled pro- 
 longation of the pollen-tube which reaches into the upper 
 end of the corpusculum is intersected and ultimately 
 ruptured, whereupon an active current begins to flow out 
 of the corpusculum into the pollen-tube. Frequently, but not 
 always, one of the round cells in the pollen-tube forces its way 
 into the prolongation which is sent out by the membrane 
 
426 HOFMEISTER, ON 
 
 of the latter into the corpiisciilnm which is to be impreg- 
 nated. These cells, which now become very easily dis- 
 integrated, contain nmnerous spindle-shaped motionless 
 bodies, consisting of a snbstance coloured brown by iodine. 
 These bodies are short in Thnja and elongated in Juniperns 
 (PL LXIV, fig. 3*).* 
 
 The first change which is visible in tlie corpusculum after 
 the entry of the pollen-tube, is an increase in the granular 
 matter contained in the larger germinal vesicle. This cell 
 gradually moves towards the lower end of the corpusculum, 
 against which it ultimately presses itself (PI. LXV, fig. 10). 
 The larger germinal vesicles which lie in its way are dis- 
 placed and dissolved ; the smaller ones remain unaffected. 
 Since any successful longitudinal section through the 
 endosperm of an impregnated germinal vesicle lays bare 
 many different stages of development of neighbouring 
 corpuscula, there cannot, in the great number of cases 
 which are brought into comparison, be any doubt as to the 
 order of their succession. Even in Juniperus, especially in 
 Juniperus communis, the smaller impregnated germinal 
 vesicles which are immediately attached to the end of the 
 pollen -tube, very often possess firm membranes composed 
 of cellulose. 
 
 In all the Coniferae the impregnated germinal vesicle, 
 which is pressed into the bottom part of the corpus- 
 culum, divides by a transverse se])tum, so far that is as 
 this division has not already taken place during its descent. 
 The two daughter-cells — of which the upper is the larger 
 one and the lower more rich in protoplasm — divide by lon- 
 gitudinal septa : in some cases this di^'ision occurs only in 
 the lower one (PI. LX, fig. 1 1 ; PI. LXI, figs. 3—7). Shortly 
 afterwards the septum which divides the upper, more empty 
 cell or cells, from the rest of the cavity of the corpusculum, 
 is dissolved. The two longitudinal portions of the low^er 
 daughter-cell of the germinal vesicle form the first rudiment 
 of the pro-embryo of the Coniferae. Its formation is always 
 
 * It miglit, easily be imagined that the cellules produced in the interior of 
 the ends of the pollen-tube of Coniferse might produce spermatozoa. My obser- 
 vations however have hitherto only yielded negative replies to the question, as 
 will be seen by the account given above. 
 
THE HIGHER CRYPTOGAMIA. 427 
 
 tlie same, even in species which differ widely as to the 
 period of development. 
 
 In the Abietineae both the cells — whose form is that of 
 the longitudinal moieties of a blunt cone, with a convex 
 basal surface — either divide again immediately by longi- 
 tudinal septa at right-angles to the one last formed (PL LX, 
 figs. 11, 12 ; PI. LXI, fig. 3), or else a division first occurs 
 in each of them by transverse septa perpendicular to the 
 longitudinal axis of the corpusculum, by which the cells are 
 divided into two very UMcqual portions, the upper one being 
 much the largest. In the lower, smaller ones of the newlj- 
 formed cells, which contain much more concentrated mu- 
 cilage than the upper ones, the division by longitiidinal septa 
 then ensues, which latter septa are perpendicular to the 
 septum dividing the two cells (PI. LXI, fig. 6). The latter 
 phenomenon is the most common. 
 
 The pro- embryo now consists of two pairs of two-celled, 
 parallel rows of cells, having their edges of contact rect- 
 angular. The number of its cells is increased by repeated 
 division of each of the (lower) terminal cells by means of 
 septa at right-angles* to the longitudinal axis of the organ. 
 It is a rule without exception that the lower of the newly- 
 formed cells are the smallest, but the richest in formative 
 matter. The pro-embryo up to this time occupies only a 
 proportionably small space, filling the lower part (a tenth 
 to a fifth part) of the corpusculum. As the development 
 of the pro-embryo has stretched the lower part of the cor- 
 pusculum downwards whilst its upper part remained sta- 
 tionary, tlie portion of the corpusculum which is filled by 
 the pro-embryo bears a much larger proportion to the 
 upper part, than the portion occupied by the germinal 
 vesicle when first impregnated. The pro-embryo exhibits 
 110 upward growth. The lateral walls of its uppermost 
 oldest cells are as intimately amalgamated with the inner 
 wall of the corpusculum as the thickening layers of the 
 same wall are with one another. 
 
 * Speaking more accurately we might say, transverse septa radial to the iuner 
 wall of the corpusculum. Tiieyare often strongly inclined downwards from the 
 longitudinal axis of the pro-embryo, and are thus convex upwards (pi. Ix, fig. 13 ; 
 pi. Ixi, fig. 16) ; the position at right angles to the axis of the organ is first 
 assumed by them after the subsequeut longitudinal and transverse expansion of 
 the latter. 
 
428 HOFMEISTER, ON 
 
 In the upper part of tlie corpusciilum the nuracrous 
 spherical sister-cells of the germinal vesicle are still dis- 
 tinctly perceptible (PL LX, fig. 13 ; PI. LXII, fig. 5). From 
 the fact of their presence* it is impossible that the opinions 
 of Schleiden, Schacht, and Geleznow, as to the process of 
 embryo-formation in the Coniferae can be correct. Accord- 
 ing to the two former the pollen- tube penetrates into one 
 of the corpuscula, fills it up by degrees entirely, and pro- 
 duces the pro-embryo in its lower end, which is pressed 
 against the inner surface of the corpusculum. If this were 
 so, the pollen-tube must pierce through the mass of spheri- 
 cal cells which fills the cavity of the corpusculum before 
 impregnation. Nothing however is easier than to see that 
 those cells are still present when the pro-embryo appears. 
 They are only dissolved very gradually, and become changed, 
 together with the rest of the contents of the upper part of 
 the corpusculum, into a yellowish grumous mass. 
 
 The increase in length of the pro-embryo ultimately rup- 
 tures the base of the corpusculum. A considerable longi- 
 tudinal expansion immediately takes place in the two pairs of 
 cells of which it consists ; this expansion usually occurs in the 
 second cell reckoned from above (PI. LXI, fig. 7 ; PL LXII, 
 fig. 8), but sometimes the first expands also. The lower 
 end of the pro-embryo is thus driven deeply into the tissue 
 of the endosperm underneath the corpuscula. The axile 
 cells of the middle portion of the endosperm become in the 
 mean time loosened and softened, by which the course of 
 the continually-descending end of the pro-embryo is pointed 
 out beforehand. The courses of the continually-elongating 
 pro-embryos through the pultaceous mass of the softened 
 cellular tissue, form delicately-winding spirals. 
 
 Soon afterwards the longitudinal rows of cells comprising 
 the pro-embryo become detached from one another. The 
 separation commences at the lower end and progresses 
 from thence upwards (PL LXI, figs. 9, 10). During this 
 breaking up of the pro-embryo into four (very rarely more 
 than four) simple rows of cells, the four shorter cells which 
 formed its upper end which was enclosed by the corpus- 
 culum, become dissolved (PL LXI, figs. 8 — 10). 
 
 * Observed by Gottsche (' Bot. Zeit.,' 18i4, 509), and by Pineau, * Arm. d. 
 Sc. Nat.,'3id ser., vol. ii. 
 
THE HIGHER CRYPTOGAMIA. 429 
 
 Shortly after the rows of cells of the pro-embryo have 
 separated from one another, the formation of the embryo 
 itself commences in the terminal cell of each row, either 
 immediately, or after the occurrence of divisions by hori- 
 zontal septa. This formation takes place by the repeated 
 division of the aj^ical cell for the time being by means of 
 septa inclined in the first place alternately to the right and 
 to the left, and soon afterwards in three different directions. 
 The cells of the second degree divide into inner and outer 
 cells by radial, and those of the third degree by longitudi- 
 nal septa parallel to the axis, and so on, following the mode 
 of cell-multiplication in the terminal bud of Equisetum and 
 other plants (PI. LXI, fig. 11; PL LXII, figs. 9, 10). In the 
 half-ripe seed the number of rudimentary embryos is at 
 least four times as great as that of the corpuscula impreg- 
 nated. Of these however, in the greater number of cases, 
 one only is developed rapidly and vigorously ; the rest are 
 much less fully developed, shrivel up by degrees, and ulti- 
 mately die. During the formation of the embryo the 
 younger lower cells of the pro-embryo — which latter has be- 
 come the suspensor — also expand considerably in length, and 
 at last the same expansion occurs in its massive portion im- 
 mediately adjoining the embryo (PI. LXI, fig. 10 ; PI. LXII, 
 fig. 10). The latter also then become disconnected from 
 the laterally-adjoining cells (PI. LXII, fig. 10), and often, 
 especially near the lower end, bear a deceptive resemblance 
 to a pro-embryo not yet broken up into its longitudinal rows 
 of cells.* 
 
 After the penetration of the pro-embryo into the middle 
 region of the endorsperm, the walls of the corpusculura can 
 easily be separated from the surrounding tissue. They 
 exhibit now prominent reticulate ridges on the outer side, 
 corresponding in direction with the edges of contact of the 
 neighbouring cells, and they have also somewhat large flat 
 pits. These phenomena are especially manifest in Fi/iiis 
 cariadensis (PI. LXII, fig. 8). In this species the upper 
 portion of the four uppermost cells of the pro-embryo are 
 normally much thickened, and then exhibit manifest 
 lamination (PL LXII, fig. 7) ; sometimes strange-shaped 
 
 * It is doubtless from this pheuomenon that some observers, especially 
 Gelezuow, deny the breaking up of the pro-embryo into distinct suspensors. 
 
430 HOFMEISTER, ON 
 
 accumulations of gelatinous matter are found on the outer 
 walls of these cells (PI. LXII, fig. 8). 
 
 I have never seen the pollen-tube ramify in the Abietineae. 
 Each pollen-grain sends forth only one tube ; if several 
 corpuscula of the same ovule are to be impregnated, it is 
 indispensable that several pollen-tubes should reach the 
 nucleus. There is no ground for assuming an incapacity 
 for impregnation in any of the different corpuscula of the 
 same endosperm. The impregnation of all the corpuscula 
 of one endosperm, when not exceeding three in number, 
 happens not wnhequenüj in Finus s?/hestris and canadensis, 
 each being acted upon by a special pollen-tube. In Taxus 
 the impregnation of several corpuscula by the very widely 
 expanded end of a single pollen-tube, is of very frequent 
 occurrence ; and in Juniperus and Thuja it is the ride. 
 
 The impregnated germinal vesicle of Taxus haccata 
 and canadensis divides frequently by longitudinal septa 
 before any increase takes place in the number of 
 its cells in a longitudinal direction. The pro-embryo 
 not unfrequently consists of only four longitudinal rows 
 of cells, but usually of six (PI. LXIII, fig. 12). In 
 the longitudinal development of the pro-embryo its rows 
 of cells behave very differently. In some, multiplica- 
 tion and growth cease at a very early period ; it usually 
 happens that the upper end of the pro-embryo exhibits 
 some three-sided cells which renew themselves rapidly 
 downwards, and belong to no one of the longitudinal 
 rows underneath, of which the pro-embryo is composed. 
 Very commonly two or one of the longitudinal rows of cells 
 immediately adjoining the longitudinal axis of the pro- 
 embryo are more vigorously developed and multiply their 
 cells in a longitudinal direction more rapidly, than the 
 cells nearer to the periphery (PI. LXIII, fig. 13). The 
 pro-embryo does not break up into single rows of cells 
 until a later period, and then usually only partially. Nor- 
 mally one only of them goes beyond the first commence- 
 ment of embryo-formation.* 
 
 * ' Hartig zur Entwickelungsgescli. d. Pflanzen,' Leipzig, 1844, fig. 25, and 
 Scliaclit (1. c. pi. ix, figs. 11, 13) represent the first stage of development of 
 tlie pro-embryo as an oval mass of parenebymatal eclkilar tissue. 1 cannot 
 coüürm this ; the pro-embryo appeared to me, even in its earliest youth, to be 
 always clearly composed of longitudinal rows of cells. 
 
THE HIGHER CRYPTOGAMIA. 431 
 
 The impregnated germinal vesicle — which is pressed into 
 the lower end of the corpiisculum— of Juniperus communis 
 and sahina, as well as that of Thuja orientalls, divides by 
 a transverse septum into two daughter-cells (PL LXV, fig. 
 10), of which the lower one frequently encloses the larger 
 portion of the protoplasm of the mother-cell. The upper 
 wall of the upper cell is usually soon dissolved (PL LXI, 
 fig. 4) ; when it lasts longer (as is often the case) the 
 same vigorous downward expansion which takes place 
 after some time in all the cells of the pro-embryo, takes 
 place also in the up[)ermost of the two cells of the rudi- 
 mentary pro-embryo (PL LXV, fig. 3).* The farther 
 development of the daughter-cell of the impregnated 
 germinal vesicle resembles, in its essential features, that 
 of the Abietineae. It divides by longitudinal septa, and 
 the elongated daughter-cells divide by transverse septa, 
 which latter division is repeated in the terminal cells. The 
 number of longitudinal divisions of the second cell of the 
 pro-embryo is however far less definite than in the Abietineae. 
 The most usual number of the rows of cells of the pro- 
 embryo is four, but pro-embryos are also often found which 
 consist of only two or — on account of the longitudinal di- 
 vision of one of the latter — of three longitudinal rows of 
 cells (PL LXV, fig. 4). 
 
 These rows of cells very soon become disconnected after 
 the pro-embryo has broken through the base of the corpus- 
 culum. Their longitudinal expansion is still more re- 
 markable than in the Abietineae (PL LXV, fig. 5). If 
 after the last transverse division (PL LXV, fig. 6) of the 
 terminal cell of one of the detached rows of cells, the for- 
 mation of the embryo commences by the production of 
 differently inclined septa in the lower one of the newly- 
 formed cells, then the lower end of the last cell of the pro- 
 embryo, upon which the embryo is seated, grows very 
 
 * These enlarged upper portions of the impregnated germinal vesicle exhibit 
 a very large nucleus with proportionably large nucleoli. The occurrence of the 
 division of the germinal vesicle into an upper and a lower portion, of which the 
 latter is destined for more active further development, tlie former remaining 
 stationary, and sometimes containing a nucleus, sometimes not — brings to 
 mind the similar phenomena in Gageaaud Fritillaria (' Entstehung des Embryo,' 
 pp. 20, 21). 
 
432 HOFMEISTER, ON 
 
 considerably in breadth (PI. LXV, figs. 7, 8). In Jimi- 
 perus also all the numerous young embryos usually mis- 
 carry, except one. 
 
 The stages of development of the embryos of the Co- 
 niferae which follow next after the impregnation of the 
 germinal vesicle, are passed through with just as much 
 rapidity as contemporaneity. A very short time, scarcely 
 twenty-four hours, elapses between the arrival of the 
 end of the pollen-tube at the upper end of the corpus- 
 culum of the Abietinese, and the formation of the four- 
 celled compound pro-embryo at its base ; and these 
 processes of development occur almost contemporaneously 
 in all ovules of all trees of the same species growing 
 under similar circumstances. Thus in J 854 I found 
 that on the 22nd of June, near Leipzig, no single pollen- 
 tube of Finns sylvestris had reached a corpusculum; 
 whereas only three days later, on the 25th of June, there 
 was only one amongst several hundreds of impregnated 
 corpuscula which I examined, whose impregnated ger- 
 minal vesicle was not already divided into four cells. In 
 Taxus and the Juniperinese the contemporaneity of the 
 development is less complete ; here we find different stages 
 of development extending over about eight days, consist- 
 ing of germinal vesicles unimpregnated, impregnated and 
 unicellular, or imj)regnated and multicellular, all near one 
 another. 
 
 Robert Brown* was the discoverer of the poly-embryony 
 of the Coniferae. In a later treatisef (1834) he pointed 
 out the origin of the pro-embryo in large cells of the en- 
 dosperm, to which he gave the name of corpuscula. Cordaj 
 first proved that the pollen-tubes penetrate into the in- 
 terior of the corpuscula. Schleiden,^ in 1843, gave the 
 first accurate account of the nature of the pro-embryo. As 
 many subsequent observers have done, he mistook the 
 
 * 'Ann. d. Sc' 1st ser., vol. viii, p. 211. 
 
 f 'Ann. d. Sc' 2nd ser., vol. xx, p. 193. 
 
 X ' Nova Acta,' vol. xvii, p. 599. Upon other points this work is of no 
 nse. 
 
 § 'Grundzüge,' 1st edn., vol. ii, p. 375. R. Brown's acconnt of the young 
 pro-embryo is incomplete. lie figures (1. c, vol. xx, pi. v, fig. 9) a pro-embryo 
 whose smaller terminal growing cells are torn off. 
 
THE HIGHER CRYPTOGAMIA. 433 
 
 pro-embryo for the embryo. Hartig* was the first to 
 observe that the upper part of the suspensor is a single 
 row of cells. He had not a clear idea of the relation of the 
 suspensor to the pro-embryo. Mirbel and Spachf dis- 
 covered the breaking up of the pro-embryos into single 
 rows of cells in Finns, Thuja, and Taxus, Gottscheds | 
 excellent work contains the most careful critique of the then 
 known facts, and the first accurate description of the struc- 
 ture of the corpuscula of Pinus ; it also gives a renewed 
 and complete proof of the advance of the pollen-tube to the 
 corpuscula, as well as proof of the fact that the rudiment 
 of the pro-embryo is visible in the low^er end of the cor- 
 pusculum, whilst the sister-cells of the germinal vesicle are 
 still present. 
 
 The greater part of the above investigations were under- 
 taken in the years 1848 and 1849.§ I have already 
 mentioned their agreement with Pineau's views, and their 
 divergence from those of Geleznow and Schacht. 
 
 * ' Naturgeschichte der Porstcultur pflanzen,' Erklärung zur Tafel, XXV. 
 
 f ' Ann. d. Sc. nat.,' ii Ser. vol. xx, p. 257. 
 
 + 'Bot. Zeit.,' 18i5,377. 
 
 § Head at the August sitting of the Leipzig Natural History Society. 
 
 28 
 
CHAPTER XVI. 
 
 REVIEW. 
 
 The comparison of the development of the mosses and 
 liverworts on the one hand, wath that of the ferns Equiseta- 
 ceae, Rhizocarpese, and Lycopodiacese on the other, dis- 
 closes the most complete uniformity between the fruit- 
 formation on the one hand and the embryo-formation on the 
 other. The structure of the archegonium of the mosses — 
 the organ within which the fruit-rudiment is formed — is 
 exactly similar to that of the archegonium of the vascular 
 cryptogams, the latter being that part of the prothallium in 
 the interior of which the embryo of the frond-bearing 
 plant originates. In both the large groups of the higher 
 cryptogams there is a cell which originates freely in the 
 larger central ceil of the archegonium, by the repeated 
 division of which (free) cell, the fruit of the moss and the 
 frond-l)earing plant of the fern are produced. In both, 
 the divisions of this cell are suppressed and the arche- 
 gonium miscarries, unless, at the time of the opening of 
 the top of the latter, spermatozoa find their way to it. 
 
 Mosses and ferns thei'efore exhibit remarkable instances 
 of a regular alternation of two generations very different 
 in their organization. The first generation — that from the 
 spore — is destined to produce the different sexual organs, 
 by the co-operation of which the multiplication of the 
 primary mother-cell of the second generation, which exists 
 in the central cell of the female organ, is brought about. 
 By this multiplication a cellular body is pioduced w^hich in 
 the mosses forms the rudiment of the fruit, and in the 
 vascular cryptogams, the embryo. The object of the 
 
HOFiMEISTER, ON THE HIGHER CRYPTOGAMIA. 435 
 
 second generation is to form numerous free reproductive 
 cells — the spores — by the germination of which the first 
 generation is reproduced. The leafy plant in the mosses 
 answers therefore to the prothallium of the vascular 
 cryptogams ; the fruit in the mosses answers to the fern 
 in the common sense of the word, Avitli its fronds and 
 sporangia. The pro-embryo, that is to say the confer- 
 void process produced by the germinating spore of most 
 of the mosses and many of the liverworts, cannot be 
 looked upon as a special generation any more than the 
 similar organ (the suspensor) m phaenogams. It is to be 
 remend3ered that wdien new individuals are produced from 
 single cells of the leaf of a moss, and also during the 
 development of the gemmae of many mosses, the formation 
 of the rudiment of the first leafy axis is preceded by the 
 formation of a similar confervoid pro-embryo. This holds 
 good as well in the mosses * as in those liverworts which 
 possess a pro-embryo. When new individuals are formed 
 from the fragment of a leaf of Lojjhocolea heteroj^hyUa or 
 of Badula complanata, the cell of the sm'face of the leaf 
 which becomes the mother-cell of the new plant produces 
 in the former of the above-named plants a single or double 
 row of cells, and in the latter a cellular surface. In each 
 case the body produced is exactly similar to the pro- 
 embryo which originates from the germinating spore in 
 both species. 
 
 The vegetative life of the mosses is confined exclusively 
 to the first, and the fructification to the second generation. 
 The leafy stem alone sends forth roots : the spore-forming 
 generation draws its nourishment from the first generation, 
 'rhe life of the fruit is usually much shorter than that of the 
 leaf-bearing plant. In the vascular cryptogams this state 
 of circumstances is reversed. It is true that the prothaUia 
 send out capillary roots : this is always the case in the 
 Polypodiacese and Equisetaceae, and frequently in the 
 Rhizocarpeae and Selaginellae. But the prothallium lives a 
 much shorter time than the leaf-bearing plant, which latter 
 in most cases does not produce fruit for several years. 
 
 * W. p. Schimper's CKcelleut work, ' ilecherclies sur les mousses,' reudcis 
 it uuuecessary for me to cite examples. 
 
43G H0r3I KISTER, ON 
 
 The contrast however is not so marked as it appears at first 
 sight. The apparently iinUmited life of the leaf-bearing 
 moss depends merely upon continual renovation. Pheno- 
 mena of a similar kind are met with in the sprouting 
 prothallia of Polypodiacese and Equisetaceae. In the lowest 
 liverworts (Anthnceros and Pellia) the structure of the 
 fertile shoots is less complicated, and their duration little 
 longer, than that of the fruit. On the other hand the 
 ramification of the prothallium of the Equisetaceae is veiy 
 variable ; its life is not of shorter duration than that of an 
 individual shoot. 
 
 It is a circumstance worthy of notice that in the second 
 or spore-forming generation of mosses and ferns, compli- 
 cated thickenings of the cell-walls usually occur (witness 
 the teeth of tlie peristome in mosses, the capsule-wall and 
 the elciters in liverworts, and the vessels in ferns), whilst in 
 the first generation these thickenings are rare and excep- 
 tional. 
 
 An unprejudiced consideration of the subject will show 
 that the separation into two groups only of the plants com- 
 prising the mosses on the one hand, and the liverworts 
 (Jungermannice, March antiese, Anthocerotea?, and Riccieae) 
 on the other, is not natural. There is no marked feature 
 by which these two groups can be distinguished. It is 
 true that a pro-embryo like that in the mosses is wanting 
 in most of the genera of liverworts, especially in all the 
 leafless ones. Many leafy Jungermannieae, however, espe- 
 cially the true Jungermanniae, exhibit the phenomenon of 
 the conversion of the germinating spore into a single row 
 of cells, one of which cells, by repeated divisions in all 
 three directions of space, becomes the rudiment of the leafy 
 axis. This phenomenon is as well marked as hi any of the 
 mosses. The outward form of the antheridia and arche- 
 gonia in the two groups difiers very slightly. The first 
 stages of development of the fruit-rudiment of the mosses 
 on the one hand and the Jungermanniae on the other, are, 
 it is true, very different. In the former the longitudinal 
 growth is caused by the conti i mal ly repeated division of a 
 single conical apical cell of the organ, by means of septa 
 inclined alternatelv in two directions ; in the latter this 
 
THE HI (11 1 KR CHYl'Tü(!AMr.\. 437 
 
 growth is caused by the repeated division by horizontal 
 septa, of four cells constituting the upper end of the fruit- 
 rudiinent. But the normal mode of cell-multiplication in 
 the fruit-rudiment of the iMarchantie?e (including the 
 Targioniese), and of the Riccieae, coincides exactly with 
 that of the mosses. Lastly Anthoceros exhibits a form of 
 cell-multiplication of the endogonium which is the same 
 as that of the punctum vegetationis of the ends of the axes 
 of a great number (probably the majority) of phaenogams. 
 The septa produced in the one apical cell of the organ, are 
 inclined in regular succession towards the four points of 
 the compass. The presence or absence of a columella, or 
 of elaters in the ripe fruit, are points of no characteristic 
 value; Anthoceros has the columella, but this genus and 
 the Riccieae have no elaters. Radula in the Jungerman- 
 niese has a vaginula, and so has Anthoceros. 
 
 Upon instituting a closer comparison between the mode 
 of development of different forms, four types soon become 
 conspicuous, around which all the phenomena hitherto 
 sufficiently investigated may be conveniently arranged. 
 We thus arrive at the following equivalent groups, which 
 are not however equally rich in the number of genera and 
 forms. 
 
 1. Mosses according to the ordinary limits of the family, 
 including the Sphagnacese. 
 
 2. Jungermannieae ; in which the leafy ones are con- 
 nected with the leafless ones by a succession of inter- 
 mediate stages. 
 
 3. Marchantiese, Targioniese and Riccieae; all intimately 
 connected with one another by the similarity of the earliest 
 conditions of the fruit, as well by many vegetative pheno- 
 mena.* 
 
 4. Anthocerotese. 
 
 The mode in which the second generation originates 
 from the first is much more various in the vascular crypto- 
 gams than in the others. All ferns however agree in the 
 
 * As for instance the precisely similar succession of the shoots ; the separa- 
 tion of the tissue of the shoots into an upper layer with intercellular caviiies, 
 and a lower layer without cavities ; the occurrence of peculiar thickenings upon 
 the inner wall of the capillary roots, &c. 
 
438 HOFMEISTER, ON 
 
 fact that the first axis of their embryo has only a very 
 Hmited longitudinal development ; it is an axis of the second 
 order which breaks through the prothallium and becomes 
 the princi|)al axis ; and they all agree further in this, that 
 the end of the axis of the first order never forms the root. 
 All vascular cryptogams are without main roots ; they have 
 only adventitious ones. 
 
 In more than one respect the formation of the embryo of 
 the Coniferse is intermediate between the higher crypto- 
 gams and the phaenogams. Like the primary mother-cell 
 of the spores of the Rhizocarpeae and Selaginellse the 
 embryo-sac is one of the axile cells of the shoot, which in 
 the one case becomes converted into the sporangium, in 
 the other into the ovule. In the Coniferae also the embryo- 
 sac soon becomes free from any mechanical connexion with 
 the surrounding cellular tissue. The filling of the embryo- 
 sac by the endosperm may be compared with the produc- 
 tion of the prothalHum of the Rhizocarpeae and SelaginellcC. 
 The structure of the corpuscula bears the most striking 
 resemblance to that of the archegonia of the Salvinige, and 
 still more of the Selaginellse. Irrespective of the different 
 mode of impregnation — which in the Rhizocarpeae and 
 Selaginellae takes place by free spermatozoa, and in the 
 Coniferse by a pollen-tube, in the interior of which sperma- 
 tozoa are probably formed — the transformation of the 
 germinal vesicle into the primary mother-cell of the new 
 plant in the Coniferse and the vascular cryptogams, only 
 differs in the fact, that in the latter there is usually one 
 single germinal vesicle only, whilst in the former there are 
 very numerous germinal vesicles, of which, normally, one 
 only is impregnated. The embryo-sac of the Coniferae 
 may be looked upon as a spore remaining enclosed in its 
 sporangium ; the prothallium which it forms does not come 
 to the light. In order to reach the archegonia of this 
 prothallium the impregnative matter must make itself a 
 passage through the tissue of the sporangium. 
 
 Moreover, the development of the pollen of the Coniferae, 
 when dispersed, varies in a marked manner from that of 
 phsenogams, and exhibits vital phenomena similar to those 
 met with in the microspores of Pilularia, Salvinia, and 
 
THE HIGHER CRYPTOGAM lA. 439 
 
 Isoetes. The extinction of its sexual function (the protru- 
 sion of the pollen-tube) is preceded by a cell-formation in 
 its interior, of which no instance is to be found amongst 
 monocotyledons and dicotyledons. 
 
 Two of the phenomena which have led me to compare 
 the embryo- sac of the Coniferse with the large spores of the 
 higher cryptogams, is common to the embryo-sac of pha^^no- 
 gams, viz., the origin of the ovule from an axile cell, and 
 the w^ant of connexion with the adjoining cellular tissue. 
 This is very remarkable in the RhinanthaccEe on account of 
 the independent growth of the embryo-sac. The Coniferae 
 are closely allied to the phaenogams in the fact that their 
 pollen-grains develope tubes. 
 
 - The phaenogams tlierefore form the upper terminal link 
 of a series, the members of which are the Coniferae and 
 Cycadeae, the vascular cryptogams, the Muscineae, and the 
 Characeae. These members exhibit a continually more 
 extensive and more independent vegetative existence in 
 proportion to the gradually descending rank of the gene- 
 ration preceding impregnation, which generation is deve- 
 loped from reproductive cells cast off from the organism 
 itself. The closing members of this series, the Characeae, 
 pass through their entire vegetative development in this 
 generation, whilst the vital phenomena of the generation 
 which follows impregnation are limited to the filling with 
 oil and starch of the newly formed cell in the central cell 
 of the fruit-branch or archegoninm. The development of 
 the latter generation in the Muscineae is far more important, 
 although in some instances, as for example in Riccia, it is 
 very limited in comparison with the first generation, that 
 namely which precedes impregnation.* This state of things 
 is reversed in the Ferns, the Equiseta, and the Ophioglosseae. 
 From the Characeae up to these orders, there is an uncer- 
 
 * Anthoceros — which iu the development of tlie second generation stands 
 very low in the scale — exhibits a remarkable analogy with the Characca?, in the 
 fact that, as in the latter, the formation of its antheridia commences by tiie 
 growing out of the cells of the wall of an intercellular cavity. The well-known 
 red globules of Chara are manifestly states of antiieridia. Cavities com- 
 municating with one another are formed round the middle ])oint of the hitherto 
 solid globular mass of cells, within which cavities the antheridia — or cellular 
 threads in whose joints the vesicles which produce the spermatozoa are formed 
 — become developed. 
 
410 HOFMEISTER, ON 
 
 tainty in the different species as to the sexual function of 
 the reproductive cells which are cast oft' from the organism 
 itself, viz., the spores. In these orders species nearly alUed 
 to one another are partly mona?cious and partly dia^cicjus. 
 Certain species amongst theCharae.MuscineEe, the Ferns, and 
 the Equiseta,* produce both kinds of sexual organs, arche- 
 gonia and antheridia, upon the same individual of the genera- 
 tion preceding impregnation : the latter are always produced 
 before the former. In other Characeae, Muscineae and 
 Equiseta, the male and female sexual organs are distributed 
 upon different individuals — a separation which is very com- 
 plete in certain species of mosses, and not in others. The 
 spores from which, in the Characeae, Muscinae, and Equi- 
 seta, diaecious prothallia are developed, exhibit no indica- 
 tion of the sex of the individual to be produced from them. 
 But there is often a marked difference in the conqjlete form 
 between the male and female individuals : the former are 
 much smaller than the latter ; they are dwarfish. Extreme 
 instances of this are to be found, amongst mosses, in 
 Dicranv.m tDuhilatinn and Hypniim Jiitesccns. In the Equi- 
 seta also the male prothallia ai-e always smaller than the 
 females. 
 
 Lastly, the reproductive cells of the Rhizocarjjea, Isoetes, 
 and Selaginella exhibit, according to their sex, the most 
 remarkable differences in their mode of development, size, 
 and form, so long as they continue in vital connexion 
 with the organism belonging to the generation following 
 impregnation. In the Coniferae the reproductive cells differ 
 in tlieir origin and formation but little from those of phae- 
 nogams; they differ only in the nature of the vegetative 
 growth subsequent to their formation — wdiich growth in 
 the Coniferae is in a high degree independent — in the 
 formation of the row of cells in the interior of the pollen- 
 grain, as well as in the formation of the endosperm, and of 
 the corpuscula in the interior of the embryo-sac. 
 
 There are so many essential points of agreement between 
 the Coniferae and the phaenogaras, that it is more to the 
 point to get rid of the marked differences in their respective 
 
 * The greater number of tlie CIku-sc and Miisciuese, a few only of the Equi- 
 seta, and all the known forms of I'crns and Ophioglosseaj. 
 
THE HIGHER CRYPTOGAMIA. 441 
 
 processes of embryo-formation, than to indicate in what they 
 agree. One of these differences is the cell-formation inside 
 the pollen-grain, bnt the principal one is the development 
 of the endosperm and of the corpiiscula, a process exactly 
 analogous to the formation of the prothallia and archegonia 
 of the vascular cryptogams, and which is entirely wanting 
 in the phgenogams. The whole series of developmental 
 processes which occur in the ConiferEB between the filling 
 of the embryo-sac with the cellular tissue of the endosperm 
 and the production of the germinal vesicles in the corpus- 
 cula, is entirely passed over in the phsenogams. Here the 
 germinal vesicles are formed inunediately in the embryo- 
 sac. In the phaenogaras there is no vital phenomenon 
 analogous to the development of the prothallia and of the 
 endosperm of gymnosperns, just as in the cryptogams and 
 the Coniferae there is no analogue to the endosperm- 
 formation which takes place in so many phsenogams after 
 the arrival of the impregnating organ at the embryo-sac. 
 The breaking up of the pro-embryo of the Conifera3 into 
 a number of independent suspensors is a phenomenon of 
 the most peculiar kind, to which nothing amongst the vas- 
 cular plants bears any resemblance,* and to which the 
 division of the spore (/. e. the mother-cell of the oospores) 
 of Fucus into several cells capable of impregnation and 
 developraentt is hardly analogous, inasmuch as with the 
 latter process the impregnation of the free spore commences 
 and forthwith terminates. 
 
 The observations contained in the following note are the 
 result of investigations made subsequently to those detailed 
 in Chapter III. These inquiries have led to the conclusion 
 that Frnllania — and probably iA^o Lojjhocolca bidenfaia m\& 
 
 * Tlie formation of the pro-embryo of Loranthus eurojpmis out of four longitu- 
 dinal rows of cells may be looked upon as a slight indication of this. One only 
 of these cells, tlie terminal cell, becomes transformed into an embryonic globule. 
 (Hofmeister, in ' Abh. Kon. Sachs. Ges. d. VViss.,' vi, 543. 
 
 t Tiiuret, • Ann. d. Sc. Nat.,' iv Ser., 185-t, p. 273.) 
 
142 UÜFMEISIER, 0>f TIFK HKillKR CRYPTOGAMIA. 
 
 Ptilidium ciliare — must be cxckidod from the category of 
 plants having a two-edged terminal cell of the stem. 
 
 Note on ihe Cell-multiplication of the Apex of the Stem 
 in the Leafy Jimyermannice. 
 
 The end of the stem in vigorous shoots of Jungermannia 
 hicuspidata exhibits, when viewed from above, a three- 
 sided apical surface of the terminal cell, and an arrangement 
 of the cells adjoining the latter, which leads to the con- 
 clusion that the cells of the second degree are formed 
 by the production of septa in the apical cell parallel to 
 each one of the three plane lateral surfaces. The order of 
 succession of the cells of the second degree represents a 
 spiral. All those Jungermannise which I examined which 
 had inferior leaves, and consequently trilinear phyllotaxis, 
 exhibited a similar state of circumstances — for instance, 
 Alicularia scalaris, Calypoyeia Trichomanes, Lepidozia 
 reptans, Fridlania dilatata, Madotheca platyphylla. The 
 same was the case also with another Jungermannia — besides 
 J. hicuspidata — with bilinear-leaves, viz. Playiochila as- 
 plenioides. In the latter — as in J. bicmjndata — a leaf 
 originates out of each cell of the two longitudinal rows of 
 cells of the second degree which are turned upwards to- 
 wards the creeping stem. Each of the cells of the longi- 
 tudinal row of cells of the second degree which occupies 
 the under surface of the stem, developes from its fore-edge 
 a transverse row of two- or three-celled hairs with elongated 
 clavate terminal cells, which hairs soon fall oflF. 
 
EXPLANATION OF THE FIGURES. 
 
 PLATE I. 
 
 ANTHOCEROS LiEVIS. 
 FIG. 
 
 1. Germ-plants seen from above, x 15.* 
 
 2. Slioot of a plant cultivated for some time in a room under a hand-glass, 
 
 X 15. 
 
 3. Longitudinal section through an actively growing shoot, perpendicular to 
 
 the surface. The contents are only shown in the cells of the fore-edge. 
 The youngest cell of the second degree belongs to the upper side of the 
 shoot. The fore-edge of the shoot is surrounded by a layer of mucilage, 
 hardened on the outside, to which grains of dust and sand adhere. 
 X 300. 
 
 4. A similar preparation. The section has passed through three archegonia in 
 
 process of development, x 300. 
 
 5. A young shoot seen from above, X 300. 
 
 6. Fore-edge of a half-developed shoot in the epidermal cells of which the 
 
 final division is going on, x 300. 
 
 7. A young shoot ; on the right and left of the middle shoot are the two 
 
 rudimentary lateral shoots, seen from above, x 300. 
 
 8. Transverse section of a delicate young shoot, X 200. 
 
 9. Cells of the interior of a perfect shoot cut through longitudinally, and 
 
 which, abnormally, contain two chlorophyll-granules, x 300. 
 
 10. Portion of a section perpendicular to the surface of a perfect shoot, treated 
 
 with caustic potash, x 300. 
 
 11. Portion of the inner tissue of a longitudinal section of a perfect shoot. 
 
 One of the cells — that one whose contents are figured — shows the com- 
 mencement of the formation of a gemma, x 300. 
 
 12. A further developed gemma cut through parallel to the surface of the shoot 
 
 in which it was formed, x 300. 
 
 13. A gemma which has sent out a capillary root whilst still within the decay- 
 
 ing tissue of the mother-shoot, x 100. 
 
 14. Chlorophyll-bodies from one of the cells of the wall of a young fruit, 
 
 X 400. 
 
 * •' X 15" means "magnified 15 diameters," and so on all through the 
 fifjures. 
 
444 EXPLANATION Ol' THE FKiL'RKS. 
 
 FIG. 
 
 14*. A similar body in llic act of dividing, x 400. 
 
 15. A yonnü:arclicgouiuin with tlic adjoining tissue, cut tlirough longitudinallv, 
 
 X 300. 
 
 16. An arclicgonium more fully developed, after the formation of the germinal 
 
 vesicle in the basal cell, x 300. 
 
 17. Portion of a longitudinal section of a shoot perpendicular to the surface, 
 
 bearing an arcliegonium just impregnated. A bud which has been cut 
 through is seen in the tissue underneath, x 300. 
 
 18. Lono-ifudinal section of an arcliegonium (with the adjoining cells) with a 
 
 bieellular fruit-rudimeut, x 300. 
 18*. The mouth of the latter seen from above, X 300. 
 
 19. A similar preparation with a multicellular fruit-rudiment, x 300. 
 20a. A 3-cellular fruit-rudimeut, detached, x 300. 
 
 20*. The same preparation turned round 90^, X 300. 
 
 21". Longitudinal section of a further developed fruit-rudiment, x 300. 
 
 21*. The apex of a detached fruit-rudiment, similarly developed, seen from the 
 outside, X 300. 
 
 21". Optical section of the preparation in the same position, X 300. 
 
 21''. Optica;l section of the same after being turned 90° round its longitudinal 
 axis. 
 
 22. Longitudinal section of a further developed fruit-rudiment, x 250. 
 
 23"'*. Optical longitudinal sections of the unper end of a more advanced fruit- 
 rudiment. The position of 23* differs from that of 23" by a revolution 
 of 90° round the longitudinal axis. X 250. 
 
 24. Transverse sections of a similar fruit-rudiment, x 80. 
 
 25. Apex of a slightly more developed fruit-rudiment, separated from the lower 
 
 portion by a transvcise section, and seen from above, x 150. 
 
 PLATE II. 
 
 1. Longitudinal section of a young fruit-rudiment enclosed by the surround- 
 
 ing tissue, X 150. 
 
 2. Longitudinal section of a further developed condition of the same parts. 
 
 A large cavity filled with mucilage has been formed above the apex of 
 the fruit-rudiment. Some of the cells of the wall have grown out into 
 multicellular hairs. X 120. 
 
 3. Upper portion of the wart-like protuberance (above the upper surface of 
 
 the stem) by which the young fruit is enclosed ; cut off so that the upper 
 end of the fruit is visiijle. The cells of the jointed hairs which traverse 
 the mucilaginous mass in the inlerior of the cavity above the fruit, have 
 already become detached. X 100. 
 
 4. Longitudinal section of the u])per end of a fruit at the moment of breaking 
 
 out from the sheath. Only the mucilaginous mass and the dry cellular 
 tissue covering it are shown in detail; Ihe fruit and the sheath are only 
 in outline, x 200, 
 
 5. Longitudinal section of a half-developed fruit just after breaking forth 
 
 from the tissue of the stem, x 100. 
 
EXPLANATION OF THE FIGURES. 445 
 
 FIG. 
 
 5*. The cast,-ofT calyptra (coiisisiing of the ruptured portion of the tissue of 
 the stem, which covered the cavity, together with the mucilage whicli 
 filled tlie latter), seen from below, x 100. 
 
 5°. Some of the cells of the edge of this calyptra, X 300. 
 
 PLATE III. 
 
 1. Columella and right-hand longitudinal moiety of the lower part of a young 
 
 fruit, the place at which the separation of the graud-mother-cells from 
 the surrounding tissue commences, X 250. 
 
 2. Transverse section (high up) of a young fruit, x 100. 
 
 3. Spore-moiher-cells, just detached, x 250. 
 
 4. 5 and 5*. Spore-mother-cells during the formation of the two secondary 
 
 nuclei, x 250. 
 6. A similar cell after the formation. 
 
 7 and 8. The same cells during the dissolution of these nuclei. 
 9. Spore-mother-cell after the formation of the four tertiary nuclei, x 250. 
 
 10. The same shortly before the commencement of division, showing the begin- 
 
 ning of the swelling of the cell-membrane. 
 
 11. Spore-mother-cell (after the dissolution of the primary nucleus) in alcohol 
 
 and water, which makes the cell-membrane swell, x 750. 
 
 12. Spore-mother-cell at the commencement of division, examined in alcohol, 
 
 X 750. 
 
 13. A similar preparation after treatment with water, which makes the cell- 
 
 membrane swell, X 750. 
 
 14. Spore-motlior-cell in alcohol before the termination of the division. The 
 
 course of the edges of the septa — which do not yet reach the middle 
 point of the cell — upon the inner side of the cell-membrane is shown in 
 the drawing, x 750. 
 
 15. An abnormal spore-mother-cell, x 250. 
 
 16. Longitudinal section, perpendicular to the surface, of the end of a shoot 
 
 which bears a group of rudimentary antheridia, x 300. 
 
 17. Optical longitudinal section of two young antheridia, x 150. 
 ] 8. Optical transverse section of one of these antheridia, x 150. 
 
 19, 20. Optical longitudinal section of more-developed antheridia, x 300. 
 
 21. Longitudinal section of an almost ripe autheridium, x 300. 
 
 22. Two mother-cells of spermatozoa, each containing a spermatozoon, x 500. 
 
 PLATE IV. 
 
 VELLTA EPIPHYLLA. 
 
 Longitudinal section of a ripe spore, x 300. 
 
 Sketch of a ripe spore in which the outlines of the cells only are shown. 
 
446 EXPLANATION OF THE FIGURES. 
 
 FIG. 
 
 3. A ripe spore begiuuing to germinate, three days after sowing, x 300. 
 
 5 — 9. Germinating spores more developed; six days after sowing, x 100. 
 
 rig. 6 is fig.5 turned round 4i5° ; fig. 7 is the same object turned round 
 
 90° ; fig. 8 turned round 270°. 
 ]0. A germinating spore wliose first capillary root is just breaking tlirough the 
 
 exosporium, x 300. 
 11 — 14. Sections of spores more advanced in germination ; figs. 11 and 14 seen 
 
 from above, figs. 12 and 13 from the side. Figs. 11 — 13 are magnified 
 
 300, fig. 14, 150 times. Tigs. 13 and 14 represent spores eleven days 
 
 after sowing. 
 
 15. Fore-end of a somewhat more developed germ-plant, 36 days after sowing, 
 
 seen from above, x 200. 
 
 16. Longitudinal section of a similar fore-end, x 200. 
 
 17. Fore-end of a germ-plant 42 days after sowing, x 200. 
 
 18. Germ-plant 49 days after sowing, x 30. 
 
 19 — 22. Half-developed spring shoots of fertile specimens, x 5. 
 
 23. Half-developed spring shoot seen from above, x 200. 
 
 24, 25. Longitudinal section, perpendicular to the surface, of half- developed 
 
 shoots of fertile plants— fig. 24, x 200 ; fig. 25, x 400. 
 26, 27. Longitudinal section, perpendicular to the surface, of young shoots of 
 barren plants, x 200. 
 
 28. Transverse section of an older shoot of a barren specimen which bears four 
 
 rudiments of adventitious shoots. Very delicate fungoid threads are 
 seen upon the outer surfaces of the epidermal cells of the mother-shoot. 
 X 200. 
 
 29. Longitudinal section of a rudimentary antheridium, x 300, 
 
 30. Longitudinal section of an unusually slim antheridium almost ripe. The 
 
 contents of the cells, and the mother-cells of the spermatozoa, are not 
 
 shown, X 200. 
 31«.*. Mother-cell of spermatozoa from an unripe antheridium, x GOO. 
 32"'*. The same after its escape from a ripe antheridium. The included spiral 
 
 spermatozoon is already revolving, x COO. 
 33"'*''. Free spermatozoa, killed by iodine. In 33" and 33"^ the mother-cell is 
 
 attached to the hinder end. x 600. 
 
 PLATE V. 
 
 PELLIA Eril'UYLLA. 
 
 1. Vertical longitudinal section of a shoot bearing the rudiments of archego- 
 
 nia, X 30. 
 
 2. A similar shoot with more developed archegonia, x 30. 
 
 3. Longitudinal section of a very young archegonium, x 400. 
 
 4. Longitudinal section of the upper cud of a somewhat more developed 
 
 archegonium, x 300. 
 
EXPLANATION OF THE FIGURES. 44? 
 
 FIG. 
 
 5. A young arcbegonium at the time of the dissolution of the transverse septa 
 
 of the cells of the axile cellular string, x 300. 
 
 6. Longitudinal section of an archegouium fit for impregnation, X 200. 
 6*. Transverse section of the neck of a similar archegouium, x 200. 
 
 7. Similar view of an archegouium ready for impregnation and of a very young 
 
 one similarly magnified, x 200. 
 
 8. Three-celled fruit-rudimeut, detached, x 300. 
 
 9". Group of three archegonia impregnated artificially, with two young abortive 
 archegouia, X 40. 
 
 9*. Young fruit-rudiment, longitudinal section. 
 
 10. Longitudinal section of a more developed fruit- rudiment, x 300. 
 
 IL Longitudinal section of a young fruit, showing the commeucement of the 
 
 separation of the tissue of the interior of the capsule (about the 20th 
 
 August), X 150. 
 
 12. Primordial utricle of a cell of the interior of a capsule in the same state 
 
 of developmeut, set free by the dissolution of the swollen substance of 
 the wall, X 200. 
 
 13. Longitudinal section of a further developed fruit, x 40. In part of the 
 
 interior of the capsule the arrangement of the elaters and spore-mother- 
 cells is visible (middle of September). 
 
 14. Spore-mother-cell with protrusions (one turned away from the observer) of 
 
 the wall ; on the 8th of September, x 500. 
 
 15. The same, in which the cell-contents are not shown, x 500. 
 156. The same, turned round 90°, x 200. 
 
 16. Mother-cell with four protrusions (one turned away) answering to the 
 
 special-mother-cells. Beginning of December, x 400. 
 
 17. A set of four spores just formed (one is turned away from the observer) 
 
 which are held together by the remnants of the mother-cell. Middle of 
 December, x 400. 
 IS. A young spore still attached to the remnants of the mother-cell. In the 
 place of the primary central nucleus (which in the spores shown in 
 Fig. 17, has already become dissolved) two new ones have been 
 formed. X 400. 
 
 19. The same division has taken place in the two halves of the spore which is 
 
 still attached to the remains of the mother-cell, x 400. 
 
 20. Remnants of the mother-cell from which the spores have escaped, x 400. 
 
 21. A septum is formed between the two nuclei dividing the spore into two 
 
 halves, x 300. 
 
 22. One of the two newly formed cells has divided again by a transverse 
 
 septum, x 300. 
 
 23. Outlines of the cells of a five-celled spore, x 400. On the 20th Decem- 
 
 ber. 
 
 24. A free spore similar to that in Fig. 7, X 400. 
 
 25. A young spore, one half of which has become divided irregularly by an 
 
 oblique septum, x 300. 
 
 The originals of Figs. 18, 19, 20, 22 and 24, were taken from the same cap- 
 sule as the original of Fig. 17. 
 
448 EXPl.ANATION OF THE FIGUKES. 
 
 PLATE VI. 
 
 Figs. 1 — 10. Äneura multifida. 
 
 FIG. 
 
 1. A delicate brauch seen from above, x 10. 
 
 2. Fore-end of a growing shoot, seen from above, x 400. 
 
 3. Longitudinal section of a similar shoot. (The section has not touched the 
 
 cell of the first degree.) x 300. 
 
 4. Longitudiual section of inflorescence, with a fruit-rudiment lately formed, 
 
 and enclosed by a calyptra already much enlarged, X "0. 
 
 5. Very young fruit-rudiment, detached, x 300. 
 
 6. Longitudinal section of a more advanced fruit-rudiment, x 150. 
 
 7. Longitudiual section of the upper part of the fruit-rudiment at the com- 
 
 mencement of the formation of the capsule, x 400. 
 
 8. Fruit-rudiment somewhat more advanced, enclosed by the large calyptra 
 
 which is cut through longitudinally. On the left near the calyptra are 
 two abortive archegonia. x 50. 
 
 9. Longitudinal section perpendicular to the surface through the gemmiferous 
 
 portion of a shoot. In one of the epidermal cells a bud is in process of 
 formation. A two-celled bud lies loose in another epidermal cell which 
 has been torn, x 300. 
 
 10. Two gemmae, one seen from the side, the other (which is about to send out 
 
 a capillary shoot) seen from the front. 
 
 Figs. 11 — 15. Aneura ]^ingids. 
 
 11. Fore-end of a growing flat shoot seen from above, x 400. 
 
 12. Longitudinal section perpendicular to the surface of a thicker shoot. It 
 
 bears the rudiment of an antheridium. x 300. 
 
 13. A similar longitudinal section not exactly through the middle of the shoot, 
 
 x 300. 
 
 14. A young antheridium seen from the outside, x 300. 
 
 15. Rudiment of an archcgonium seen from above, the microscope being 
 
 focussed somewhat below the apex of the organ, X 300. 
 
 Figs. 16 — 24. Blasia imsilla. 
 
 16. Barren gemmiferous shoot seen from below, x 25. 
 
 17. Growing fore-end of a shoot seen from above, x 200. 
 
 18. End of a delicate shoot after the removal of the under leaves, seen froni 
 
 below, X 400. 
 
 19. Section perpendicular to the surface through tlie fore-end of a growinc: 
 
 shoot, X 200. 
 
 20. Similar section of a shoot where the latter has a bud-receptacle iu process 
 
 of formation, x 200. 
 
 21. Longitudinal section of a further developed bud-receptacle, X 60. 
 
 22. Portion of a longitudinal section of a less develüi)ed bud-receptacle, upon 
 
 the inner wall of which rudimentary genmise, iu different stages of 
 development, are seated, x 200. 
 
EXPLANATION OF THE FIGURES. 449 
 
 FIG. 
 
 22*. A portion of the uppermost bud of the former figure, x COO. The dotted 
 
 lines show the course of the two nuclei during the molecular motion 
 which they exiiibited. 
 
 23. Two spore-mother-cells held together by the common membrane of the 
 
 mother-cell, after the formation of the tertiary nuclei, X 300. 
 
 24. A similar mother-cell somewhat more developed, x 300. 
 
 Figs. 25 — 37*. Fossomhronia pusilla. 
 
 25. Two-celled rudiment of a leaf, x 300. 
 
 26. A young leaf with eleven cells, x 300. 
 
 27. 28. Tips of somewhat more developed leaves, X 300. 
 
 29, 30. Sections of young archegonia, fig. 29, x 100 ; fig. 30, x 400. 
 
 31. Section of an archegonium in whose central cell tlie germinal vesicle is 
 
 being formed, x 300. 
 
 32. Section of an archegonium in whose central cell the germinal vesicle is 
 
 completely formed, and the primary nucleus almost dissolved, x 300. 
 
 33. Longitudinal section of an archegonium, with its central cell almost filled 
 
 by the germinal vesicle, x 300. 
 
 34. Spore-mother-cell, after the formation of the four tertiary nuclei, X 300. 
 
 35. Mother-cell from the same capsule, after long soaking in water. The inner 
 
 layer of the cell-membrane is much swollen, and has squeezed the con- 
 fluent cell-contents into a globular lump. X 300. 
 
 36. Young elater from the same capsule after soaking in water for a short time. 
 
 The middle layer of the cell-membrane is much swollen, and has ruptured 
 the outermost one. X 300. 
 
 37. Longitudinal section of a ripe antheridium whose ai)ex has burst by the 
 
 separation of the cells and the tearing of the cuticle, x 150. 
 37*. Ruptured mother-cellule of a spermatozoon, which is escaping out of the 
 fissure, X 600. 
 
 PLATE Vll. 
 
 Figs. 1 — 3. Haplomiti'ium Uookeri. 
 
 1. Longitudinal section of the apex of a leafless subterranean shoot, x 300. 
 
 2. Similar section of a similar shoot farther from the apex, X 300. 
 
 3. Similar section of a detached young fruit rudiment, x 300. 
 
 4. Trichocolea tomentella. — Longitudinal section of a terminal bud, X 200. 
 
 5. Madotheca platyphylla. — Longitudinal section of an antheridium, x 200. 
 
 6. Ripe mother-cell of a spermatozoon from the same. 
 
 Figs. 7—9. Ptilidium Ciliare. 
 
 7. Half of a young leaf, x 150. 
 
 8. A young leaf slightly more developed, detached from the stem and ex- 
 
 panded, X 200, 
 
 9. Lateral view of a terminal bud, which has developed a lateral branch close 
 
 underneath the apex. 
 
 29 
 
450 EXPLANATION OF THE FIGURES. 
 
 Figs. 10 — 11. ÄUcularia Scolaris. 
 
 FIG. 
 
 10. End of the stem being a half-ripe fruit, in a longitudinal section which 
 
 has grazed the capsule and laid bare the outer surface of the fruit-stalk 
 and of the swelling at its lower end, x 30. 
 
 11. Longitudinal section of a germ-plant, x 300. 
 
 11*. A young leaf detached from the stem spread out, X 100. 
 
 12. Jtingermunnia bicuqnäata. — An archegonium just impregnated, and an un- 
 
 impregnatcd one ; both laid open by a longitudinal section passing through 
 the perianthium, which already extends far above the archegonium, and has 
 the apices of its edges inclined towards one another. In the inner cavity 
 of the perianthium several moving spermatozoa were found ; the arrow 
 shows the direction of their motion, x 400. 
 
 Figs. 1 3 — 20. Jungermannia divaricata. 
 
 13. Longitudinal section of a rudimentary archegonium, x 600. 
 
 14. Longitudinal section of a perianthium containing only two young arche- 
 
 gonia, X 600. 
 
 15. Archegonium ready for impregnation (or just impregnated ?), cut through 
 
 longitudinally so that the knife passed through tlie central cell, x 600. 
 
 16. The germinal vesicle detached from the central cell of a similar archegonium. 
 
 The cell-mcnibrane has been injured by the dissecting needle; the 
 nucleus escaped out of the fissure, and lies near it, x 500. 
 
 17. Longitudinal section of an impregnated archegonium which has grazed the 
 
 two-celled fruit-rudiment. At the apex of the archegonium, between 
 the globular lumps of glassy transparent mucilage, thread-like bodies, 
 like spermatozoa are seen, x 600. 
 
 18. A young, and 19, a somewhat older fruit-rudiment, the former seen from the 
 
 outside, the latter in longitudinal section, x 400. 
 20. Longitudinal section of a more developed fruit, x 250. 
 
 PLATE VIII. 
 Figs. 1 — 20. Jungermannia biciispidata. 
 
 1. Avery young perianth laid open by a longitudinal section, with three arche- 
 
 gonia still clos(;d at the apex, x 300. 
 
 2. Longitudinal section of an archegonium ready for impregnation, x 300. 
 
 3. Similar section of a somewhat more developed perianth. In the middle is 
 
 an archegonium just impregnated ; near the latter are two unimpregnated 
 ones, with ruptured apex ; on the outside are two still undeveloped 
 X 250. 
 
 4. Four-celled fruit-rudiment detached, x 300. 
 
 5. Young fruit-rudiment. 5*. The same turned round 90". 5". A similar 
 
 fruit-rudiment detached, x 300. 
 
 6. Longitudinal section of the lower part of a perianth enclosing two fruit- 
 
 rudiments, X 250. 
 
EXPLANATION OF THE FIGURES. 451 
 
 FIG. 
 
 7. Longitudinal section of a lialf-ripe fruit, with tlie calyptra, two abortive 
 arcliegonia, and the lower part of the perianth, x 200. 
 
 8 and 9. Yonng leaves which have not yet formed the rudiments of the two 
 tips, X 500. 
 
 10. A further-developed leaf, X 500. 
 
 11. Tip of a half-developed leaf, x 300. 
 
 12. Section of the tip of a leafless subterranean shoot ; 12*, section of the same 
 
 shoot after being turned round 90". x 300. 
 
 PLATE IX. 
 
 Figs. 1. — 12. Jungermarinia bicuspidafa. 
 
 1. Ripe spore, x 300. 
 
 2 — 10. Different stages of germination. 2, 3 one week. 4, 5 three weeks. 
 6, 7 four weeks after sowing. 8 — 10, germ-plants a year old. 2 — 6, 
 X 300 ; 7, x 200 ; 8, 9, 10, x 100; 10* is the upper end of fig. 10; 
 turned round 90** and x 400. 
 
 11. Fore-end of a germ-plant at the stage of development shown in fig. 8, seen 
 
 from the outside. The boundaries of the cell of the first degree, and of 
 the first cell of the second degree, as they appear in an optical section, 
 are shown by dotted lines, as is done also in the following figures. 
 X 400. 
 
 11*. The same. The apex of the stem turned round 90". 
 
 11''. The same, turned round 270". 
 
 11''. The apex of the stem of a more-developed germ-plant, in a position inter- 
 mediate between that of figures 11 and 11*, seen from the outside, 
 X 400. 
 
 12. An abnormal pro-embryo, in which the rudiment of the first leaf-bearing 
 
 axis does not proceed from one of the apical cells of the pro-cm biyo, 
 but springs from a point lower down (five months after sowing), 
 X 200. 
 12*. Rudiment of the leafy axis, turned round 90". 
 
 Figs. 13 — 16. Lophocolea bidentata. 
 
 13. Longitudinal section of a terminal bud, x 600. 
 
 14. A very young, 15 a somewhat older leaf seen from above, X 600. 
 
 16. A more developed leaf, the two halves of which have developed unequally, 
 X 300. 
 
 Figs. 17 — 30. Lophocolea heterophylla. 
 
 17 — 25. Germination of the spores; (17, a spore just detached, 18 a spore 
 twenty-four hours afterwards), x 200 except fig. 23, which is x 600. 
 
 26. Production of the first leafy axis out of the pro-embryo, x 250. 
 
 27. More advanced germ-plant, whose hinder end is already dead, X 200. 
 
 28. Lower portion of a germ-plant which has already formed some perfect leaves, 
 
 X 100. 
 
452 EXPLANATION OF THE FIGURES. 
 
 FIG. 
 
 29. Portion of the stem of a young plant, lateral view of the outer surface. 
 
 The inner edges of contact of the cells are shown by dotted lines. 
 X 150. *■ 
 
 30. Longitudinal section of the upper end of a young archegonium, x 200. 
 
 Pigs. 31, 32. Jungermannia intermedia. 
 
 31. Longitudinal section of a half -ripe antheridium, x 300. 
 
 32. Similar section of a young fruit-rudiment of the same plant, X 300. 
 
 Figs. 33, 34. Jungermannia trichophylla. 
 
 33. Longitudinal section of a young fruit, x 200. 
 
 34. A set of special-mother-cells out of the same fruit, x GOO. 
 
 PLATE X. 
 
 CALYPOGEIA TRICHOMANES. 
 
 1 and G. Longitudinal sections of young fruit-branches, X 200. 
 
 2, 4, 5. Detached fruit-rudiments seen from the outside, figs. 2 and 4, X 300, 
 
 fig. 5, X 150. 
 
 3, 7. Longitudinal sections of similar fruit-rudiments, X 300. 
 
 8. Longitudinal section of the lower part of a young fruit-sac, x 200. 
 
 PLATE XI. 
 
 Pigs. 1 — 7 and 15 — 2G. Eadula complanata. 
 
 1. Lateral view of an inflorescence ; the antheridia and archegonia are repre- 
 
 sented in section ; the cell contents are not shown. 
 
 2. A very young, 3 a half-ripe antheridium, both in longitudinal section, 
 
 X 500. 
 
 4. Longitudinal section of a more developed fruit-rudiment, together with 
 
 the lower part of the surrounding calyptra, X 200. 
 
 5. Longitudinal section of a young fruit-rudiment, X 500. 
 
 6. Longitudinal section of a somewhat dwarfish fruit-rudiment at the com- 
 
 mencement of the diifereutiation of the capsule-wall and contents, 
 X 300. 
 
 7. Lower end of the stalk of a half-ripe fruit, x 200. 
 
 15. Two lobes of a somewhat developed leaf spread out, x 200. 
 
 IG. Ripe spore, X 200. 
 
 17 — 24. Different states of the development of the flat pro-embryo, 20, 21, 
 
 and 22 arc lateral views, x 200. 
 25". The terminal bud of the first leafy axis, x 300. 
 25', 2G. The first leafy axis proceeding from the pro-embryo, X 300. 
 
EXPLANATION OF THE FIGURES. 453 
 
 Figs. 8—14, 27—42. Frullania dUatata. 
 
 FIO. 
 
 8°, *, ^ Three successive stages of development of superior leaves. lu 
 fig. 8'' the under lobe of the leaf is shown as a single row of cells. 
 8" and 8* are x 300, 8'- is x 150. 
 
 9. Leaf bud seen from above, x 200. 
 
 10. Leaf bud seen from the upper side, X 200. 
 
 11. A young inferior leaf, x 300. 
 
 12. Two lobes of a young superior leaf spread out, x 200. 
 
 13. 14. Upper lobes of older superior leaves, X 200. 
 
 27. Ripe spore just set free, x 300. 
 
 28, 29. Spores at the begiuning of germination, having become bicellular, 
 
 X 300. 
 30 — 36. Outlines of the cells of germinating spores ; in figs. 30 — 33 the outer 
 spore-membrane is shown ; 36* is the germ-plant shown in fig. 36 turned 
 round 90°. 
 
 37, 38. Germ-plants more developed seen from the outside. 
 
 39. A very young, 40 a more developed, 41 a half-ripe, 42 a ripe ruptured 
 antheridium ; near the latter are some escaped mother-cells of sperma- 
 tozoa, from some of which tlie spermatoza have already escaped, x 400. 
 
 PLATE XII. 
 
 FKÜLLANIA DILATATA. 
 
 1 . Two young archegonia surrounded by the rudiment of the perianth, x 400. 
 
 2. Longitudinal section of a perianth seen from the outside, x 400. 
 
 3. Longitudinal section of an inflorescence containing two half developed and 
 
 one impregnated archegonium, x 400. 
 
 4. Longitudinal section of the lower part of an impregnated archegonium, 
 
 with a seven-celled fruit-rudiment, x 400. 
 
 5. Longitudinal section of a more developed fruit-rudiment, with the arche- 
 
 gonium becoming transformed into the calyptra, x 400. 
 
 6. 7. Young fruit-rudiments, detached. 6 and 6*, 7 and 7s, are the same pre- 
 
 parations, 6 and 7 being the figures obtained by adjusting the microscope 
 to the longitudinal axis, and 6* and 7* by adjusting it to the outer sur- 
 face, X 4Ö0. 
 
 8. Longitudinal section of a more developed fruit, at the time of the differ- 
 
 entiation of the capsule-wall and contents, x 300. 
 
 9. Longitudinal section of a half-ripe fruit, x 300. 
 
 10. Spore-mother-cell with four protrusions (one turned away from the ob- 
 server) of the membrane, taken from a similarly developed capsule, 
 X 300. 
 
454 EXPLANATION OF THE FIGURES. 
 
 PLATE XIII. 
 
 KICCIA GLATJCA. 
 FIG. 
 
 1. Germ-plant (from a shady habitat) to which the spore is still attached, 
 
 X 200. 
 
 2. Developed germ-plants from the same locality, X 20. 
 
 3. Perfect shoot seen from below, x 8. 
 
 4. A young shoot in the bud seen from above, X 30. 
 
 4*. Fragment of a capillary root of the median line of a perfect shoot. The 
 inner wall is furnished wilh prominent points, x 200. 
 
 5. Three-celled rudiment of anMieridium not yet grown over bv an annular 
 
 wall, X 200. 
 
 C. Rudiment of an antheridium and part of a longitudinal section of a very 
 young shoot. The yet undivided mother-cell of the organ is already 
 grown over by an annular wall, x 300. 
 
 7". Longitudinal section through the fissure of the fore-edge of a perfect 
 shoot. The upper part of the figure is the lateral surface — tlirough 
 which the section has passed — of tlie deep indentation of the fore-edge; 
 the shaded part is the cavity of the lower portion of the latter, in which 
 the median shoot is developed, x 30. 
 
 7 . Longitudinal section of the median shoot bearing two rudiments of anthe- 
 ridia, one is unicellular and the other is a few-celled oval body sur- 
 rounded by a wall closing over the apex of the organ, X 400. 
 
 8. Longitudinal section of a half- developed antheridium, x 300. 
 
 9. Similar section of an almost ripe antheridium, x 200. 
 
 10. Mouth of the sheath of a ripe antheridium, seen from the outside, X 300. 
 
 11. Longitudinal section of a young shoot bearing the rudiment of an arche- 
 
 gonium, X 400. 
 
 12. Section of a more developed rudiment of an archegonium, x 400. 
 
 13. Section of an archegonium whose longitudinal growth is terminating, 
 
 X 300. 
 
 14. Longitudinal section of a shoot bearing an archegonium ready for impreg- 
 
 nation, X 300. 
 
 15. An abortive archegonium whose mouth has been laid open by a longitu- 
 
 dinal section through the shoot, x 300. 
 
 16. Section of an impregnated archegonium with a fruit-rudimeut still unicel- 
 
 lular. 
 16*. Lower part of a section of an archegonium lately impregnated with a three- 
 celled fruit-rudimeut, x 200. 
 
 17. 18, Longitudinal sections of an archegonium with more fully developed 
 
 fruit-rudiments, X 300. 
 19. Longitudinal section of a young capsule enclosed by the calyptra, x 200. 
 
EXPLANATION OF THE TIGURES. 455 
 
 PLATE XIV. 
 
 KIELLA REUTEKI. — Mont. 
 
 no. 
 1 and. 2. Germ-plants witli spore attached, x 150. 
 
 3. A plant produced by the multiplication of a cell of a leaf separated mecha- 
 
 nically from an older individual, x 130. 
 
 4. Adventitious shoot of an older plant, x 150. 
 
 5. Full-grown shoots (cultivated, more slender than in the natural state) ; 
 
 the older part of the plant is dead, X 5. 
 
 6. Another similar shoot, x 20. 
 
 7". The end of the shoot a of the latter, x 200. 
 
 8. Terminal bud of a strong shoot after the removal of the older leaves, 
 
 X 200. The leaves and the upper layer of cells of the massive portion 
 of the stem — which latter, as far as the drawing extends, consists of only 
 two layers of cells — are shown in dark lines above the outlines of the 
 membranous wing and the second cellular layer of the stem. 
 
 9. Longitudinal section of a terminal bud perpendicular to the surface of the 
 
 stem, X 200. 
 
 10. Terminal bud after the removal of all leaves. Two antheridia are being 
 formed, the one sunk half down, the other deep down into the duplica- 
 tions of the margin of the wing, x 150. 
 
 10. Young unicellular antheridium with adjoining tissue, laid bare by a sec- 
 tion parallel to the surface of the wing of the stem, x 150. 
 
 12. Longitudinal section of a half-ripe antheridium, x 150. 
 
 13. Section through a portion of a fertile shoot which has laid bare an arche- 
 
 gonium recently impregnated, and has grazed a lateral axis bearing 
 
 antheridia, x 100. 
 14°. Unimpregnated archegonium with its apex still closed, x 250. 
 14*. Archegonium ready for impregnation, x 250. 
 
 15. Longitudinal section of a recently impregnated archegonium, x 250. 
 
 16. Young calyptra just visible through its veil, X 25. 
 
 17. Longitudinal section of a calyptra with sporangium (a younger state than 
 
 Fig. 16), X 200. 
 
 18. Longitudinal section of the same when half ripe, the section not having 
 
 passed through the mouth, x 100. 
 19". Mother-cell with four spores enclosed in special-mother-cells, x 250. 
 19*. Rudimentary elater from the same sporangium, x 250. 
 
 PLATE XV. 
 
 Figs. 1 — 18. Marchatttia polymorpha. 
 
 1. Longitudinal section perpendicular to the surface of a shoot bearLig a very 
 
 young bud-receptacle, x 50. 
 1*. The bud-receptacle of the last figure cut through, x 200. 
 
 2. Young bud, x 400. 
 
 PLEAiTE CO ri' . UCIL, MAKN 
 or? OTHERWISE INJURE 
 
456 EXPLANATION OV THE FIGURES. 
 
 FIG. 
 
 3, 4. Lou2:iludiual moieties of more developed buds, seen from the surface, 
 
 X 30Ü. 
 5. Half of tlie fore-edge of a more advanced bulbil, X 300. 
 
 7. Bud, whose upper part is beginning to widen, seen from the surface, x 50. 
 
 8. The cells of an indentation of a lateral margin of the latter bud, X 300. 
 
 9. Bud which has rooted and is beginning to sprout, x 15. 
 
 10. Longitudinal section through a shoot bearing the rudiment of a fruit (be- 
 
 ginning of April), X 50. 
 
 11. Head of young.fruit from below (end of May), x 100. 
 
 12. More advanced fruit in longitudinal section, X 100. 
 
 13. 14. Longitudinal section of impregnated archegonia, x 300. 
 
 15. Impregnated archegonium, enclosing a four-celled fruit-rudiment, and 
 
 which together with its special covering has been laid open by a longi- 
 tudinal section grazing the fruit-rudiment. 
 
 1 6. Margin of a growing disk of antheridia (end of November) in longitudinal 
 
 section, X 300. 
 
 17. Transverse section of the stem of a developed antheridial dislc, x 100. 
 
 Figs. 18 — 20. Lunularia vulgaris, 
 
 18. Longitudinal section perpendicular to the surface, of a very young shoot, 
 
 X 300. 
 
 19. Similar section of the end of a young shoot bearing the rudiment of a bud- 
 
 receptacle. 
 
 20. End of a shoot, x 5. 
 
 Figs. 21 — 28. Targionia hypo'phylla, 
 
 21. Longitudinal section, perpendicular to the surface, through a shoot whose 
 
 fore-end bears archegonia, enclosed by the rudiment of the veil, x 100. 
 
 22. Similar section of a recently impregnated archegonium, x 300. 
 
 23. Longitudinal section of an archegonium enclosing a multi- cellular fruit- 
 
 rudiment, X 300. 
 
 24. Young fruit-rudiment detached, 24* is the same turned 90° round its longi- 
 
 tudinal axis, X 300. 
 
 25. Longitudinal section of a more developed fruit-rudiment detached, x 500. 
 
 26. Simüar section of a more developed fruit-rudiment, x 300. 
 
 27. Spore-mothcr-cell still exhibiting its primary nucleus, X 400. 
 
 28. Spore-mother-ccll in which the four secondary nuclei have been produced, 
 
 and having projecting ridges upon the inner surlacc of the cell-mem- 
 brane, X 400. 
 
 29. Young elatcr from the same fruit as that which produced the mother-Cell 
 
 shown in fig. 27, X 400. 
 
 30. Young elatcr fiom the fruit which produced the sporc-molhcr-ccU shown in 
 
 fig. 28, X 400. 
 
EXPLANATION OF THE FIGURES. 457 
 
 PLATE XVI. 
 
 Figs. 1 — 13. Fegatella conica. 
 
 FIG. 
 
 1. Section parallel to the surface of a shoot formed in autumn and destined 
 
 for development in tlie following spring, x 30. 
 
 2. One of the side shoots of this shoot, x 300. 
 
 3. Longitudinal section perpendicular to the surface of a similar vouns shoot. 
 
 X 300. •' ° 
 
 4. Stomata, in process of development, x 300. 
 
 5. Rudiment of a fruit-head (beginning of February), in longitudinal section, 
 
 X oUU. 
 
 6. Young fruit-head from below, x 100. 
 
 7. Fruit-head at that stage of development when the archegonia are ready for 
 
 impregnation, x 50. 
 
 8. Youug fruit-rudiment with the calyptra enclosing it, and the adjoining por- 
 
 tions of the fruit-head, in longitudinal section, x 200. 
 
 9. Five-celled fruit rudiment, detached, x 400. 
 
 10. More developed fruit rudiment in longitudinal section, x 300. 
 
 11, 12. 11 a very young, 12 a somewhat more developed leaf, x 300. 
 13. Outline of a half-developed leaf, x 30. 
 
 Figs. 14 — 20. Rebouillia hemispherica. 
 
 14. Longitudinal section perpendicular to the surface through tlie very young 
 
 rudiment of a shoot, x 300. 
 
 15. Outer aspect of tlie same preparation, after it has been laid upon the sec- 
 
 tional surface passing through the longitudinal axis of the shoot. The 
 rudiments of two leaves are seen, x 300. 
 
 10. A young leaf, x 300. 
 
 17. Longitudinal section perpendicular to the surface of a fertile shoot. On 
 the riglit is a fruit-head ; the section has passed through two unimprc"-- 
 nated archegonia and four scales. Stomate-formation is just com- 
 mencing in the covering cells of the air-cavities of the fruit-head. 
 Further back is a cushion of antheridia, cut tln-ougii. The outlines of 
 the cells only are drawn, and the contents of the antheridia omitted. 
 X 300. 
 
 IS. An impregnated archegonium in longitudinal section. The mother-cell of 
 tlie fruit-rudiment is still undivided, x 300. 
 
 19. Longitudinal section of an impregnated archegonium, enclosing a more de- 
 
 veloped fruit-rudiment. One only of the ' rows of cells of which the 
 young fruit-rudiment consists is seen ; the position of the nuclei of the 
 second is shown by a dotted circle, x 300. 
 
 20. One of the sheathing prolongations of the friiit-liead which enclose the 
 
 fruit, seen from below. The curved neck of the impregnated archc- 
 aroniuin is also seen, x 30. 
 
458 EXPLANATION OF THE FIGURES. 
 
 PLATE XVII. 
 Figs. 1 — 8. Sphagnum cymhifolmm. 
 
 FIG. 
 
 1. Longitudinal section of the terminal bud of the median shoot of a full- 
 
 grown plant. The section has passed underneath the fifth leaf of the 
 left side of a lateral shoot, x 150. 
 
 2. Longitudinal section of a young innovation, x 600. 
 
 3. Terminal bud of a median shoot, detached and seen from the outside, 
 
 X 600. 
 
 4. Terminal bud of a median shoot with left-handed | phyllotaxis, seen from 
 
 above, x 500. 
 
 5. Terminal bud of a median shoot, detached by two transverse sections, of 
 
 which one passed close down the apical point of the transverse cell, the 
 other through the stem close underneath tlie third-youngest leaf. All 
 the older leaves are cut through transversely. The leaves from a to /3 
 have a right-handed f arrangement ; from thence upwards the arrangement 
 is I and left-handed. X 500. 
 5*. Diagram. 
 
 6. Young lateral bud, seen from the outside, x 500, 
 
 7. Longitudinal section of a part of an innovation, taken at the point where the 
 
 growth in thickness of the stem ends, x 500. 
 
 8. Longitudinal section of one of the longitudinal moieties of a somewhat 
 
 lower part of the same innovation, x 200. 
 
 9. Sphagnum acutifolium. — Fragment of a longitudinal section of the circum- 
 
 ference of the stem of the principal slioot from the lower boundary of 
 the region where lateral shoots are crowded together. The cells of the 
 interior of the stem have pitted walls. X 200. 
 9*. One of these pitted cells, x 600. 
 
 PLATE XVIII. 
 
 L A young leaf of Sphagnum acutifolium, seen from the surface, x 400. 
 
 2. Fragment of a somewhat more developed leaf of the same species, in whose 
 
 cells the third division is beginning, X 400. 
 
 3. Fragment of a leaf of Sphagnum cymbifolium in which the cells with, and 
 
 those without chlorophyll are entirely differeutialed. Several of the 
 former have divided by transverse septa, X 400. 
 
 4. Fragment of a leaf of Sphagnum acutifolium in whose cells, which are 
 
 devoid of chlorophyll, the formation of annular and spiral vessels has 
 commenced. Several of the latter cells have divided by longitudinal 
 or transverse septa. X 400. 
 
 Figs. 5 — 13. Sphagnum acutifolium. 
 
 5. Pro-embryo which has not yet developed any leafy shoots, x 10. 
 
 6. A very young pro-embryo, x 200. 
 
EXPLANATION OF THE FIGURES. 459 
 
 FIG. 
 
 7. An unusually small pro-embryo ; on the left , near the lower angle, the bud 
 
 of a leafy shoot is seen. A new pro-embryo has originated at one of 
 the rows of cells springing from the marginal cells. X 100. 
 
 8. Basal fragment of a highly developed pro-embryo to which the spore is still 
 
 attached. The smaller longitudinal moiety of the leafy bud, which is 
 seated very near the cell, has been removed by the section. X 200. 
 
 9. Lobe of a pro-embryo, without any processes from the marginal cells, with 
 
 a bud attached, x 100. 
 11, 32. 11 a very young, 12 a half ripe autheridium, in longitudinal section, 
 X 300, 
 
 13. Ripe spermatozoa, killed by iodine, x 800. 
 
 Figs. 14 — 17. Sphagnum cymhifolium. 
 
 14, 15. 14 a very young archegonium, 15 archegonium near the period of 
 
 opening; in longitudinal section, x 250. 
 
 16, 17. Longitudinal sections of the ends of stems in which the rudimentary cells 
 of a lateral branch have been exposed by the section (see the left side of 
 both figures ; in fig. 16 underneath the uppermost, in fig. 17 under- 
 neath the second uppermost leaf). X 150. 
 
 18. Scldstostega osmundacca. — Portion of a pro-embryo, X 300. 
 
 PLATE XIX. 
 
 Figs. 1 — 16. Funaria hygrometrica. 
 
 1 — 4. Sections of antheridia in difi'erent stages of development, x 300. 
 
 5 — S. Mouths of unimpregnated archegonia. 6 and 7 the central cell, 
 X 300. Figures 5 and 6 are young states, figures 7 and 8 more de- 
 veloped conditions. 
 
 9. Young fruit-rudiment in longitudinal section, x 300. 
 
 10. The upper end of the same, X 300. 
 
 11. Upper part of a growing calyptra, with the upper half of the enclosed fruit- 
 
 rudiment : in longitudinal section. The fruit-rudiment which has not 
 been cut through is shown in an optical longitudinal section, x 300. 
 11*. The fruit-rudiment out of the same calyptra, detached, turned round 90°, 
 and in longitudinal section, X 300, 
 
 13. Spore-mother-cell after the formation of the two secondary nuclei, x 400. 
 
 14. The same; after the formation of the four tertiary neuclei, X 400. 
 
 15. Tiie same ; after the divisions of its internal cavity into four special mother- 
 
 cells, X 400. 
 
 16. The same ; after considerable thickening of the walls of the special-mother- 
 
 cells and the formation of the spore-membrane, X 400. 
 
 17. Longitudinal section of the upper half of the mouth of a recently impreg- 
 
 nated archegonium of Dicrmmm heteromallum. Underneath is the primary 
 cell of the fruit-rudiment detached from the central cell of the arche- 
 gonium by contact with the dissecting needle. X 300. 
 
 18. Bryum. coespiticium. — lludiment of a lateral bud, detached and seen ob- 
 
 liquely from above, x 300. 
 
460 EXPLANATION OF THE FIGURES. 
 
 FIG. 
 
 19. Racomitrium ericoides. — Fragment of a lateral branch of a pro-embryo 
 
 with the attached germ -plant, x 300. 
 
 20, 21. Fissidens bri/oides. — Longitudhial sections of archegonia, fig. 20 ready 
 
 for impregnation, fig. 21 just impregnated, X 300. 
 
 22. Young fruit-rudimeut of Brj/um argenteum detached, x 300. 
 22*. The same turned round 90°, X 30O. 
 
 23. Longitudinal section of the vaginula, and of a fragment of the seta, and 
 
 the adjoining parts of the shoot of the same species, x 25. 
 
 PLATE XX. 
 
 PHASCUM CUSPIDATUM, 
 
 1. Longitudinal section of a rudiment of an arehegonium, x 400. 
 
 2. Similar section of a young arehegonium, x 400. 
 
 3. Upper end of the same, x 600. 
 
 4. Longitudinal section of an arehegonium, whose apical cell has ceased to 
 
 multiply, X 250. 
 
 5. Longitudinal section of an arehegonium shortly before the rupture of the 
 
 apex, X 500. 
 G. Arehegonium whose apex has lately burst, in longitudinal section. The 
 still globular daughter-cell within the central cell only fills a small por- 
 tion of the latter, X 250. 
 
 7. Accidental transverse section of the place of junction of the neck, and the 
 
 ventral portions of an arehegonium, x 250. 
 
 8. Central cell of the ventral portion of an arehegonium which has been 
 
 cut longitudinally, in the state of development shown in fig. 6, x 500. 
 
 9. Arehegonium just impregnated, x 400. 
 
 10. Longitudinal sections of the lower part of the neck, and of the upper part 
 
 of the ventral portion, of an arehegonium, with a two-celled fruit- 
 rudiment uninjured by the section, x 300. 
 
 11. Similar section of an arehegonium with a four-celled fruit-rudiment, 
 
 X 200. 
 11*. A fruit-rudiment, detached, x 400. 
 11". Perspective view of the course of the cell walls of the same. 
 12". A four-celled fruit-rudiment, detached, x 400. 
 12*. The same turned round 90°. 
 
 13. Longitudinal sections of an impregnated and abortive arehegonium. 
 
 X 300. 
 
 14. Similar section of a detached fruit-rudiment, x 200. 
 
 15. Similar section of a fruit-rudiment with the growing calyptra and vaginula, 
 
 X 75. 
 15*. Outside of the apex of the same fruit-rudiment, x 400. 
 
 16. Portion of the contents of an almost ripe antheridium. Each of the poly- 
 
 gonal cellules of the interior of the organ encloses the mother-cell of a 
 spermatozoon, x 600. 
 
EXPLANATION OF THB FIGURES. 461 
 
 PLATE XXI. 
 
 FIG. 
 
 1. Lougitudinal section of a fruit-rudiment, x 200. 
 
 2". Section of the apex of a less advanced fruit-rudiment, X 250. 
 
 2*. Tiie same turned round 90°, X 250. 
 
 3. A younger fruit-rudiment whose lower part is very highly developed, seen 
 
 from the outside, x 30. 
 3*. Upper part of the same in longitudinal section, x 250. 
 
 4. Longitudinal section of calyptra ; the outer side of the spindle-shaped fruit- 
 
 rudiment is seen, x 60. 
 
 5. Longitudinal section of a young fruit, X 200. 
 
 6. A portion of the layer of mother-cells and of the adjoining tissue of a fruit 
 
 at a similar stage of development. The primordial utricles of the 
 mother-cells are contracted by having lain in water for a quarter of an 
 hour. X 500. 
 
 7. Section at right angles to the longitudinal axis of a fruit, passing through a 
 
 larger portion of the layer of mother-cells, x 150. 
 
 8. A spore-mother-cell out of whose bursting membrane the globular distended 
 
 primordial utricle is emerging, x 300. 
 
 9. Primary mother-cell from the transverse section of a young capsule. The 
 
 cell-contents are beginning to become contracted and constricted, indicat- 
 ing the commencement of the formation of the spore-mother-cells, x 250. 
 
 PLATE XXII. 
 
 1. Spore-nriother-cell whose primordial utricle only partly fills the cavity and 
 
 is lying against the wall, x 500. 
 
 2. Two primary mother-cells of the second degree, formed by the division of 
 
 of a primary mother-cell of the first degree by means of a septum 
 parallel to the longitudinal axis of the fruit. Eacii exhibits only one of 
 the longish ellipsoidal spore-mother-cells enclosed within. One of the 
 latter cells is beginning to divide. The section is at right angles to the 
 longitudinal axis of the fruit, x 300. 
 
 3. Primary mother-cells, each with two free globular spore-mother-cells, in 
 
 which division is about to commence. Direction of the section as in 
 the last figure. X 300. 
 
 4. Longitudinal section through some primary mother-cells of a somewhat 
 
 more developed fruit, X 200. 
 
 5. Young spore from the same, X 500. 
 
 Figs. 6 — 21. Gymnostomum pyriforme. 
 
 6. Longitudinal section through the upper end of a fruit-rudiment whose 
 
 apical cell has ceased to multiply in the direction of its length, and 
 whose expansion in breadth underneath the apex is just beginning. 
 The top of the specimen was destroyed by the section ; the representa- 
 tion of the boundaries of the cells at that part is shown bypothetically 
 by dotted lines, x 400. 
 
462 EXPLANATION OF THE FIGURES. 
 
 riG. 
 
 7. Longitudinal section of a very young fruit, whose apophysis is far larger 
 
 tlian tlie capsule, x GO. 
 
 8. A portion of the layer of mother-cells and of the adjoining tissue of a simi- 
 
 lar fruit cut tiirough longitudinally, X 300. 
 
 9. A similar preparation from a somewhat more developed thcca. The con- 
 
 tents of the primary mother cells of the spores and of tlie adjoiuing 
 cells of the columella are also shown. The primordial utricles of the 
 latter have contracted by lying in water, x 300. 
 
 10. A similar preparation from a more advanced capsule, X 300. Here the 
 
 nuclei of the cells immediately adjoining the layer of spore-mother- 
 cells, i. e., of the so-called inner capsule-wall, and the arrangement of 
 tlie chlorophyll of the outermost cells of the same are shown. The 
 chlorophyll in these cells lies closely attached to the free outer wall. 
 
 11. Similar preparation from a capsule in which the formation of the spore- 
 
 mother-cells within the primary mother-cells is just about to take 
 place, X 300. 
 
 12. 12*. Spore-mother-cells with the enveloping primary mother-cells, X 300. 
 13 — 21. Stages of development of the spore-mother-cell, X 600. 
 
 13. Young spore-mother-cell with central nucleus and homogeneous granular 
 
 mucilaginous fluid contents. 
 
 14. The nucleus is pushed near to the wall ; the protoplasm is accumulated 
 
 chiefly in the middle point of the cell. 
 
 15. This accumulation has divided into two halves. 
 
 16. A secondary nucleus appears in each of them. 
 
 17. 18. Four tertiary nuclei are seen in the place of the two secondary nuclei. 
 
 19. The primary nucleus of the mother-cell has disappeared. 
 
 20, 21. Spores fully formed. 
 
 PLATE XXIII. 
 
 Figs. 1 — IL Archidium phascoides. 
 
 1. Archegonium ready for impregnation, X 250. 
 
 2. Archegonium just impregnated, x 400. 
 
 3. Fruit with two archegonia which have been some time impregnated, in 
 
 longitudinal section, x 200. 
 
 4. A young calyptra just ruptured by the swelling fruit, opened laterally, 
 
 X 300. 
 
 5. Young fruit cut through longitudinally and detached, x 200. 
 
 6. The same somewhat more developed. The primary mother-cell of the 
 
 spores has fallen out, x 200. 
 
 7. The same, with the full number of cells. In the interior is a primary 
 
 mother-cell enclosing four mother-cells. The contents of the latter are 
 omitted in the drawing, x 300. 
 
 8. Primary mother-cell, with four mother-cells. The contents of the special 
 
 mother-cells have contracted. 
 
 9. Mother-cell with four lately formed spores, x 300. 
 
EXPLANATION OF THE FIGURES. 463 
 
 FIG. 
 
 10. Mother-cell with four spores. The membrane of the former is begimiiug 
 
 to dissolve, x 300. 
 
 11. Longitudinal section of ripe fruit, x 100. 
 
 Figs. 12 — 15. Fissidens iaxifolius. 
 
 12. Young leaf seen from the surface, X 300. 
 
 -13 — 15. Cells of a somewhat more developed leaf of the same species, show- 
 ing different stages of development of the chlorophyll-granules, 
 X 400. 
 
 PLATE XXIV. 
 
 1. Germinating spore of Flaiycerium alcicorne. The inner spore membrane 
 
 has emerged from the ruptured exosporium in the form of a row of 
 three clilorophyll-bearing cells. The lowest of these cells has already 
 developed a capillary root. X 400. 
 
 2. Young prothallium of Gymnogramma cahmclanos, x 25. 
 
 3. Young prothallium of Asplen'mm septentnonale, X 50. 
 
 4. A shoot spontaneously detached from an old luxuriant prothallium of 
 
 .Gymnogramma calomelanos. It has developed a number of autheridia, 
 X 150. 
 
 5. End of the shoot of an old prothallium of the same species, X 2. 
 
 Figs. 6 — 12, Pteris serrulata. 
 
 6. Fore-edge of a developed prothallium, x 150, 
 
 7. Longitudinal section perpendicular to the surface, of a fully developed 
 
 prothallium. The small papillae below are antheridia,Hhe longer ones 
 archegouia. X 75. 
 
 8. Longitudinal section of a young antheridium, x 400. 
 
 9. Apical aspect of the same. The course of the septa of the central cell is 
 
 shown by dotted lines, x 400. 
 
 10. Same view of a more developed antheridium, whose central cell is already 
 
 divided into sixteen cells, x 400. 
 
 11. Side view of an almost ripe antheridium, X 300. 
 
 12. Same view of an empty antheridium, X 400. 
 
 13,14,15. Spermatozoa of Aspletiium sepfentrion(ile,\\\\GdiVi\i]\\od.m&, 13 is 
 X 1200, 14 and 15 are X 300. 13 and 14 are lateral views, and 15 is 
 seen from above. The mother-cell is still attached to the spermatozoon 
 in fig. 14. 
 
 Figs. 16 — 19. Ceratopierls thalictroldes. 
 
 16. Young prothallium with attached spore, and an antheridium, x 150. 
 17 — 19. Lateral views of young antheridia, x 300. 
 
464 EXPLANATION OF THE FIGURRS. 
 
 PLATE XXV. 
 
 FIG. 
 
 1. Aspidium filix-mas. — Longitudinal section of a young arclicgonium in 
 
 process of formation, x 200. 
 
 2. Gymnogramma calomelanos. — Similar section of a slightly more developed 
 
 antheridium, x 400. 
 
 3. Pteris scrrulata. — Archegonium soon after the formation of the germinal 
 
 vesicle, X 400. 
 
 4. An archegonium of the same fern without the axile cellular row of the neck, 
 
 at the same stage of development, x 400. 
 
 5. Aspidium filix-mas. — Longitudinal section of a similarly developed arche- 
 
 gonium, X 200. 
 
 6. Gymnogramma calomelanos. — Transverse section of the neck of an arche- 
 
 gonium at the same stage of development, X 200. 
 
 7. Further developed archegonium of the same fern sliortly before the burst- 
 
 ing of the apex, in longitudinal section, x 400. 
 
 8. Pteris serrulata.—K similarly developed archegonium, x 400. 
 
 9. Central cell of an archegonium of the same fern, it has been grazed by a 
 
 longitudinal section, and the germinal vesicle thereby injured, so that it 
 exhibits folds of the membrane, x 500. 
 
 10. Central cell of an archegonium of the same fern seen from above. Tlie 
 
 microscope bas been focussed to the upper surface of tiie cell of one of 
 the first archegonia of a young prothallium, whose parenchymatal 
 cushion was still thin, and permitted the passage of much light, x 400. 
 
 11. Pteris serrulata. — Portion of a longitudinal section of a prothallium with 
 
 two archegonia ; one with the apex just burst, the other nearly ready 
 to burst, X 40O. 
 
 PLATE XXVI. 
 
 1. Gymnogramma calomelanos. — End of a shoot of a prothallium, x 5. 
 
 2. Gymnogramma cJirysophylla. — Abnormal archegonium, from a longitudinal 
 
 section of an old luxuriant prothallium, x 200. 
 
 3. Gymnogramma calomelanos. — Portion of a longitudinal section of an old 
 
 luxuriant prothallium, which has a knob-like excrescence, x 50. 
 3*. Cortical layer and some of the cells of the inner tissue — filled with a mass 
 of mucilage and oil — of the above knob, x 300. 
 
 Figs. 4 — 20. Aspidium filix-mas. 
 
 4. Archegonium at the moment of impregnation. In tlie central cell of the 
 
 archegonium — whicii has been grazed by two longitudinal sections — are 
 three spermatoza still in motion. The iniier mouth of tlie canal of the 
 neck has already become closed again by the expansion of the surround- 
 ing cells. X 300. 
 
 5. Longitudinal section of an archegonium shortly after impregnation. The 
 
 enlarged impregnated germinal vesicle does not yet quite fill the central 
 cell. X 300 
 
EXPLANATION UF TUE FIGURES. 465 
 
 FIG. 
 
 6. Longitudinal section of the fragment of a prothallium, sliowiug an impreg- 
 
 nated arcliegonium with a multi-cellular embryo which has been grazed 
 by tlie section. 
 
 6*. The net of cells of this embryo ; the boundaries of the cells are drawn of 
 different thicknesses, accordincf to their ajre. 
 
 7, 7 . More advanced states of 6 and 6*. 
 
 8. The end of the first frond of a more developed embryo, seen from the 
 
 surface, X 300. 
 
 9, 10, 11. Transverse sections througli the stipes of a frond of a one-year-old 
 
 seedling— 9, at the base; 10, somewhat higher up; 11, still higher. 
 X 20. 
 
 12, 16, 17. Transverse sections through the stem of a one-year-old seedling. 
 
 12, at the base ; 16, in the middle ; 17, near the top. x 30. 
 
 13. Germ-plants after the development of the frond, in longitudinal section. 
 
 Between the first and second root of the primary axis of the embryo. 
 
 X 20. 
 11. The top of the stem of a seedling of ten mouths old, seen from above. On 
 
 the left is the rudiment of the youngest and on the right that of the 
 
 next oldest frond. The roundish cells, with granular contents, are 
 
 either mother-cells, or cells of attachment, of scales, x 200. 
 15. A ten-months old seedling, in longitudinal section. The protuberance 
 
 below on the left is the primary axis of the embryo, x 20. 
 IS. Basal outline of a young frond of a seedling, and of the scales surrounding 
 
 it, X 30. 
 
 19. Upper part of the stem of a full-grown plant cut through longitudinally. 
 
 The cellular tissue — up to the vascular bundles — of the divided frond is 
 removed, to show the course of the bundles. Natural size. 
 
 20. A mesh of the net of vascular bundles of a similar stem, with the stumps 
 
 of the vascular bundles passing from it to the fronds, x 5. 
 
 PLATE XXVII. 
 
 1, 2. Apical views of the ends of the stem of full-grown plants. Fig. 1 with 
 a right-handed, fig. 2 with a left-handed, cell-succession, x 200. 
 
 3, 4. Longitudinal sections of terminal buds of full-grown plants. Fig. 3 
 X 200, fig. 4 X 170. In fig. 4, lo represents the rudiment of a frond 
 divided by the section. 
 
 5. A frond still rolled up, the scales having been removed, seen from the back, 
 
 showing the rudiment of an adventitious bud. Natural size. 
 
 6. Lower part of a stipes, whose lamina is already dead ; with an adventitious 
 
 bud in process of development. Natural size. 
 
 7. The same object, laid bare up to the vascular bundles of the cortical tissue, 
 
 Natural size. 
 
 8. Longitudinal section of the tip of a root, x 200. 
 
 9. Transverse section of the same, passing through the punctum vegetationis 
 
 at the height a b of the previous figure, x 300. 
 10. The middle region of a similar section, somewhat lower down, at the posi- 
 tion c d oi the root in fig. 8, x 300. 
 
 30 
 
4G6 EXPLANATION OF THE FIGURES. 
 
 PLATE XXVIII. 
 
 Figs. 1 — 6. Pteris aquiliiict. 
 
 riG. 
 
 1. Arcliegonium, with the adjoining cells of the prothnllium, in lonc^ihidinal 
 
 section. The enibi-yo consists of four cells lying in the plane of the sec- 
 tion. X 300. 
 
 2. Longitudinal section of the fore part of the cushion of a prothallium, which, 
 
 besides the impregnated archcgonium laid bare by the section, and 
 whose central cell is not quite filled by the rudimentary embryo, bore a 
 second impregnated archegonium with a far more developed embryo. 
 Above the cusliion of cellular tissue there is seen a portion of the mem- 
 branous wing of the prothallium, which has been cut by the section. X 
 150. 
 
 3. An unimpregnated archegonium, and one which has been some time im- 
 
 pregnated, in a longitudinal section of one and the same prothallium. 
 X 300. 
 3*. The cellular net of the embryo of the latter figure. The lines which 
 answer to the boundaries of the cells of the older generation are much 
 thickened. The group of cells « c is the rudiment of the principal bud, 
 and of the first frond ; the group a d is the rudiment of the root. 
 
 4. A similar preparation from a more developed prothallium. The cells of 
 
 the first degree of the root are here very visible, x 300. 
 
 5. Longitudinal section through the cushion of celhdar tissue of a prothallium. 
 
 The section has passed through an archegonium with a far more deve- 
 loped embryo, x 300. 
 
 Tigs. 7 — 8. Pteris serrulata. 
 
 7. Optical transverse section of the central cell of an archegonium just im- 
 
 pregnated. The germinal vesicle contains two nuclei. X 300. 
 
 8. Longitudinal section of a prothallium, with an embryo in the state of 
 
 development of that of Pteris nquili)ia, as shown in fig. 5. X 35. 
 
 PLATE XXIX. 
 
 PTERIS AQUILINA. 
 
 1. Longitudinal section of a young plant which has recently broken through 
 
 the archegonium. A portion of the prothallium to which it is 
 attached is figured. X 150. 
 
 2. Imaginary outline of a more developed germ-plant — b the primary axis, 
 
 A the first, D the second frond; between the two the position of the 
 a))ical cell is indicated ; c the first, e the second, F the third adventi- 
 tious root. 
 
 3. The fore-edge of the first frond of a germ-plant in the same state of deve- 
 
 lopment, seen from the fore-surface, x 100. 
 
EXPLANATION OF THE FIGURES. 467 
 
 riG. 
 
 4. Longitudinal section of tlie end of the bud of the principal axis of the 
 
 same, x 400. 
 
 5. A further developed germ-plant shown in a longitudinal section through 
 
 the median lines of the first two fronds. The lirst and fourth adventi- 
 tious roots have been cut by the section. 
 
 6. A more developed germ-plant shown in a longitudinal section at riglit 
 
 angles to the former one, the section passing through the second and 
 third adventitious root. 
 
 7. Transverse section of the older portion of the axis of a seedling of a 
 
 month old, x 30. 
 
 8. 9. Transverse section of the same nearer the apex. 
 
 9*. The same at another neighbouring point of the same axis, x 5. 
 10, 11.- Seedling of a year old. Natural size. 
 12, 13. Transverse section of the stem of the same, taken near the apex, x 5. 
 
 14. Transverse section of the third frond of a germ-plant, x 10. 
 
 15. The end of a vigorous shoot in November. Natural size. Adjoining the 
 
 end of the stem is seen the frond destined for development in the follow- 
 ing spring. More to the left is seen the lower part of the frond of the 
 current year, whose lamina has already opened. 
 
 16. Forking stem-end, seen in a section through the longitudinal ridges. The 
 
 sheath of vascular bundles of the middle of the stem is laid bare by 
 the section. Twice the natural size. 
 
 PLATE XXX. 
 
 PTEEIS AQUILINA. 
 
 1, "' *• '■ A similar shoot in the spring, peeled as far as the cortical vascular 
 bundle, in order to show its course. Seen from the left, from the riglit, 
 and from above. Natural size. 
 
 1. ''•^- The principal vascular bundles of the shoot, with their ramifications 
 
 to the frond of the previous year. 
 
 2. Transverse section of a stem at the place of insertion of a frond. Natural 
 
 size. 
 
 3. Transverse section of a stem, x 3. 
 
 4. Longitudinal section of the terminal portion of the apex of a frondless stem 
 
 of a very old plant, x 15. 
 
 5. Apex of a stem bearing a young frond, with the rudiment of an adventitious 
 
 bud, seen from above. Natural size. 
 
 6. Frond destined for development in the following year, as it appears late in 
 
 autumn, after the removal of the scales ; seen in front. Natural size. 
 6". The rudiment of the lamina of this frond, x 15, 
 
 7. 8, 9. Transverse sections of a stipes — fig. 7 close to the stem, figs. 8 and 
 
 9 somewhat higher up, x 3. 
 
 10. Transverse section of a portion of the lower principal vascular bundle of the 
 stem-bud, one and a half line backwards from the apex, x 150, 
 
468 EXPLANATION OV THE FIGURES. 
 
 riG. 
 
 10*- Transverse section of the same portion of the same vascular buiitlle, one 
 
 line and a half further back. The number of the cells has considerably 
 
 diminished during the thickening of the walls of those Mhich remain. 
 
 X 150. The vessels are figured as they appear under a moderate 
 
 magnifying power, the sections not being very thin. 
 
 11. Two vessels and the neighbouring cells of a complete vascnlar bundle seen 
 
 in a very delicate transverse section, x 500. 
 
 12. Longitudinal section of the margin of a principal vascular bundle, at 
 
 the place where the thickening layers begin to appear in the spiral 
 vessels, X 500. 
 
 PLATE XXXI. 
 
 PTERIS AQUILINA. 
 
 1 . Similar longitudinal section of a more advanced vascular bundle, in which 
 
 the thickening layers of the scalariform vessels are seen, x 200. 
 
 2. Apex of the stem seen from above, x 300. 
 
 3. Apical aspect of the apical region of the stem exposed by a transverse section 
 
 passing through the surrounding cortical substance, which has the form 
 of a circular M'all. The radiating light spots indicate the course of the 
 cortical vascular bundles which converge towards the punctum vege- 
 tationis. X 30. 
 3*. The apical surface of this end of the stem. The apical-cell is seen in the 
 middle; on the left hand, near (and above) it is the rudiment of the 
 youngest frond. X 300. 
 
 4. Longitudinal section, perpendicular to the horizon of the end of the 
 
 stem, X 300. 
 
 5. The same in a longitudinal section parallel to the horizon, x 200. 
 
 6. Horizontal section of the end of a stem which has passed transversely through 
 
 several rudimentary roots ; that shown by the letter a is exactly 
 in the punctum vegetationis. x 5. 
 6*, The above rudimentary roots, X 200. 
 
 PLATE XXXII. 
 Figs. 1 — 3. Pteris aqiiiliiia. 
 
 1. Longitudinal section of the end of a stem. At the vascular bundle, to the 
 
 left, is the rudiment of a root laid bare, for its whole length. X 15. 
 1*. The rudiment of a root just mentioned, X 300. 
 
 2. Longitudinal section of the very young frond of a seedling one year and a 
 
 half old. Above the scale is the rudiment of a bud. x 250. 
 
 3. Longitudinal section of a one-year-old frond of a full-grown plant. A 
 
 dormant adventitious bud is laid bare. xlO. 
 3*. The adventitious bud, x 200. 
 
EXPLANATION OF THE FIGUUES. 469 
 
 ri.i. 
 
 4. Apical view of the terminal bud of Aspidiim spinulosum, surrounded by the 
 
 rudiments of the youngest fronds, X 250. 
 
 5. Diagrammatic representation of three divisions of the apical-cell of Axpulum 
 
 fiUx-mas or f.piindosHm, and of the disjilacement caused by tlie change of 
 form of the apical-cell (see p. 239). The original position of the older 
 walls is shown by dotted lines, the later ones by continuous lines ; both 
 are indicated by the same (Arabic) figures. The Roman tigures refer to 
 the cells of the second degree; II is the oldest, III the intermediate, 
 IV the youngest, of the latter cells. 
 
 C. Diagram of the displacements caused by the next; three divisions following 
 the same rule. 
 
 7, 8. Stages of development of the scales of Nephrolepis splendens. 
 
 9 — 13. The same in Niphobolus rupeslris. 
 
 PLATE XXXIII. 
 
 Tigs. 1 — 6. Aspidium filix-femina. 
 
 1. A frond which has been torn off, and kept for a long time in a close, warm 
 
 place, and which has produced an adventitious bud at its base. Natural 
 size. 
 
 2. Longitudinal section of a terminal bud, x 250. 
 
 3. The apex of the lamina of a half-developed frond seen from above, X 250. 
 
 4. Longitudinal section of a young frond, with the rudiment of a root, X 300. 
 
 5. The same somewhat more advanced, x 100. 
 
 6. Longitudinal section of the apex of a root which has not yet broken 
 
 through the tissue of the frond, X 250. 
 
 7. Longitudinal section of tlie upper end of the frond of Strut liiopferis ger- 
 
 manica, X 30. On the developed frond, to the left, is seen the rudiment 
 of an adventitious root. 
 
 8. The last-mentioned rudiment, x 150. 
 
 Figs. 9 — 20. Mnrottia circutcefoUa. 
 
 9. Longitudinal section of the end of a stem, x 10. The small circles dis- 
 tributed through the parenchyma are gum-passages. An adventitious root 
 lies deep down in the cortical tissue. Of the youngest of the two visi- 
 ble fronds there is only a small fragment at the side remaining, to which 
 the corresponding membranous lateral portion of the stipule is at- 
 tached. 
 
 10. Longitudinal section of an adventitious bud of the base of the stipule, 
 
 X 30. 
 
 11, 12. Young fronds of different ages seen from above, x 10. 
 13, 14. Somewhat older fronds, in longitudinal section, x 10. 
 
 15. Lateral segment of the same, showing a stipule in process of develop- 
 ment, X 10. 
 
470 EXPLANATION OF THE FIGURES. 
 
 FIG. 
 
 16. Transverse section of the place of attaclimeut of a more developed frond. 
 The circle in the middle shows the place of insertion of the cylindrical 
 stipes (witiiin it are the vascular bundles); the rest of the tissue be- 
 longs to the stipule. 
 
 17, 18. Transverse sections through the stipule and sti])es of the same frond, 
 one and two lines higher up. 
 
 19, Longitudinal section of a similarly developed frond. Twice the natural 
 
 size. 
 
 19*. Lateral half of the stipule of the latter froud, after the removal of the 
 leafy portion. 
 
 20. Apical region of a half-developed frond, seen from above, x 100. 
 
 PLATE XXXIV. 
 
 1. Swollen end of a runner of Nephrolepis undulata, in longitudinal section, 
 
 X 20. 
 
 2. Perfect and growing tuber of the same plant. Natural size. 
 
 3. Shoot of a similar tuber, detached from the latter. It has already pro- 
 
 duced two runners. 
 
 4. Longitudinal section of the terminal bud of Polypodlum vulgare, x 250. 
 
 5. 6. Apical aspect of the tips of the stem of the same fern, x 250. 
 
 7. Apical view of the tip of the stem of Poli/podlum dryopkris. 
 
 Figs. 8 — 12. Plati/cerium alcicorne. 
 
 8. Transverse section of the perfect stem. Natural size. 
 
 9. Transverse section of the stem close under the growing terminal bud. 
 
 Natural size. 
 
 10. Net of vascular bundles of the stem seen from above. Natural size. 
 
 11. The same seen from below. 
 
 12. Longitudinal section of the bark of a root, x 100. 
 12*. Some cells of the latter, x 450. 
 
 PLATE XXXV. 
 
 1. Terminal bud of a very vigorous autumn shoot of Equiselum limosum^ x 400. 
 
 2. Longitudinal section of the end of the bud of a lateral shoot of Equisetum 
 
 mijense, at the beginning of INIay, x 200. 
 
 3. Equisetum limosum. — Apical view of an end of a stem divided by a transverse 
 
 section, underneath the third cell from the apex. The edges of contact 
 of the cells within the stem, underneath the cell of the first degree, are 
 shown by dotted lines, x 500. 
 
 4. Similar terminal bud; the section has passed somewhat lower down: x 
 
 200. 
 
 5. Transverse section of the stem of Equisetum limosum close under the apex, 
 
 x 300. 
 
EXPLANATION OF THE TIGURES. 471 
 
 FIG. 
 
 6. Lateral view of a terminal bud of the same species laid bare by two parallel 
 
 longitudinal sections, X 30. 
 
 7. Terminal bud of the same Equisetum exposed by thin parallel sections 
 
 perpendicular to the axis of the stem. The youngest and the second 
 youngest leaf are uninjured; the rest are cut transversely. X 20. 
 
 8. Portion of a very young leaf of Equisetum limosum exposed by transverse 
 
 section through the end of the stem, seen from above, x 300. 
 
 9. Lateral view of two tips of a somewhat older leaf; the one to the right is 
 
 about to fork. X 300. 
 10. Llother-cell of one of the whorled adventitious shoots of Equisetum limosum 
 exposed by two parallel longitudinal sections through the young stem-end. 
 X300. 
 
 11. Longitudinal section of a similar shoot in a somewhat later stage of de- 
 
 velopment, X 300. 
 
 12. Longitudinal section of a portion of an older internode, with a fragment of 
 
 the leaves belonging to it. The section has kid open the cavity of the 
 base of the leaf, in which an adventitious bud is concealed. X 60, 
 
 13. Part of a longitudinal section of a young internode of Equisetum pratense. 
 
 In the cells of one longitudinal row annular vessels are formed. The 
 transverse septa of these cells are still present. X 300. 
 
 PLATE XXXVI. 
 
 1. Left side of a delicate longitudinal section of the apex of a growing 
 
 delicate shoot of Equisetum variegatumy X 300. 
 
 2. A portion of the seventh internode (reckoning downwards from the apex), 
 
 from the same longitudinal section. 
 
 3. Lon"-itudinal section of the rudiment of the fruit of Equisetum limosum at 
 
 the beginning of April, X 30. 
 
 4. 5. Longitudinal section of the youngest sporangium-receptacle from the 
 
 same specimen, X 200. 
 G. Half-developed fruit (at the end of October) of Equisetum arvense, in 
 
 longitudinal section, X 50. 
 7, 8, 9. Stages of development of the sporangia of the same species, all ia 
 
 longitudinal section, X 300. 
 
 10. Transverse section of a young sporangium of the same species, x 300. 
 
 11. Group of young primary mother-cells of the spores of Equisetum variegatum; 
 
 two of them are about to divide, X 300. 
 
 12. Four spore-mother-cells of Eq. limosum adherent to one another, more 
 
 developed, X 300. 
 
 13. Half of a young receptacle, with sporangium of the same species, x 150. 
 
 PLATE XXXVII. 
 
 Figs. 1 — IS, 21, 21. Equisetum limosum. 
 
 1. Free spore-mother-cell, X 400. 
 
 2. Spore-mother-cell, whose primary central nucleus has dissolved, x 300. 
 
472 EXPLANATION OF TIIK FIGURKS. 
 
 riG. 
 3, 4, 5. Spore-mother-cells, with two secondary nuclei, between which a 
 flattened agglomeration of granules is gradually being formed. Fig. 3 
 is X 300, figs. 4 and 5 are x 400. 
 
 6. Mother-cells, with four tertiary nuclei, arranged in the angles of a tetra- 
 
 hedron, X 450. 
 
 7, 8. Mother-cells divided into four speeial-mother-cells, X 300. 
 
 9. Special-mother-cell divided from its sister-cells, and which has become 
 globular. A spore is just forming in it. x 3U0. 
 10 Special-mother-cell, with the globular spore. Upon the inner wall of the 
 special mother-cell the first traces of the two wide spiral threads are 
 visible. X 400. 
 
 11. Ripe spore, after the stripping off of the remains of the special-mother-cell 
 
 (the elaters), crushed in sulphuric acid, x 400. 
 
 12. Commencement of germination ; numerous chlorophyll-granules are visible 
 
 in the fluid contents. The central nucleus of the spore has disap- 
 peared ; in the cell two accumulations of granules are seen, each of 
 which surrounds a secondary nucleus, x 400. 
 
 13 — 18, 21. Differently developed germ-plauls, from the beginning to the 
 middle of June, x 300. 
 
 24. Fragment of the margin of an older prothallium (in the middle of July), 
 with a half-developed and a ripe antheridium, both shown in longi- 
 tudiual section, x 200. 
 
 Tigs. 19, 20, 22, 23, 25 — 37. Eqidsehtm arvense. 
 
 19, 20, 22. Germinating spores developed in water, x 300. 
 
 23. Somewhat older prothallium, showing the earliest antheridia, x 150. 
 
 25. Portion of the contents of a half-ripe antheridium ; small tessellated cells 
 
 enclose the ellipsoidal mother-cells of the spermatozoa, x 400. 
 
 26. A free mother-cell of spermatozoa, X 300. 
 
 27. A mother-cell, showing the spermatozoon, X 300. 
 
 28. Spermatozoon crippled by treatment with very diluted, watery solution of 
 
 iodine. The stiffened cilia are already visible, whilst the tail still 
 escapes observation by its undulations. X 500. 
 
 29. Spermatozoon quite killed by the same reagent. Its hinder end, already 
 
 somewhat swollen, is in such a position as to enclose a globe of 
 highly refractive matter; this is of rare occurrence. The membrane 
 of the mother-cell is attached to the frontal turns of the thread, x 500. 
 
 30 — 33. Spermatozoa killed by tincture of iodine. They are far more con- 
 tracted than those whose motions have ended spontaneously or have been 
 terminated gradually by treatment with a very wateiy solution of iodine. 
 Great differences are apparent in their size, as appears by the comparison 
 of spermatozoa, drawn with the same magnifying power. X 500. 
 
 35. Longitudinal section of a rudiment of an archegonium, x 300. 
 
 3G, 37 Similar sections of more developed archegonia; fig. 3G x 200, 
 fig. 37 x 300. 
 
EXPLANATION OF THE FICUKES. 473 
 
 PLATE XXXVIII. ;; 
 
 EQUISETUM ARVENSE. 
 FIG. 
 
 1. Longitudinal section of an archegouium shortly before the opening of the 
 
 apex, X 300. 
 
 2. The same immediately after the opening, x 300. 
 
 3. Perspective view of an archegonium lately opened, shown by means of 
 
 two parallel longitudinal sections of the prothallimn, x 300. 
 
 4. Longitudinal section of an archegonium jnst impregnated, x 300. 
 
 5. 7—10. Detached embryos iu different stages of development, seen in lon- 
 
 gitudinal section, x 200. 
 
 6. Longitudinal section of an impregnated archegonium, with the embryo in 
 
 the central cell, x 300. 
 n. Accidental transverse section of a rudimentary embryo, x 200. 
 
 PLATE XXXIX. 
 
 ], 2. Longitudinal sections of impregnated archegonia, with embryos; fig, 1, 
 before the falling off of the cells of the mouth ; fig. 2, after the same. 
 X 200. 
 
 3. Longitudinal section of a lobe of a prothallium, with two impregnated 
 
 archegonia, X 200. 
 
 4, 5. Embryos more advanced, seen in the front, so that both the primary and 
 
 the secondary axes are in the line of sight, x 200. 
 6. Longitudinal section of the lower part of a gerni-])lant, at about the stage 
 of development of fig. 3 in the next plate, X 100. 
 
 PLxiTE XL. 
 
 1. Lobe of a highly developed prothallium cut through longitudinally. Be- 
 
 sides abortive archegonia, the section has exposed an impregnated one 
 with a considerably developed embryo. X 100. 
 
 2. Embryo just breaking through the prothallium, shown in longitudinal 
 
 section. 
 
 3. Portion of a prothallium with a germ-plant, whose root and first leafy shoot 
 
 have recently emerged from the prothallium, x 10. 
 
 PLATE XLI. 
 
 EiGS. 1 — 4. Ophioglossum vulgatum. 
 
 Longitudinal section of a stem at the beginning of December. Above, on 
 the left, is a rudimentary pair of fronds (about |incli long), destined for 
 development in ilie following spring. The section is exactly through 
 the median line of the protuberance of cellular tissue, which is situated 
 somewiiat laterally in front of the latter frond, and which encloses the 
 younger fronds, x 20. 
 
474 EXPLANATION OF THE EIGUllES. 
 
 FIG. 
 
 2. Loiigituflinal section tlirounli flic middle line of tiie frond dcsliiied for 
 
 development iu the following spring in the bud-region of a similar stem, 
 X 20. 
 2*. The terminal bud and the two youngest fronds of the latter speeimen, 
 X 200. 
 
 3. Transverse section close above the terminal bud of a similar stem, x 20. 
 3*. Transverse section through the same stem, ^ line lower down. 
 
 4. Transverse section close above the terminal bud, which is seen through the 
 
 opening of the narrow canal leading to it, x 300. 
 
 Figs. 5 — 11. Bolri/chium Lunaria. 
 
 5. Longitudinal section of a protliallium, x 50. Above, to the right, is an 
 
 archegonium ; on the left of this are five antheridia, of which tiirce are 
 empty. 
 
 6. Longitudinal section of antheridia shortly before opening, x 300. 
 
 7. Hinder end of a prothallium, with remains of the spore-membrane, X 300. 
 8 — 10. Germ-plants with adherent prothallia, X 0. Figs. 8 and 9 seen from 
 
 the side, fig. 10 from above ; p, prothallium ; a, the end of the primary 
 axis of the germ- plant. 
 10*. The germ-plant. Fig. 10, longitudinal section, with adherent prothallia; 
 ff, tLe end of the bud of the principal axis of the germ-plant. X 30. 
 
 PLATE XLTI. 
 
 1. Germ-plant with prothallium seen from above, x 6. 
 
 1*. The same cut through longitudinally in the direction from a to p. 
 
 2, 3. Abortive germ-phuits whose prothallia are already dead, x 6. 
 
 4, 5, 6. Normally developed germ-plants, about one year old. Natural size. 
 
 7, 8. Germ-plants whose second frond already projects out of the lower first 
 frond, X 2. 
 
 9. The same cut through longitudinally, x 20. The first frond has already 
 died down to a hardly perceptible membranous border. In the stipule- 
 like second frond the rudiments of the third and fourth lie concealed. 
 
 10. A plant dug np in September, 1854, cut through parallel to the surface of 
 
 the frond destined for development in the following spring. Natural 
 
 size. 
 10*. The lower part of this specimen, x 20. 
 10". Terminal bud of this specimen, iu a position turned from the right to the 
 
 left, X 300. 
 
 11. Section of the bud of a plant in full growth at the beginning of June. The 
 
 rudiment of the fertile frond is already visible close by the enclosed frond 
 destined for development in the next year but one. 
 
EXPLANATION OF THE FIGURES. 475 
 
 PLATE XLIII. 
 
 riLULARIA GLOBÜLIFERA. 
 FIG. 
 
 1. Lougitudinal section of a ripe large spore. 
 
 2. Longitudinal section of the upper part of a large spore at tke I'irst cora- 
 
 nieucemeut of germination, x 300. 
 
 3. Lateral view of a very young protiiallium, x 400. 
 3*. The same cut through longitudinally, X 400. 
 
 4. Lougitudinal section of a germinating spore, with the protiiallium still con- 
 
 cealed between the lobes of the outer spore-membrane, x 50. 
 
 5. Longitudinal section of a young prothallium, x 300. 
 
 6. A small spore whose inner membrane has burst and from the fissures in 
 
 ■which the mother-cells of spermatozoa are emerging ; from some of the 
 latter the spermatozoa are escaping, x 600. 
 6*, G", 6''. Spermatozoa in different positions; 6*, one which has just made its 
 way out of the mother-cell, X 500. 
 
 7. The upper part of a germinating inner spore seen from the outside, with 
 
 some spermatozoa, x 150. 
 
 8. Longitudinal section of a prothallium ready for impregnation, X 500. 
 
 9. Prothallium ready for impregnation (or just impregnated ?) in longitudinal 
 
 section. The contents of some of the cells of the covering layer, and also 
 the layer of a portion of the outer spore-membrane, is shown. X 400. 
 10, 11. Longitudinal sections of prothallia just impregnated, enclosing rudi- 
 ments of embryos, x 300. 
 
 12. Prothallium with a more developed embryo, in longitudinal section, x 300. 
 
 13. Embryo of a similar prothallium, x 300. 
 
 14. Prothallium with an embryo which is beginning to develope the first frond, 
 
 in longitudinal section, x 300. 
 
 15. Embryo enclosed by the prothallium in the act of forming the first frond and 
 
 the first root, x 300. 
 10. Longitudinal section of an abortive prothallium, x 300. 
 
 PLATE XLIV. 
 
 Figs. 1 — 7. Pllularla globuUfera. 
 
 1. Longitudinal section of a prothallium containing an eml^ryo about to burst 
 
 forth, X 50. 
 
 2. Longitudinal section of a spore and germ-plant whose first frond has 
 
 broken through the prothallium. 
 2*. Bud-end of the latter germ -plant, x 300. 
 2". Hoot-end of the latter germ-plant, X 300. 
 
 3. Longitudinal section of a young macrosporangium, x 300. 
 
 4. Central cell of the latter, rather more developed, x 300. 
 
476 EXPLANATION OF TUE F[r,UR3',S. 
 
 riG. 
 
 5. Two spore-motlier-cells, and some of the small mucilaciiious cells out of 
 
 the inner cavitj' of a sporangium destined to form a hirge spore, X 300. 
 
 6. One of the young, large spores, wiih a set of four abortive special-mother- 
 
 cells, from a similar sporangium, X 300. 
 
 7. A similar sporangium, cut through longitudinally, at the same stage 
 
 of development, x 200. 
 
 Pigs. 8 — 14. Pilularia rniincta. 
 
 8. Longitudinal section of a very young fruit, x 100. 
 
 9. An almost ripe fruit, cut transversely close above the lowest sporangia, 
 
 X 10. 
 
 10. Mother-cell of large spores divided into four spccial-mother-cells, x 400. 
 
 11 — 14. Stages of development of large spores ; by the side of figs. ]1 and 12 
 abortive mother- cells from the same sporang^ia are drawn. Fig. J 1 is 
 X 300, fig. 2 is X 150, and figs. 13 and 14 are x 250. 
 
 Tigs. 15 — 24. Marsilea ptclescens. 
 
 15. Outlines of a large spore just escaped from the opening fruit, in longitudi- 
 
 nal section. 
 
 16. Apex of the same ((he gelatinous covering in this and the following figures 
 
 is not shown). The jirimary spore-menibranc and the lenticular cell 
 occupying its apex iiave been carefully drawn out from the introvert^iuu 
 of the inner layer of the exosporium. X 300. 
 
 17. Commencement of germination. Ju each lenticular cell two globular nuclei 
 
 are seen in the place of the primary one. X 300. 
 
 18. Bicellular rudiment of a prothallium, laid bare by means of two parallel 
 
 longitudinal sections through the spore. The primordial utricles of the 
 cells are contracted by the action of a concentrated solution of caustic 
 potash. X 400. 
 
 19. Lateral view of a four-celled rudiment of a prothallium, x 400. 
 20 — 21. Lateral view of a more developed prothallium, x 300. 
 
 22. Prothallium ready for impregnation, in longitudinal section, x 300. 
 
 23. Half-developed prothallium, seen from above, X 300. 
 
 24. The same from below, x 300. 
 
 Figs. 25 — 32. Sahinia nutans. 
 
 25. Microsporangium cut transversely ; the antheridia (microspores which have 
 
 shed their outer mcmhianes) are falling out, X 200. 
 2G. A single microspore less developed, x 200. 
 
 27—28. Cellular bodies (antheridia) squeezed out of the sporangia with small 
 
 spores in the midtile of March, X 3Ü0. 
 29, 30. Riper antheridia already half emptied, x 300. 
 
 31. Spermatozoon with attached mother-cell, x 500. 
 
 32. Spermatozoon killed by iodine, x 500. 
 
EXPLANATION OF THE ElGUllES. 477 
 
 TLATE XLV. 
 
 SALV1NI4. NATAXS. 
 FIG. 
 
 1. Longitudinal section of a large spore at the commencement of germination, 
 
 X 30. 
 
 2. A fragment of the exosporinm of a microspore, in longitudinal section, 
 
 X 300. Three layers are distinguishable. A thin inner laj'er, a thiclccr 
 middle layer, and a very thick, apparently cellular, outer layer. 
 
 3. A very young prothallium, detached, with a fragment of the inner spore- 
 
 membrane adhering to it, x 200. 
 
 4. The same, the longitudinal section passing through the entire spore, 
 
 X 200. 
 
 5. A more advanced prothallium, in which the first archegonium is developed ; 
 
 in longitudinal section, x 200. 
 6 — 7- Longitudinal section of uuimpregnated archegonia, in which germinal 
 vesicles are visible, x 300. 
 
 8. Transverse section of an uuimpregnated arcliegonium with two terminal 
 
 vesicles. The observer is looking into it from below, and in the middle 
 of the figure the interior of the mouth of the canal is seen. 
 
 9. Fragment of a prothallium cut tlu-ougii longitudinally, in which archegonia 
 
 are visible, one uuimpregnated and the other just impregnated, X 300. 
 
 10. Longitudinal section of the angle of a prothallium, exhibiting an archego- 
 nium with an unusually long canal, X 300. 
 
 IL Three-celled embryo, entirely filling the central cell of its archegonium. 
 The position of the mouth of the canal is shown by two lines. X 200. 
 
 12. An impregnated archegonium, with an abnormally large central cell, a small 
 
 part of the latter only being filled by the few-celled embryo, x 200. 
 
 13. An impregnated arcliegonium enclosing an eight-celled embryo, x 300. 
 
 14 A 16-celled embryo detached, a from the outside, laterally, b in longitudinal 
 section, c seen from behind. 
 
 15. A somewhat more developed embryo detached, « from above, b from the 
 
 side, c also from the side turned round 90°. x 20. 
 
 16, 17, 18. More advanced embryos; figs. 16 and 18 entirelv, and fig. 17 half 
 
 detached. Figs. 16 and 18 are X 200, and fig. 17 is x 300. 
 
 19. Embryo enclosed by the prothallium, x 300. 
 
 20. Detached embryo seen from the front surface, X 200. 
 
 21. Embryo enclosed by the prothallium. The first leaf is beginning to develope 
 
 itself above. X 300. 
 
 22. Spores with prothallium and embryo somewhat more advanced, in longitu- 
 
 dinal section, x 50. 
 
 23. A similar embryo, X 200. 
 
 24. A similar embryo detached and seen from the front surface of the first leaf, 
 
 at tiie lower margin of which the end of the principal axis is clearly 
 visible, x 200. 
 25". An embryo more advanced, seen half in front. Near the first leaf a the 
 principal axis b — whicii is already once forked and is in the act of 
 forking again — is visible ; behind it is the hinder end of the germ-plant c. 
 
478 EXPLANATION OF THE FIGURES. 
 
 FIG. 
 
 25*. Front view. > rn i .. . ,i , 
 
 „-.,;. f , J llie same letters represent the same parts. 
 
 2o . view from above. > ' '■ 
 
 20. A germinating spore, whose protliallium is broken through by the first leaf 
 (not by the chjngating axis of the embryo), X 50. 
 
 27. Spore with prothallium and embryo after the elongation of the axis of the 
 
 latter, X SO. 
 27*. The terminal bud of the latter embryo, x 300. 
 
 28. A more developed germ-plant, with spore attached, in longitudinal section, 
 
 X 150. 
 
 29. Terminal bud of a similarly developed gevm-plant, seen from above. Near the 
 
 third leaf, whicii is still closely folded (to the left in the figure) is seen the 
 end of the principal axis; underneath it are three of its delicate forks, 
 which are developed into the so-called roots. 
 
 PLATE XLVI. 
 
 ISOETES LACUSTB.IS.* 
 
 1. A large spore, a fortnight after sowing, and after soaking for several hours 
 
 in glycerine, seen from above. Tlie first-formed cells of the prothallium 
 appear spread over the inner wall. 
 
 2. Longitudinal section of prothallium four weeks after sowing, x iO. 
 
 3. Portion of the apex of a prothallium cut through longitudinally, with two 
 
 arehegonia still in process of development, x 300. 
 
 4. Arehegonia ready for the separation of the angles of contact of the upper 
 
 three double pairs of cells, in longitudinal section, x 300. 
 
 5. 6. Longitudinal sections of arehegonia ready for impregnation, x 300. 
 
 7. A ripe microspore seen from above (perpendicular to ,the transverse dia- 
 
 meter) X 500. 
 
 8. Lateral view of a microspore four weeks after sowing. The mother-cells 
 
 of the spermatozoa are formed, x 500. 
 
 9. Microspore three weeks after sowing. By rolling the spore under the cover- 
 
 ing glass the exosporium has burst and is pushed on one side. The 
 mother-cells of the spermatozoa entirely fill the inner cavity of the spore. 
 X 500. 
 10. A small spore, burst, four weeks after sowing. It has already sent forth 
 several spermatozoa; one of them, still partly enclosed by the mother- 
 cell, is seen within the latter in active motion. 
 
 * Plates XLVI to LIII relate to Loeles lacustris, and the letters a, b, &c., 
 have the following significations : 
 
 a Arehegonium. ac Central cell. </ü Mouth of the same. ff.r End of the primary 
 axis of the embryo, cb Camium. ct Back of the stem, e Embryo. //• Leaves ; 
 //•' the first,//-'^ the second, leaf of the germ-plant, and so forth. /b Vascular 
 bundle. In some cases the vascular bundles passing to the leaves are merely 
 represented by//' &c., and those passing to the roots by ?•', r", &e. (so also in 
 fig. 16 of PI. XLIX). g Terminal bud ; gc the apical cell of the latter. / Woody 
 mass; hp the upper, and /«/the lower, portion of the latter. /^ The supple- 
 mentary shoot of the fore-side of the leaf covering the base of the scale. rKoot. 
 re The cell of the first degree of the root, v Sheath of the base of the root. 
 
EXPLANATION OF THE FIGURES. 479 
 
 FIG. 
 
 11. A spermatozoon enclosed by its motber-cell, set free by the crushing of a 
 
 spore. 
 
 12. Spermatozoon still partly sticking in the mother-cell, killed by iodine. 
 
 13 — 15. Free sj)ermatozoa in motion. In fig. li the spermatozoon drags along 
 a small vesicle at the thin end. 
 
 16, 17. Spermatozoa killed by iodine. 
 
 18, 19. Archegonia, just impregnated, cut through longitudinally, with two- 
 celled rudiments of embryos. Seen from the narrow side, x 400. 
 
 20. A similar preparation ; in the lower cell of the embryo-rudiment division is 
 
 commencing by the appearance of two nuclei, x 400. 
 
 21. The apex of a prothallium cut through longitudinally, with one abortive and 
 
 one impregnated archegonium, which latter encloses the four-celled 
 rudiment of an embryo, X 300. 
 
 22. The last-mentioned embryo detached, and seen from the hinder surface. 
 
 The line a b is parallel to the section through the impregnated arche- 
 gonium. 
 
 23. An impregnated archegonium laid open by a longitudinal section parallel to 
 
 the front surface of the enclosed embryo. 
 
 24. Longitudinal section of an embryo; the number of its ceils is less than in 
 
 the preceding figure, but the characteristic extension of the apical cells 
 of the primary axis has already commenced. 
 
 PLATE XL VII. 
 
 ISOETES LACUSTRIS. 
 
 1. A more advanced embryo, cut through longitudinally, X 300. 
 
 2. Longitudinal section of a still more advanced embryo, x 200. 
 
 3. Longitudinal section of a germ-plant three months old. The apices of the 
 
 first and second fronds and of the first root are omitted in the figure. 
 X 200. 
 
 PLATE XLVIII. 
 
 ISOETES LACUSTRIS. 
 
 1. Lateral view of a six-months-old germ-plant, x 3. 
 
 2. Longitudinal section at right "angles to the larger transverse axis of the 
 
 stem of a four-months-old germ-plant, x 200. 
 
 3. Lono-itudinal section of the stem at right angles to the lateral surfaces of 
 
 the woody mass of a germ-plant about eight months old, x 200. 
 
 4. Transverse section of a one-year-old plant at the height of the terminal bud, 
 
 X 30. 
 
 5. Transverse section of a two-year-old plant at the place of junction of the 
 
 upper and lower portions of the woody mass, x 10. 
 G. Transverse section of an abnormal, three-furrowed, about six-years-old, stem 
 of Isoeles lacustris at the same place of junction. Natural size. 
 
 7. The middle part of the same preparation, X 30. 
 
 8. The terminal bud of the same individual seen from above, X 300. 
 
4S0 EXPLANATION OF THE FIGURES. 
 
 PLATE XLIX. 
 
 ISOETES LACUSTRIS. 
 FIG. 
 
 1. Longitudinal section at right angles to the furrow of the stem of a tcn- 
 
 niontiis-old plaut, X 30. 
 1*. Woody mass and terminal bud of the same, X 300. 
 
 2. Transverse section of the middle of the stem of a plant about eight years 
 
 old. The principal portion of the bark and the two side lobes are 
 omitted. X 20. 
 
 3. Rudiment of a scale seen from the surface, x 200. 
 
 4. The same more developed. 
 
 5. A perfect scale, X 6. 
 
 PLATE L. 
 
 ISOETES LACUSTRIS. 
 
 1. The terminal bud and the upper portion of the woody mass of the stem 
 
 shewn in PI. XLIX, fig. 1, X 300. 
 
 2. The same parts of a stem cut through at right angles to the indentation, 
 
 X 250. 
 
 PLATE LL 
 
 ISOETES LACUSTRIS. 
 
 1. Longitudinal section through the furrows of the stem of a plant eight 
 
 years old, x 30. 
 
 2. Similar section of the lateral surface of the middle region of the woody 
 
 mass of an older plant, together with a portion of the cambium. One 
 of the cells of the latter^separated from the next wood-cells by three 
 cambial cells — is beginning to become liquefied, x 250. 
 
 3. Longitudinal section of a fragment of a vascular bundle from the older 
 
 part of the bark, x 250. 
 
 4. Transverse section near the woody mass of a vascular bundle running to 
 
 an older frond, X 250. 
 
 5. Terminal bud of an eight-years-old plant seen from above, x 200. 
 
 PLATE LII. 
 
 ISOETES LACUSTRIS. 
 
 1. Longitudinal section of the stem (at right angles to its furrow) of a six- 
 years-old plant, X 20. 
 
EXPLANATION OF THE FIGURES. 481 
 
 I'IG. 
 
 2. Similar section of the apex of a root in which forking has commenced a 
 
 short time previously, x 400. 
 
 3. Half of a forked root in longitudinal section, x 100. 
 
 4. Transverse section of a root-tip, x 400. 
 
 5. Transverse section of the forking tip of a root, X 400. 
 
 6. Fragment of the lower part of the woody mass of an older plant cut through 
 
 longitudinally in the direction of its larger transverse axis (part of the 
 preparation figured in PL XLIX, fig. 1), x 200. 
 
 7. Young frond of an older plant seen from the front, x 300. 
 
 8. Similar view of a somewhat more developed frond, x 300. 
 
 PLATE LIII. 
 Pigs. 1 — 19. Isoetes lacustris, 
 
 1. Longitudinal section of a young fertile frond, x 300. 
 
 2, 3. The lower portion of the front surface of a somewhat more developed 
 
 fertile frond in longitudinal section, x 300. 
 
 4. The lower end of a young fruit cut through longitudinally (agcordiug to its 
 
 position it is destined to produce microspores), x 300. 
 
 5. Longitudinal section of the base of a frond, which bears a half-ripe micro- 
 
 sporangium, x 20. 
 
 6. 7. Sets of four adherent spore-mother-cells, x 400. 
 
 8 — 17. Stages of development of the mother-cell of microspores. 
 
 8. The mother-cell filled with homogeneous granular protoplasm, in which the 
 
 central nucleus floats freely, x 400. 
 
 9. Accumulations of more firm mucilage — the rudiments of the second nu- 
 
 clei are forming at the two poles of the globular nucleus, x 500. 
 
 10. After the absorption of the primary nucleus and the formation of the 
 
 secondary ones the primordial utricle of the mother-cell becomes con- 
 tracted, preparatory to its division, x 400. 
 
 11. The secondary nuclei are in the act of dissolution, before the division of 
 
 the cavity of the mother-cell, X 400. 
 
 12. A mother-cell divided into two halves by a septum through its equator, 
 
 X 400. 
 
 13. 14. Mother-cells, each with four free tertiary nuclei ; those in fig. 13 are in 
 
 one plane, those in fig. 14 at the angles of a tetrahedron, x 400. 
 
 15. Four special-mother-cells united by the mother-cell; produced by the re- 
 
 peated division of the two halves of the mother-cell (the special mother- 
 cells of the first degree). The septa dividing the latter have different 
 inclinations, X 400. 
 
 16. A similar preparation. The four special-mother-cells are lying in the same 
 
 plane, X 400. 
 
 17. Set of special-mother-cells arranged decussately in the last stage of for- 
 
 mation, immediately before their individualisation. The innermost 
 layer of the much tiiiekcned cell-mcinbrane of the s[)ecial mother-cells is 
 far more liigldy refractive than the already swollen outer la;yers. Treat- 
 ment with tincture of iodine has contracted the primordial utricles of 
 the cells, x 400. 
 
 31 
 
482 EXPLANATION OF THE FIGURES. 
 
 FIG. 
 
 18. Young microspores enclosed by the sjiecial-mother-cells, x 300. 
 
 19. Half-ripe microspores after the absorption of the special-mother-cells, 
 
 X 300. 
 
 Figs. 20, 21. Isoetes temiissima. 
 
 20. Transverse section of the stem of Isoetes ienuissima at the height of the 
 
 lower portion of the woody mass of that species, x 20. 
 
 21. Longitudinal section of a stem of the same species, x 20. 
 
 Fig. 22. Isoetes setacea. 
 
 22. Terminal bud of hoetes setacea seen from above, x 300. 
 
 Fig. 23. Isoetes te/missima. 
 
 23. Longitudinal section of a young root enclosed by the cortical parenchyma, 
 
 together with a ])ortiüu of the downward-growing wood and of the cam- 
 bium adjoining the latter. The contents of the cell of the first degree 
 and of the upwardly directed daughter-cells of the latter are shown. 
 X 300. 
 
 PLATE LIV. 
 
 Figs. 1 — 2. Selaffinella helcetica. 
 
 1. Young fruit in longitudinal section, x 30. 
 
 2. Same section of a very young sporangium, x 300. 
 
 Figs. 3 — 12. Helaginellu hortensis, Mett. 
 
 3. Longitudinal section of the forking end of a shoot, x 30. The last fork to 
 
 the left is a young fruit-spike. 
 
 4. Outline of a longitudinal section of a slightly more developed I'ruit-spikc, 
 
 X 30. 
 
 5. Forking end of a vegetative-shoot, the under side, x 30. 
 
 6. End of a vegetative- shoot laid bare by a longitudinal section parallel to the 
 
 axis; seen from the narrow side, x 50. 
 7". Forked end of a stem, seen from the (wide) upper side, x 80. 
 7*. The same, seen from above. 
 T. The same as 7", X 350. 
 7''. The same as 7*, X 350. 
 S. Half of an end of a shoot which has receully forked (like that shown in fig. 
 
 5), in longitudinal section, X 500. 
 9. End of a shoot at the commencement of forking, in longitudinal section, 
 
 X 350. 
 
 10. A similar specimen ; the fork is somewhat more advanced. 
 
 11, ]2. Apices of shoots whose development is almost intermediate between 
 
 those shewn in figs. 8 and 9 ; seen from above, x 350. 
 
EXPLANATION OF THE FIGURES. 483 
 
 PLATE LV. 
 
 SELAGINELLA HORTENSIS. 
 FIG. 
 
 1, 2. Longitudinal section through that part of the naked end of a young 
 fruit-spike, at which a sporangium is going to be formed, x 500. 
 
 3. A very young sporangium in longitudinal section, X 600. 
 
 4. A more developed sporangium (destined to form large spores), together 
 
 with the leaf above it, cut through longitudinally, X 400. 
 
 5. Longitudinal section of a more developed sporangium, X 150. 
 5*. A portion of the same specimen, x 300. 
 
 6. Longitudinal section of a large sporangium, whose mother-cells are begin- 
 
 ning to isolate themselves, x 300. 
 
 7. Mother-cell of large spores, which has just divided into four special-mother- 
 
 cells, surrounded by some of its abortive sister-cells, x 400. 
 8 — 10. Double pairs of very young large spores, still slightly held together by 
 the last remains of the dissolved special-mother-cells. Tig. 8, X 300; 
 figs. 9 and 10, X 500. 
 
 11. A young spherical capsule from tlie outside ; through its walls the four 
 
 spores, already of a considerable size, are just visible, X 30. 
 
 12. A slishtly more developed spherical capsule, opened by a longitudinal sec- 
 
 tion, X 50. 
 12^. One of the spores of the latter, after long soaking in water, X 300. 
 
 13. A somewhat more developed large spore, X 300. 
 
 14. Transvere section of a more perfect large spore, X 300. 
 
 14*. The same spore treated with a solution of caustic potash. The exosporium 
 is not shown. 
 
 15. Half- ripe spore, X 50. 
 
 16. Fragment of the wall of a ripe spherical capsule, in longitudinal section» 
 
 X 200. 
 16'. A fragment of the latter wall, seen from the outside. The boundaries of 
 the larger cells of the second inner layer are just visible through the 
 small ones of the upper surface, x 300. 
 
 17. Fragment of the membrane (the inner and the outer) of a ripe large spore, 
 
 cut through longitudinally, X 500. 
 
 18. Mother-cells of small spores. The lower one still exhibits the primary 
 
 central nucleus ; in the upper one to the right it is already dissolved ; in 
 the upper one to the left are four daughter-nuclei, X 300. 
 
 19. A similar mother-cell which has just divided into four special-mother-cells, 
 
 X 300. 
 
 20. A set of four mother-cells arranged tetrahedrically, in each of which a spore 
 
 is just forming, X 300. 
 20*. A similar specimen. The special-mother-cells are placed decussately. 
 
 21. First rudiment of a leaf (part of an especially successful longitudinal sec- 
 
 tion of a leaf-bud), X 600. 
 
 22. 23. The stages of leaf-development following next after fig. 21, in longitu- 
 
 dinal section, x 600. 
 24, 25. Fore-ends of young leaves seen from the surface, X 300. 
 
484 EXPLANATION OF THE FIGURES. 
 
 riG. 
 
 26. Longitudinal section of the apex of a very young stipule, x 400. 
 
 27. Same section of a half-developed stipule, X 200. 
 
 28. Outline of a slightly more developed stipule, seen from the surface, 
 
 X 100. 
 
 29. Longitudinal section of the growing apex of a young fruit-branch, x 350. 
 
 Figs. 30, 3L Selaginella spinulosa. 
 
 ui 
 re 
 31. Young maerospore. 
 
 30. Rudiment of a fruit in longitudinal section, x 30 
 30*. Young maerospore. 
 
 PLATE LVI. 
 Figs. 1 — 9, 11 and 12. Selaginella Galeottil ; 10. Selaginella Martensi, 
 
 1. End of a shoot bearing only leaves ; seen in longitudinal section of the 
 
 wide side (obtained by adjusting the microscope to the longitudinal 
 
 axis), X 400. 
 1*. The same, seen from outside. 
 1". The same, seen from outside the narrow side. 
 
 2. Oblique view from above of the end of a shoot, x 400. 
 
 3. Longitudinal section of terminal bud parallel to the wide side, X 400. 
 
 4. Apex of the same seen from above, X 400. 
 
 5. Middle of the fore-edge of a young superior leaf, X 300. 
 
 6. Tip of a somewhat more developed inferior leaf, x 600. 
 
 7. Fragment of the lateral margin of a perfect inferior leaf, X 300. 
 
 8. Fragment of the same, nearer to the mid-rib. 
 
 9. A very young stipule seen from the surface, X 500. 
 
 10. Adventitious shoot of S. Martensi, produced by a fragment of a stem bitten 
 
 off by wood-lice, x 10. 
 
 11. Half of a longitudinal section of a very vigorous shoot of S. Galeottii, 
 
 passing through the median lines of two opposite rows of superior and 
 inferior leaves (the former are to the right in the figure), x 200. 
 
 12. Portion of a similar specimen, x 200. 
 
 PLATE LVII. 
 Figs. 1 — 12. Selaginella Martensi. 
 
 1. Mother-cell of large spores, witli some of its abortive sister-cells, x 300. 
 
 2. A similar mother-cell. 
 
 3. Mother-cell of large spores, in which, near the large vanishing primary 
 
 nucleus, four daughter-nuclei are formed (three only of the latter are 
 visible), x 300. 
 
EXPLANATION OF THE FIGURES. 485 
 
 FIG. 
 
 4. Mother-cell, whose primary nucleus is no longer visible ; the four newly- 
 
 formed nuclei lie in one plane, x 300. 
 4*. The same specimen treated with watery tincture of iodine. The action of 
 the tincture has separated the four nuclei to some extent from one 
 another. 
 
 5. Mother-cell which has already divided into four special-mother-cells, 
 
 X 300. 
 
 6. View from above of a half-ripe spore, x 400. 
 
 7. Set of four special-mother-cells, each of which contains a similar half-ripe 
 
 spore, X 50. 
 7*. A similar special-mother-cell, together with its enclosed spore, isolated by 
 gentle pressure with the covering glass, x 400. 
 
 8. A young large spore with abnormally developed exosporium, x 400. 
 
 9. Mother-cell of small spores, divided into four special-mother-cells, in each 
 
 of which a spore has originated, x 300. 
 
 10. Set of four special-mother-cells, x 400. 
 
 11. Set of two vigorous special-mother-cells, and one abortive one, x 400. 
 
 12. Cell with abnormally thick walls from a young capsule, x 300. 
 
 Figs. 13 — 17- Selaginella helvetica. 
 
 13. Small spore, five months after sowing. In the internal cavity a large 
 
 number of small globular cells has been formed, x 400. 
 
 14. A similar spore subjected to gentle pressure. Some of the above cells have 
 
 escaped. 
 
 15. A similar spore two weeks later, lightly pressed. Each of the escaped 
 
 cellules now exhibits a very delicate spiral spermatozon. 
 
 16. Large spore shortly after sowing ; in longitudinal section, x 200. 
 
 17. Prothallium seen from above, six weeks after sowing, x 300. 
 
 Figs. 18 — 23. Selaginella Martensi. 
 
 18. Inner membrane of a large spore just taken from the capsule, removed out 
 
 of the exosporium, and viewed perpendicularly to the surface of the 
 rudiment of the prothallium which is attached to its inner side, x 400. 
 
 19. Prothallium six months after sowing, in longitudinal section, X 200. 
 19*. One of the archegonia of this specimen. 
 
 20. Young germ-plant isolated, and cut through longitudinally, x 200. 
 
 20*. The spore, from the interior of which this germ-plant was taken. The 
 distended prothallium enclosing the somewhat developed embryo, pro- 
 jects far out of the fissures of the apex of the spore-membrane, X ] 5. 
 
 21. An unfolded germ-plant, drawn out of the spore, x 3. 
 
 21*. The prothallium in which it originated, taken out from the exosporium, 
 X 3. 
 
 22. Germ-plant whose first leaves have been removed (the stipules of the latter 
 
 are remaining), together with the prothallium freed from the outer spore- 
 membrane, X 30. 
 
 23. A germinating spore, in whose prothallium (which projects from the outer 
 
 spore-membrane) two germ-plants have originated, X 5. 
 
486 EXPI-ANATFON OF THE FTGURKS. 
 
 PLATE LVIII. 
 
 SELAGINELLA DENT1CULATÄ.. 
 FIG. 
 
 1. Longitudinal section of an unimpregnated prothallium, eleven months after 
 
 sowing. Several arcliegonia have been exposed by the section ; in one 
 
 of them the spherical cell produced in the central cell is represented, 
 
 X 250. 
 1*. Mouth of an archegonium, seen from above, x 350. 
 1". Aperture of an archegonium, where the cells are extended upwards in a 
 
 papillate manner ; seen obliquely from above, x 150. 
 
 2. Archegonium whose upper cells are still in close connection. The free 
 
 spherical cell is not yet formed in the basal cell, X 600. 
 
 3. An archegonium just impregnated, laid open by a very successful longitu- 
 
 dinal section. The motiier-cell of the embryo is divided by a transverse 
 septum. Unfortunately the specimen was spoilt before the drawing was 
 finished. A portion of the cellular tissue of the prothallium has been 
 drawn from recollection. Ineffectual attempts have been made to 
 obtain another similar specimen, x 600. 
 
 4. An impregnated archegonium ; in a longitudinal section, which has exposed 
 
 the archegonium in which the rudiment of the embryo has originated, 
 and also the course of the proembryo which has formed the suspensor. 
 X 200. 
 
 5. A similar preparation in which the apex of the second axis of tlie embryo — 
 
 which is destined to develope leaves — is turned towards the observer, 
 X 150. 
 
 6. A young embryo detached, with a uni-cellular suspensor (a rare case), 
 
 looking upon the wide side of the second axis, x 500. 
 
 7. 8. Similar preparations seen from the narrow side, X 500. 
 
 9. From the wide side ; 10. from the narrow side of the second axis, x 500. 
 
 11. Outlines of a prothallium, in which the embryo lies concealed, which latter 
 
 has already begun to form its cotyledons, X 30. 
 
 12. Longitudinal section of a spore whose embryo has lately broken through 
 
 the prothallium ; its leaves are beginning to turn green. The section 
 has carried away the larger part of one cotyledon, its stipule, and several 
 leaves of the two rudimentary axes of the third degree of the embryo, 
 X 30. 
 
 PLATE LIX. 
 
 1 — 5. Mother-cells of the pollen of Finus bdsamea, x 300 ; fig. 1, at the end 
 of March ; figs. 2 — 5, in the first half of Aj)riL 
 
 6. Pollen-mother-cell of Pmtis Lcirix, divided into si.x. special-raother-cells ; 
 
 beginning of March, X 300. 
 
 7. Pollen-cell of the same Pirns on the 21st March, after treatment with a 
 
 solution of caustic potash. The second nucleus is already formed. 
 
EXPLANATION OF THK FIGURES. 487 
 
 FIG. 
 
 8. A similar pollen-cell, already divided into two ceils, treated with caustic 
 
 potash and freed from tJie exiue by rolling under the covering glass, 
 X 300. 
 
 9. Pollen-cell of Pinus Larix, taken from the nucleus of an ovule in the middle 
 
 of May. The exine has been stripped off by the swelling of the intine, 
 X 400. 
 
 10. Longitudinal section of an ovule of a cone of Finns Austriaca (just opened) 
 
 at the beginning of June, x 150. 
 
 11. Longitudinal section of the nucleus of an ovule of Finns Mtighus from a 
 
 cone just in flower, x 300. 
 
 13. Embryo-sac of the same species, somewhat later, after the dissolution of 
 the central nucleus, X 500. 
 
 13. Embryo sac of Finus sylvestris with the neighbouring cells, whicli are be- 
 
 coming detached ; beginning of June, X 500. 
 
 14. Longitudinal section of the nucleus of the ovule of a cone of the same 
 
 species which has lately flowered (beginning of June). The pollen-tube 
 has already penetrated rather deeply into the nucleus, x 100. 
 
 15. Fragment of a detached embryo-sac of Finus Austriaca, in the middle of 
 
 June. Numerous free secondary nuclei are attached to the inner wall, 
 X 300. 
 
 16. Longitudinal section of the embryo-sac of Finus sylvestris, filled with cellular 
 
 tissue ; end of June, x 300. 
 
 17. Ovule and basal portion of the spermophore of Finus maritima, at the be- 
 
 ginning of January of the second year. The walls of the cells of the 
 very advanced endosperm (E) are much thickened by the addition of 
 layers of gelatine. Two pollen-grains (P) have emitted tubes for a short 
 distance only into the nucleus, x 50. 
 
 18. A single cell of the endosperm at the same time, treated with tincture of 
 
 iodine. The primordial utricle of the cell is contracted, x 300. 
 
 19. A single cell of the endosperm of the same species in the middle of March. 
 
 The thickening layers of the cell-wall are already almost dissolved ; only 
 the primary membrane of the cell is still intact, x 300. 
 
 20. Fragment of the membrane of the embryo-sac of Finus Strobus cut through 
 
 longitudinally, with some endosperm-cells loosely attached to the inner 
 side ; at the beginning of April, x 300. 
 
 PLATE LX. 
 
 1 . Longitudinal section of the embryo-sac of Finns sylvestris, at the begin- 
 
 ning of April of the second year, x 30. 
 1*. One of the cells of the interior, X 300. 
 
 2. Embryo-sac detached, at the beginning of May. A layer of newly-formed 
 
 cells has attached itself firmly to the inner side of the hardened mem- 
 brane of the embryo-sac, whicli has now entirely displaced the loosened 
 cells of the surrounding |)orti()n of llie nucleus, x 30. 
 2*. Portion of the outer side ol' the embryo-sac of the latter figure, X 300. 
 It will be seen that the cells attached to the inner wall of the embryo- 
 sac are not yet firmly attached to one another at the surfaces of contact 
 with the latter. 
 
488 EXPLANATION OP THE FIGURES. 
 
 FIG. 
 
 3. Portion of the membrane of a similar embryo-sac ruptured by gradually 
 
 increased pressure. Numerous actively-multiplying cells are forced out 
 from the fissure of the membrane; the cells also attached to tlie inner 
 side of the wall have been detached from it by the pressure, X 200. 
 
 4. Longitudinal section of an embryo-sac, for the second time partly filled 
 
 with cellular tissue ; in the middle of May of the second year. The 
 detached membrane of the embryo-sac lies in folds near it, x 50. 
 
 5. Young corpusculum, detached, with some of its neighbouring cells ; at the 
 
 end of May. At this time the connection of the individual cells of the 
 endosperm is still very loose, x 300. 
 
 6. Longitudinal section of the upper part of an endosperm ; end of May. 
 
 Two young corpuscula are visible. The cells covering the apex of the 
 latter have not yet divided by cross longitudinal septa, x 150. 
 
 7. Transverse section through the same part of the less developed endosperm, 
 
 on May 27th. The observer is looking from below into four corpuscula 
 opened by the section. The large uuclei attached to the inner arch of 
 the apex are visible, x 200. 
 
 8. Longitudinal section of a corpusculum at the beginning of June, x 200. 
 8*. The rosette of cells covering the apex of the corpuscula, seen from above, 
 
 x 200. 
 
 9. Longitudinal section of a corpusculum, at the top of which the end of a 
 
 pollen-tube has just arrived, x 200. 
 10. The lower end of a corpusculum just impregnated, with the germinal vesicle 
 
 pressed into the arch (on the 16th June), X 300. 
 11 — 13. Stages of development of the pro-embryo (the lower ends of the 
 
 longitudinally-divided corpuscula), from the 16th to the 18th June of 
 
 the second year, X 300. 
 
 PLATE LXI. 
 
 1. Apical arch of a longitudinally-divided corpusculum of Pimis Abies, L. 
 
 {Pinus excelsa, DC), at which the end of a pollen-tube has lately 
 arrived, and in which several germinal vesicles adhere, of which one has 
 increased largely in size ; on the 23rd June (1858), x 500. 
 
 2. Longitudinal section of the upper part of an endosperm of the same species 
 
 at the same time. Two impregnated corpuscula are opened by the 
 section. In the one to the right the rudiment of a pro-embryo is 
 pressed into the lower end ; in that to the left a similar rudiment is still 
 at some distance from tbe base, X 40. 
 2*. The rudiment of the pro-embryo of this latter corpusculum, X 500. 
 
 Figs. 3 — 11. Plnus Strohiis. 
 
 3. A germinal vesicle just impregnated ; on the 26th of June, x 200. 
 
 4 — 7. A series of stages of development of the pro-embryo, arranged accord- 
 ing to their state of advancement (from 2öth to 28th June). Figs. 
 4—6, X 300 ; fig. 7, X 200. 
 
 8. The pro-embryo immediately before dividing into four longitudinal rows of 
 cells, X 100. 
 
EXPLANATION OF THE FIGURES. 489 
 
 FIG. 
 
 9, 10. Pro-embryos during the division into their longitudinal rows of cells ; 
 on the 30th June, X 300. 
 11. (The middle figure.) — One of the fourtli parts of the pro-embryo, at whose 
 lower end the multiplication in the direction of the thickness has begun, 
 X 100. 
 
 Fig. 11 (left-hand figure) to Fig. 14. Plnus Larix. 
 
 11. (Left-hand figure.) — End of a pollen-tube drawn out from the corpus- 
 
 culum, whicli has been just impregnated. 
 11*. The same object after its apex and the cell hanging to it have been pushed 
 out. 
 
 12. Apex of a pollen-tube, and portion of the cell attached to it, x 400. 
 
 13. 14. Longitudinal section of corpuscula just impregnated, x 150. 
 
 PLATE ]jX1I. 
 
 Figs. 1 — 8. Plnus Canadensis. 
 
 1. The upper part of an endosperm shortly before the arrival of the pollen- 
 
 tube at the embryo-sac (on the 7th July of the first year), with two 
 corpuscula laid open by the section, x 200. 
 
 2. Longitudinal section of a corpusculum, into which a pollen-tube has lately 
 
 penetrated (beginning of July), x 200. 
 
 3. Longitudinal section of an endosperm (middle of July). It exhibits two 
 
 corpscula. A pollen-tube has shortly before penetrated to the upper 
 surface of the left hand one. Against the base of this corpusculum the 
 four-celled rudiment of the embryo is compressed, x 200. 
 
 4. A recently impregnated germinal vesicle (middle of July) confined at tlic 
 
 lower end of the corpusculum, which has been cut through longitudinally, 
 X 400. 
 4*. The same specimen treated with an alkaline ley. 
 
 5. Longitudinal section of a corpusculum containing a rudimentary pro- 
 
 embryo pressed into the base, and another less developed one floating 
 freely, X 100. 
 
 7. A further developed pro-embryo. The walls of the upper cell, which are 
 
 are turned towards the corpusculum, are much thickened by the addition 
 of glassy transparent layers, x 300. 
 
 8. A more developed pro-embryo. In its upper cells are found spherical 
 
 irregular masses, of a glassy substance. The wall of the corpusculum — 
 which is detached from the neighbouring cells, and is adherent to the 
 specimen — exhibits shallow pits, and flat ridges, seated on the outer 
 side, whose course corresponds with that of the edges of contact of the 
 neighbouring cells (end of July), x 300. 
 
 Figs. 9, 10. Pinus sylvestris. 
 
 9. 10. Young embryos in longitudinal section ; from the 28th June until 7th 
 
 July, X 250. 
 
490 EXPLANATION OF THE FIGURES. 
 
 Fig. 11. Pinus balsamea. 
 
 TIG. 
 
 11. Longitudinal section of the embryo-sac of P. balsamea, filled by a few large 
 cells ; at the beginning of May of the first year. 
 
 PLATE LXIil. 
 Figs. 1 — 12. Taxus haccata. 
 
 1. Longitudinal section of an ovule at the end of March. Tlie shaded part 
 
 shows the position of the cells destined to become embryo-sacs, X 30. 
 
 2. The cells of this part, X 300. The contents of the rudiments of the 
 
 embryo-sacs are contracted by tincture of iodine. 
 
 3. Apex of the ovule in the middle of April, in longitudinal section. The 
 
 course of the pollen-tube, which at this time is very delicate, is exposed, 
 X 150. 
 
 4. The embryo-sac and neighbouring cells from an ovule cut longitudinally ; 
 
 end of April, X 300. 
 5 — 7. Further developed embryo-sacs ; detached (6th May), X 300. 
 
 8. Embryo-sac and one of its neighbouring cells ; detached (17th May), 
 
 X 500. 
 
 9. Embryo-sac ; detached, X 300. 
 
 10. Longitudinal section of the nucleus of an ovule, through which two pollen- 
 
 tubes have penetrated to the embryo-sac (22nd May), X 200. 
 
 11. Lower end of a pollen-tube with a portion of the endosperm cut through 
 
 longitudinally ; boUi detached. Impregnation lias not yet occurred ; the 
 rosette is still uninjured, x 350. 
 
 12. Young rudiment of a pro-embryo with a portion of the membrane of the 
 
 corpusculum detached, x 350. 
 
 Fig. 13. Taxus Canadensis. 
 
 13. Apex of the endosperm with the end of the pollen-tube and an impregnated 
 
 corpusculum with the rudiment of a pro-embryo in longitudinal section ; 
 on the 10th June, x 300. 
 
 PLATE LXIV. 
 
 Fig. 1. Taxus Canadensis. 
 
 1. Longitudinal section of the upper end of an endosperm witli the pollen- 
 
 tube; on June 5th. Two corpuscula are laid open by the section; 
 the right hand one is impregnated ; the impregnated germinal vesicle 
 occupies the lower third part of it, x 300. 
 
 Fig. 2. Taxus baccala. 
 
 2. Lower ends of two pollen-tnl)cs with portions of the endosperm, whicli has 
 
 been cut througli longitiidiually, soon after impregnation. Tiie pollen- 
 tubes are drawn away for a short distance from the endosperm ; the left 
 hand one has in consequence been torn at the outermost apex, X 300. 
 
EXPLANATION OP THE FIGURES. 491 
 
 Figs. 3, 3*, 4. Thuja orientalis. 
 
 PIG. 
 
 3. End of a pollen-tube, detached, x 250. 
 
 3*. Some of the contents of the pollen-tube shown in fig. 3, x 500. 
 
 4. End of a pollen-tube detached, x 250. 
 
 Figs. 5, 6, Juniperus Siberica. 
 
 5. Nucleus of the ovule with the lower portion of the integument of the 
 
 ovule, in longitudinal section ; on June 5th of the first year, x 300. 
 
 6. Detached embryo-sac at the end of May of the second year, which has be- 
 
 come filled with cellular tissue for the second time. The membrane of 
 the embryo-sac is swollen with water, x 60. 
 
 PLATE LXV. 
 
 Fig. 1. Juniperus Siiirica. 
 
 1. Apex of the embryo-sac filled with endosperm, in longitudinal section ; 
 
 three corpuscula are exposed ; on June 9th of the second year, x 300. 
 
 Figs. 2 — 7. Juniperus communis. 
 
 2. Corpuscula cut longitudinally, with a small portion of the endosperm and 
 
 the pollen-tube ; on the 20th July, x 300. 
 
 3. Three impregnated corpuscula, with the lower portion of the pollen-tube 
 
 (longitudinal section of an endosperm on July 28th), x 300. 
 
 4. Pro-embryo consisting of three longitudinal rows of cells. 
 
 5. Longitudinal section of an impregnated ovule (the integument is omitted 
 
 in the drawing). The pointed line in the endosperm shows the 
 boundaries of the region in which the cells are loosened and partly dis- 
 solved. The development of the embryos of this specimen corresponds 
 almost with that of the one shown in fig. 7. (Beginning of August.) 
 X 30. 
 
 6. Lower end of one of the isolated longitudinal rows of cells of a pro-embryo, 
 
 with the mother-cell of the embryo still undivided, x 150. 
 
 7. A similar specimen, with a more developed rudiment of the embryo. 
 
 8. A similar specimen. 
 
 Figs. 9 — 10*. Thuja orientalis. 
 
 9. Upper end of the endosperm with the group of corpuscula and two pollen- 
 
 tubes which have penetrated into the depression above it, in longitu- 
 dinal section ; on June ISlh, x 250. 
 
 10. A similar specimen with a single pollen-tube, which has sent prolongations 
 into the corpuscula; on June 28th, x 250. 
 
 10*. The pollen-tube of the latter preparation detached. 
 
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INDEX. 
 
 Abies excelsa, fecundation of, 418. 
 
 Abietineae, anatropal ovules of, 400 ; 
 nucleus in, 400 ; corpuscula of, 
 410. 
 
 Abnormal fruit in mosses, Gumbel's 
 observations on, 180. 
 
 Adiantum, antheridia of, 187; germi- 
 nation of, 183. 
 
 Adventitious roots, 203 ; of Isoetes, 
 336. 
 
 Adventitious shoots of abortive pro- 
 thallia of ferns, 197. 
 
 Agardh, observations on the germina- 
 tion of EquisetaceEB, 304. 
 
 Air-cavities of Marchautiese, 111. 
 
 Air-cavities of antheridial discs in 
 Marchantia poli/morpha, 121 ; of 
 receptacle of do., 117. 
 
 Alicularia, antheridia of, 65. 
 
 Alicularia scalaris, arrangement of 
 cells in leaves of, 63 ; cell-multipli- 
 cation in apex, of stem of, 442 ; 
 development of fruit of, 74, 77, 78 ; 
 development of perianth in, 69 ; 
 germination of, 54 ; ramification of 
 prothallium of, 84. 
 
 AUosurus, abortive prothallia of, 197. 
 
 Alternation of generations in mosses 
 and ferns, 434. 
 
 Amoeboid movements of primordial 
 utricle of spore-mother-cells in 
 Phascum cuspidal urn, 163. 
 
 Analogy of the prothallium and frond 
 of ferns, to the leafy plant and fruit 
 of mosses, 435. 
 
 Aneura, archegonia of, 44 ; cell- 
 development in stem of, 43 ; growth 
 of stem in, 43 ; ramification of, 
 44. 
 
 Aiieura muUifida, 21 ; elaters of, 86 ; 
 spermatozoids of, 87. 
 
 Aneura pinguis, 21 ; development of 
 antheridia of, 45. 
 
 Anther of Pinus, 401. 
 
 Antheridia of Aneura pingicis, 45 ; of 
 Anthoceros, 7 ; of Botrychium Lu- 
 naria, 308 ; of Equisetacese, 293 ; 
 observed by Thuret and Milde, 306; 
 of ferns, 185 ; discovered by Nägeli, 
 258 ; of Fossombronia pusilla, 65 ; 
 of Jungermanniae, 87 ; of Junger- 
 manuia, Lophocolea, Radula, Mado- 
 theca, Alicularia, Frullania, Fossom- 
 bronia, Haplomitrium, 65 ; of 
 Liverworts, Gottsche's views on, 
 erroneous, 88 ; oi Lophocolea biden- 
 tala, rarity of, 72 ; of Lophocolea liete- 
 rophi/lla, Radula complanata,Junger- 
 mannia divaricata, and Frullania 
 dilafata, 73 ; of Madotheca platy- 
 phi/lla, 65, 67; of Marchantia poly - 
 morpha, 120 ; of Metzgeria f areata, 
 43 ; of mosses, 152 ; Hedwig on, 
 175 ; of Ophioglossum, Mettenius on, 
 316 ; of Pel Ha epiphylla, 29 ; great 
 number of in Pellia epiphylla^ 31 ; 
 of Rebouillia hemispherical 122 ; of 
 Riccia glauca, 93, 94; of Riella, 
 99 ; of Sphagnum, 154 ; observa- 
 tions on, in Sphagnum, by Schleideu, 
 155, 177; and by Schimper and 
 Unger, 177. 
 
 Antheridia, production of, on adven- 
 titious shoots of the protliallium of 
 ferns, 197. 
 
 Anthoceros, early growth of, 1, 3 ; 
 reference to figures of, and observa- 
 tions on, by BischofF, Nees vou 
 Esenbeck, and Schacht, 19. 
 
 Archegonia of Aneura, 44 ; of Antho- 
 ceros, 9 ; of Archidium, 149 ; of 
 Archidium phascoides, 152; oi Botry- 
 
494 
 
 INDEX. 
 
 chinm Lunaria, 308 ; of Calypogeia 
 Trichomanes, 70 ; of Dicrauum, 149 ; 
 of Equisetaceae, 298 ; Bischoff aud 
 Milde on, 306 ; of Fegatella conica, 
 114 ; of ferns, 189 ; their nature 
 detected by Lesczye-Suminski, 258 ; 
 observations on by Nägeli, 258 ; 
 Schacht, 2G0 ; aud Von Merckliu, 
 2G1 ; of i'issideus, 149 ; of Fossom- 
 bronia ptmlla,^! ,1\; of FruUauia, 
 68 ; of Funaria, 149 ; of Isoetes 
 lacustris, 340 ; structure of in 
 Jungermannise, described by Hed- 
 wig, 85 ; of leafy Liverworts, 67 ; 
 of Marchantia polymorpha, 115; of 
 Marsilea pubesceiis, 327; oi Metzgeria 
 furcata, 43 ; of mosses, 148 ; obser- 
 vations on, by Hedwig, 175 ; 
 Schimper and Valentine, 177 ; of 
 Ophioglossum, Mettenius on, 316; 
 of Feliuiepiphylla, 32 ; of Phascum, 
 149 ; of Filularia globulifera, 322 ; 
 Nägeli on, 335 ; of Polytrichum, 
 149 ; of Radula complanuta, 67 ; of 
 Rebouillia hemispkerica, 113 ; of 
 Riccia glutted, 93, 95 ; of Kiella, 
 99; of Salvhna nutans^ 329; of 
 Selaginella, 393 ; of Sphagnum, 
 142, 150 ; Targiouia hypophylla 
 118. 
 
 Arcliegonia of Mosses, Liverworts, 
 Ferns, Equisetacese, Rhizocarpese, 
 and Lyco])odiacese compared, 434. 
 
 Archidium, Schimper on the fructifica- 
 tion of, 169. 
 
 Archidium phascoides, archegonia of, 
 149, 152 ; fruit of, 160, 168, 169. 
 
 Arrangement of fronds in Isoetea;, 
 Alexander Braun on, 335. 
 
 Asjndiunißlix-mas, autheridia of, 187 ; 
 archegonia of, 191; development of 
 embryo in, 200 ; development of 
 vegetative organs of, 208, 226 ; 
 germination of, 183 ; production of 
 fronds in, 226 ; production of roots 
 in, 243. 
 
 Aspidium spinulosum, development of 
 fronds in, 230. 
 
 Asplenium Bellangeri, adventitious 
 buds of, 247 ; vegetation of, 245. 
 
 Asplenium filix-femina, adventitious 
 buds of, 247 ; development of 
 fronds in, 230 ; division of stem of, 
 247 ; structure of terminal bud, 
 stipes and roots of, 246; vegetation 
 of, 245. 
 
 Asplenium septetitrionale, germination 
 
 of, 183. 
 Asplenium Trichomanes, development 
 
 of fronds in, 230. 
 
 Balantium Karstenianum, cellular 
 hairs of stem-bud of, 212. 
 
 Bark of stem of Fteris aquilina, 215. 
 
 Bast-cells of stem of Fteris aquilina, 
 215 ; formation of in stem-bud, 
 217. 
 
 Bischoff on Anthoceros, 19 ; his dis- 
 covery of the archegonia of Equise- 
 tacese, 306 ; on the production of 
 antheridia and archegonia on the 
 prothallium of Equisctum sylcuticum, 
 297 ; on the germination of Equi- 
 setacese, 305 ; on the sexual organs 
 of the prothallium of ferns, 257; 
 on the development of the fruit- 
 stem in Fegatella, 115 ; on the 
 germination of the spores of the 
 Jungermannise, 83 ; on Luaularia 
 vulgaris^ 126; on Marchantiese, 122; 
 on Pellia, 26 ; on Rebouillia hemis- 
 pkerica, 114, and its autheridia, 122; 
 on the fructification of lliccia, 97; 
 on the sporangia of Selaginella, 387. 
 
 Blasia, 47. 
 
 Blasia pusilla, germination of, 83 ; 
 sj)ore-mother-cells of, 82. 
 
 Botrychium. Lunaria, germination and 
 development of, 307 ; succession 
 of fronds in, 311. 
 
 Branches, fertile, of Selaginella, 
 384. 
 
 Braun, Alexander, on the fronds and 
 roots of Isoetese, 337 ; on the stem 
 of Isoetes, 354 ; on the interchange 
 of fertile and sterile leaves in 
 Isodtes lacustris, 362 ; on the growth 
 of Ophioglossum aud Botrychium, 
 310; on phyllotaxis in Sphagnum, 
 136. 
 
 Broguiart on the stems of ferns, 
 262. 
 
 Brown, Robert, his discovery of the 
 poly-embryony of Coniferae, 432. 
 
 Bruchs on the fruit of mosses, 180. 
 
 Bryum, antheridia of, 152; develop- 
 ment of leaves of, 142. 
 
 Bryum argcntcum, development of 
 fruit of, 156. 
 
 Bryum ctespitosum, antheridia of, 153. 
 
 Bud-receptacle in Blasia, 50. 
 
 Bud, terminal, of Aspidium ßlix-mas, 
 
INDEX. 
 
 495 
 
 227 ; division of, in Äsplenium filix- 
 femuia, 247; of Pilularia, 325. 
 
 Buds, production of, in Äneiira mulli- 
 ßda, 46 ; in Anthoceros, 18, 48 ; 
 development of, in Fteris c(quilina, 
 225 ; of Lunularia, 104, 107 ; of 
 Marchautia, 104, 107 ; of Kiccia, 
 48. 
 
 Buds, adventitious, of Aspldiiim filix- 
 mas, A. spinulosum, and A. oreopteris, 
 245 ; Asplenium Bellangeri, 247; of 
 Asplenium fili.v-femina, 245, 247 ; 
 of Equisetacese, 275, 303 ; of Ma- 
 rattia CicuiafuUa, 255 ; of Nepiiro- 
 lepis, 247 ; of Opliioglossum, 315 ; 
 of Struthiopteris Germanica, 245, 
 247. 
 
 Buds, reproductive of Blasia, 48 — 50 ; 
 Corda's description of their germi- 
 nation, 48. 
 
 Bulbils of Lunularia, 104, 107 ; of 
 Marcbantia, 104, 107. 
 
 Cali/pogeia Trichomanes, archegonia of 
 70 ; calyptra of, 80 ; cell-multiplica- 
 tion in apex of cell of, 442 ; deve- 
 lopment of fruit of, 74, 77, 80; 
 observed by Gottsche, 86; develop- 
 ment of perianth in, 70. 
 
 Calyptra of Aneura wuUiJhhi, 45 ; of 
 Anthoceros, 13 ; of Calypogeia 
 Trichomanes, SO ; of Liverworts, 
 development of, 79 ; of Junger- 
 maniiia biciispidata, 79 ; of Frul- 
 lania dilatata, 80 ; of Marchantia 
 poll/ morpha, 11^^ \ of mosses, 159; 
 of liadulu complanata, 79 ; of Rebou- 
 illia heiiiUphenca, 113 ; of Ricci a 
 glauca, 9G ; Targionia hypophylla, 
 119. 
 
 Calyx of leafy Liverworts, 68. 
 
 Cambium layer peculiar to Isoetes 
 among vascular Cryptogams, 372. 
 
 Capsule of Fegatella conica, 115 ; of 
 Pellia epiphglla, 37 ; of Riella, 100. 
 
 Cell, apical, of terminal bud of stem 
 in Aspidinm filix-nuts, 231 ; in 
 Equisetacese, 267; in Ferns, 231 — 
 239 ; in Marattia cicutce/olia, 254 ; 
 in Nephrolepis undulata, and N. 
 splendens, 248 ; in Niphobolus ru- 
 pestris, and N. chinensin, 248 ; in 
 Opfiioglossiim vulgutum, 314 ; in 
 Flatyceriam alcicome. 253 ; in Pohj- 
 poditim aiiream, P. punciatum, P. 
 cgmatodes, and P. vulgare, 248 ; 
 
 division of, in Selagiuella, 273 ; of 
 Sphagnum, 129. 
 
 Cell-development in the stem of 
 Aneura, 43 ; in stem and shoots of 
 Anthoceros, 4 ; in the germ-plant 
 of Frullaiiia dilatata, 52 ; in the 
 germ -plant of Jungermannia bicus- 
 pidata, 53 ; in the stem of Metz- 
 geria /areata, 42 ; in the shoots of 
 Pellia epiphglla, 27. 
 
 Cell-division in leaves of Fegatella 
 conica, 109. 
 
 Cell-formation in spores of Isoetes 
 lacustris, 339 ; importance of the 
 study of the spores of Pellia epi- 
 phylla in regard to, 39. 
 
 Cell-multiplication in autheridia of 
 Equisetacese, 294 ; in archegonia of 
 Equisetaceae, 298; of ferns, 190; 
 in the developing fruit of Equise- 
 tacese, 301 ; in the embryos of 
 Ptcris aquilina and Aspidium filix- 
 mas, 201; in the embryo of Sal- 
 vinia natans, 333 ; iu germ-plant 
 of Radula complanata, 55 ; in the 
 stem of Equisetum, 272; in the 
 stem oi Fnillania dilatata, 56, 57; 
 in the stem of the leafy Juuger- 
 mannise, 56, 442; Kiigeli on, 84 ; 
 in the stems oi Jungermatinia biciis- 
 pidata, 56, 57, J. coanivens, 57, 
 J. exsecta and /. trichophylla, 84 ; 
 in stem oi Lophocolea bideiUata, 56 ; 
 in stem of Metzgeria f areata, 84 ; 
 in stem of Selaginella, 374; in 
 stem of Sphagnum, 130; iu stem 
 of Trichocolea tomentella, 56 ; in 
 terminal bud of Blasia, 49, of 
 Equisetaceae, 267, of Pteris aquilina, 
 217 ; in first frond of Pteris aqui- 
 lina, 208 ; in young fronds of 
 Niphobolus rupestris and N. splen- 
 dens, 249, and of Poly podium 
 aureum, 250 ; in leaves of Bryum, 
 Hypuum, Phascum, and Poly- 
 trichum, 142; in leaves of Ortko- 
 trichum affine, 139 ; in leaves of 
 Sphagnum, 136 ; Nägeli on, 140 ; 
 in leaves of Sphagnum squarrosum, 
 142; in roots of Aspidium filix- 
 mas, 244, of Equisetum, i^79, aud 
 of Isoetes lacustris, 348 — 356. 
 
 Cell-succe£si(m in apex of Aspidium 
 Jilix-mas and A. spinulosum, 241 ; 
 in apex of leat'-buds of phaenoga- 
 mous plants, 239. 
 
496 
 
 INDEX. 
 
 Cells, arrangement of in stems of 
 Equiseta, 272 ; pitted iu Sphag- 
 num, 134 ; scalariform of Pteris 
 aquilina, 219. 
 
 Ceratopteris, germination of, 183. 
 
 Ceratopteris thalictroides, autheridia 
 of, 187 ; archegonia of, 191, 193. 
 
 Clilorophyil-bodies in cells of Antho- 
 ceros, 6 ; of Pbascum, 146. 
 
 Chloropbyll-granules of Metzgeria 
 furcata., small size of, 42. 
 
 Chlorophyll-vesicle, 6. 
 
 Cilia of spermatozoids of ferns, 189. 
 
 Classification of mosses and liver- 
 worts, 407. 
 
 Columella of Anthoceros, 13. 
 
 Coniferae, development of pollen in, 
 401 ; differences of, from plioeno- 
 gams, 441 ; ovules of, 400 ; poly- 
 embr^'ony of, discovered by Robert 
 Brown, 432. 
 
 Corda on the reproductive buds of 
 Blasia, 48 ; on the pollen-tube of 
 Couiferai, 432. 
 
 Corpuscula of Coniferae, 410 ; num- 
 ber of, in different species, 411, 
 412; free cells in, 412; of Pinus 
 canadensis and P. picea, 411. 
 
 Cramer on cell-succession in the end 
 of the stem of Equisetum, 267. 
 
 Creeping-stem of Pteris aquilina, 212. 
 
 Cupressus, corpuscula of, 410; de- 
 velopment of endosperm in, 410. 
 
 De Bary, observations on the spores 
 
 of Lycopodium iiiiindatum, 399. 
 De Vriese and Harting on the Marat- 
 
 tiacese, 254. 
 Dicksonia rubiginosa, cellular hairs of 
 
 stem-bud of, 212. 
 Dicksonise, stems of, 213. 
 Dicranum, archegonium of, 149. 
 Dicranum scoparium, terminal bud of, 
 
 129. 
 Dillenius on Marchantia polymorpha, 
 
 123. 
 Dijüolsena, 47. 
 Disc, antheridial, of Marchantia poly- 
 
 morpha, 120. 
 Duriena, leaf of, 98. 
 
 Ehrhart on the prothallium of ferns, 
 257. 
 
 Elateis of Aneura muUifida, develop- 
 ment of, 45 ; Schmidel on, 86 ; of 
 Anthoceros, 13; of Equisetaccse, 
 
 287, Sanio's observations on ab- 
 normal formation of, 291; of Fos- 
 sombronia pitsilla, 82 ; of Junger- 
 mannia bicuspidata, 78, 79, 81 ; of 
 Jiingermannia divaricala, 75 ; of 
 Jungermannise, Gottsche on, 87 ; 
 of Pellia epiphylla, 38; of Tar- 
 gionia hypophylla, 120. 
 
 Embryo, development of, in Abietineae, 
 421 ; position of, on the prothal- 
 lium, in Botrychium Lunaria, 308; 
 development of, in Coniferae, 406, 
 observations of Hartig, Gottsche 
 and Pineau on, 407 ; formation of, 
 in Coniferae, intermediate between 
 that of cryptogams and phceno- 
 gams, 408, opinions of Schleiden, 
 Schacht and Geleznow on, 428 ; 
 development of in Equisetaceae, 301 ; 
 of Ferns, 200 ; development of in 
 Isoeles lacustris, 343 ; formation of, 
 in Larix, Geleznoff's statements 
 on, 422, of üphioglossum, Mette- 
 nius on, 316 ; formation of in 
 Pilularia, 323 ; production of in 
 Salvinia nafans, 332 ; development 
 of in Selaginella, 395. 
 
 Encalypta, autheridia of, 152 ; ca- 
 lyptra of, 159 ; spore-mother-cells 
 of, 160. 
 
 Endosperm, development of, in Coni- 
 ferae, 408. 
 
 Epidermis, formation of, in Equise- 
 tacea;, 273. 
 
 Equisetaceae, production of autheridia 
 in, 293 ; development of archego- 
 lu'a in, 298 ; fecundation and de- 
 velopment of embryo in, 300, 301 ; 
 obstacles to germination of, 296 ; 
 prothallium of, 292; spermatozoids 
 of, 294; terminal bud of, 267; 
 vegetation of, 303. 
 
 Equisetum arvense^ adventitious buds 
 of, 276, 304 ; autiieridia of, 296 ; 
 apical cells of autheridia of, 294 ; 
 fructifying shoots of, 280 ; germi- 
 nation of, 292, 297 ; development 
 of germ-plant of, 304 ; prothallium 
 of, dioecious, 294 ; production of 
 male prothallia in, 297 ; spermato- 
 zoids of, 296. 
 
 Equisetum hyemale, stem of, 271. 
 
 Equisetum limosum, adventitious buds 
 and shoots of, 276, 277 ; anlheridia 
 of, 294, 296 ; cell-multiplication in 
 terminal bud of, 268 ; germination 
 
INDEX. 
 
 497 
 
 of, 292 ; growth of leaves of, 271 ; 
 
 pith of, 275 ; rhizome of, 278 ; 
 
 stem of, 271. 
 Eqidsetum palustre, adventitious buds 
 
 of, 276 ; germination of, 292 ; pith 
 
 of, 275 ; prothallium of, dioecious, 
 
 293 ; spore-mother-celis and spores 
 
 of, 2S3 ; stem of, 271. 
 Equüetum pratense, formation of ad- 
 
 vejititious buds in, 275 ; pith of, 
 
 275 ; prothallium of, dioecious, 293 ; 
 
 stem of, 271. 
 'Eqidsetum variegatum, pith of, 275 ; 
 
 stem of, 271. 
 Exosporium of Anthoceros, Kützing 
 
 on, 17 ; of Isoetes lacustris, Roper 
 
 and Schleiden on, 338. 
 
 Fegatella conica, Hedwig on, 123 ; 
 Schmidel on, 123 ; archegonia of, 
 Hi; capsule of, 115; rudimen- 
 tary fruit of, 115 ; cell-division in 
 leaves of, 109 ; shoots of, 102 ; 
 vegetative organs of, 102. 
 
 Ferns, 182 ; alternation of genera- 
 tions in, 434, 435 ; antlieridia of, 
 ]85; antheridia and spermatozoids 
 of, discovered by Kägeh, 258 ; 
 archegonia of, 189, observed by 
 Nägeli, 258; embryo of, 200; 
 growth of first fronds of, 207 ; 
 germinal vesicle of, 193 ; germina- 
 tion of, 182 ; impregnation of, 198, 
 described by Lesczyc-Suminski, 
 258 ; prothallium of, observed by 
 Ehrhart, 257 ; development of 
 roots of, 203, 205 ; spermatozoids 
 of, 187, 188, 189; development of 
 vegetative organs of, 208. 
 
 Fissidens, archegouium of, 149 ; de- 
 velopment of fruit of, 156 ; leaf of, 
 143, 144. 
 
 Fossombronia pusilla, antheridia of, 
 65; archegonia of, 67, 71 ; develop- 
 ment of leaf of, 58, 63 ; spermato- 
 zoidsof, 67; discovered by Schmidel, 
 8 7 ; spore-mother-cells and elaters 
 of, 82. 
 
 Fritzsche, observations on the pollen 
 of the Abietinese, 405. 
 
 Fronds, of Aspidiitm fillx-mas, ar- 
 rangement of, 228, first formation 
 of, 243, production of, 226 ; of 
 Aspidiwn i'pimdosum, Asphnium 
 filiX'fem'ma and A. Trichomanes, 
 development and arrangement of, 
 
 230; of Botrychium, succession of, 
 311 ; of Ferns, growth of, 207 ; of 
 Isoetea;, A. Braun on the arranjje- 
 nient of, 337 ; adventitious, oilLa- 
 ratfia cictitafolia, 255 ; of Opldo- 
 glossuni vwlgatuvi, arrangement and 
 succession of, 313 ; of Pilularia, 
 production of, 324 ; of Plati/cerium 
 alcicoriie, 251 ; of Flatycerium 
 gründe, 253 ; of Folypodiuvi vul- 
 gare and P. Bryopteris, 249 ; of 
 Pteris aquilina, arrangement of, 
 212 ; duration of development of, in 
 young and old plants, 222 ; produc- 
 tion of new, 221 ; and production 
 of in old plants, 224. 
 
 Fronds and sporangia of ferns, analo- 
 gous to fruit of mosses, 435. 
 
 Fructification of Anthoceros, 7; of 
 Archidium, Schimper on, 169; of 
 Riccia glauca, 92, 93. 
 
 Fruit, development of, in Alicularia 
 scaluris, 74, 77, 78 ; in Aneura 
 midtifida, 44, 45 ; in Anthoceros, 
 11, 12; in Calypogeia Trichomanes, 
 74, 77, 80; inEquisetum, 280 ; in 
 ferns, 256 ; in Frullania ddatata, 
 74, 78, 80, 82 ; in Jungermannia 
 divaricata, 74, 75, 76 ; in /. bicus- 
 pidata, 74, 11, 78,_ 82; in /. 
 trichophylla, 77, 82 ; in Lophocolea 
 helerophylla, 77, 78 ; in mosses, 
 156; in Pellia epiphylla, 34; in 
 Radida complanata, 74, 77, 78, 82 ; 
 in Bebotdllia hendspherica, 114 ; in 
 Riccia glauca, 97. 
 
 Fruit, abnormal, in mosses, 180; of 
 Anthoceros, 18; oi Fegatella conica, 
 115; of Jungermannife, observed 
 by Gottsche, 86 ; of Lophocolea 
 bidentata, its rarity, 72 ; of Mar- 
 chantia polymorj)ha, 116; of mosses, 
 H. von Mohl and Lantzius-Beniuga 
 on, 179, Bruchs on, ISO; sheath 
 of, in Pellia epiphylla, 36 ; of Pilu- 
 laria globulifera, 320 ; of Riella, 
 100 ; of Targionia hypophylla, 119. 
 
 Fruit-stem of Fegatella conica, ISchmi- 
 del and Bischoff on the detachment 
 of, 115. 
 
 Frullania, 441 ; antheridia of, 65 ; 
 archegonia of, 68. 
 
 Frullania dilatata, relations of anthe- 
 ridia and archegonia in, 73 ; calyp- 
 tra of, 80 ; cell-multiplication in 
 stem of, 56, 57, 442 ; fruit of, 74, 
 32 
 
498 
 
 INDEX. 
 
 78, 80, 82 ; germination of, 51 ; 
 development of leaves iu, 61 ; de- 
 velopment of perianth in, 69 ; 
 sperniatozoids of, 67 ; spore-mothcr- 
 cells of, 81. 
 
 Funaria lu/grometnca, antlieridia of, 
 152, 153 ; arcliegonia of, 149 ; 
 fruit of, 156,157; germinal vesi- 
 cle of, 151; Hedwig on the ger- 
 mination of, 176 ; paraphyses of, 
 153; spermatozoidsof, 154; spores 
 and spore-motlier-cells of, 160, 167. 
 
 Furrows of stem in Isoetes, 367. 
 
 Geleznow on the formation of the 
 
 embryo in Coniferse, 428. 
 Gemmae, formation of, xnRiccia glauca, 
 
 97. . . • 
 
 Generations, alternation of, iu mosses 
 
 and ferns, 434. 
 Geocalycea?, development of fruit of, 
 
 78. 
 
 Germinal vesicle, of Coniferse, evolu- 
 tion of, 426 ; of Equisetaceffi, 299 ; 
 of ferns, 193; of Funaria hygro- 
 metrica, 151 ; of Juniperus commu- 
 nis and /. sahina, 431 ; of mosses, 
 150 ; of Riella, 100 ; of Taxus 
 baccata and T. canadensis, 430 ; of 
 Thtija orieräalis, 431. 
 
 Germination of Alicularia scalaris, 
 54 ; of Blasia pusilla^ 83 ; of Bo- 
 trychium lunaria, 307 ; of Equise- 
 tacese, observations on by Vaueher 
 and Agardh, 304, by Bischoff, 305 ; 
 of fern-spores, described by Kaul- 
 fuss, 257 ; of Isoetes, 371, Mette- 
 nius on, 337 ; of Isoetes lacustris, 
 Karl Miiller's observations on, 337 ; 
 of Jungermannise, 83 ; of Junger- 
 mannia bicuspidata, 52 ; of /. 
 crenulata, 54, 84 ; of /. divaricata, 
 54 ; of Lophocolea heterophylla, 54 ; 
 of mosses, 160, Hedwig on, 175, 
 Nägeli and Sehimper on, 176; of 
 mosses and ferns, 435 ; of Ophio- 
 glossum, Mcttenius on, 315 ; of 
 Pellia epiphylla, 21 ; of Pilularia 
 fjlohulifera, 321; of Radula com- 
 planata, 55 ; of Salvinia natans, 
 329 ; of Sarcosryphus Funkii, 54 ; 
 of Selaginella, Mettenius on, 337. 
 
 Germ -plant, of Botryckium Lunaria, 
 307 ; of Equisetaeese, development 
 of, 302, 304 ; of Riccia glauca, 89 ; 
 of Selaginella, 396. 
 
 Gottsche, on the fructification of 
 Calypogeia Trichomanes, 70, 80; 
 on the development of the embryo 
 in Conifera?, 407 ; on the shoots of 
 Ilaplomilrium Hookeri, 64 ; on the 
 antlieridia of Haplomitrium, 88 ; 
 on the elaters and perianth of 
 Jungermannise, 87 ; on the young 
 fruit of Jungermanuise, 86 ; on the 
 germination of the spores of Jun- 
 germannifE, S3 ; on the develop- 
 ment of the leaves of Jungermauniffi, 
 85 ; on the sperniatozoids of Jun- 
 germannise, 87 ; his erroneous 
 views of antheridia of Liverworts, 
 88; on Marchantiese, 122 ; on the 
 seed and embryo of Pinus, 433 ; 
 on Preissia commutata, 127. 
 Gris, Arthur, on chlorophvU-bodies, 
 
 147. 
 Grünland on the germination of the 
 spores and the ramitication of the 
 protliallium in Jungerniannia;, 84 ; 
 on Lunularia vulgaris, 127; on 
 Marchaniia polymorpha, 127. 
 Gunibel, observations on abnormal 
 
 fruit in mosses, 180. 
 Gymnogranma calomelanos, archegonia 
 of, 192, 194 ; abortive prothallia 
 of, 197. 
 Gymnojramma chrysophylla, abortive 
 
 protiiallia of, 196, 197. 
 Gymnostomum, antlieridia of, 152; 
 calyptra of, 159 ; spore-mother- 
 cclis of, 160. 
 Gymnostomum ovaium, spore-mother- 
 cells of, 104. 
 Gymnostomum pyriforme, antheridia 
 of, 153 ; fruit of, 157, 160 ; Hed- 
 wig's observations on the germina- 
 tion of, 175 ; spore-mother-cells of, 
 166 ; spores of, 167. 
 
 Hairs, cellular, of the stem-bud in 
 Pleris aquilina, 212. 
 
 Hanstein on the stems of ferns, 202. 
 
 Haplomitrium Hookeri, antheridia of, 
 65 ; Gottsche on, 88 ; development 
 of leaves of, 63, 85 ; half-subterra- 
 nean shoots of, 64. 
 
 Hartig, on the suspensor in the Coni- 
 fers;, 433 ; on the development of 
 the embryo in the Coniferse, 407. 
 
 Hedwig, on Fegatella conica, 123 ; 
 on tlie antheridia of Jungermannise, 
 87 ; observations on the archegonia 
 
INDEX. 
 
 499 
 
 üf Jungermannioe, 85 ; ou the ger- 
 mination of tlie spores of Junger- 
 maunise, S3 ; on the reproduction 
 of mosses, 175 ; on tlie germina- 
 tion of mosses, 175 ; experiments 
 on the germination of Gymnodomum 
 pyri forme, 175, and of Funaria 
 Iiyyrometrica, 176 ; on the fructiti- 
 cation of Riecia, 97. 
 
 Uemitelia Cctpeiisis, frond-like bodies 
 at base of stipes of, 213. 
 
 Henfrey on the impregnation of ferns, 
 261 ; ou Marchantia polymorpha, 
 127. 
 
 Hubener on the pro-embryo of Schis- 
 tostega, 173. 
 
 Hybridity in mosses, 181. 
 
 Hypnum, develooment of leaves of, 
 142; terminal "bud of, 129. 
 
 Impregnation in Coniferae, 406 ; 
 Schacht's observations on, 422 ; in 
 Equisetacese, 300; in ferns, 198, de- 
 scribed by Lesczyc-Sumuiski, 258, 
 observations on by Wigand, 259, 
 Hofmeister, 260, Von Mercklin, 
 Mettenius and Henfrey, 261 ; in 
 Isoetes, 370 ; in Isoetes lacustris, 
 370; in mosses, 156; in Pellia 
 epiphylla, 34 ; in Pilularia, 323. 
 
 Indusium of ferns, 256. 
 
 Inflorescence of Marchantia, 111. 
 
 Isoetese, peculiarities in the growth 
 of, indicated by H. von Mohl, 336. 
 
 Isoetes, germination of, Mettenius on, 
 337 ; different numbers of furrows 
 in the stem of, 367, and differences 
 of growth in accordance witii them, 
 368 ; resemblance of, to Coniferse, 
 in mode of reproduction, 370. 
 
 Isoetes adspersa, leaves of, 363. 
 
 Isoetes Burieui, leaves of, 363. 
 
 Isoetes Hystrix, leaves of, 363. 
 
 Isoetes lacustris^ 335 ; Karl Miiller's 
 observations on the germination of, 
 337. 
 
 Isoetes velata, leaves of, 363. 
 
 Jungermannia, antheridia of, 65 ; 
 archegonia of, 67. 
 
 Jungermannia biciinpidata, calyptra of, 
 79 ; cell-multiplication in stem of, 
 56, 57, 442; elaters of, 78, 79; 
 development of fruit of, 73, 74, 77, 
 78, 82 ; germination of, 52 ; Grön- 
 
 land on the ramification of the germ- 
 plant in, 54 ; development of leaves 
 in, 59 ; development of perianth in, 
 69 ; shoots of, 64 ; production of 
 spore-mother-cells in, 78, 79. 
 
 Jungermannia conniveus, development 
 of leaves of, 59 ; cell-multiplication 
 in stem of, 57. 
 
 Jungermannia crenulata, germination 
 of, 54, 84 ; arrangements of cells 
 in leaves of, 63 ; ramification of 
 protiiallium of, 84. 
 
 Jungermannia curla, arrangement of 
 cells in leaves of, 63. 
 
 Jungermannia divaricata, antheridia 
 of, axillary, 73 ; cell-multiplication 
 in stem of, 56 ; elaters of, 75 ; de- 
 velopment of fruit in, 73, 74, 75, 
 76 ; germination of, 54 ; develop- 
 ment of leaves of, 59 ; development 
 of perianth in, 69 ; spermatozoids 
 of, 67. 
 
 Jmigermannia exsecta, cell-multiplica- 
 tion in stem of, 84. 
 
 Jungermannia trichopJiylla, develop- 
 ment of fruit of, 77, 82 ; cell-mul- 
 tiplication in stem of, 84. 
 
 Jungermannise, antheridia of, 87; 
 germination of, 83 ; impregnation 
 of, 73 ; development of leaves in, 
 85 ; variety of forms of leaves in, 
 57; perianth of, 87; ramification 
 of, 64, 85; development of spores 
 of, 86. 
 
 Jungermannise, leafy, development 
 of archegouium in, 67, 68 ; calyx, 
 or perianth of, 68 ; spermatozoids 
 of, 67. 
 
 Juniperus, cell-division in anthers of, 
 404 ; corpuscula of, 410 ; develop- 
 ment of endosperm in, 408 ; nu- 
 cleus of, 400. 
 
 Juniperus communis, fecundation of, 
 424. 
 
 Juniperus sabina, fecundation of, 424. 
 
 Karsten on the stems of ferns, 263. 
 
 Kaulfuss on the germination of fern- 
 spores, 257. 
 
 Kunze on the scales of Hemitelia 
 Capensis, 243. 
 
 Kiitzing on the exosporium of Autho- 
 ceros, 17. 
 
 Lantzius-Beninga on the fruit of 
 mosses, 179. 
 
500 
 
 INDEX. 
 
 Leaves, of Alicularia scalar is, arrange- 
 ment of cells in 63 ; of Blasiapusilla, 
 ill ; of Equisetacese, formation of, 
 269 ; of Vegatella coiiica, cell-divi- 
 sion in, 109 ; of Fossombronia pusilla, 
 development of, 58, 63 ; of Frul- 
 lania dilatata, development of, 61 ; 
 of Haplomitrium, development of 
 63 ; of Iso'etes lacustris, arrangement 
 of, 354, 356; development of, 344; 
 fertile, of Isoetes lacustris, 362; 
 sterile and fertile, interchange of 
 in Isoetes lacustris, 362 ; of Jun- 
 germannise, 57, 63 ; Gottsche on 
 the development of, 85 ; of Jun- 
 germannia curta and crenulaia, 
 arrangement of cells in, 63 ; of 
 Jtingermannia bicuspidata, conni- 
 vens, and divaricata, development 
 of, 59 ; of Lophocolea, development 
 of, 58 ; of Lunularia, development 
 of, 110 ; of Marchantia polymorpha, 
 110 ; of mosses, 142, 147 ; Nägeli, 
 Schieiden, and Grisebach on the 
 growth of, 147 ; pocket at base of, 
 143 ; of Orthotrychum affine, deve- 
 lopment of, 139 ; of Phascum cuspi- 
 datum, 146 ; of Ptilidium ciliare, 
 development of, 60 ; of Eadula 
 complanata, 63; of Rebouillia, 110; 
 of Riccia glauca, 92 ; of Riella 
 Reuteri, and R. (Duriena) helico- 
 phylla, 98 ; of Selaginella, produc- 
 tion of, 376, 396 ; of Sphagnum, 
 arrangement of, 136 ; development 
 of, 135 ; of Targionia, development 
 of, 110. 
 
 Lepidozia reptans, cell-multiplication 
 in apex of stem of, 442. 
 
 Lesczyc-Suminski, on the archegonia 
 and fecundation of ferns, 258 ; on 
 the spermatozoids of Pteris aquilina, 
 189. 
 
 Lindenberg on the fructification of 
 Riccia, 97. 
 
 Linnaeus on Marchantia polymorplia, 
 133. 
 
 Liverworts and mosses not natural 
 equivalent groups, 436 ; classifica- 
 tion of, 437. 
 
 Liverworts, leafy anthcridia of, 65 ; 
 development of arcliegonia in, 67 ; 
 calyx or perianth of, 68. 
 
 Lophocolea, antheridia of, 65 ; deve- 
 lopment of leaves of, 58. 
 
 Lophocolea bidentata, 441 ; cell-multi- 
 
 plication in stem of, 56 ; scarcity of 
 
 antheridia and fruit in, 72. 
 Lophocolea heterophylla, antheridia of, 
 
 axillary, 73 ; development of fruit 
 
 of, 74, 77 ; germination of, 54; 
 
 leaves of, 58. 
 Lunularia, buds or bulbils of, 104 : 
 
 development of leaves of, 110. 
 Lunularia vulgaris, shoots of, 108 ; 
 
 vegetative organs of, 102 ; Bischoff 
 
 on, 126; Grönland on, ]27. 
 Lycopodiacese, reproduction of, 398. 
 Lycopodium, mode of vegetation of, 
 
 resembling that of Polypodiacese, 
 
 398. 
 Lycopodium clavatum, inundatum, and 
 
 Selago, experiments in sowing spores 
 
 of, 398. 
 Lycopodium inundatum. De Bary's 
 
 observations on the spores of, 
 
 399. 
 
 Maerosporanglum of Selaginella hor- 
 ten sis, 387. 
 
 Macrospores, structure of, in Isoetes 
 lacustris, 338 ; development of, in 
 Selaginella horfe7isis, 387 ; in S. 
 Galeottii, helvetica, Martensi, and 
 spinulosa, 398 ; in S. helvetica, and 
 hortensis, 393. 
 
 Madotheca platyphylla, development 
 of antheridia of, 65, 67 ; cell-multi- 
 plication in apex of stem of, 442 ; 
 spermatozoids of, 67. 
 
 Maraitia cicutafolia, vegetation of 
 254. 
 
 Marattiaceae, De Vriese and Harting 
 on, 254. 
 
 Marciiautia, buds or bulbils of, 104 ; 
 104 ; inflorescence of. 111 ; motile 
 spermatozoids first seen in by 
 Unger, 127. 
 
 Marchantia polymorpha, antheridia of 
 120 ; development of leaves of, 110 ; 
 shoots of, 108 ; spermatozoids of 
 121; vegetative organs of, 102; 
 Dilienius, Linnaeus, Micheli, Mirbel, 
 and Rupp on, 123 ; H. von Mohl 
 and Niigcli on, 124 ; Grönland and 
 Henfrey on, 127. 
 
 Marchanticse, 102 ; air-cavities of, 11 ], 
 117 ; antheridia of, 120; leaves of, 
 
 109 ; stem of, 110 ; stomata of, 
 
 110 ; Bischoff, Gottsche, and Nees, 
 von Esenbeck on, 122 ; Schmidel, 
 123 ; Thuret on, 128. 
 
INDEX. 
 
 ;o]. 
 
 Marsilea p?ibescens, 318 ; niacrospore 
 of, 3'25 ; germination of, 326. 
 
 Merckliii on tlie arcliegonia of ferns, 
 261 ; on vessels in tlie protliallium 
 of ferns, 207. 
 
 Mettenius on the growth of Botry- 
 chium 310, 311 ; on the impregna- 
 tion of ferns, 261 ; on the stems of 
 ferns, 263 ; on the spermatozoids of 
 Isoeles lacustris. 342 ; on the spores 
 and germination of Isoeles and 
 Selaginella, 337 ; on the germina- 
 tion of 0|ihioglossiun, 315 ; on the 
 Rhizocarpeae, 335 ; on the spores 
 oi Scilv'mia nutans, 330; on the pro- 
 thallium of Selaginella, 392 ; on 
 abortive archegonia in Selaginella, 
 395 ; on the spores of Selaginella, 
 390. 
 
 Metzgena furcafa, cell-multiplication 
 in stems of, 84 ; Nägeli on the 
 growth of, 41. 
 
 Meyer on spermatozoids of Aneura, 
 87. _ 
 
 Micheli, on Marchaniia poli/morpha, 
 123. 
 
 Microsporangia of Selaginella, 391. 
 
 Microspores of Isoetes lacustris, struc- 
 ture of, 341, production of sperma- 
 tozoids by, 342 ; of Salvinia nutans, 
 331 ; of Selaginella, 391, 394. 
 
 Milde, description of the antheridia and 
 spermatozoids of Equisetaceae, 306; 
 observations on the arcliegonium of 
 Equisetaceae, 306. 
 
 Mirbel, on the pro-embryo of the 
 Coniferse, 433 ; on Marchuntia 
 poli/morpha, 123. 
 
 Mniiini hornum, paraphyses of, 153. 
 
 Mohl, H. von, on the formation of the 
 sejita of the spore-mother-cells in 
 Anthoceros, 16 ; on chlorophyll 
 bodies, 146 ; on the bark of ferns, 
 215 ; on the structure of the stems 
 of ferns, 262 ; on the vascular 
 bundles of ferns, 225 ; on the 
 growth of Isoeteae, 336 ; on the 
 development of the spores of Jim- 
 germanniae, 86 ; on Marchantia 
 polymorpha, 124 ; on the fruit of 
 mosses, 179 ; ou the sporangia of 
 Selaginella, 387. 
 
 Moonwort, 307. 
 
 Morison on the growth of Scolopen- 
 drium officinurum from spores, 257. 
 
 Mosses and liverworts, not natural 
 
 equivalent groups, 436 ; classfica- 
 tion of, 437'. 
 
 Mosses, alternation of generations in, 
 434, 435 ; antheridia of 152 ; arche- 
 gonia of, 148 ; development of fruit 
 of, 156; abnormal fruit in, Gum- 
 bel's observations on, 180 ; ger- 
 minal vesicle of, 150 ; germination 
 of spores of, 170; impregnation of, 
 156; pocket at base of leaves of, 
 143 ; spore-mother-cells of, 160 ; 
 growth of stems of, 129; so-called 
 stigma of, 151. 
 
 Mother-cell, persistence of, in Equise- 
 taceae, 291. 
 
 Müller, Karl, ou the germination of 
 Isoetes lacustris, 337. 
 
 Müller, E.., on the stipules of Selagi- 
 nella, 378. 
 
 Nägeli, on chlorophyll-bodies, 145 ; 
 on the archegonia, antheridia, and 
 spermatozoids of ferns, 258 ; on 
 the spermatozoids of ferns, 189; 
 on the stems of ferns, 202 ; on 
 cell-multiplication in the stems of 
 Jungermanuije, 84; oi\ Marchantia 
 pol'i/morphrt, 124; on the growth of 
 Metzf/eria fur cut a, 41 ; on the ger- 
 mination of mosses, 176; on the 
 leaves of mosses, 147 ; ou the pro- 
 embryo of mosses, 172 ; on cell- 
 multiplication in the leaves of 
 Pliascum, Bryura, Hypnum, and 
 Polytrichum, 142; on the produc- 
 tion of spermatozoids in Pilularia, 
 335 ; on cell-multiplication in leaves 
 of Sphagnum, 140 ; on cell-multi- 
 plication in apex of stem of Sphag- 
 num, 130. 
 
 Neckera complanatUy antheridia of, 
 153. 
 
 Nees von Esenbeck, on Anthoceros, 
 19 ; on the germination of the 
 spores of the Jungermannise, 83 ; 
 on the ramification of Jungerman- 
 nise, 85; on Marchantiese, 122. 
 
 Nepbrolepis, adventitious buds and 
 stolons of, 247. 
 
 Nephrolepis splendens, vegetation of, 
 245 ; apical cell of terminal bud of, 
 248. 
 
 Nephrolepis tuherosa, 247. 
 
 Nephrolepis undulata, apical cell of 
 terminal bud of, 248; vegetation 
 of, 245. 
 
502 
 
 INDFA. 
 
 Niphobolus chinensis, apical cell of, 
 
 248. 
 Niphobohis lingua, apical cell of, 239. 
 Niphobolus rupestris, apical cell of, 
 
 239,248. 
 Notliochlseua, abortive protliallia of, 
 
 197. 
 Nucleus in Abietinese, 400 ; in Juni- 
 
 perus, 400 ; in Pinus, 400 ; in 
 
 Taxus, 400 ; in Thuja, 400. 
 
 Ophioglossese, 307. 
 
 Ophioglossum, prothallium of, obser- 
 vations of Mettenius upon, 315. 
 
 Ophioglossum pedunculosum, root-buds 
 of, 315. 
 
 Ophioglossum vulgufum, development 
 of vegetative organs of, 312. 
 
 Ortliotrichum, calyptra of, 159. 
 
 Orthotrichum affine, development of 
 vegetative organs of, 139. 
 
 Ovules of Coniferse, 400. 
 
 Papillae, marginal, of leaves of Selagi- 
 nella, 380.' 
 
 Paraphyses of mosses, 153. 
 
 Pellia epiphylla, 21. 
 
 Perianth, of Alicularia scalar is, 69 ; 
 of Calypogeia Trichomanes, 70 ; of 
 Frullania dilatata, 69 ; of Junger- 
 mannise, 87 ; of Jungermannia biciis- 
 pidata and /. divaricata, 69 ; of 
 leafy Jungermanniae, 68 ; repre- 
 sented in Pellia epiphylla by the 
 pouch-shaped covering of the arche- 
 gouium, 33 ; of Radula complanata, 
 68 
 
 Phascum, antheridia of, 152 ; arche- 
 gonia of, 149 ; calyptra of, 159 ; 
 development of fruit of, 156, 157, 
 158, 160 ; development of leaves of, 
 142 ; spore-mother-cells of, 160 ; 
 terminal bud of, 129. 
 
 Phascum brgoides, development of 
 fruit of, 160. 
 
 Phascum cuspidatum,, spore-mother- 
 cells of, 160 ; spores of, 164, amoe- 
 boid movements of primordial utricle 
 in, 163. 
 
 Phascum serratum, pro-embryo of, 172. 
 
 Phyllotaxis in Sphagnum, 136. 
 
 Pilularia, development of fruit of, 318. 
 
 Pineau, on the development of the 
 embryo in Coniferte, 407. 
 
 Pinnae, of frond, formation of, in Pteris 
 aquilina, 209. 
 
 Pinus, anther of, 401 ; Gottsche ou 
 the seed and embryo of, 433. 
 
 Pinus Abies, fecundation of, 418. 
 
 Piuus balsamea, nucleus of, 400. 
 
 Pinus Canadensis, fecundation of, 418. 
 
 Pinus Laiix, fecundation of, 419. 
 
 Pinics Slrobus, nucleus of, 400. 
 
 Pinus si/loestris, fecundation of, 417 ; 
 nucleus of, 400. 
 
 Pith of Equisetum, 274. 
 
 Plagiochila asplenioides, cell-multipli- 
 cation in a})ex of stem of, 442. 
 
 Platycerium alcicorne, germination of, 
 1S2 ; vegetation of, 251. 
 
 Pocket, of leaves of mosses, 143. 
 
 Pollen, of Abietineae, development of, 
 405 ; Pritzsche's observations on, 
 
 405 ; of Couilerae, development of, 
 401, resemblance of vital pheno- 
 mena of, to those of the microspores 
 of Pilularia, &c., 438 ; of Cycadese, 
 
 406 ; of Ephedra, Schacht on, 406 ; 
 development of, in Pinus sj/lveslris, 
 P. mandma, P. balsamea and P. 
 Larix, 402 ; in Juniperus, Thuja 
 occidentalis, Abies pectinata, and 
 Picea vulgaris, 405. 
 
 Pollen-tubesofCouiferae, their entrance 
 into the endosperm, 415 ; develop- 
 ment of free spherical cells in the 
 ends of, 416 ; their penetration into 
 thecorpusculaprovedbyCorda, 432. 
 
 Pollen-tubes in Taxus, Juniperus, 
 Pinus sylvestris, P. Ilughus, P. 
 Austriacus, and P. Slrobus, 406. 
 
 Poly-embryony of Coniferae, discovered 
 by Robert Brown, 432. 
 
 Polypodiaceae, prothallia, and anthe- 
 ridia of, 186. 
 
 Polypodium aureum, apical-cell of, 
 239, 248. 
 
 Polypodium cymatodes, apical-cell of, 
 239, 248. 
 
 Polypodium Dryoplcris, apical-cell of, 
 239 ; arrangement of fronds in, 249. 
 
 Polypodium punctatum, apical-cell of, 
 248. 
 
 Polypodium punclulalum, apical-cell of, 
 239. 
 
 Polypodium vulgare, apical-cell of, 
 239, 248; arrangement of fronds 
 in, 249. 
 
 Polytrichum, antheridia of, 152 ; 
 archegonia of, 149 ; development 
 of leaves of, 142 ; terminal bud of, 
 129. 
 
INDEX. 
 
 503 
 
 Tolytrichum formosum, spermatozoids 
 of, 154. 
 
 Polytrichum juniperiimm, antlieridia 
 oV, 153. 
 
 "Precursors" of the vascular bundles, 
 in Isoetes lacustris, 352. 
 
 Preissia commutata, Gottsche on, 
 127 ; Schmidel on, 123. 
 
 Presl, on the stems and trouds of Bo- 
 trycliium, 310, 311. 
 
 Pringsheim, on the stems of ferns, 264. 
 
 Pro-einbryo, of Abietinese, 427 ; of Co- 
 nifer^e, described by Sehleiden, 432 ; 
 Mirbel and Spach, 433 ; develop- 
 ment of Juniperus conununis, J. Sa- 
 bina, and Thuja orientalis, 431 ; of 
 mosses, 171, 435 ; ditierences of, 
 from prothallium of ferns, 1?4 ; of 
 Liverworts, 435 ; of Pilularia glo- 
 bulifera, 322 ; of Sphagnum, Schim- 
 per on, 174; of Taxus, 430. 
 
 Prothallium, of Botrychium Ltmaria, 
 307 ; of Equisetaceee, develop- 
 ment of, 292 ; male, production of, 
 in Equisetum arcense, and E. pra- 
 tense, 297 ; female, production of, 
 in Equisetum pal list re, 298 ; of ferns, 
 183 ; analogous to leafy plant of 
 mosses, 435 ; observed by Ehrhart, 
 257; sexual organs observed in, by 
 Bischoff, 257 ; adventitious shoots 
 of, 197 ; abortive, continued growth 
 of, 196; of Isoetes lacustris, 339; 
 of leafy Jungermannise, 84 ; of Mar- 
 silea pubesceus, formation and struc- 
 ture of, 326 ; of Ophioglossum, 
 Metteuius on, 315; of Pilularia 
 globulifera, and P. minuta, forma- 
 tion of, 322 ; of Salvinia nutans, 
 production of, 329 ; of Selaginella, 
 production of, 392. 
 Prolhallus, universality of, in plants, 
 
 126. 
 Psilotum iriquetrum, growth of stem 
 
 in, 398. 
 Pier is aqtiilina, antheridia of, 187 ; 
 archegonia of, 191 ; development 
 of buds in, 225 ; development 
 of embryo of, 200 ; iirst frond of, 
 208 ; arrangement of fronds in, 
 212 ; production of new fronds in, 
 221; production of fronds in old 
 plants of, 224 ; germination of, 183; 
 growth of stem-bud in, 211 ; creep- 
 ing stem of, 212; structure of stem 
 
 • of, 213. 
 
 Pteris serrulata, antheridia of, 187. 
 Plilidium ciliare, develoi)ment of 
 leaves in, 60 ; ramification of, 64. 
 
 Racomitrium ericoides, pro-embryo of, 
 171 ; terminal bud of, 129. 
 
 Radula complanata, antheridia of, 65, 
 73; archegonium of, 67; calyptra 
 of, 79 ; development of fruit of, 74, 
 77, 78, 82 ; germination of, 55 ; 
 cell-multiplication in germ-plant of, 
 56 ; development of leaves in, 63 ; 
 development of perianth in, 68 ; 
 spores of, 55. 
 
 Eamification in Aneura, 44 ; in Antho- 
 ceros, 2 ; in Equisetacese, 275 ; in 
 Jungermannise, 64 ; Nees von Esen- 
 beck on, 85 ; in Metzgeria furcata, 
 42 ; in Orthotrichum affine, 132 ; in 
 Sphagnum, 137 ; Schimper on, 138. 
 
 Rebouillia hemispherica, antheridia of, 
 122; archegonia, 113; calyptra, 
 113; fruit of, 114 ; development of 
 leaves of, 110; vegetative organs 
 of, 102. 
 
 Receptacles of Marchatitia polymor- 
 phuy air- cavities and stomata of, 
 117. 
 
 Rhizocarpeae, Mettenius and Schlei- 
 den on, 335. 
 
 Rhizome, development of, in Equise- 
 taceae, 304 ; of Equisetum limosum, 
 278. 
 
 Riccia glauca, buds of, 48 ; Schmidel, 
 Hedwig, Bischoff, Linden berg, and 
 TJnger, on the fructification of, 97. 
 
 Riella, antheridia of, 99 ; archegonia 
 of, 99 ; fruit of, 100 ; germinal 
 vesicle of, 100 ; spores of, 100. 
 
 Riella {Duriena) helicophylla, leaf of, 
 98. 
 
 Riella Reuteri, mode of growth of, 
 98 ; leaves of, 98 ; shoots of, 99. 
 
 Roper on the stem and fronds of Bo- 
 trychium, 309, 310, 311, 312; on 
 the exosporium of Isoetes lacustris, 
 338. 
 
 Root-buds in Ophioglossum, 315. 
 
 Rootlets of Metzgeria f areata, 42 ; 
 development of, in Pellia epiphylla, 
 23. 
 
 Roots, adventitious, 203 ; occurrence 
 of in Equisetum, 278 ; production 
 of in Selaginella, 397. 
 
 Roots, of Asjndium filix-mas, 229, 
 243 ; of germ-plants of Botrychium 
 
504 
 
 INDEX. 
 
 Lunaria., 308 ; of ferns, development 
 of, 203, 205 ; Isoetege, A. Braun's 
 observations on, 337 ; of Isoetes la- 
 custris, development of, 348, 356, 
 358, 307 ; of Maratlia ciculcpfolia, 
 development of, 255 ; of Pilularia, 
 production of, 32i; of Platycenum 
 alciconie, 253 ; of Pteris aquiiuia, 
 development of, 210, 223; of Sela- 
 ginella, 383. 
 Rupp, on Marchaniia polymorpha, 123. 
 
 Sachs, on cliloropliyll-bodies, 147. 
 
 Salvinia nutans, embryo of, 332 ; pro- 
 thallium of, 329 ; spores of, 328. 
 
 Sanio, observations on spores of Equi- 
 setaccffi, 28ß ; observations on ab- 
 normal formation of elaters in Equi- 
 setaceae, 291. 
 
 Sarcosci/phus Ftinkii, germination of, 
 54; ramification of protballium of, 
 84. 
 
 Savi, on the fecundation of the macro- 
 spores of Salvinia, 334. 
 
 Scaiariform-cells and vessels of Pteris 
 aquiiina, 219, 220. 
 
 Scales of Aspidium filix-mas, 242 ; of 
 Isoetes laciistris, 346, 363 ; of Ma- 
 ra ttia cicutcpfülia, 255 ; of Nipho- 
 bolus riipestris, and N. splendens, 
 249 ; of Poll/podium vulgare, 251. 
 
 Schacht on Antlioceros, 19; on adventi- 
 tious buds in Botrycliiuu), 310; on 
 the formation of the embryo in Coni- 
 ferae, 428 ; on the pollen of Ephedra, 
 406 ; on the archegonia of ferns, 
 260 ; on the spermatozoids of ferns, 
 199 ; on the development of the 
 spore-mother-cells of ferns, 256 ; on 
 spermatozoids of P^/Zzae/ji/j^^y//«, 31. 
 
 Schimper on the archegonia of mosses, 
 177 ; on the germination of mosses, 
 176; on the spermatozoidsof mosses, 
 177 ; on the antheridia of Sphag- 
 num, 177 ; on pitted cells in Sphag- 
 num, 134 ; on the pro-embryo of 
 Sphagnum, 174 ; on ramification in 
 Sphagnum, 138. 
 
 Schistodega osmundacea, pro-embryo 
 of, 172. 
 
 Schleideri on buds of Aspidium fllix- 
 mas 245 ; on the formation of the 
 embryo in Coniferse, 428 ; on the 
 pro-embryo of Coniferae, 432 ; on 
 the exosporium of Isoetes lacustris, 
 338 ; on the sporangia of Isoetes 
 
 lacustris, 364 ; on the leaves of 
 nios.ses, 147 ; on the spores of 
 Hhizocarpeae, 335 ; on the anthe- 
 ridia of Sphagnum, 155, 177. 
 
 Scbmidel on the elaters of Anenra mid- 
 tijida, 86; on Fegafella conica, 115, 
 123 ; discovery of s[)crmatozoids in 
 Fossombronia pusilla, 87 ; on Mar- 
 ' chantiapolymorpha, 123; on Preissia 
 commutata, 123; on the fructifica- 
 tion of Kiccia, 97- 
 
 Scolopendrium officinarum, Morison's 
 observations on the growth of, from 
 spores, 257. 
 
 Selaginella, germination of, Mettenius 
 on, 337 ; growth of young plants of, 
 396 ; production of spores of, 388. 
 
 Selaginella cordifolia, furcation of 
 stem of, 381. 
 
 Selaginella denticulata, 374. 
 
 Selaginella Galeotfii, furcation of stem 
 of 381 ; growth of 373. 
 
 Selaginella Helvetica, 374 ; free deve- 
 lopment of microspores of 394 ; 
 spermatozoids of 395 ; furcation of 
 stem of, 381 ; formation of sporangia 
 in, 385. 
 
 Selaginella kortensis, growth of, 373 ; 
 macrosporangia of, 387 ; formation 
 of sporangia in, 385 ; furcation of 
 stem of, 381. 
 
 Selagimlla Martensi, 374; marginal 
 papillae of leaves of, 380 ; furcation 
 of stem of, 381. 
 
 Selaginella viticulosa, 374; furcation 
 of stem of, 381. 
 
 Shoots, adventitious, of EquisetaceK, 
 277; half-subterranean iSi Ilaplomi- 
 trium Uookeri, 64 ; of Jungennannia 
 bicuspid at a, 64 ; of Marchantiese, 
 102 ; adventitious, of Metzgeria 
 furcata 42 ; of Pellia epiphylla, 25 ; 
 Riella Reuteri, 99 ; laterals of 
 Sphagnum, 137; of Targioneae, 102. 
 
 Sori of ferns, 256. 
 
 Spach on the pro-embryo of the Coni- 
 ferse, 433. 
 
 Spermatozoids of Archidium, Thuret 
 on, 169; of Equisetaceae, 294 ; de- 
 scribed by Milde, 306 ; of ferns, 
 187—189; discovered by Nägeli, 
 258 ; observations on, by Thuret, 
 259; of Fossombronia pnsilla, 67; 
 discovered by Sclimidel, 87 ; of 
 Frullania dilatata, 67 ; of Funaria 
 }iygrometrica,\h^L; oi Isoetes lacus- 
 
INDEX. 
 
 505 
 
 fris, 3 .12 ; of Jungertnanriise, 67 ; 
 Gottsche on, S7 ; oi Madotheca pla- 
 typhylla, 67 ; of Marchantia poly- 
 morplia, 121 ; first noticed by Uuger, 
 127; Tliuret on, 128; of mosses, 
 Uuger ou, 176 ; Scliimper and 
 Tliuret on, 177 ; of Tellia epiphi/lla, 
 30; observations on, by Scliaclit 
 and Tliuret, 31 ; production of, by 
 small spores of Pilularia, 323 ; ob- 
 served by Nageli, 335 of Poli/tri- 
 chiim formosum, ISi; oi Selagiiella 
 Helcefica, 395 ; of Sphagnum, 155 ; 
 oi Salciiiia nutans, 331. 
 
 Sphagnum, antheridia of, 15-i ; pitted 
 cells of, 13-1 ; development of fruit 
 of, 159 ; development of leaf of, 135 ; 
 ramification of, 137 ; growth of 
 stem of, 129 ; spermatozoids of, 
 185 ; terminal bud of, 129- 
 
 Sphagnum acutifoUum, leaf of, l'±3. 
 
 Sphagnum cusindatum^ pro-embryo of, 
 174. 
 
 Sphagnum cymhifolium, development of 
 fruit of, 159. 
 
 Sphagnum squarrosnm, development of 
 fruit of, 159 ; cells in leaves of, 
 142. 
 
 Sporangia, of Equisetum, formation 
 of, 281 ; of ferns, 256 ; of Isoeiesla- 
 custris, formation of, 364 ; Schleideu 
 on, 364 ; of Pilularia, development 
 of, 318; of Selagiuella, production 
 of, 385 ; views of Bischoff and von 
 Mohl on, 387. 
 
 Spore mother-cells oi Aneura multifida, 
 45; of Authoceros, 14^17; von 
 Mohl on the formation of septa in, 
 16 ; of Blasiapusilla, 82 ; of Equi- 
 setum, 282 ; of ferns, 256 ; of Fos- 
 sombronia picsilla, 82 ; of Frullania 
 dilatata, 81 ; of Isucles lacustris, 
 365 ; of Jungermannia bicuspidala, 
 78, 79, 81; of mosses, 160; of 
 Pellia epiphylla, 38 ; of Pilularia, 
 319 ; of liiccia glauca, 96 ; of 
 Riella, 100; of Targionia hypo- 
 phylla, 120. 
 
 Spores of Anthoceros, 13, 17, disper- 
 sion of, 18 ; of Equisetaceaj, deve- 
 lopment of, 283, 290 ; Sanio's obser- 
 vations on, 286 ; germination of, 
 291; of ferns, 182, 256; of Frul- 
 lania dilatata, germination of, 51 ; 
 of Gymnostomum pyri/orme, 167 ; of 
 Isoeteee, Metteuius on, 337 ; of Jun- 
 
 germannia, von Mohl on the deve- 
 lopment of, 86; observations on 
 the germination of, by Hedwig, 
 Nees von Esenbeck, Bischoff, 
 Gottsche, and Grönland, 83, 84; of 
 Jungermannia bicuspidala, germina- 
 tion of, 52 ; of Marsilea pubescens, 
 germination of, 326 ; of mosses, 
 Hedwig on, 175 ; of Pellia epi- 
 phylla, 21 ; development of, 39 ; 
 their importance in the study of 
 cell-formation, 39 ; irregularities 
 in, 41 ; of Phascum cuspidatnm, 
 164 ; of Pilularia, development of, 
 319; germinationof large, 321; pro- 
 duction of spermatozoids by small, 
 323 ; of Radula complanata, 55 ; 
 of Rhizocarpese, Schleiden's opi- 
 nions on, 335 ; of Riella, 100 ; of 
 Salvinia nutans, 328, 330 ; Met- 
 teuius on, 330 ; production of Sper- 
 matozoids by small, 331 ; of Sela- 
 ginella, production of, 338. 
 
 Stem, of Anthoceros, 3 ; arrangement 
 of cells in, 4 ; of Aspidium filix-mus, 
 227 ; of Blusia pusilla, 47 ; of 
 Equisetacete, growth of, 267 ; of 
 Equiseium, structure of, 271 ; of 
 ferns, growth and bifurcation of, 
 262 — 264 ; Priugsheim and Irmisch 
 on, 26i ; structure of, described by 
 Von Mohl, Brogniart, Stengel, 
 262 ; Karsten and Mettenius, 263 ; 
 of Isoetes lacustris, st ructure of, 356, 
 357; development of, 361 ; of Mar- 
 cliantieae, 110 ; of Orthotrichum 
 affine, 139 ; of Pilularia, 325 ; of 
 Pteris aquilina, growth of, 211 ; 
 cellular hairs of, 212 ; structure of, 
 213 ; of Selagiuella, furcation of, 
 375, 380 ; of Sphagnum, cell-multi- 
 plication in, 130 ; growth of, 129. 
 
 Steiu-bud of Aspidium fiUx-mas, 227 ; 
 of Pteris aquilina, formation of 
 vessels and bast-cells in, 217 
 
 Stengel ou the stems of ferns, 216. 
 
 Stigma, so-called, of Mosses, 151. 
 
 Stipule, of Marattia cicufafoliu, pro- 
 duction of, 254; of Ophiqr/lossum 
 vulgatuni, 313; of Selagiuella, first 
 observed by R. ^liiller, 378. 
 
 Stolons of Nephrolepis, 247. 
 
 Stomata, of Marchantiea;, 110; of 
 the autheridal discs of Marchantia 
 polymorphu, 121 ; of the receptacle 
 of Marchantia poly morpha, 117. 
 
 53 
 
506 
 
 INDEX. 
 
 Struthiopteris germanica, adventitious 
 shoots of, 247 ; vegetation of, 245. 
 
 Suspensor of Conifcra^, Hartig on, 433. 
 
 Sympodium of Fteris aquilina, 224, 
 225. 
 
 Targionia, 102. 
 
 Targionia h_i/popJii/lhi, archegonia of, 
 118 ; calyptra of, 119 ; elaters of, 
 120; fruit of, 119 ; development of 
 leaves of, 110; spore-motlier-cells 
 of, 120; vegetative organs of, 102. 
 
 Taxus, corpuscula of, 410 ; develop- 
 ment of endorsperm of, 409 ; fecun- 
 dation of, 422 ; nucleus in, 400. 
 
 Thuja, corpuscula of, 410 ; develop- 
 ment of endorsperm in, 4]0; nucleus 
 of, 400. 
 
 Thuja occidentalism cell-division in an- 
 thers of, 404. 
 
 Thuja orienfalis, fecundation of, 424. 
 
 Thuret, on the spermatozoids of Arclii- 
 dium, 169 ; observations on the 
 antlieridia of Equisetaceaj, 306 ; on 
 the spermatozoids of ferns, 189, 
 259 ; on Marchantiese and their 
 motile spermatozoids, 128 ; on the 
 spermatozoids of mosses, 177 ; on 
 the spermatozoids of Pellia epi- 
 phylla, 31. 
 
 Trichocolea tomentella, cell-multiplica- 
 tion in stem of, 56. 
 
 Unger, motile spermatozoids first seen 
 in Marchantia by, 127 ; on the 
 spermatozoids of mosses, 176 ; on 
 
 fructification of Riccia, 97 ; on tiic 
 antheridia of Sphagnum; 177. 
 
 Vaginula of mosses, 189. 
 
 Valentine on tlie archegonia of mosses, 
 177 ; on the reproduction of mosses, 
 178. 
 
 Vascular-bundles of the stem of Aspi- 
 diim filix-mas, 228, 229, 230, 231 ; 
 formation of, in stems of Equisetum, 
 273 ; production of, in Isoetes lacus- 
 iris, 352 ; of stem of Niphobolus, 
 251 ; of Ophioglossiim vulgafum, 
 314; of the stem of PlatyceriuM 
 alcicorne, 253 ; of the stem of Foh/- 
 j)odium aureuni and P. viilj/are, 251 ; 
 in the stem of Pleris aquili/ia, 213 ; 
 in the stipes of fronds of Pterin 
 aquilina, 215 ; arrangement of, in 
 frondless slioots of old plants of 
 Pteris aquilina^ 225 ; of Salviniu 
 nutans, 334 ; of stem of Selaginella, 
 382. 
 
 Vaucher, observations on the germina- 
 tion of Equisetacese, 304. 
 
 Vegetation of Isoetes, compared witii 
 that of other vascular cryptogamia, 
 371. 
 
 Vessels, formation of, in stem-bud of 
 Pteris aquilina, 217 ; sealariforni, 
 of Pteris aquilina, 220. 
 
 Wigand, on the growth of the second 
 frond in ferns, 207 ; observations on 
 the impregnation of ferns, 259 ; on 
 the roots of ferns, 203 : on the 
 spermatozoids of ferns, 187. 
 
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