IMAGE EVALUATION TEST TARGET (MT.3) 1.0 I.I 1.25 liilM 1 2.5 li 2.0 1^ ■ 4.0 MUU 1.4 .8 1.6 150mm V & /, *; -^ *^''/ /. ^4r O 7 /IPPLIED^ IIVMGE . Inc ^=: 1653 East Main Street .=^ ^ Rochester, NY 14609 USA .a=-.^ Phone: 716/482-0300 .^S"-^^ Fax: 716/288-5989 <0 1993. Applied Image, Inc., All Rights Reserved a^ ^\' \ \ N tlte provient: □ Title page of issue/ Page de titra dc la livraison D Caption of iuue/ Titre de depart da la livraison I j Masthead/ Generique (piriodiquas) de la livraison 10X 14X 18X 22X 26 X XX J I^X 16X 20X 24X 28X 32X vue The copy filmed hara has baan raproducad thanks to tha ganarosity 9f : Library Agriculture Canada Tha imagas appaaring hara ara tha bast quality possibia considaring tha condition and lagibility of tha original copy and in kaaping with tha filming contract spacificationa. 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Lea cartes, planches, tableaux, etc., pauvent itrm filmte A dee taux de reduction diffirents. Lorsque le document est ttop grand pour dtre reproduit en un seul ciich«, il est film* A partir da I'angle sup*rieur gauche, de gauche i droite. et de heut en bea. an prenant la nombre d'Imegea nicassair* , Las diagrammes suivants illuatrent la m*thode. 1 2X 1 2 3 1 2 3 4 5 6 ELEMENTARY BOTANY GEORGE BELL & SONS LONDON : YORK STREET, COVENT GARrtEN NEW YORK: 66 KIFTH AVEWUK, AND nOMIlAV: .... 53 ESPLANADE ROAD CAMBRIDGE: DEIGHTON HELL AND CO». s ELEMENTARY BOTANY BY PERCY GROOM, M.A. (Cantab, et R^nminerin Botany to the U.uversity of Oxford '"""■"""■ ^''■''^^^^or of Botany at H''^^.:^;:^, WITH 275 IIJ.USTRATrONS Oxon.), F.L.S. and 'fioa (China) TOGKTHER WITH A MANUAL OF TMK MORE COMMON HERBACEOUS PLANTS OF QUEBEC AND ONTARIO. (ADAPIKD KKOM ORaVs MANI-AL.) BY I>. I'. PENHALLOW, B. Sc. TORONTO • 'HK COP.., CXARK COMPANY, LIMITED. All Jin/htH lifisei-rcd. AI'I'ENDfX Entered according to Act of the I'ailianient of Canada in the rlfcr one thousand eitrht hundre' ^"^^ ^" lens should be used to afd the Lt ^ T'^ '"^^Pensive hand, in commencing he s uSv of Xl ^"'' "" ^^^ ^^^er microscope is absolutely needless^.ni ^ If^ '' compound begmners, does more 'hlrm ":'n'"^;,J" %,--^e of young Physiology has been so written^hff nA i. ^t i^^^^°" °" histology of plants is assumed . f . knowledge of the here introduced for the fi^t t^ %l'^ T^^^^ is, I believe, "cram-book" for e ernenfarv l - ^•^°"^'' ^^ "^ means a ledge of the contents of S booTTiT'' K, ^'°^°"^^ ^"°- pass with distinction. '" ''"^hle a candidate to and".^;h':^:JTo"silh^^^^^^^^^^ the observation of facts, no unnecessary tecSaWermlt. ""?"'"' ^ ^^^^ ^^^^^ted of students who afterward use'" 'F^n ' ?%'^' oonvenience appendix for use as a dSionarv h . ' / ^^^^ ^^^ed an elementary study. ^^^^^^"ary, but not for the purpose of VI PREFACE Some words of explanation may be required in reference to the definitions i){ flowers ■w\C^ fruits. In more advanced works we are told that a flower is a collection of sporophylls inserted on a simple axis. This definition seems to me im- perfect. That the young carpels and stamens are homologous with leaves, and particularly with sporophylls, is proved beyond a doubt. But the mature carpel with the ripe ovules is no longer homologous with a sporophyll ; it is a sporophyll containing parasitic and symbiotic gametophytes. The sym- biosis of the gametophytes and the sporophylls before, during, and subsequent to fertilisation constitutes a phenomenon which is unique in the vegetable kingdom. Consequently, it appears that, when judged by the facts of the case and on historical grounds, it is at least incomplete and inexpedient to employ to the cone of Equisetum the same term as to the flower of a Buttercup. A single 'flower of a Buttercup is no more a mere collection of sporophylls than a frog is a fish because it passes through the tadpole stage. In reference to the definition of a fruit, I have followed that given in the "Lehrbuch der Botanik" written by Professors Strasburger, Noll, Schenck, and Schimper. The definition of a fruit is thus brought closer to the popular usage of the term, while we are extricated from any dilemma in reference to distinguishing between an inferior and a false fruit. In conclusion, it should be stated that for the most part the illustrations have, after careful consideration, been specially executed by my friend Mr A. H. Church of Jesus College, Oxford, to whose skill and care I am much indebted. To him, also, I owe a careful revision of the proofs of this book. Further assistance in the matter of illustrations has been rendered by Mr A. Robinson of the University Museum, Oxford. Students who desire a simple introduction to the study of Microscopical Botany are recommended to procure Dr D. H. Scott's "Structural Botany"; while those who wish for a comprehensive work, dealing with the science as a whole, will find all they require in " The Student's Text-book of Botany," by Professor S. H. Vines. Finally, such students as desire to identify wild British plants, and to do field-work, will find Hayward's "Botanist's Pocket Book" an excellent little work which contains all the necessary information, CONTENTS Part I.— General Mc^RpiioLOdv CIIAI'TKK I. INTRODUCTION II. ROOT AND .SHOOT • • , ROOT ^Root's"' ^'"°''' ^-'^^'■''P'' «f K^ots. S-Aerial III. VEGETATIVE SHOOT Adventitious Shoots, II. • ARRANGEMENT OF LEAVES Whorled Leaves. ii-Alternate Leaves, 1 2-Diagrams," F0LIAGE-1.EAVES . Sheath, 15-Stalk I5-BIa Scramblers, 36, ng Plants, 34— Tendrii-Cliii.l jcrs. viii CONTENTS VI. CHAI'TKK SUBSII^IAKV OUTGROWTHS (haIRS, ETC.) METAMORPHOSED SHOOTS . . ' Spines, Thorns, and Prick 1,..; -,'■, t a'-, C:ia(Iodc.s, 38. ' ' 37 -Tendrils, 38— V. LIFE-HISTORY OF FLOWERING l-LANTS ^^Ju.,.eaUon.4.^;,^?^;;;^torv^^ VII. OYMNOSI'ERM.K .-—SCOTCH PINE VIII. INFLORESCENCE . . ' ' ' Racemose Inflorescences ct <\. r n ' ^4-Hracts, 55. ' S'-tj.nose Inflorescences, IX. FLORAL LEAVES PERIANTH . . ' • Calyx. 57-Corolla, s8-Perianth, 60 ANDR(ECIUM GYN/ECIUM " ' ' • 66. ^ ■rt.usence of Stamens or Carpels, X. ARRANC-.EMENT OF THE FLORA!, LEAVES CYCLIC FLOWERS ' ' Branching or Doubli^g.^^^.l^i^y -70"' ''- ACYCLIC AND HEMICYCLIC FLOWERS ' FLORAL DIAGRAMS Estivation, 73-Floral Formula.- and Symbols 7. " SHAPE OF THE RECEPTACLE ' ^^• ilypogynous Flowers, 74-lVriLrvnons vi " Epigynous Flowers. 75-Oth " V ode^ nfT''' ^-^-^ 75— Disk, 76. -nodes of Insertion, XI. NECTARIES POLLINATION ' " ' * ' Insect-: .olhnated Flowers. So-Self-pollination', ll PAGE 36 39 43 47 51 57 57 60 63 67 67 72 72 74 77 77 CONTENTS Jrils, 38 — Life, 39 - Vcjjetaiive Events, 42, riiic, 44 — I'ACE 36 39 43 • , 47 rescences, 51 57 57 -•ciiim, 64 Carpels, 60 Atrophy 1, 69— 67 67 . 72 . 74. 72 -s 75-" sertion, 74 idering . 79— 77 77 CHAI'. X". OVUI.L , «2 FKkTII.|.s.\Tf(.\ AVI) r-irvvrr... FKLIT fHA.VOKS ,.V ti.K „vulK Cla.s.sincati,.n of .Sininle Fruits So "r 94-Con,pletc l-ruits' 94 ' ^'-^-Conipoim.l Fniits, XIII. IMSI-KK.SAL OF SEEDS AND SEEDS . ^ '^•■'. i-KLlis, ' • . Part II.-C,.a.ssikicat.on of Angiospickms dicotyledons ""iSl^iilMaS-Ji^l"""^-. .07-Salionc.., ,„_ ['"i.vinTAr.K, iiS-Raminailacc^ iiS r. ;3;-i.,,.„a4i^?3,XS;',^SiS Composite', 161. ^ '-'ipntolmcoa', i59-_ MONOCOTYLEDONS. Liliacciv, 169— Amaryllklacecp i-rri^i ■ i ' /o ^racuL, 170— Craminacca', 181. Part HI.— Physiology XV NUTRITION OF THE PLANT Chemical Composition of a Phnf iSo n the Air and Soil rnn \ ."r'- , ^-Composition of 191-ManufLr ue' of^?, Jani'^A"' Culture-soiutions. or urganie Compounds, 192. iX I'Acii-: .S4 «7 95 58 103 107 i6y 189 CONTENTS CHAP. XVI. ARSORPTION OF CARBONIC ACID . Influence of Temperature, 194— Influence of Lifrht, 104 — Chlorophyll, 194. ^^ XVII. ASSIMILATION OF CARBON Proteids, 196— Carbohydrates, i97_Fats, 197— Forma- tion of Starch, 198— Entrance of Carbonic Acid, 199 ~^/^?"^Pa''ts not producing Starch, 200— Why Light IS Essential, 200— Transport of Carbohydrates 200— Starch, Sugar, Fats, as Food-substances, 201— Nutrition of Plants devoid of Chlorophyll, 202. XVIII. XIX. TRANSPIRATION Measurement of Transpiration, 209— Leaves as Tran- spiring Organs, 210— Conditions influencing Tran- spiration, 210— Function of Transpiration, 2U. EXCRETION OF LIQUID WATER ROOT-PRESSURE . CAUSE OF ASCENT OF WATER • " • XX. RESPIRATION Oxygen essential to Flowering Plants, 217— Conditions affecting Respiration, 217— -Liberation of Heat during Respiration, 218. XXI. GROWTH ... Essential Conditions, 219— Growth in Length, 220— Rate of Growth in Length, 220— Influence of Tem- perature, 220— Influence of Water-supply, 220— Influence of Light, 221— Nutation, 221— Direction of Growth in Length, 221— Heliotropism, 221— Geotropism, 222— Hydrotropism, 222. XXII. IRRITABILITY AND MOVEMENTS OF LIVING PARTS. Periodic Movements, 224 — Irritability of Moving Organs, 226. APPENDIX . . • • • a INDEX . . PAOE 196 203 ABSORPTION OF WATER AND INORGANIC SALTS Absorbing Functions of Roots, 203— Influence of Exter- nal Conditions, 204— Essential Chemical Elements and their Absorption, 205. ASCENT OF WATER AND SALTS . , .206 209 212 213 214 219 224 229 -39 PAGE . 196 203 206 209 212 213 214 PART f GENERAL MORPffOLGGV 219 224 229 ^39 ELEMENTARY BOTANY CHAPTER I INTRODUCTION ^^d"^:^. ^^L^S&^r r '^ -yarded sidered as a liv ng machine desi?.lS.' ^^''"^ "^^y be con- and consisting of definite narts" ^''"""''^ "^^'^^in work there is allotted a pa?t cular offi?/'''^^^?'' '° """^ °^ ^'^ich definition we naturally injure hoZZ/7f''\ ^^''' '^^' and multiplies. ^Ve then Islnr.? i ^ f '^ ^'''^'' ^^^^S' S^ows, by the various organs such ^^^^^^^^ This aspect of botany is termed pL^f'' ''"'"'' ^nd roots, look at a plant simp"y as a ZcL^^ •°^-^- "^^^in, we may or .W.i, which I^re^Lngedln a naS,"^ °';'"°"^ P^^^' certain shapes. In fact vve lenrn^fK ^' ''''^^' ^nd have plant without taking 'Sic %f"Lworr it T '' '''' department of botany is termed MomiTJ? " ^°'''' I'^^^s this point of view we find VhlT i ^^^^^}'>Sy. Studied from and differences frim one anothef^F^^^^ resemblances t^ very unlike a Mushroom and vet hlZ '" '"n^' ''•^^''" '""""^ neither of them possesse flot Jr' On the nl^' I," 'S ^'' ^« of Grass and a Buttercup are wMelv HJf^ l^-' ^^"^' ^ tuft but at the same time they resemb]; t^l '" .^PPearance, hey both produce true se'eds f^m floTers Th ""°""^^ ^^ ikeness and unlikeness amon^ nkntr In i' ^^'^ P°'"^^ ^^ latter into groups. This grounL^. ? t"^."' *° ^""^ange the and constitutesVstemalc Bow Fn '^ '' Classification, let us be content to divide S; -^"^ °"'* Present purpose, namely, ^/.z,.^,>,^. ^/^,^;^e two great classes-! first group are includTah ImTw^tT?'^ ^''"f • ^" '^^ flowers, whether they have s ovvv Tu ^""^^ seed-producing 2 INTRODUCTION them are the Ferns, Mosses, Seaweeds, and Fungi. In this book we treat only of flowering plants, so far as they can be studied with the naked eye aided by a simple lens. Method of using this book. — This book is divided into three Parts: — Part I. relating to General Morphology (and including a special chapter on the Scotch Pine); Part II. referring to the Classification of Angiosperms ; and Part III. relating to the Physiology of plants. Beginners should first read chapters ii. to v. in Part I., and should practically examine the roots, stems, and leaves described. They may then pass on . to the study of Physi- ology contained in Part III. (chapters xv. to xxii.) ; or they may read the remaining chapters of Part I. (omitting that which relates to the Scotch Pine), at the same time studying the ft^milies specially marked at the commence- ment of Part II. (chapter xiv.). In this book the char- acters of each family are denoted by a description of one or more representatives which are types of that family. While a student is reading the description of one of these types, he must have before him a specimen of the plant described, so that he can constantly examine and refer to it. Should any point in the description be beyond the compre- hension of the learner, reference should be made to the teacher or, by means of the index, to the explanations given in Part I. The families should not be studied in the exact order in which they are placed in the book : the season of the year and other considerations will determine the order in which the types are to be examined. As examples of flowers appropriate for beginners we may mention the Buttercup, Poppy, Wallflower, Pea, Rose, Primrose, Dead Nettle, Hyacinth, and Daffodil. In beginning the study of the types for the first time, students should entirely ignore, and omit to read, the characters given at the commencement of the description of each family. If the beginner has studied the systematic portion of the book thus outlined before working at the Physiology, he should then pass on to Part III. Finally, when the student has acted as previously advised, the whole of Part I. should be read over again : and the remaining types and families in Part II. might also be dealt with. J igi. In this they can be s. divided into hology (and i); Part II. nd Part III. in Part I., >, and leaves iy of Physi- ) xxii.) ; or I. (omitting : same time commence- )k the char- tion of one that family. >ne of these 3f the plant I refer to it. the compre- lade to the ations given in the exact le season of the order in ;s of flowers ; Buttercup, ead Nettle, of the types e, and omit ment of the rtion of the Physiology, jsly advised, n : and the Iso be dealt CHAPTER II THE DISTINCTION OF A PLOWERINa PLANT INTO ROOT AND SHOOT ^pJL SJi^^i^^f^-^t ordinary flowering plant together compose the shoot .tlf' ^"^ ^^^^'^''^ ^^ the visible and above ground %^f°^^-^y^^^^, and are generallv ally embedded in^the "oil ' whi tTonr^ ^''T ''' '-^^^^' above the ground on sub aiial ^^t °^^^^^^^ ^^""d raised cannot define a root as beini ^ h u^^ P^^"^- Hence we plant nor the shoot as beShe suh^ "T^^" P^^^ of the herefore, be well to consider firs^vh;"^^ P^^'^^on. It will, "root " and "shoot." Fo/ . h . ' ''^ "^"'^" ^y '^^ term bean may be examined The '/wi"^'"'" '^^ ^^^^dling of a axis which bears certSn structures 2 ?""^^^ ^^ ^ "^-n on Its sides. The ascendi^J nnrtrnn^^^^^ members- which possesses the flattre'd ^wJl ^ ^^'' ^•"'"^ '' the stem At the tip of the stem theleave ar?' ^^"!, ^""'''^^ "^^mbeS I bud The main stem n'v also n "?^'^"? ^^S^ther to form branches-which are like tself Tr^^^""" ^^'^'"^^ stems-th^ I'"'" ocoiyl{/ip), which connects the root and stem. The tip of the young root lies close within the pore of the testa. No lateral roots occur on the radicle at this stage. The main body of the embryo is constituted of the two large fleshy leaves — the cotyledons {cot), which are attached to that Fig. I. — Seed of Be.in. Fig. 2. — Knibryo of Hcaii, with Cotyledons separated. portion of the axis which is termed the hypocotyl. Lying hidden between the two cotyledons is the minute main stem, which terminates in a small bud. Thus, beginning at the root, the axis has no lateral members on its root-portion : above succeeds the hypocotyl* with two lateral cotyledons : still higher the axis represents the young main stem, and bears a few lateral commencements of leaves. When the seed germinates, the various parts of the embryo emerge. The radicle elongates and becomes the primary root : it grows downwards and produces lateral roots which may branch in their turn. The little stem grows upwards and sends out from its sides, leaves, branches, and flowers; its branches may in turn bear, not only leaves, but also branches of their own. We thus see that the development of this flowering plant from its embryo consists in the elongation of its primary axis, and the production of lateral members on that axis. The parts possessed by a mature flowering plant, whether it be a large tree or a small herb, are all to be traced back to the primary axis. * It is impossible to define exactly the limits of the hypocotyl unless the compound microscope be employed. ) (fig. 2) has e primary or m (//) ; and the root and lin the pore at this stage, "le two large :hed to that with otyl. Lying : main stem, 5 at the root, tion : above ledons : still and bears a ' the embryo the primary roots which Dws upwards and flowers; es, but also development isists in the on of lateral jy a mature small herb, y'pocotyl unless ROOT "^Ve can now define a root and a shoot ^ c/ • w/ii,/i bears lateral memher, 7i. 7 .- '^'"' '' «^' "^^'^ A Stan together withUsZ:;',^^ '' ^'^^^^ termmates in a bud ■JdZ.Tf 1 " '''''''^' ^ ^^oot of the plant: at least parts of T^ '''" ascending portion „. the shoot bears the flowers ^ ^'^^^'^^'^^^^y green. Lastly, I produce leaves as ialZ inerlTol' it%r' '"'''' ^^«^^ I does not terminate in a iZ* A "L f ^" T''^"'"^^y 't 3 lateral members branches like itsdf- '^"^^' ^""^^""^ ^« descending axis, and has no ^^^luring^t^ " '' ^ THE ROOT. ^^^^^^^t^^Z ^-le contain- 'n fig. 3, when once thr roo? h? ' '" "^^^ '"^""^''- ^^own stmight,wecanfollov^hemXdof;ro:^^^^^^ ^^ ^-^^' n In2 ^'^' " ""'^'^^^ °f transverse marls" ^^^°"^P'^«h A short distance behind its anex /fin- . \ .u a broad encircling band of finp «^r ^ ?" ^ ''''^ ^^^ ^^^^ has As the root grows at il. ni ^^^ hairs-root-hairs (rk) behind thetir^ictffco^ "rjr'"" '°T ^°-^-'^y hat the youngest roo -hairs Ire fhn« "" '^^'"'^^ ^^^^^'•d, so hairs live for a short imeonlv for th ' ''""''' '^^. '^P' Th^se It has a root-cap, which is not possessed by a stem. F'g. 3. 6 ROOT apex than the last-formed lateral roots ; so that the youngest and smallest of them are seen to be nearest to the tip of the main root (fig. 4). The lateral roots are therefore said to arise iti acropetal succession. They do not appear at indifferent points ; on the contrary, they emerge only on certain determined sides of the main root, so as to form regular ranks or lows along the length of the latter. For Fig. 4. — Development of a typical Dicotyledon. example, the branches of a Wallflower-root form two rows, while those of the Creeping Buttercup-root are ranged in four rows.* Adventitious Roots.— Lateral roots frequently arise on stems — for instance, on the creeping stems of the Strawberry (fig. 54), Creeping Buttercup, and Grasses ; or on the under- ground parts of the stem of the Primrose or on "Cuttings." Inasmuch as these roots do not arise in the normal method — * One important character concerning the origin of lateral roots is that they arise as internal growths, which push their way through the rind of the mother-root, and eventually reach the soil. They are said to be endogenous (arising within) in origin. he youngest ) the tip of i^refore said : appear at ^e only on as to form latter. For I two rows, ranged in ise on stems Strawberry the under- " Cuttings." .1 method — II roots is that ;h the rind of re said to be ROOT tiousand normal lateral rootVi. u if •^f'' ^^^^^■*'^^" ^^^'^'»ti- the root-system ofZfoS' n 1 f'""''^ '^>' considering fhe general characterisS o a J Wvf r''''''t''^^^'^- ^"^' °f ^" the seed has two cotyledon?/ 'J '' '^'^' ''' ^^^'^yo Frequently the root-^ysten? of dTco vf ' l ^'" •' ?^^^^' ^ak). the manner described^as occurrtrt ^^ i' ^^'"^^"^ ^^'^' Illustrated by fig. . Tl e emhr .^ r ^\% ^''^"' ^"^ well ^____^_^J^J^^jmhryoof a Monocotyledon, on Fig. 5--DeveiopmeT;;?r;;;;i;in^j;;;^^;;^^ ledon develops in Imannpr •'^f^^"i- °^ ^ Monocoty! pursued by the Bean The ' '"'^ ^'^^'^''' ^'^^ that embryo g/ows for a 'shoTt tinro^n^"'';^ ^°°' ^«) «f the most few lateral roots, eventualv ^h^ fv^ ^'^^""^^ ^^ ^he or later, lateral roots ariLsucceL^^^^^^^^^^^ "^^ ^"'' '''°"'' on the hypocotyl (a), then on ^1^-^^^^^"^ '^^ ''^"^' ^^'^ '" fig- 5. Consequently in f,% "" ^"^^T"'^ ^"^ ^^"^^^d practically the whol? ro<^l^yZrnt^T'' -Monocotyledons >s no main-root with branches It ^t^^^^^^ous^ and there pulled the base of the sCt' dU ^^ fhe^S^] ^°"^ ^^^^ 8 ROOT Shapes of Bdots. — The roots may be thin and fibrous^ or they may present various forms between this and a swollen or tuberous condition. The main root of the Carrot and Turnip, thickens and forms the swollen part which we eat. The Dahlia-plant produces a number of adventitious tuberous roots, which grow out from the base of the stem. As will be shown later on, tnese thick fleshy roots serve as reservoirs in which food is stored for future consumption by the plant. Aerial Boots. — Some plants, like the Ivy, climb by means of adventitious roots which, in place of dipping down into the soil, adhere to the surface of a tree, wall, or rock. Roots above the surface of the soil are described as being aerial roots. CHAPTER m VEOETATIVE SHOOT-LEAVES are packfd close toge'hebu'S K"'""^' ^"<'- •^' n-"h''y elongates they become separa ed bv dt?'?"' ''"'■' "^ ""•• ^'■-™ latter (figs. 6-11) Thi,« th . ^ diitinct intervals aloni; the n-resl L tip, Ld' h': o deHaris'l' .°' ' ''"'^^ »'™ '^ nearest its base. P"" '^ ">at portion which is ^^f^^^tt::::::^:^:^^^^ bud or a bud are inserted lower down the stlltu "^"'"/"^^ ^^'^^'^''^ ^^ ^'^-^ and are larger than the Ta ter and Th. ' '^' ^"^'""^^^ ^''^^^<'^«. smallest, and are inserted "eare^fhet J" "J^^'i""''''^ ^'^ ^^e i hus /eaves arise* only in ^^ wi, !/2"^^ ^""^ °^ ^^e stem. one which is nearest the end of fh '. >'°""g^-'^t leaf is the •stem elongates, the lea es afe so t?'""^" i t ^^^ ^'P ^^ ^he points, whicrarrterm:?:^, r^^^^ '^ ^'^ ^^- ^^t certain , are separated by portions nftl , . I''''"*^ ^f attachment are devoid of iervefbut connect'Th"''*^^ ^ I figs. 4, 5). ""^ connect the successive nodes (see I -4-tJr Sigir " "^'^'"^^ '"-P^ - the side of the stem, and are thus 10 VE ..TATIVE SHOOT If the young part iA .i shoot Ik- examined, it will he found §mt m the an^le between the lapper face of each leaf and Wu tiU:ui\ ^here is a bud (fig. 3 /;). This angle is described as the axt/ tiif the leaf. Thus we may say that a lateral bud* arises on a stem in the axil of every leaf These buds are the beginnings of the lateral shoots or branches, and can develoi) into shoots (lig. 3 ii.). ^^'c see, therefore, that lateral shoots arise in the axils of leaves— in other words, the b ranching of the 1 .1 7 Figs. 6-11.— Development of bud of Hazel. (After Dennert.) shoot ts axillary. A shoot possessing an unbranched .t^m is described as sini/>le (figs. 3, 4, the two left-hand drawing-?), hvt when the stem is branched, the shoot is said to be ov^^j'ouf.i/ (figs. 3, 4, the right-hand drawing). Normal buds, then, are terminal or axillary. A bud does not necessarily develop at once into a branch. It may remain ■.; a resting or dormant condition, and is then descri'oe( •.:; a resting-bud, to distinguish it from an active bud. * The bud i;,;- irt: jo an exter,/ : outgrowth of the stem ; it is exogenous. nil l)c found icli Iciif and (Icsrrihfd as lateral bud* l)iul.s arc the can develop iteral shoots nchingofthe rt.) bed ;-:tenri is iwina;«i), 1)ut: •e . oy:j'vund K bud does It may d is then I an active t IS exogenous. LEAVES Adventitious Shoots -I af..rni ^ " flowenng plants in ,,laccs o h , r Th T'' "^''>' ''''^'^ "" some ^^hoots are said to Le '^^vv L./" f "^ "' ^''''■'^- '^"< ^ shoots may burst out fn,ni 1^^^ ;on ° /T''^'^' ^^'^'^'"^'''"^nis Ha;cels, and raise themseh v. .h ."^ ^'^M^r^, Rose-trees Agam, .-Klveniftious shm^K , '•' ^''^' •'^"'•'"^^'^' of the soil' ^;an.leiion-roots, ^/t^ K.^lJ^T^, ^^ -^ t>aKn;:i.t:^ produce .uttings. \N-i,,„ om .1 7 ^'"^'^^^'^' ^"^^n to ^^'^ler parts of tree-trunl. H ^ branches shoot out from -f their appearance s^^relVT °^'^'"/^i"-y bra.u'lr of restmg-buds which vere L^",'' ^" ^'^^, '^"^d^'n ac:tiv^y he case of AViiJow-trees from uh; 1 ^T'"" ^'^■^"'•^- J^ut in '^^^-■n lopped, many emire v^ie v I . "'," l'^'^'''' '^^oots have upper part of the trunk Th ''"''■''' ^"^'^ ''^''^^^ on the which are adventitious, becLse'th^'""' °"^ ^" ^^"""^ '""^ c es velopment of restirig ^xillarv burk'^ 't' ""/ ^'"^' ^^ ^he Je- adventttious branching the sLot. /" .^" ^'^^'^^ ^^^es of leaves, and therefore fre shoots ^ ""^"'"^ ^""^' "^'^'"^^ and ARRANGEMENT OF THE LEAVES fhes;;J:rrsZ^;&:^^:;[;-^-/^hestem. On eaves are inserted I the same tvlf^c:,?' '''"'?"^'^> "° ^-o Js, there is only one leaf nf . " ^ ^'"^Pl^' stem— that ;"ent is descriLd as ate'nate n"°>" ^h is leaf-arrange --'■f'-). On other stem Z ^or Ir/f '^ ^^'"' ^^ '^^W -^He collection o/^^^av^^^tl/Lr:^, (^^-^ angular distance^": '"""'1 ^" ^^^ I waj" hat^'tj ^^'-e. Thus, lY tlte b^ uvo \ '"" ^'^^^-^ '^'-esis he '"Sorted on the opposite s des ST. "' '^''^ ^"^^^^ they Ire and south sides), as in the rl i "^^ '^"^"^ ^"^y the nonh Nettle; if there be fou Tea^^s ^^^^ ^^^' 43)^"^ Dead our po,,,3 ,f , compaL s'v yhey ^^-"ged like the • ^^-Ieavesatanod,each^^3epar.eJ^,;:^iJ^„^^^^ 12 LEAVES by one-third of the circumference. The relative disposi- tion of the leaves at the different nodes is equally regular. In some cases the leaves at the successive nodes are exactly above one another (superposed), so that there are just as many rows of leaves along the stem (longitudinal rows) as there are leaves at each node — for instance, there will be two longitudinal rows of leaves if there are two leaves at each node. But on other stems with whorled leaves, the leaves at one node stand above the gaps midway between the leaves of the next lower or next higher node ; thus the leaves at the successive nodes exactly alternate with one another. Consequently, the leaves of every second node will stand above one another. In this case there will be exactly twice as many longitudinal rows of leaves as there are leaves at a single node. For example, the Dead Nettle, the Chickweed (fig. 43), have two leaves at each node, but those at the successive nodes alternate so that there are four rows along the stems. Alternate or Spiral (Acyclic) Leaves. — When only one leaf stands at each node (fig. 12), the leaves are arranged in spirals, and not in circles or whorls. They form rows, and are ranged one above the other along the stem, as is the case with whorled leaves. Each leaf is separated from the one at the next node, either below or Fig. 12.— Erect shoot of Hazel with J leaf- above it, not Only by a vari- arrangcment. (After Dennert.) ,. ' i /i 4. „ ^ able distance along the stem, but also by a certain invariable angular distance round the stem. For example, on Grass-stems and most Hazel-stems 3 LEAVES is attached ; cinseaulntlv i L ^ '^^ ^ff ^' ''^^ "^^^ node stem (as we 1 argoSe^ Z!^" ? ''T'^ ^'^f'^'^y ^°""d the at the next h4er node thi H '' '° '"^'^ '^"^ ^"^S^^ leaf is described a beL? i ' A.l 7""^^'"' V ^^^^^^'^ ^^^^^^^^^ we have to travT^one-tl^rd of ^h'"""' ^^^^'^^^oots (fig. X2 passing from one lelf to t - ^^ ^^ '""""^ ^^^ '^'™ ^" the divergence s safd to b .P^^^.^^^^^ ^' ^"^?"°^' ^"^ Red Currant, Pear, ^^^ !.u£\^,T'^Jt,^^ ^r f:?r s^i j5i^^ ^ " t^ar a;: gence, the leaves are ranged inTu' ^""'"^-'^^^l' ^^ith ^- diver- with -I divergent L?hfer rn ^ '°''^^' '" ^^^ ^azel-shoots clivergince, inTv^V.l^'^^L^ hLTcfst^T' ^^^:' '''''' ^ the fraction denotes the nunTir of f "--f H- ^ denominator of And the numerator of the frnrH ^°"Situdmal rows of leaves. times it is necessary to tavelro^^^^^^ thf:?"''- ''' """^^^^ °^ one leaf on a stem to thr. . -^^"^"^ ^" passing from same time touTng'^lf'^^HrSv^ror/h^t-'ilirhj;' "t^ gives us an easy method for determin^nr^h ?^'' arrangement of a shoot. The commonest ^ ""''"' "''^' sented by the fractions i- l^l^ T^ "'T^'^"'^^^^^ ^^^P'"'^' remembered with ease if ^vo no£ that' ^' ''^"''' "^^^ ^^ I + 2_ 3 2 + 3+5 «' 5+« 13' tree, or to remember thnf, hi i the. cone of a Pine- step's of a spMsT^rcase "'™' "''= *^'*""^d "1"= *e the'^SS^V^Z^'l^^ir* "r^^"'''"'--^^^ -" denote or map, represent a J de view oT^'? °" T'^'*. ''>' ^ '"'•"' 14 FOLIAGE-LEAVES on the top of the stem. We then draw a plan such as would be seen in cutting across a bud, the outermost leaves being those which are inserted at the lowest level, and the innermost leaves being those which are nearest the apex. Thus the diagram represents a sort of ground plan of the leaves and Fig. 13. Fig. 14. Stem. Figs. 13, 14, 15, 16, will explain this second method of representing leaf-arrangement by diagrams. Fig. 13 represents whorled arrangement with two leaves in each whorl. Figs. 14, 15, 16, are diagrams of spirally-placed leaves with divergences of },, J, and f respectively. FOLIAGE-LEAVES. A complete type of green leaf (fig. 17) consists of three parts : (i.) a flattened green If/ade or Imnitia (s/>), which is the most conspicuous portion of the leaf; (ii.) a narrow, elongated sfa/A or Jietto/e {st), which connects the blade with (iii.) the h as would saves being 3 innermost Thus the leaves and nd method Fig. 13 each whorl, leaves with ts of three hich is the ?•, elongated h (iii.) the FOLIAGE-LEAVES outgrowths known as the ./^tl" (J^f'^^'^'^^' ^'''' ''''^ ^^^^ral (i.) THE SHEATH. cup";c:*Vol;al:n^^^ ^T^°P^^ (-'^- ^utter- guishable. ^ P^' ^"^ frequently it is not distin- JpTed^^^siot^^thf ^^^^^^^^^ ^orm of two ^^ngle leaf. A leaf possessing stipules t "^ "'" ^''''' "^" ^ 0;scnbed as .//>/«/,; ^ leaf devoid of sttpules .s said to be .x.//>,,/«/,. °Mo?t , frequently the stipules afe small and serve merely to protect the yo"mg ' 0"^ ing leaves of a bud : in which cal^ hlv %f^ (^--- Pear) or shrivel as thev unfold from the bud. But the stipules persist as long as the leaf -blade— , f^f- Hawthorn (fig. 58 .,), Pea (fig cf,,) ■ Violet. In the rhubarb-family, the two ^ stipules of each leaf are replaced b a . membranous pipe embracing that Lt ;: of the stem which is near the^eaf ^ t .hi^u l^l"" S'-ass has a long tubular i sheath which surrounds the stem but I IS usually split down one side The lea J possesses no stalk, so that the sheith i. I stands out from the^ up^er faH'ThrLaf ^^^^^'^^^ ''^'^''^ 1 ("•) STALK OR PETIOLE. ' in ''Ji*ht::thV'leafT -JS f V' ™^^ ^= -''-'y ''bsen, I ^talk is attached 'o one end of ."hi'h/r*- «••'"<■•"% "« J to the lou-cr face of tlL hminV t- jt' """^y "' ''^ fi^tcl ■■ (™™.on.y, though intrS^t^^^^iVj^Lfut;?"^'^"'- (.Vfter Deimert.) i6 FOLIAGE-LEAVES (iii.) BLADE or LAMINA. The blades of foliage-leaves exhibit great diversities of form and size. In form the lamina is usually a flat expanded plate or ribbon-like structure ; but it exhibits all variations from the narrow needle of the Scotch Pine to the circular disk of Tropccolum. Its apex may be drawn out into a fine point or end bluntly, or even terminate in an indentation. The martjfin is even {entire) or uneven (toothed, saw-like, scalloped, etc.). Venation of the Lamina.— The substance of the blade is traversed by veins or nerves which frequently stand out more or less prominently. ■ ^ The arrangement of the veins h may be grouped under two 3 general headings — (\.) paral- i. kl-veining; (n.) net-like vein- ing. In parallel-veined leaves a number of veins, approxi- mately equal in size, run side by side from the base of the lamina towards its tip. The veins are more or less parallel, and are connected by a limited number of smaller ones which join them at right angles. This type of venation is characteristic of Grasses, Lilies, and most other Monocotyledons. In net-veined leaves the finer veins are numerous, and form a complicated network (fig. i8). Most Dicotyledons have net-veined leaves. There are two sub-types of net-like venation— //«//a/^ and pa/mate veining. A lamina which is p innately -veined (feather-veined) has a single main vein— the mid-rib — which traverses the centre of the blade, running from the base towards the apex ; this mid-rib gives off from its two sides smaller veins, which are arranged much like the pinnce of a feather— r.^,". Hazel (fig. 1 8), Pear, Primrose. A palmately-veined leaf, in place of possessing a Fig. i8, —Venation of Hazel leaf. (After Dennert.) ties of form id plate or ns from the liar disk of I fine point ition. The (entire) or i, saw-like, .e Lamina. — F the blade is ns or nerves y stand out prominently, t of the veins 1 under two s — (i.) paral- net-like vein- veined leaves ins, approxi- size, run side i base of the its tip. The r less parallel, id by a limited er ones which right angles, s, Lilies, and ves the finer v'ork (fig. 1 8). here are two mate veining. .) has a single :entre of the this mid-rib are arranged fig. 1 8), Pear, possessing a FOLIAGE-LEAVES , single mid-rib, has several lar^e main v.>,-nc i • , ^• various directions from the base ofhT ''' '''^''''" '" margins-^.^^ Mallow. ^ '''"'"''^ towards its Division 'of the Lamina.— The form of fi. i • very simple, because all the spaces be ween I "^ "^""^ ^' pletely occupied by leaf-sub tani-l^"^^^^^^ "^7 ^'^^^r' however, inc sions of mncVi io ^;<'>- •^, <-ar, Hazel. Often, margin, 'thus te„"din/ o co^tate iff '""^^ /T "'^ and to split it into snVilIm- „,l, • -^ ^ ^°™ °' *e lamina the leaf 'is dividS^oti'^'arjaril'^f'''-^^"" '" ''"'''' .arge nerves, the leaf i^Tairt^' V."^;^"'(4:. X^^fJ^. Figs. T9..3.-Div;sion of pinnately-veined lamina. lirrS^tif't^olSfe'r Irt'T,-''^ --" *e exist a number of disunS felar /I TT' ^"^ "lere as expound (f,s. .^^^^'k^:^ l^ ^ 5,)f 0*^^ 24 25 26 Figs. 24-27.-Divis!on of palmately-veined lamina. a^"cLvrr™^,i:::;°t'] °f ^ t\ °' ^'-'"« -«ets not term it a b mch a'l'n t '"^^^k'^d «hy should we Several reasons .™ gi vl nS s'irv 't ''f "' ^ '''''''■ 1-und leaf, a single lea^ and is noVa branch " "' ' '°"'- B 1 8 SIMPLIFIED LEAVES i (i) It does not arise in the axil of a leaf; on the contrary, it has a bud in its axil. (2) Often it possesses two stipules at the base of its stalk —e.g. Rose, Pea (fig. 59 «). (3) The leaflets do not necessarily arise in acropetal succes- sion on the stalk of the compound leaf, neither does the latter terminate in a bud. (4) The leaflets have no buds in their axils. (5) A leaf is always lateral on an axis, but a leaflet may be terminal on a leaf-stalk — e.g. Rose. When the leaflets are ranged along the sides of an elongated stalk, the leaf is said to be pinnately-compoutid (flg, 23)— f.^JT- Rose, Pea. On the other hand, when the leaflets spring from a single point at the summit of the stalk, the leaf is digitate (fig. 2'])— e.g. Clover and Strawberry, with three leaflet's (fig. 54), Horse-chestnut with about seven SIMPLIFIED LEAVES. Some leaves are much simpler than the green foliage-leaves. They may be described as simplified leaves, and be arranged under four heads: Scales, Cotyledons, Frophyils, and Bracts. Usually they are not differentiated into .sheath, stalk, and blade: frequently they represent merely parts of complete leaves. SCALES. Scales are small, simple leaves, usually with even (entire) margins. They possess little or no green colouring-matter, but are brownish or pale in colour. They are without stalks, and are attached to the stem by a relatively broad base. Scales occur upon parts of the stem which are above ground in the form of biid-scahs, as in the Hazel and Oak, or quite apart from the buds, as in the Scotch Pine and Asparagus. But they are also present on subterranean stems, as in the Hyacinth, some Grasses, and Potato-tubers. Scales are therefore not defined by their position on the stem. A scale may represent the persistent base of a foliage-leaf, the upper portion of which has died away (as in some bulbs) ; in other cases the scales may be arranged in pairs, and are merely the stipules of leaves the blades of . 'hich never develop (as in the resting-buds of the Hazel) ; finally, some scales represent complete leaves (as in the bulla of a Lily). n the contrary, se of its stalk ropetal succes- ither does the a leaflet may sides of an lately-compound ind, when the it of the stalk, trawberry, with about seven 1 foliage-leaves, id be arranged '!y, and Bracts. talk, and blade; ite leaves. h even (entire) ring-matter, but lout stalks, and i base. Scales J ground in the juite apart from But they are Hyacinth, some ore not defined y represent the on of which has the scales may es of leaves the ing-buds of the te leaves (as in SIMPLIFIED LEAVES 19 COTYLEDONS. I^roduceJ foliage-leaves. TW tt [ "^ '^" subsequently the cotyledons. fFrecmentlv fh I'ff ^'^" ^"°^vn as seed-leaves, becausithT rre^ound "^^^^^^^^^^ "^^' ^^^"^ed this expression seed-leavx^Ts I barf T'^"^ " '''^- ^^' to suggest that the seed bJars rnH 1 S '' ^'T''''' '' ^eems the stem of the embryo ns.^eThf . "/' ^'^^'^'^'^ ^' ^' ^o belong. Cotyledons are sZle l,^ '^'"^ '^^^ ^^^'^ ^^^^ves devoid of any incisions • o,"^''"-'' T^'^^y ^^th margins stipules or definite ^eklhrthou^ '"''^^- ^° '^^y P««'^ss diHtmct stalks. When the occasionally they have ^eed germinates the cotyle- dons may remain hidden in the soil, ,n which case thev are not green in colour-^ . IJean ; but in other cases the cotyledons emerge (fiff .) from the soil and become r Ea7d?^- '^^^^' ^^— ' Opposed to the Dicotyle- dons are Monocotyledons - • Monocotyledonous emb^o ^ "P""'' "' ^mining a .sho:™rM*«[^„ of Wheat <«& ^«).-A,s wi„ be with a single /eefThferXie, "t he " ff' ^"'.'■^ ^ f"^' rhe gra,n is smooth and con ' " ^ """"y- deeply furrowed down Tl e mWdk T ,^*' ■?"" ''''I'-'' ^"d mam mass is formed b^^ . k ? °'^ *"-' o'l'^'r side. Its «• The emb'o k a'small bSdv' T'f '^'^ ""'-Am ,;? ^L:rLrrz3« ?- --" -^e -.cates the position oHL^X;^ ^.-JXt "^ Fig. .8.-Vertical section through a gram of Wheat. 20 SIMPLIFIED LEAVES 4 ir !! complicated in form. The r 'ot-system consists of a short primary root (r), with a peculiar sheath, and several small lateral roots. l"hc axis (/>/) above the primary root bears a number of alternate sheathing-leaves. But one character- istic feature of the embryo of this and other grasses is that, attached to the hypocotyl, is a shield-like outgrowth— the scutelliim {sc) — which separates the rest of the embryo from the endosperm. Botanists are not agreed as to which portion of the embryo represents the cotyledon. There are the three following views :— (r) The scutellum is the cotyledon. (2) The first sheathing-leaf and the scutellum together constitute the cotyledon. (3) The scutellum is merely a "subsidiary outgrowth" (emergence) of the hypo- cotyl : and the first sheathing-leaf represents the cotyledon. Comparison behveen a Wheat-grain and a Bean-seed and their Germination. Grain of Wheat. 1. Is a fiuit which contains one seed. The wall is composed of the fruit-wall (pericarp), together with a very thin testa, which can be distin- guished only with the help of a compound microscope. * 2. The space within the testa is occupied by endosperm and an embryo. The seed is conf^equently described as endospcr»iic. 3. Embryo has one cotyledon. 4. In germination. (a) The endosperm shrivels as the seedling develops : it is the food - supply of the embryo. _ The scutellum is the sucking-organ which absorbs nutriment for the benefit of the young plant. {h) The main root forces its way through a peculiar root- sheath. {c) The main root soon ceases to grow, and adventitious roots arise on the stem. * Recent investigations tend to show destroyed before the grain is ripe. Bean-Seed. I. Is a seed. Its wall is formed by the thick testa only. 2. The space within the testa is occupied by an embryo only. There is no endosperm. The seed is said to be noii-endospertnic. 3. Embryo has two cotyledons. 4. In germination. (a) The cotyledons shrivel as the seedling develops. ' They contain the food- supply of the embryo. {!>) The root has no peculiar root-sheath. (r) The main root continues to develop and produces acropetal lateral roots. that, in reality, the testa is entirely SIMPLIFIED LEAVES at PROPHYLLS OR PROPHVLLA two simple Icavc^s--theS^l/, //"''" ^"^ ^^'alc-hke. These faces, the right andlJsfdfoT^" h'^^f "" °I''^°-^'^^' cotyledons, on the other haml i '^'^ ^'"^^"f h- I" Mono- simple leaves at the W of ' " u ""^'^ ^^"''' ^^ these alone on the uppJrface of the br.n'h'^^"^- " ^"^ ^"'^'-'•■t^^d which is directici towards h^ma^axi7w ''' °" '^'^ ^^'^ member these farts if xu» , ^ f'^''^' ^^^ can eas ly re- Monocotyledons the iJIve "fir rfn'' " f^icotyledons'and usually simplified. Tl ^fir t Ses of'th °"- ""^ '"'"^ ''' cotyledons; those of a lateral sh m n ^ P'^^^'^ ^^^^"^ ^^^ ledons the primary axis ha. tl T, P^^Pl^yHs. In Dicoty- prophylls; i^ M^ocot ledons he 'S^ t-> cotyledon, the branch one prophyll ' ^ ''^' ^"^^^^^^^^^ ""^" BRACTS. foliage -leaves of the same pla'^ "th ^ ''"'"^■^^ ^^^^" ^^^ borne in the region of tht fl^ • "-'^ simplified leaves termed bracts 1^." Li^v ^11^"^ ^S"' ^^ '^' '^^^' ^^e majority ofcases,bmcts are smflJ?^' .^^T"^^' ^^ ^^e by broad bases their ma^rnf^^^^^^^ may assume the form of smal" scales \. f ''^' , -^^^"^^ case of the g/u„^es of graSesVfiLr .!\f V?' l^^S'P^ ""^ ^he the Sunflower (fig 208) TZ3^' ^A ^^"^ ^^^^^ ^^^cts of which enclose the whole fnfloT n"^"^ ^^'^' '^?^^^^"g tracts, also in the SnowdropT^^^d ^^f ?=1;S (f/^ ^^^^ ''-''' positions on the p Ian anH -^ ^T'^ °''''"P^ '^^''^^" ^^'^"^^6 as by their simpl^ t;^:" ' ThafSf T" '^ ^'^^^ P^'^^^^" -proved by /he followinrconSonT"7i\ ^^^^^^^ lateral appendages of the^stem art^d ^ ^ iaget^avr ; t h', " 'i'. " 1 1 ■ ! K) ! I M'-^ y ? i. tit ^ 22 BUDS and have buds in their axils. Often it is an easy matter to cause these axillary buds to develop into branches; for in- stance, if we nip ofT the stem of a Scarlet Runner just above the points of insertion of the cotyledons, the buds in the axils of the latter will shoot out and become branches, (ii.) In many plants transitions from foliage - leaves to bracts (e.i^\ Rose, Christmas Rose), or to scales (e.g. buds of the Horse- chestnuts), or even to cotyledons, occur, (iii.) It is possible to cause foliage-leaves to api)ear in place of scales ; for ex- ample, some stems (t^J,^ Potato-tubers), which are normally subterranean, when caused to develop above ground, pro- duce foliage-leaves instead of small scales. BUDS. .Estivation is the term applied to denote the arrangement of the different leaves of a bud with reference to one another. In the bud the leaves forming a single whorl or spiral may not be in contact, in which case the aestivation is said to be Figs. 29-37.— Diagrams of Vernation. In figs. 32-37 the sh.ided face of leaf is the upper face. The leaves are transversely cut. Open. When their edges just touch, without overlapping, the aestivation is valvate. Finally, when th" leaves overlap the aestivation is imbricate. BUDS 23 Vernation is the tf-rm -,, r 1 each si„Klc. leaf is pXi, T',r' ,'" f""?' '"'^ "«"" i.. which //«'« (figs. 20 ,,1 T, "" '""'• ^ach leaf nnv h I the lamina may he simolv Z/ ^ .'''"'• ^ '^^" f^v., halves of two pages of a hook ^ ^ "^"^^^'^^ ^"t^^"^''^''' ^long the mid-dh 1 U ff^-'^- 30, 33); or tliere may he a number of folds (%• 34) along several of the large veins, especiallv in leaves with parallel venation (^.,^.-. 0,^,^^ grasses) and with palmate venation, j^o that the young Jeaf reminds us of a closed fan or a pleated garment. in other instances *'g- 38-— Unrolling of leave.; a / z , the leaf is .^S from side , • , "' -y be rolled .owarr , e „ d°dS„e'',?fH ""'^ °' "- '-™na Sh%tr--'>-pe^^Xtffotd:;rL^^^^^^^^^ i ■ I : L||l CHAPTER IV 40 3^ STEM AND SHOOT DEFINITE AND INDEFINITE CIROWTH IN LENGTH. An ordinary stem of a flowering plant elongates solely by means of growth at its apex. The apex may continue to grow for a long period, so that the stem will bear many leaves and lateral buds ; such a stem is said to be unlimited or indefinite in its growth. On the other hand, the apex may soon cease to grow, so that the stem attains only a limited or definite length. The Scotch Pine (fig. 62) has shoots which exhibit both these methods of growth. The main trunk and con- spicuous branches are of indefinite growth, and bear leaves only in the form of scales ; they constitute the so-called long-shoots. In the axils of mnst of the scales on the long-shoots there arise lateral dwarf-shoots (fi^'- 39)' Each dwarf-shoot consists of a short definite stem, bearing just below its apex two needle-like green foliage- leaves (/), and below these a number of scale-leaves {s) : the apex {a) of the stem lies between the two needles (fig. 40). Stem or axes of different orders (fig. 41). — A stem is an axis bearing leaves. This definition gives us no means of Fig. 39.-A dwarf-shoot Stating simply whether the stem be a of Pine, inaxii of scale (,yr). main Stem or a lateral one: hence it is ofdiuo?°" '' "^'^ "^'^ '"" advisable to adopt some terms by which we can explain to which stem we are alluding. The main stem (i.) is described as an axis (stem) of the first order, or as the firimary axis. A lateral axis (11.) 24 A' grass w Ji(in sum i invisible LENGTH, tcs solely by itinue to grow ny leaves and d or indefinite »er hand, the vv, so that the :d or definite (fig. 62) has hese methods ink. and con- sfinite growth, 3rm of scales ; ;d long-shoots. scales on the 1 dtvarf-shoots 3t consists of ng just below jreen foliage- a number of :) of the stem 5 (fig. 40). t orders (fig. saring leaves. 10 means of } stem be a : : hence it is rms by which stem we are axis, (stem) of sral axis (11.) FiK- 4'. STEM secondary axis is an iv/.w///,;J;^ 7^^^ ""^'^ ('"•) ^^"«i"g on a ^"t'^^;! ^-^^7 axis; and so ' nnJ^ ^V°"°^ false-Stems or sym- podia -A snnj.lo stem bein.. !^ brajK^c^ obviously must be an ax;; I ot the first, second, or third etc I order. Frecjuently, branched t^«>niplc;thisisparticuhulvthe ^^ m plants possessing stJn s of ; delinite growth. ^ "' . ''"';^" ^"ormation of such a falselv simpi, stem-a s^mpodium-in^^t : '1 >'strated by considering the groVth t of a grass which lives fbr sct^^^i . ■ terranean shoot-svstem. Follou'-.l, n^? T^ .possesses a sub- Horizontal under-ground sten of , ^ ^ >^''' 'i-velopment of a -*' ■ ;;'id tfrminatcs in an inl Uorescence. iiut the base ot the erect i)ortion of this stem produces a bud which grows for a certain distance in the soil and presents the false appear- ance of |)eing a continua- t-^on of the original stem. I his lateral axis in turn bends out of the soil and produces flowers as did the first stem. A third a-xis arises on the second lateral axis and behaves in exactly the same manner as Its predecessors. Fig ,n..,K,:..-):. ,-\>- ^«;;'-';;:,''°- flowers (^Ste '^ possessed a leafy branch (11.), the fig.4^.-.Methodofgrowthofaper;nnial VJrass. ir II •r' 26 STEM termination of which had emerged from the soil. This year, axis ii. is flowering, and its branch (axis in.) has just emerged from the soil with its foliage-leaves, and will next year terminate in an inflorescence. Axis in. has a branch of its own, (axis IV,), which next year will push above the soil and assume the present condition of axis in., and in the second year after will flower. It will thus be seen that the creeping subterranean axis is not a true axis, but is composed of the subterranean portions of axes i., n., in., iv., apparently strung together end to end. Each true axis is rougnly L-shaped, and the sym- podium is made up of the bases of successive Ls. Some of our trees, especially Willows, Elms, Limes, Beeches, have sympodial branches, which are produced in a slightly different manner. In these trees the terminal buds of the branches often die in autumn, and in the following year the highest axillary bud on each shoot grows out and behaves as if it were the true terminal bud. Again, in the Hazel occasionally an axillary inflorescence arises close to the apex of a shoot, and as it develops it causes the terminal bud to die and drop off (see fig. 131). ARRANGEMENT OF BRANCHES. So far as we have considered a flowering plant, we have found that every leaf has a bud in its axil. An axillary bud is simply a small lateral shoot which may develop into a branch. If all the axillary buds of a plant were to grow out, the branches would be arranged on exactly the same plan as the leaves {i.e. in whorls or in spirals). But many leaves have no branches in their axils ; this is due to the fact that, though the buds are present they remain inactive. Thus we may range buds under two heads : those which are active or growing, and those which are inactive or resting. The disposition of branches on a stem depends, therefore, not only on the arrangement of the leaves, but also upon the behaviour of the axillary buds. Racemose branching. — When a stem grows strongly and produces a considerable number of branches which remain smaller than itself, the branching is said to be racemose (fig. 4). Cymose branching. — When a stem grows only for a limited time and produces only a few branches which subsequently develop more vigorously than the stem which bears them, the branching is said to be cymose (fig. 43). le soil. This IS III.) has just i will next year inch of its own, soil and assume cond year after ig subterranean le subterranean ig together end and the sym- Ls. Jmes, Beeches, i in a slightly il buds of the owing year the id behaves as if zel occasionally of a shoot, and ie and drop off plant, we have A.n axillary bud ievelop into a re to grow out, 3 same plan as ^ leaves have no hat, though the we may range Dr grozving, and ion of branches arrangement of xillary buds, s strongly and which remain 'cemose (fig. 4). ly for a limited h subsequently bears them, the HERBACEOUS AND WOODY STEMS. _ There is considerable variety in the toughness, consistence, and longevity of stems. A stem may be soft and relatively short-hved : in which case it is •said to be herbaceous. A plant the above-ground stems ot which are invariably her- baceous, is described as a /ler/K With the exception of our herbaceous climbers (e - Convoh'u/us) nearly all British herbs are plants of low stature. Jiihich fre<,uen y eSs n rL'-""^^^^^^^^^ ftsstemofeXarTc its whi.hr''''"' V''^^'"°" ^" ^'^^ '^^^ 'ives off advent^u ; r ta";" iTl^"^""^^ '^"' '' ""^^ -. ^or instance in Grasse. ^^^ ST SSfS m -i4a 30 SUBTERRANEAN SHOOTS i 'I subterranean portions being formed of the persistent bases of successive lateral axes, whose sub-aerial portions produce flowers and then die. The development of the rhizome of a grass as given on page 25 illustrates the mode of formation of the underground sympodia. The ^Voodsorrel {Oxalis acetosella) affords an exception to this rule ; the axis of its rhizome is a single true axis which does not emerge from the soil; the shoots (flowering axes) which protrude into the air are axillary branches of this horizontal subterranean stem, which bears scale-leaves and compound foliage-leaves. A tuber is a subterranean shoot, which consists of a short swollen stem bearing small membranous scales. The tuber gives off adventitious roots. The Potato-tuber is a tuberous stem ; its " eyes " are buds which arise in the axils of minute scale-leaves. The difference between these tubers and tuberous roots is well brought out by a comparison between the Dahlia and the Porato-plant. The subterranean tuberous bodies of the Dahlia anse on the base of the stem, in positions which bear no i-elation to the leaves on that stem ; they possess no leaves. (They arise endogenously, and their tips are clothed with root- caps.) In fact, they are adventitious roots. The tubers of t!ie Potato-plant are thickened portions of lateral stems which definitely arise in the axils of leaves (fig. 48) at the base of the main stem of the plant; furthermore, they bear scales, and when caused to develop above the soil they produce foliage- leaves. (They are exogenous in origin.) A corm is a subterranean shoot which consists of a short thickened stem more or less invested by membranous scales. The corm has relatively larger scales than a tuber. Life-History of the Garden-Crocus {Crocus vermis) (figs. 49-52).— Each corm of this plant is the swollen basal part of an axis which terminates in a flower ; but the corm does not develop_ on that axis until after the latter has blossomed. Examining a plant in spring (fig. 50), shortly after the flower has withered (or even whilst it is flowering), we note that there is a yellowish wrinkled corm, on the upper face of which is either the stunip or the scar of the flowering axis of the preced- ing year. This is encased in brown scales, and represents an axis which we will term "axis 11." On its upper face there i- also inserted the axis which terminates in the recently withered flower (/). This is really a lateral branch of "axis 11.," and may be below it limited : basal sh scales si swelling, corm, sc r-'i.Ljs. 49-52.- '•'1,1;. 50.— I'lan winter-rest afte older corm at the expt and also th corm (axis parting with leaf of the next year d duce a new above the p hranch of i axis II. is a 1 in the resti several axillj II SUBTERRANEAN SHOOTS limited nuZ'o fo, g „a™"'fo'S;r'^i '""^■^/'; "''-■h -'^ - basal sheaths : and stm'lmvJwI„f "''■'"''•'' '■^> '"* l'™--«I scales succeed/ A,. dVr base of Ms'flT ' '"~' ^''•'•■""''"« swellmg, above the inserdono is love IcrfJn'V ■'''''' '"• '' corm, so that one slender in^.JrS^^i']^:^'^ 4'%~l^^l^i!:Hif ^"^^^^^^^^ Fi, ,,._p,,„, .estln. In winter wmter-rest after fruiting. '^•^'' P'^"' ^ruuing. I'ig. 53.-Plant pr^^aring t; older corm and the younger onp tk^ at the expense of thp fnnH ; ^^ "^''' ^o™ is growing and also C fu Wnt^v^ic^^^f ''"''^ 'T- ^^^^ ^^'i^S-leaves! corm (axis ii J Thrktte r . ^? 'iP'^'u^ by the mother^ l-rting\vithits%onlnts fntl^l^^^^^^^^^ "P -^ leaf of the flowerin.r stem ?n It f • ^? uPPemiost foliage- next year develop •^.o'rflot'ng'airf.^ifv S';''-^!- '"" cluce a new basal corm. Thus each v'r.,^ "'" P™" ahove the preceding one and rlnnt /?u new corm arises l.ranchofS,s prefe™:™"'''b7,S i l"?7"?^L^^^^^ axis n. ,s a braml, of the shrivelled axis J : ■ "'r'^""''-' 'u the resting corm during wi.erfe':^'* 1^ '"''.'= ^'^li" several a.,l,ary buds develop on araxta„1?Lh°Srs''i; li .,'18 32 SUBTERRANEAN SHOOTS corm, so that when the niother-corm shrivels up, the several new corms become separate and form distinct individuals. 'I'he adventitious roots are given off from the old corm, and serve to supply water and nutriment to the flowering axis and to the developing corm. A bulb is a subterranean shoot which consists of a short bun- like stem with fleshy scales. The main mass of the bulb is made up of leaf-structures. In the case of the bulb of the Tulip the scales are complete scale-leaves, and the plant has foliage-leaves in addi- tion. But the scales of some bulbs are not complete leaves, they are merely the persis- tent basal portions of green leaves, the blades of which have decayed. For in- stance, the single stem of a Snowdrop, which terminates in an in- florescence, bears two long, narrow foliage- leaves, which are to its base, season ad- the green upper portions of these two leaves decay and their bases thicken to form two fleshy scales. The bulb of a Snowdrop consequently consists mainly of two thick scales borne on a short axis. In the axil of one of the scales is a bud which, in the following year, will develop to form a new flowering axis. As the latter grows, the two scales will shrivel as they pass their contents on to the growing stem. This new flower- ing shoot will subsequently behave just like its predecessor, and the brown shrivelled remains of the two old scales will be attached As the vances. .F^'g' 53- —Vertical section of bulb of Hj-acinth ; X IS the flattened axis ; // is the iiilloresce.ice axis ; lb is an additional lateral bud forming a small bulb. Occ above springing leaves an ^k' S5.-PIf several new luals. The I, and serve and to the I short bun- the bulb is lulb of the scales are ;cale-leaves, plant has as in addi- : the scales libs are not eaves, they the persis- portions of ives, the vhich have For in- single stem Irop, which in an in- , bears two )w foliage- hich are ) its base, eason ad- he green rtions of laves decay ses thicken vo fleshy 3 bulb of a :ales borne 3ud which, flowering el as they lew flower- ■edecessor, les will be DIRECTION OK GROWTH seen outside th„ daugl,fcr-i,ulb rr u ^^ has scales of both sons .,n, ' '"-' "y'-"^""!'!."!!. (Fm !,> as scales (m which t'/h '" '•""= »'ale-leave» (/;i f wi '■='!;;« (/r In al th^sx' bulbs' e?'-'"'^"' ''•™' "-'» "f t'r^'e , o.-.~"e ^:r ™™ '"■■ — •■ Ii,ll,.l fPnngnig from the ground-.^ n j ,• kaves are then .aid t'o l^ij&S';^^ -'" Daisy. 'J'he F'>. 55.-PInnt of 0,Wr<«/„, «„,,„„.^ , . , . no suppo. up w..^1-CS^r 'l^!^:^- » - met wi.h iH? 34 1 1 1 i 1 r if i il! 1. Jjii Fig. Twining Con7>oivulus arvensis, (After Den- nert.) CLIMBING PLANTS As a rule the sub-aerial foliaged axis is of appreciable length. It may be erect, as in the Sunflower, or it may be extended hori//.ntally over the surface of the. soil (fig. 55). The "runners" of the Strawberry are creeping stems which have long internodes and produce tuft-like shoots and adventitious roots at the nodes (fig. 54). Between erect and prostrate stems various transitional stages occur. CLIMBING PLANTS. A prostrate trailing plant usually has long, slender stems whic'u call in the assistance of the soil to bear the weigiit 0.' the branches and leaves. Another group of plants — climbers — also require external support ; they rise above the soil and lean against, or fix themselves to, other plants, rocks, walls, etc. Like the majority of prostrate plants, climbers have slender stems, usually with long internodes — in fact, a climbing plant may become prostrate if it finds no external object up which it can climb (fig. 55). Climbing plants may be rangL-d for the present under four heads : root - climbers, twiners, irritable. - climbers, scramblers. (i.) Root - Climbers. — The Ivy ascends by means of numerous aerial adventitious roots, which are given off by the stem and serve to fix it to the supporting object. (ii.) Twining Plants are those possessing stems which twist round the supporting objects. In most cases the twining stem twines in a definite direction ; for example, the Bindweed {Convolvuhis) climbs in a left-handed spiral, as is shown in fig. 56 ; whereas the stems of the Hop and Honeysuckle ascend in a right- handed spiral. The differences between these twiners and the following class of climbing plants are not easy to explain in this ele- J| mentary work, but it may be generally stated Jg (^..^ i !d axis is of 'ct, as in the horizr.ntally • 55)- The re creeping and produce roots at the nd prostrate cur. ly has long, assistance of )ranches and —climbers — !y rise above emselves to, Like the mbers have internodes — me prostrate vhich it can Its may be four heads : le. - climbers, ascends by titious roots, ind serve to 3 possessing ■ting objects. twines in a le Bindweed led spiral, as stems of the in a right- etween these of climbing in this ele- lerally stated CLIMBINC; PLANTS <-"'a^^,r™r»ra-r.-c- ill 36 METAMORPHOSED SHOOI'S II termed temh-ils (figs. 57, 59). A tendril is a simple or bruiuhed string-like irritable* structure which is capable of coiling round, or fixing itself to, suitable objects. Tendrils and other irritable climbing organs can embrace slender supports which are horizontal in position. 'I'hc leaf-stalks of the garden 7>opiC()Ium and of Clematis^ also the finely-divided leaves of the Fumitory, act like tendrils and coil round slender stems. (iv.) Scramblers do not adopt any of the methods above mentioned; they merely lean against or scramble over other plants. Some clamber up by the aid of hooks or prickles, as in the case of Galium (Cleavers) and Riibus (Brambles). SUBSIDIARY 0UT(;R0WTHS (Hairs, etc.). So far we have men,tioned roots, stems, and leaves, but have given no account or explanation of the hairs, hooks, and prickles scattered over various parts of plants. We have learnt that roots, stems, and leaves all arise, and are arranged, in accord- ance with certain definite laws. Furthermore, they are recog- nisable by their structure. The hairs, prickles, etc., which are irregularly arranged over the plant, cannot be regarded as being roots, stems, or leaves, because they do not occupy the definite positions assigned to these members. In particular, hairs are lound on roots, stems, and leaves : prickles occur on leaves and stems ; these structures are not axillary in position,, nor do they have buds in their axils. We therefore require a term to include all outgrowths which are neither roots, stems, nor leaves, but are, more or less, irregularly disposed on those members. We may term these structures ^'subsidiary outgrowths" [In the majority of text-books "subsidiary out- growths" are referred to under the heading of "hairs and emergences"; but it is impossible to give the complete defini- tion of a hair or an emergence without assuming a knowledge of microscopical botany.] METAMORPHOSED SHOOTS. Stems and leaves assume many different forms, and they may present appearances so changed, or metamorphosed, as to * See the section on Physiology. i III mi:tamori>ii(,ski) shoots , . 37 '•'or instance, stems m.v . ^ recognise Hum, as siirh. •sterns, Jc.av<^^/ r ,^0^71^' ''^'' '^'^^'''^^^^•^ "^ '-v-; of spines or of ten Is ft "' "Y>'/H>|Har in the forn: ^irrangenu-nt tluit i :,,, J'- '"^■"''^' ''>' ^'^"' •^'^'*'>' ^^^ their ''suLdiaryoulgroutt." '^'"^' """ distinguish ihe.n Iron, SPINES, THORNS, AND PRlrKLKS (i.) Stem-s{)ines.-Thc ' '"^'"•^'^'^ subsidiary outgrowtlis. ■spines of tlie Hawthorn "" (!'g. 58) occupy the po- sition of branches, for they stand in the axils of eaves; they bear small leaves, which soon fall off. These spines, there- tore, .represent stems of definite growth, whose growing points become hard and woody. Certain branches of the Pear-tree often end in spines, \vhich, therefore, are metamorphosed stems, ('!•) Leaf-spines. -^The --"■■'■■"• ^-Aiter ucmen > ■ " leaves of Thistles and of th*. T-rr.ii,. u ^vh'.h are obviously poio^ o^ 1^ 1''' ''""T. "^'^.^^''^'^vths, plant has branched Cn^ in """•?• ^^^^' '^^rberry- l-nce they are ntti^^rsedl^vi^'^n^^^ •'""^••^- -'- = by the fact that on a stem of ttR i ^'^'^^'.^'^^ '' confirmed t" see all the transition s^aL^/shf/ ^^'7 '' '' °^^^'" I^O'^-^i^^ tl^e branched spi, e Eadi t Ih- I'^'^r '^' ^''''' ^'^'-'^ ^"^ two spines occupying the no it^>nS^^^ "^'"y ^^^^^'^^^ has the spines are mUam^'phSS'sl^uLf "^''^ ''''''''' ^'--^°- some of'^wh'h'posser! Oorse (^. ,,,,^,,, ,,, ^,„^^ terminate stems. ^Thts in h?' f''^\"",^ "^^^^^^ ^^ ^^hich have changed to form spinas ^''"' ^"^'^ '''''' ^^^ «tems III lii, 't;:4 li 38 ME TAMORPHOSKl ) SHOO'IS (iii.) Spines, Prickles \vhi( li arc subsidiary outgrowths.— 'i'hu Iciiws anil stems of Braml)ks (fig. 57) ami of many Roses have prickles, woody hooks, or long spines scattered over them in indefinite positions, 'i'hese structures, therefore, represent "subsidiary outgrowths." TKNDRILS. (i.) Leaf-tendrils. —The leaves of the Pea (fig. 59) are pin- nately-compound, and have large green sti[)ules. The positions which should he occupied l)y the terminal leaflet and the two or more pairs of upi)ermost leaflets are taken l>y a single terminal tendril and two or more pairs of lateral ones. The tendrils of the Pea, therefore, represent metamorphosed leaflets. (ii.) Stem -tendrils. — The tendrils of the Passion - flower arise in the axils of leave-:, and are therefore modified branches. The tendrils of Bryonia dioka (tig. 57) are not so easily understood. They probably represent meta- morphosed shoots, the leaves of which are absent. LEAF-LIKE STEMS (CLJDODES). The green feathery part of an Asparagus-shoot consists of numerous green stems arising in the axils of minute colourless scales. The Butcher's Broom {Rusa/s aculeatus) has short, flattened, leaf-like branches, each terminating in a sharp point. That these leaf-like members are lateral stems is evident from the fact that they bear leaves and flowers, and arise in the axils of the true leaves, which Fifj. 59. — Compouiul leaf of Garden Pea. n stipules ;/(J<'i leatlels ; /i>- leaflets convc-rteci into tundrils. In this leaf the terminal icndril is wanting. (After Deniiert.) iCii are inconspieUoUb ;,eales. ^growths. uaiiy RosL'S i over them L', rt'j)rcsL'nt ;9) arc pin- ie positions c occupied leaflet and re pairs of ts are taken inal tendril re pairs of 'he tendrils therefore, niorphosed Bndrils. — of the arise in eaviK, and modified of Bryonia are not so )d. They lent meta- t. consists of colourless has short, harp point, ident from in the axils CHAPTER V THE LIFE-HISTORY OF FLOWERING PLANTS FKEQUENCV OF FLOWERING AND DURATION OF LIFE ^ yt.v.ausc ineir and vetretates m {t<^Z months. A plant which germinates in ifc ? ^ • '^ ^""^'^"^ ^^^s«"» and blossoms and dies i^rr^ ^'' ^ Pi'"' ''^T'' ^-^ ^^'^'^^^^^ "^ ^'^'-^ting for seve al years ?s termed a/>eremaa/; and if it can blossom only once Tt s described as a momcar/>/c/>ereuHia/~e.,o: some Pa ms PolycaiDic plants are 'all perenniail ?hey vegetate and produce flowers and seeds season after season-. rDrdehon British trees and shrubs. '^" -^^n^^^^on, a Dkn't Z'fln'^PT"' '° ^^y ■^'•■^•^•^ "PO" the number of times latter ar^ la/elyTb^^^./^ K^^ intrctmlnrpTaS ^ll^h^ tbi^o?Tuits otf "' ^' '^ ^''''''' ° '-'-^' m^an^^ f^Lt m"; 1 ve for yearrinT? T k'^ ^''^ P^^^^^"'^'^' ^^e annual Mi^on^til^^-^ Sjt-^r^^T^ KlSytLich t perennial m England, is annual at St Petersburg! ^' MFJTIIODS OF RESTING. of Sli''"'T^' """^ '"""^'^ '■'^•^t ^"""g the winter in the form 'ome annuilsTh' '''" ''"'' ^^^^^'^'^^^ "^^ans are dead Z .omt annuals, when sown in autumn, can pass the winter in tht-^form of young green plants. P ^ me wmttr in vegeSe'o?.ls'Tr'' ''^"" °"^^ ^^^^^^" P^^^ions of their vegetative organs at the resting season. There are certnin broad distinctions between the modes of resting of herbs ^S of woody plants belonging to these classes ^ . Resting condition of perennial herbs. -A number of neren nial herbs retain their sub-aerial stems and gre^leavcs dun'nir" ngSnV XTth'^^'" manyGrassfs, and Wallflt'rt he shoot whlh . '^" '"^J°"ty of perennial herbs the parts of tne snoot ^vhlch are above the soil die down, and only sub earn""Sr^ '' '''' P^"^', ^^°"''""^ '^ -iLt at the /estrng season. Herbaceous perennials may rest in the form of sub ckweed and ;e only one cause their I germinates ms and dies e.g. Turnip, eral years is ' once it is ns. 2getate and Dandelion, )er of times be annual, )ngst these lants which rest during ct, they act the forma- the annual nnial : e.g. y, which is 1 the form lead. But winter in ns of their re certain herbs and ■ of peren- ^es during 'allflowers le parts of only sub- 16 resting n of sub- LIFE-HISTORV terranean shoots :--rhi/omes (^ .r i^ a v ^ I'otato), bulbs {e.,r HvacS n ^ ^.^"^^-^''^nX tubers {e.^r, form of roots. ^ ■^I„rhefoImvw' <'-^^' }^\^^^^)~or in \he underground parts ind up hoo,/wh-\''?'^^^ '^'^^°" ^hese orthe sol, a J bear folia^iatr ndt'werf " ^'^'^ ''''' ^^ Besting Condition of Trees ami ol^! l r woody plants a considerable part of ^h ''"7^" l^^"*^""'^' persists during winter ThpuLf . , sub-aerial shoot covered with icales r;presen ?h ^ ' r'"' '"^ '^" b"^«' ^^^^^^ of these vvoody plants she^^^ '? -"^ '?^ «^ «hrub. Some sets in-.,,, Hazel and Larch and nT'^-^^r , ^^^°^^ ™'-^ Others retain their green Icavi^H ' "^"f "'^^'^ ^^ deciduous. termed evergreensleTlV.TyLT'"^.''^''\ ^"^^^^"' ^"^ are But even he evergPc^en do nn/ ^?'^ ^"^^Z ^°-^' ^"d Heaths^ leaves for an indeSe period ''?'" '^"u^^°'^ ^^ ^^eir drop Off, so that a green^ Sts ^^^ /^'l ^t^: yl^T ''^'' METHODS OF VEGETATIVE MULTIPLICATION ouuSS?:?i -i^- in-se in "T^er with- become separated from the SSZt bvT'"; °^ ''^^' ^^'""^ wh.ch connect them with the laUe" Th '^T^ °^ P""'"' younger sections, having prodnr. J : ? ^^^ disconnected distinct individuals pt^examle thf,^^ '^''' °^^"' ^^^°"^-' Strawberry-runners may deca^^ank ,h ^7?/"^^?°^^^ °^ ^^e nodes consequently become semmt V '"^ '^°°'^ ^^ ^^e decay of those parts of the stem whth P^"""''' /^ain, the a Potato with the mother plant h 7. h^ '°""''^ '^'^ '"^^^'"^ °f tuber can produce a new VotTto pfan f""'"' ''f'^ ^'J '^'^ plants young bulbs arise in the ax is J/*:^!"^"^^ '"bulbous number of little brlbs mav inn^.f -^ [ '^^^'^^ •'^^^'^«' or a one scale; in eitb^'r casTTheT ^k'^'^.'' u^ '^^^ ^" '^'^ ^^'1 of separation^ofthechlXbu^hs Th °/ '-^^ °'^ '^"^'^ ^^'^ds to the Hazel, Poplar n d Rn"' I*"^ horizontal lateral roots of the so-called 2'.-^^^^^^ g,^« ^f^rect adventitious shoots- assume the apperrLcf o^^ rarl'^ho^Ts' ^ become separate individuals h^ 2 a - 7^,^ ^"^''^'"^ may root and the productio.w^- ,h.^ . f • "^''^"^ °^ *^« connecting their own Stemf '' CutuW?''"^?^ 'T '' '^' ^^««« of 'liustrate the vegetative'^Cu^Ltt^n^S ^^^'^"^^^' ^^^ i 1. 42 LIFE-HISTORY ORDER OF SUCCESSION OF EVENTS. ,rrflu ^Ti""" n^^'u"" P'""'^ ""^ ^'^^ ^°"fi"es itself to vegetative growth and finally bears flowers and fruits. Even in each vegetative season a shoot tends to adopt the same course of .^nd^'tV S "' vegetative buds flush, the foliage-leaves unfold, and the stems e ongate, and eventually the flowers open In some plants this order of succession in one single veieta- Tntr'TiJ' '''''"^'u^ '^^ ^°^"^^^ "^^y appear before the lomTcheJl^fe's." '" ''' "'' ^^'^ '^^ ""'''''' ^''"°"^' ^^ CHAPTER VI THE FLOWER FLOWER OF A BUTTERCUP (Figures 6o, 6i). ronsIlTr"?'"^ the flo^^■cT of a Buttercup, we note that it consists of four kinds of members inserted laterally upon a _ central axis. This is //•Ss,,-'"" ^'^tit-'n with particular V n. JQ) ^^^^"^"^^^"^ if ^^'<^ tut the flower down the centre (fig; 6i). The portion of the axis which bears these lateral members is termed the receptacle {r\ The outermost series of lateral members is formed by a whorl of Dissected flower of Buttercup. five small, green, leaf-like sepals {sp. cat) Standing immediately within the gaps between the five sejjais, and thus al- ternating with them, are five yellow, leaf- like petals (/. cor). Again, within these succeed numerous yellow stamens {and). Each stamen con- sists of a stalk— the filament (/)— and a ''■''' head — the anther («)• The young anther has four closed little cham- pollen- -o •-"-"""='-"u'ioi newer or iJuttercup. wx-which contain innumerable microscopic rounded bodies 43 Fig. 6i.-Vertica! section of flower oflJuttercup. jfr 44 THE FLOWER ll siyollen basal portion-tlic; ovarv (o,^ Th. „ * * "^ "' ""^ directly on thJrccei>tirl,. Th ' '' r"" °™y '" nisertcd which containVa miim ■. \"™''^ "j™'" '' '^'"^^'-'d -chamber attached to I floor '" '^'"g-shaped body-the ov,.le {„)- FLOWERS OF THE SCOTCH PINE (F,cu«ks 63.67) a„cl':nTrs.ru«u'-;e'™!.';l|.'''r' rr '-■"' '"'■'■--• '" wear. a short taV ^^T^t^:^^'^^ ■ for they pos ess pol Ln sa- tT Y'^' 'f^^''^ ^^''^ «^^"^-"«. simple aiis-tL rece^^^^^^^^ >k ^""'-"'n '^^"^ ^""'^^^ts of a stamens. At its base the ~n'^^ f -""^^ "'"''""^'^'d '^^-"^^^' short portion o the axifh'fl'^^"'" 'n ^°»ti""""« ^vith a are attached. '^^'^-the flower-stalk-to which bracts The carpel-bearinff flowers (TiL'- f.'y r yP\ ^ ^ present the appearfnce oTetS rt.dd.^? b^'s "ST' "^'' (fig. 65) arises in the axil of a scale i '^mni;. . ^ ''''"' tmuous with a sho-t stnlL- . k; i u ^. ^'^'•'^ ^^ ^on- Above these brIrN t • ' ^''^'' ^ ^^^^' tracts (..). pecu.iarX^b;:-,-t^rSr\=h^efL^^^^^^^^^^ pe, the polleii- ti to escape in ly small green portion of the in a minute inected by a ) — with the fy is inserted 3sed chamber ^ ovule {<)) — !nt in appear- Js of flowers those which es clustered e flower witli {sc). The bears simple erted lateral > pollen-sacs ire stamens, insists of a iged lateral lous with a hich bracts ' cones, and Each cone xis is con- bracts {sc). > scale-Jike imber con- 3f which a upper sin- v). These ules. The THE FLOWER ^^ receptacle. ' ^^^'"-^ '' ^^ntmuous with the DEFINITION 01- A Vl.Q\\VA\ a bract (.,,. Scotch Pine, Hyac n^S Thn. tl '"^ "-''^^^ ""' ""^ \p) Ihey are often distinctly leaf-like in fnrn, (. and^peta. of the Buttercup, stai^en. and Jp^^of ^llt Sh arrt^STfcllj Pfandr"" 'T'^' •"^™^"'' "'h-h are "gcu uKc leaves and assume forms intt^rmorii^f,. k >. leaves, bractsr:nd"seS n ^ WhL^ w't:^^ 'rh'^"^^^- numerous lateral floral menibers wh rh • ^^f'^'^^ ^^ere are medkte between petals a "dstimLs'"' "^ '"" '"^ ^"^- fo/ms Vr wS^he^S r r-%P-"l- abnormal modified rsucnowersirf^ I a ""^ ^"^'^ ^^'^ ^^^rangely "l)ouble'Bu?tercup^^^^^^ f ^^''"S ''^^''^^''^-^- I" petals; i„ green roses l^Zl f ^ '^'''"''"' ^""^ '"^^P^aced by ^d") I nfpr.l fl!! 1 ^[ ''^ '''^''^^ appear in place of carnels thiy ia o' budsT t • '^''^-^ 'T °^^"^^^ leavesti^hai fli budrSo^^j^^^ -|y ^-- "^ -- monstrous Ihus the position of a flower and the arrangement of its HI t i 46 THE FLOWER Si^'fZT^ '^' f""™""-' "^fi"'"- °f^ flow r:^'; It IS apparent that there is a frn nrriiff u -^""^rcup, carpels They are tvne. of tlf f clifference between their flower, the HaJzel gZZT Jri'T' I ^^^^ ^^e Wall- !|-l !jsj CHAPTER VII* GYMNOSPERM^ CONIPERjE (PINE lAMILY) Trees or shrubs with simple leaves and inconspicuous naked cLchnous Howers. The ovules are borne on open carpels Type: SCOTCH PINE {FI^-US SYLVESTRIS). Vegetative Characters—A tali evergreen, resinous tree (Consult fig. 62 for an explanation of the following descr^i CP Fig. 62.-Diagram of branching o^ Pinus sylvestris, also showing the position of flowers. * i!,° W. Jk"" f'''''^l ^'■^"^^es (lateral long-shoots) are arranged m false whorls. Ihe vegetative shoots and leaves are of two * Beginners should omit f^his chapter. 47 i- — "*-' r 48 GYMNOSPERM/E (AV) ) enters into VreL'n^ ^^ ^f^ ''T' ^""^-^^^^ axillary buds form i whoHin. n ' • ^ '''"'^' beneath it the Th.se%c.nnnaT buds" and t la^' '"" ""' T'' ''''^''^ '^"^«- develop into cones), 'g'ow out t t! > 'foli' ^ •''"P^'"^' ^"^"'^ ^« long-shoots. ConseauenTlv hi /«Jlo>ving year to form lonl-shoots denotefr Lumber o?"v"' "'r''"' ^'^"'''^ ^^ stem which bears them i k . ^ '' "^ ^'''"^^'^'^ ^^ the three to the number thui b nin r^""' "^'^^^"^^^'•y ^^ ^dd the age of a tree becau e no fn u T ''''^' ^« ^^^^^^^te ee, Decause no false whorls are formed till the end of the third year of the me ot the main stem. In fig 62 the part of the stem above the top whorl of branches, and opposite j. is a one-year- old sten ; that part (11.) be- ^^^'5^'\tne uppermost whorl and the second whorl is a two-year-old stem, and so on. Inflorescence and Flowers. — Ihe staminate and carpel- iary flowers have been described on page 44. They arise in the axils of scale -leaves on the long-shoots. (Consult fig. 62.) Ihe open flowers are found only on the young shoots of the current year. The car- pellaryflowers(^,ry) are small erect lateral cones, often two or three together, immediately behind the terminal bud of the long-shoot. They occupv positions similar to the lateral buds which would grow out to lorm long-shoots. But the staminate flowers (m) are in- basal parts of the long-shoots'^of'lh^*^'''"^ °" '^^ ""^'^ is, they are just above ?hl ''""''"* year -that ;' e just above the uppermost false whorl of 64 Fig. 64.— Stamen of ditto. I .'tative season ral long-shoot L'ncath it the resting buds. )ting such as year to form e whorls of uwth of the 'ury to add to calculate ■med till the year of the em. In fig. stem above branches, a one-year- irt (ii.) be- nost whorl ^vhorl is a and so on. i Flowers. Lnd carpel- n described irise in the -s on the lilt fig. 62.) are found shoots of Ihe car- I are small often two mediately I bud of -y occupy he lateral ow out to But the ) are in- he more ar — that v^horl of CONIFERJ.; branches, vegetative and occuj)y positions ')ranrhes. Above the 66 49 taken by dwarf-shoots on spike-hke inflorescence of 65 staminate flowers, a few foliaged dwarf- branches are seen. On older shoots, two to three years old, the spurs (/-/) or scars of the fallen stamin- ate flowers denote the points at which the latter were at- tached. Thus a car- pel lary flower takes the place of a lateral long-shoot ; whereas a staminate flower replaces a vegetative dwarf-shoot. Pollination and 'ts consequences. — The flowers are pol- linated bytheagency of the wind. AVhen ready for pollination "1 May, the carpel- liiry cone stands erect (r, cP). Its axis (receptacle) ^'longates, and thus Fig. ej.-Vertid causes the carpels ■"'•-'otch Pine, to separate to n f;^' ^^-""Carpei of ditto, slight extent. The '^^^^^i^'jH^^.:!:' '-" -'■ ^^> ^; th the integLents o "he oS ^^l\htly, and carry the poHen towards fh.f'^TT^' ""^' "P -that is, towards the bottom of th • ^ ?^ '^^ ""^"^""-^ t'^^ Pine, the pollen-grai^S r^Ict ^ Sj^^^^i^ D •section of carpellary r ■1 ij i'i i ! SO GYMNOSPERM.K in Angiosporms it is conveyed only as far as the stiL'mi Aft^r po ..KU.on the carpels again close' together, an d ^ pWe^' scal.s beconie hard, greci, and woody. JCach cone crtdua K set scales become brown m colour. Finally, the hard brow ■ scales separate at their tips, and allow the sc'ed to l^ set free I he escape of the seeds does not take pl„.e till more thin a yet after pollination ; a few seeds may escape in the Oct ur ?f .V tret till about two years subse(iuent to pollination, when th,. woody carpels gape apart as they dry. The fruit of ?£ Tne is wind 'Z^'^-'r if "' ^'"^ '""^ -^'d« -*-• scatteS by 1 wmd, the wind blows the seed, causes it to spin, and so delays its journey to the soil. In addition, the co^ne droo off and are blown along the ground, shedding at the same dm^ any seeds they may contain ^ I (. CHAITHR VIII ANGlOSPERMj; INFLORESCENCE 'oor-HKui's ^\eatlK■r-.ass O Vh ^^ ^^''^^Kc-lcaf, as in the described as an /..>..,-,^,'^^^^ ^\ Kro»p of /bwcrs is and an inflorescence lie^ tn fh • ''"^"^'""» '^^'tueen a flower flower is unhranchedrwhlt^r"'"^^ ^^ ^ - -^^"'^^hed. The axis W ^flo J^ ";^ ^^ an inflorescence is ''t> axis of an i.iflorescence bear, hi ^T^ ^'"^.'"■^ ' ^^''^^''^^^^^ hracts. We may therefore rVfin T' ''^°°^'"' "^ t'^^' 'i^'"ls of •shoot: set apart CtheTurte^^^^^ ^^ '^^ '^^^^^'h^-d »>y means of seeds. lie a v<' °[ '^'^°"^P'"^'^>"g reproduction an inflorescence may h ^^n^y ^ ^"^'^"'"^' ^h^' "^^in axis of ■s'-oj, in which ca"> i ° a STo'V"? ^'^' ^""^ °^ ^ ^^''V^ and Wallflower ; or the inflor? .. ''''^/W-^,^, Foxglov, I-f, when it is descrtd a° ^J^:;;;; "'Y -^ i" the axil^f a Just as a vegetative stem n 1 ~ -"T' ^'''' ^"^ ^^'i^-^'l- cyniose manner^ sSmay a renn!:i ?"'^ "-^ ^ '■^^^^"^^'^^ or a that a flower represents \ TrL^ T ^^'■'^- ^^-memberinK !-.sition of bud, 'i r ^sv n fi ''^""'' ^"^^' «^'^"Pi-^ 'he inflorescences (comi^are pV aG^ "' "''^'"^"^^^ ^"^ ^>'«^o«-' ^. RACEMOSE INFLORESCENrES -5^gM.^^hs ;fti^^Swnd £:rr^'" ^^r ^^^^^^ -- pf branches. These branch. .^n, !k ^ ^""'^'derable number "^ the Hyacinth, in which eae "'^>'. themselves be flowers, as ypt. Ur the maui inflorescence-axis SI -;t (I ' i . m !i^ 5« RACEMOSE INILORESCENCES may !> ir lateral inllorcsccnn s in place of flowers, as in the 71 7a 73 74 75 Fijis. 6y75. I (iagraiiis of Kacftnose inflorescencL's. Thu arrows denote the general order of succession in the openinR of the flowers. Parsley, and the inflorescence is described as being compound racemose. I. Siftiple Racemose Inflorescences. — The main axis of the inflorescence directly bears a number of flowers. {a) The flowtirs are separated by distinct internodes, so that the axis is elongated. (a) The flowers are stalked (fig. 70) = Raceme. Examples — Hyacinth, Foxglove. (P) The flowers are not stalked. (i.) The main axis is not fleshy (fig. 71) = Spike. Example — Spikelet of Grasses. (ii.) The main axis is fleshy (fig. 72) = Spadix. Example — Arum. RACEMOSE INFLORESCENCES (iii.) Am//t/,, (IlK. 13,,^) is an inflorescence ^_ar|) diary, flowers : after floworinLr it •siially drops off as a whole. ft racemose m type, hut in the axils of single, flowers, in ^,•hieh ,,., ,« the catkin (/') The flow '' ' --on^Pound in lorescenc ■ . "'^''' (0 TheJo.ers are «et close together .n . shortened .ain (a) Thi; flowers arc sCiikod _ n,,^ , a terminal flower in ,he „floreSc! a'^ -et ;yT:r'"">- ^ -'^--s ;i„„t {R\ Th fl Example-Ivy. Examples — Sunflower (fig ,08 x Dandelion (flg. .53), i^ais'f '°^^' II. G?;«/^,^//^ /?r7^m^.fe? Inflorescences 'V\. he mflorescence does not itsdfTe^r fl "~ i "'^'" ^^'^ ^^ branches which are inflore cences ''%',^"^^'^'.'-'^' '^"^ has lateral >ng of the inflorescence ^?t!4wl t7 ' "?^'" '>'t^^' °^ ^^'-^nch- inflore=ccnces winch are spikes (fig. 23,) Example-Wheat. = °''"««'»»4 Spike. I Hill 54 CVMOSE inflorescences (/^) The main axis has its lateral inflorescences set closely together to form an umbel, and the lateral inflor- escences are in turn umbels (fig. 73) - Compound Umbel. Examples— Parsley, ( 'arrot. lit B. CYMOSE INFLORESCENCES. In this type of inflorescence every axis grows only for a limited, de^m/e period, and terminates in a flower: each axis possesses only a very few (usually one or two) branches, and i/ 79 80 these latter grow morr strongly than the inflorescence-axis which bears them. Usuahy the flowers at the apex of a cymose inflorescence open before those on the branches, so thai they do not open in acropetal succession. ^ ■ There are three main types of vymes BRACTS 55 (i) Several -branched. The nnfn JmA^ more than two branTt ("fig /, «;-— --.s has Example-Some SpiJes ^^' (2) 1 vvo-hranched. The nviin Vnfl^ one branch (fig .78 80 g'-''™"''-'^''''' ''•'"' <>"'>■ 1 he so-called sa„-J.i„id „,„e of the Borace cha u„f . T' '■■■"'•'"'>• ''-■«»^"«' - "^ S, ■" fig^ 80 and^8,t« "' ' ''""'°"'"'" <^™''='- esc'enc71T .■J;err(:;i'dat"e*? "".'" ^^^^^^ ■""- different types The m W?. ; i^' '^ "^florescences are of a several-ll^Ln^hed cyme Ld rT""'{ ^^^ ^^^-P'^' "^ay be and their branches uS/feKK '^''^"^"^J^^niay be dichasia, Spurge). Frequently rLt"[nr"°'''"'' -^"^ '" ^^^^^ ^^^'^^ and the lateralinflorescenr?. . "^^^'"^''^^i'^^S^ /■'^ a dichasium Dead Nettle family) ' ' monoehasia (as often in the BRAn\S. Wal^SeSmnr ti;;"lr' ^""^^'? ^T P^^^ -)• I" the bracts. In cT, ula the .tl^^^^ '' ^'■''^"^■"^'^' ^^^^'^ of tending bracts as in the )^r 'ru "^"^^ ^*^ ^^'■thout sub- reached in'he A^um here at \ ^^' u^PP^'^'^^ ^'^^reme is the inflorescenl Caniu,l ! f ^ract-the ./^//..-encloses set collectionrof brarff a^ "T''"^' "'^"'^"^ ^'^^^^ closely- may have I it^nvSlucr^^^^^^^^ ^^>'" single floweJs A'.//^7^^-On mg^^^^^^^ ^•^Z";' '^■^ ^'- the Mallow. ihefirltWof abranSh n M? already been mentioned that -ue axis. This viell^'L u:;:Sc^b;iJ5^i;S:e". '^P^' ^"^ ''^^' ' '^^ ^'^ '^ ^ \\\m 56 BRACTS prophylls on its sides, as is shown in fig. 08 L and is clearly seen in the Violet Cfig i eS o\ 'ru ^ ^ I ^, ^ therefore bracts occ„pyi„^'i"fi^-,:f44„snh;fnZS CHAPTER IX THE FLORAL LEAVES PERIANTH and carpels compo e he *X2"*tk°"'"'^? "'= ■^'™«"-' CALYX. The whole collection of spnnio k i constitutes the ,a/j,r. In its s^mnW "^'!i? -^^ ^ ''^^""^''^ flo^v^^r sists of a whorl or spiral of i^^^. •''°"'^"'°» the calyx con- cup, Poppy), whichT^e^lSt' th'f '^'^'f ^^•^^- ^""- relatively broad bases. The cal x t^"'^'^-^^^ "•'^"^"^ ^y se/>a/ous. Often, however tLJ^, i ^^^'' '^'^ ^o be /^//. a more or less cup-likTcaiyx (V ^ 7n vvf ' "^ ^^"^'^ ^^ ^rm are then described ^sh^^^^^^^ calyx ,s gamosepalous it Ts^iuX> ^ the flower has more than one whoH nf , ^"^^'^ frequently flower, in which the sepals fornr. u '1^'"''' ^^ "^ the Wall- the other hand, the sepals m^vh ""'^"'j^ ^^ two each. On In the case of ZfolTrs'o^lZTf'^ ^" I '^'''^^ "^-""- •serves to protect the inner par^s ofT ^f'"'' '^' ^^'>''^ "merely ;s m the bud-condition. When th^-'^'," ^.°'''' '''^'^'' the latter '— called for. h.r^us^.Zno'FT'''''''' ^"""^'°" '« "« ^ back, as in so.; tttX^^^rir^; 1'^ ^^"'^^'^ Iong( may the 57 m "^^II'-IBI -■ftBRWsmK S8 COROLLA i IX'Sj'/oTjir "'''" "'^- >°™g- flowers are crowded he im-r k f Tl""" P™"-'<:'''"i on ti.e part of the ralv " are sairl tr. 1.,. i / / / • . • •^- ^^''^^''^/•*' ^"^I ^//AWr^//6' and of p"^/' ,'' .^; ,(r; ; :?,,' -^^ -- *;7 1-*-,, ,he fu,„.ti„„: Woiifl r ., o " ciuract tne notice of inserts Tn th.. ? «es 3 "' ' '"■" "'■ ""^ '^'l"'-' "="" 'o he sa"l kea th r which possesses n rim).. ..f "^^'"'n ^n^. 129), the flower of A^//... i^pbceo?t e ohx rl '" ^■"^J^.^^irS forming the o/n..frui^y\^^^::}^:^^^ -ds in the dispersal ^//m/,'a-._Out..de tlie calyx of a flower there sometimes rYv 1 "l^"^^f -Vl^P^^e"^')- forn^ing an outer calyx, L < ^ V; "" , ^ '' ^"°:^'" ^s the epicalyx. The epi calyx of the Mallow (fig. '163 i) is in ream- o bracts. Ihe epicalyx (fig. 82 f/>) of the Strawberry-flower consists of a whor of five mall green members, which alternate wih flatter: in this l^il::ir^^^3^^^^^^^^^^ flower, as it is a portion of the calyx. ^ ^ ^^'^ COROLT.A. 'i'b.e whole collection of nptnl« r^f n .■ i n narrow base • often it i. h; f • u , , ^'?^^'''t^'d by a relatively narrow portion (./)-h: ^T^'"'"^"^'^'' "^^^ '^^'« P^^^^'^' ^ lo-e^ Ihe petals form a single whorl (<■.,. But.ere,,,, Primrose) or „. —.—Calyx ill epicalyx of Strawberry COROLLA floral leaves ;^n «^"tinuous spiral of KiK.83,--Pee;,or plants Tc^onSolh 'T. ''"T'^^^^'^ «^ ^^'^i^'h , ^ "*";-- W-familyral i!'e ted T^^ "^^ ^^^- Parsley compare fig. i8t)hisar.l vv / N • f^^ ^"^^^^'^ "^ the green ring with five minute ?^tlt^.^ ^ , '" ''^'^/°'""^ °^^^ small petals alternating vvilh ' ' ''"'^"^ ^°"^''*t'^ "^ ^ve white the calyx-teeth. But the flowers of some other representatives of the same family, though they possess five white floral leaves occupying the same position with refer- ence to the stamens and carpels as in the Parsley, yet have no appreciable nng of teeth to corre- spond with the calyx of this plant. It is dear that m this case the single ..r^^l^^T^rS^,,-'!-,^^,!:;;-; of Potato : anther; o,> = ov^ry ; sjr~.iija ' ^'"'^''""' "^ — _. i.. Lin.>, ease tne Smgle •'">'"" ; <^^ = ovary ; .r=stism-i ' ^"■=1'°"''' "f penanth-whorl of five white AodI l.o,, -d the calyx is absem Simt 1?"; TT'^' f' 'T''^' "The"cJ!iTr"^-^'^^" - "b-"''(% t,/'"^^-'""'^>'' ^'^^' consXtfs Tt^:^^^^^^^^^^^ -cier the flower H'hen the flower does not irofirhl'" ""^ 'r''"^'' ^'''''^'^^' «")• small and inconsoicuo.^. .^ ° ^ insect-visits the corolla is Of absent, as Tt£e Haze pf "" '°"^" "^ ^^^' Violet, -^t^rih^UiS^^^^ ^y the attractive Z-f^.----^^ i^ 6o FLORAL LEAVES i ■-' i Stamens, or bright-coloured bracts Omsinn.iiv iu . ^ puureu out Dy the nectaries — ^.."-. sour of ^r. VJr.!^' t a l^^:RfANTH. whiS:^^i^S'';;''^? 'f °^ '^^'° °^ "^°^^ ^^°^^« «^ "^embers wnicn are all ahke, the latter are termed perianth-leaves >.v.. iwfXVls'oi:?! ''^"^f '^ '^^^ PeL.?hf composed' o d ffe en?k ed in^ fh ""''' ^^^^^^^jt^-t'^" ^^^1^^, and cannot be amerentiated intu three sepals and three petals. The nerianfh may be brightly coloured (A/a/./^), as fn Tulips Lills and H,acmths; or it may be green (seJ>a/o/d). If the perianth eaves be separate, they are said to bf /./i^^/n^L-.^Tuhp of^fpl^Tr ^''^''^''' H8)-Flowers may be devoid ^, sepals ---^.^^. some Compositae; or mthout petals T^ C^fmf^s; finally, they may possess no perianth whatev"^ £ ltrsTtheV;;r'd \l ^^V^^'-^^- the stamefbl^ri . iiuvNers oi ine Hazel and the Petty Sourpp -^rx^ tv^ f[^ r f.„, ,„„,„,,,„„ s„,,, fl„„.^^^ c'onffi'olSy o*o„e o ror°e stamens or carpels, or both of these, inserted upon a receptr/e! ANDECECIUM. « J"'' ""'^'="°" "' ^'™'"^ °f ^ «»■- ^o-titutes the =^s:!>rSi;^.,,,:iii^£^^^ generally consists of two halves or Mes, and each half has r'^^ pollen-sacs in which the pollen-^rain ,r.t^L,f(^!'l:: Occasionally an anther represents half a compkTelnhSr 3 ^liL petals example, re honey- inally the h<: honey Li otjier : accord- corolla is ■e.g. ANDRCECIUM !'>g- Ss.-Part of a stamen with the top „r the anther cut off. possesses only two pollen-sacs-.,. Mallow and Ha.el The .,, two lobes of the anther are connected 1 v ! ./ continuation of the filament, which is teried ^ the.....,../.e..(..). The connective may ; a narrow, almost imper- — ^ H ceptible, continuation of the filament, so that the two halves of the anther are close together ; or it may be wider, and thus cause the anther-lobes to be clearly separated. Oc- casionally the connective above the rest of t;;L^:!^&:f-f another'^rT "'"^ ^^ ,'^P^^^t.d from one another or they may be united by their filaments or anthers. In the Mallow (fiT i6i) and some of the members of the Pef family, the filaments of all the stamens in a as to'form onf K ^% ^ S^^^" distance so -p.n. po„e„ (,, famny (fig. T) nhlf o7 t^" T' f*^^'^ "^^^'-^ «^ ^^e Pea- /J^g. «7; nine of the ten stamens are similarly united "'''•*'^'*^ («^A /) by their filaments, but the tenth is separate (A «). In the Daisy- family the filaments of the stamens are separafb, but their anthers cohere (fm 202). ^ ^' Like the sepals and petals, the stamens may form one whorl— .j,r violet; whorls in the Wallflnw,.r ^ •°'" ^"^^^^^^ ^^'horls (two „ — • - Lonei- tudmal dehiscence of anther, showint; the escaping pollen (p). Fig. 87.-Flower of Garden Pea, with calyx- ana corolla removed. r m if 62 FLORAL LEAVES a nt cum consist., of six stamens, of which two have shorter Hlaments (at) than the ren.ainmg fotir (..,)• Many men.bers oTthe rrv^ /:\^ l^oxglove— and Dead Nettle-family (figs 191, 193) have flowers with four stamens two of which have shorter filaments! Again, in some members of the Geranium- tamily, the flower may possess five stamens with anthers, and five without. Dehiscence and insertion of the anther — \\ hen the anther is ripe, the pollen-sacs open in such a manner as to permit the escape of the pollen. Usually each anther- lobe opens by one split down the line which denotes the junction of the pair of pollen-sacs (figs. 85 d, 86) : its dehi.scence IS longitudinal. Occasionally the anther opens by small circular holes— t'.^'-. Potato ; .. r^^''/^,/''\- ^'''' dt-'hiscence \^ porous. corolla removed : «=nec. ncarJ>ot(s, hrrausc it is not madf up of several carpels joined together. V\^ 92 shows an apocarpous gynai- cium conij)osed of three cari)els. SYNCAKpous GVN.^,cru^^. AVhen ;t. flow' r possesses more than one carpel, and its mm _ irpels cohere t(..>'lher to form a single hbdy, the gyn;t( is said to he sviorrpoiis. Li such a g\naicium the ovule- containing pans (ovaries) of the carpels are joined together to 92 93 94 95 form a single ovary, which isalsodescrihed as heing syncarjjous (%«• 93. 94, 95)- ^ut the st;, les may remain separate along their whole k-ngths (fig. 95) ; or along part of their lengths (tig. 95). Again, not only may the ovaries he com plttely fused, hut also the Sty^js, so that only tHfe .'^ igmas remain distinct in the form of stigma-lobes {e.i:;. Wallflower); or fmally, the ovaries, styles, and stigmas of the constituent carpels are completely joined together —e.g. Primrose. The syiu ..rpou ^ ov.^ry, represer wig as it dc es parts of several carpels, may have several chambers, each corresponding to one carpel.* Thus the Hyacinth has three carpels joined to form a single ovary, whio is three- chambered; or the syncarpous ovary ma; iavc me general chainbei, the wall of which is formed s ral carpels joined together {e.g. Violet). PLACENTATION. The mode of arrangement of the ovule-bearing portions the placentae— of the ovary is referred to under the head of •• Rarely these chambers of the ovary are further sub-divided by additional partitions, so that the chaml)ers )f the ovary are more numerous than the carpels com posing it — e.g. Labia! v, Boraginacefc. Figs. 92.95.— A Kynaeclum composed of three carpels. |lg. 92 is ail .ipucarpous gyn.-Eciiim ; ih iher thr.;e figiires represent syncarpous gynaici.i. GYN.'KCIUM 65 two parietal placentas an 1 ve i 'T'^'V'^' ''^" ^^'^^^ has ovary is syncaVustnd 1^^ ,era T^^^^^^^ . ''''^" ^^e are attached to the central axis n^Vh '^^"^'^^''■^' ^"d the ovules meet), the placentation fs « J^ A" °''''^' ^^'^^'^^ ^^e carpels chamber of\n ova y o^n'uns on 1^-^'' 'f "j^^^^^' ^^ '- to its floor, the placenta" is / / / ""''i^'"' ''^'""^ ^'^ ^^"^^'hed when the ivary is o "J-chaml en rf ^^^^^^^^ Bmtercup). Finally, of ovules attached t^a s^d '^1 ''■'^- ^""T"''' ^ """^^er ^he ovar>-, the place tatiori"LS'?f"^'/T ^^' "'^'^^ "^ ^^/./r«/(fig 95/,.. pHn,,ose) ^ ^^ Chickweed) or >v- « .v^. 'xtr^f^sii^n f r^^ -^'^ -^- u.- s:sts of seven) carpels joined Sher^^Th'^^^ ^'^'"^^'""^ enable us to le how manv r ,rn P • ^ ^"^ ^ollowuig rules of an ovary :- - ^ ^'"'^^^^ ^"^'^'^ ^to the composition repJiems'one'can:;. ^'^ ''''''' ^^^"^^-^^ -ch chamber (' argins) of the camen^^^^ the jomed ventral sutun-s of carpels. ^ ' ^""^ ^^"^''^quently denote the number thi?i'i^£^^^:^l«^;^;^ ^''-branches, orstigma.^ carpels (see next chapter) ^^^^^^"^inmg the number of sel'ct th:rr;etf ^^:i °^ ^^e. . n.ethods, we may with one sty... one sH.. Jn f ^""^ * one-chambered ovary side. ^.I^^^T^:::^^;^^;^ placenta down onl: ^s apocarpous, m spite of th^^^^l l^']^ ^^ -;! • Exceptions to this rule occur in the Labiat. and Boraginace.. 3*1 i III \iv 66 FLORAL LEAVES It opens along two lines. In the Wallflower the L^yncTcium consists of a two-chambered ovary witli two parietal V;iacx'ntr and one style with two stigmas ; in the fruit-cindition^he o uy opens along two hnes ; therefore the gyna-cium consists 7f two carpels which are joined together (syncarpous). THE ABSENCE OF STAMENS OR CARPELS. The majority of familiar flowers possess both stamens and carpels, and are said to be mouoc/mous (e.i,-, liutterrup \Vall- flower, Pea, Hyacinth). But the stamens and carprof some plants do not, occur in the same flowers, which L then de- scribed as being dnVwous (..r. Haz.-l, Scotch Pine). A plant having diclinous flowers naturally will possess two kinds of flowers : sMmmife flowers, which have stamens hut are withou carpels ; and carpellary flowers, endowed with carpels but devoid of stamens. ^ipcis um CHAPTER X ARRANGEMENT OF THE FLORAL LEAVES ^^^^^^^^^^^ V-> the flora, ;" .spirals, the flower si^l ^Mna I^ Y^" they are inserted leaves are in spirals and others in k ^' '^'°"^"■ ''^ ''^' ^oral Ov//.fe ">osrspecies of Buttercups) "'''' '^'' ^'''''' ^' ''-'''- CYCLIC FLOWERS. a modd or'a"?ypll itr 'tH ^f''"" "^^>' '^ ^-cribed as example : suppose tha a flowJrnl';' "V'^'' ^" '^^^ -^ other whorl of the flower tSeshSfr^^ ^^ each there might be five sepals five n, . ^''^ ^^""^^ '^^^'es; so carpels. The five petals w 11 J, ^ .^''' -^f " '^^"^^^ ' ^^d five will be succeeded bvnno V ''^^?''"^te with the five sepals and (which are tlfr^V^^l'^^^^^^^^^ stamens will form an inner whoH an/'^n'\' '^^ ^''^ «ther five outer stamens (and therlfore h " '''" v^^'^^^^^ the fiMally, the five carpels wTlInL .^^'"'1^^ ^° the petals): ^^amens. ComparatSy^w cychct "^''^ '^' «^'^ ^^^^^ the three rules laid down •thov/vVK-?''''^'''.^^^^ ^ith all (i.) Obdiplostemonr- SomP fl ^' variations, whorls of stamens, there bein^in .n\'''u^^r\*^^'^ alternating of stamens as the;e are petalf n a whot°K '\'''^' ""'"be? of stamens are opposite to th^ n 7^ ' ^"^ ^^^ °"ter whorl with thrm T ,^f .^^*^ ^^ the petals m n krp nf -i- vvun rncm. m addition, J' k fremn^nfi, *u ^ t akcrnating "UH^ber of ca,pe,3 is ,k -^ S''rhS%T^,'^;;^- £ 67' 68 ARRANGEMENT OF FLORAL LEAVES carpels alternate with the inner whorl of stamens, so that thev are opposite to the petals in place of being opposite to the sepals (fig. 1 66). Such flowers are said to hQ obdipiostemonous {e.g. Gerafiiiim, Oxalis). (ii.) Unequal Growth.— In many flowers the floral leaves which form a single whorl are not all alike in size and shape. \a.s Fig. 96.— Vertical section of flower of Garden Pea. Fig. 97.— Separated petals of ditto. The flower as a whole, or the whorl itself, is then said to be irregular. The corollas of the Pansy, Pea (figs. 96, 97), and Dead Nettle are irregular. In the Dead Nettle (fig. 191) two stamens with short, and two with long, filaments form one whorl. On the other hand, the andrcecium of the Wallflower (fig. 88) consists of two stamens with shorter, and four with longer, filaments ; but the two short stamens form one whorl, and the four long ones comprise another, so that the andrcecium is not irregular. When all the floral leaves of each separate sd w CYCLIC FLOWERS ^ ^ore, IS a special example of^?n. , '^'"^^"'"^^ •• atrophy, th-re- examples of atrophy ?,^>f""'^"^' S^^^^'th- Staminodes are duced their anthers LT ''™''"' ^^'^^^^^ have not pro Umbellifera. or Co^posit^ T^^ """""'^ flowers o^hj sented byfive rn^^.Tei^'V^Z^ ?"' V'^ ^^^^"^ ^^P^- atrophy; ,n still others no ca Ivv';. ^ '""^^ '^ ^^^ undergone missing, and we then speak of ,h' represented, it is entirely In the Foxglove and tl fDead Nett^frT °^ ^^e calyx^ sepals and five petals represen^4e cas^ ^^'^'^'' ^« ^^P^^sen? stamens of the staminate Haiti flf ""' instance, the four divided down the middle, s^Lt I'' "'^ "'"^"''^^ complete?, imagine that eight stamens wem preset fi'^ observer might floJ^rl 1^-:^^^^^f^ ,^,, --byc-der-th^tS^:^---^^^ Tl 70 ARRANGEMENT OF FLORAL LEAVES there should be an equal number of floral leaves in each whorl, and the successive whorls should alternate. Often we are assisted in comprehending the apparent exceptions to these rules by obsen-ing the structure of flowers belonging to plants closely related, and therefore included in the same family (see Foxglove-family, page 157). And again we know that a foliage- leaf commences as a single little lump on the surface of the stem. A separate floral leaf arises in the same manner. If, therefore, we see five lumps grow out to form the commence- ment of the andrcEcium of a flower, and they alternate with five outgrowths which are the beginnings of the petals, we can assume that the androecium is constituted of five stamens, however the stamens may cohere or branch subsequently Symmetry of Cyclic Flowers.— If we compare the flower of a Geranium or Hyacinth with that of a Pea (figs. 96, 97) ^^\ '^'^'Ti\ '■^g"'^"' actinomorphic cyclic flower on an axis (en, a va/va^e (fig. 102) or an /mAn.a^e (figs. 103, 104) manner (see p. 128); especially frequent is the two - fifths aestivation of the calvx ('fip rr,A ^u n • '°3 104 lU Fig. 101.— Floral diagram of Garden Pea. Figs. ioa.io4._Diagrams of Estivation. In the bud. tb'epTstSiortL ''''"'"■ n^' fes,en^i„^-m/.,i}J,^ the lateral petal and thf ' '"" '''^'"^ ""^^^^ ^^''^h their edges reverse, it is ascending imblSte* °"^ '' P'"'^^^^^'>' '^' the intnion";? lh'.fan;r„i;'T'.";, ^^ ,f ^--tion of the calyx and corolla, should be denoted; but young bSn;;;;';.^;^^!^^':!:^"' '"^'' Ifc! m] m m 74 ARRANGEMENT OF FLORAL LEAVES Floral formulae and symbols—Certain symbols and formuI-B The sL^^Kd^Vn'"^^; '"^"'^ ^'^' -or'pholoro?alT n int signs and | denote actinomorphic and zyKomorohic flowers respectively; the direction of the arrow serves aZ to how the plane of symmetry. A vertical arrow | corresponds y.th a median-zygomorphic, and a horizontal atrow !l^ wifh a tran.verse-zygomorphic, flower. The signs c?, 2 § deiTote respectively staminate, carpellary, and monocinous flo™ Io)llHCn:Z'\V ^'^' ^ r^ ^ -pres^thec:!;;- Pkced immeH^n^^i ^"f «^^^T' ^"^ gyn^^cium. The numbe placed immediately after each capital letter shows the number of leaves in that particular whorl or spiral. If the gynrium be syncarpous, its number is enclosed in brackets otSs^ the number is not in l^rackets; if the ovary Te inferior a horT zontal line IS dravvn above its number, if-it^be sipedor\L Hie ha'n t:'elve fJoril' T "'"• ''''' ^^^" =^ '^-^'^ ^^1? mo Floral formula of the $ flower of the Buttercun e K5 C5 Ace Goo • P' Floral formula of the ^ flower ofThe Pea >!' K5 Co A5 + 5 Gl ' Floral formula of the ° j o~t to fo™, f ,! "■ "?.T"""",^ "' urn-like concave receptacle Th IjasuMike or deep receptacle. Ihc carpels are attached to the ('ri/£&b*;?r%l73ri:otre "r^-*/'- *e base fig. 168), of tte conclvin whik, ,h ' ''"f' ''"'**= (•■* ^"''■'' inserted on its rim ll 'e fl^ ■'' 'uP^'" """^ ?"=>'» •'"•'-■ «yn.cium is stiuXcribed a "5;:/"'" ^-<^"""«; "- Epigynous flowers (fig io,» ^ iZ'u .u possessing a receptacle^lichl Lowcd';,'ta",Lr ■''""■^ flowers, and the camels nrt^ n^f /„i ' f ,^ '"^ perigynous thus fo'rmed, but 'hey are acS^^^^^^^^ ^" !'^^' ^°"^^vity its sides Tt th, c k ^ actually fused with and coherent to the ovlry (J ova iesoTro^ th"^""^'^^ ? ^^P^^^^^^^ ^'^ -'^ of petals a^pWaff hey wire i3'd''' '"' ^'.^ ^^P^^'^ ^"^ ovaries). The flower Ts tT,Jn ^ k^"P°" ^^^ ^^'^^-^ («r gynaeciim is,Tn th ca e said to h"^-'^ '■' f'^'"'"'- ^^e 199; Daffodil, fig. 21 c) it will h?'/ K^T^'""^'^' ^g- inferior ovary reallv cnn.i.f! J .• "^^^^^at the wall of an the receptacle. ^ °^ P^''^^"'' °f the carpels and of an^t:^:^S^:^^;i7^" ^ypogynou, perigynous, on the perianth-I^a^e^S;:; ar^^i^S^^^^— ^^ ;'* {, I'! 7« ARRANGEMENT OF FLORAL LEAVES form a 'intraul °r'''^ '"^ ='™'^"' '"" ^'^'= -""- «» Disk— Frequently the receptacle of a flower has iinnn ,> Th "Hi^'''""?'; O"?"'"'*., kich collect" el, form the J^i] the disk sprr^f^c u^ "^^^P^^cit j^e.^r, xose). Very frequent y coUectLn'of neSarf ^ '" "'"" ^'^' " '^ " "-'"^ " ^ CHAPTER XI NECTARIES-POLLINATION NECTARIES. honey-gland. The oetak nf vf« w ' ? .^ ^"''"'^^ ^ '^^^^«^ or Rose assume the fo^Stf tt' which h^"'' ^"' ^'^"'^^- and are thus nectaries Thrfl ""^'^^^^'^^ewise excrete sugar, 'SI, 152) has on^wo ne^ries wh,°K '^' Monkshood (Igs.' stalks and represent portSns'V^^^ which are concealed beneath th.L ^^° P°«tenor petals (//), sepal. The two anterTor timen S^K^^'r'r^-^'^^ P°«^e"or 158) send narrow baSe process (Ji! fn^jl" "^^"^^ ^«^- anterior petal : on earh nf iu ^^^ "^'^ ^^^ ^pur of the denotes tL locatbn of Ihe hon^^^^^^^^^^ ^. ^P°' -^ich or Violet, we can distiUuL hl7'^ 1 ^^'''' ^" the Pansy portions of the stamens^and matrfh" '^ ^''^""^^ ^^^^^ ^^e /■^..//^.Z. which is The spur of th^ . ? °"'^' ^"^ '^' «^^^^^- the sugar manufacturedTrthenectari^^^^^ t?^ ^^^eives gold, and in Arum narf.; nf\h '^^'^^^^^P^' I" the Marsh Mari- whilst in the ]S1K he five nfr?^^'^""' "'' ^^ honey-glands ; (fig..i6i .). In factTsepalf pe^l^^^^^^^^^ °" ^^^ ^^^ «^Pals partially or wholly modiC rexc^etl^^'r °' ^^t "^"^ '^^ however, the nectaries do not renresent S ^ °r^^' '^^'^'' leaves, but are parts of the receptacle Fn "' ""^ '^' ^^^^^ flower of the Wallflower (fiL 88 r .i ^ I '^^^^nce, in the glands, each being in the form o/^ ''^ '^"'"^^^^ * wo honey- POLLINATION. 77 i w m I!ll! 78 CROSS-POLLINATION V ! .■I 1; fi Consequently, flowers which possess stamens but have nn carpels do not bear seeds. Whereas flowers devoid of starSens but endowed with carpels, may produce seed. Experimem has shown hat the ovules do not change into seeds unlesTpolIen grams have previously been conveyed on to the st^ma for in Gymnosperms, into the mieropvle of the ovule). The pollen m some way exerts a fertilising influence on the ovule Ihe transference of pollen from an anther to the receptive ;.i;i/:!;r ''''-' °^ ^ '^^'- ^^ -^--^ ^^ under ^^ Cross- Pollination and Self- Pollination. -The simplest method of polhnation is the transference of the pollen from the anther to the stigma of the .same flower; this is descriS as ..///.//,;,a//.., and the flower is said to be ..//^./S^^ When on the other hand, the stigma of a flower reci4sZlk^ from the flower of another individual-plant of the same kmd i" IS, said to be c.oss^o//i^,o,i Lastly, pollen may be t ansfe red from one flower on to Ihe .tigma of another flower oHhe slr^e indmdual-plant; this h ^Iviously a stage between eras -no H^^^ ion and sel -poIIin.u,-.u, hut there is no simple word c^ite"^" m use by which to distin:,i;;sh it. CROSS-POLLINATION. It has been proved that in many species of plants cross pollination leads either to larger crops T)f seeds, or to he pro duct:on of seeds which are better il; quality than k the e^ase' when the same plants are self-pollinated. Accordingly manv arrangernents exist in flowers which are calculated S^Ser Tonrtior"" '"' '^^"'^^^ ^^^ -°- invigorating 'cios: Arrangements for hindering Self-pollination •— (1.) Sometimes ^/le stamens and carpels do not occur in the sam. flowers, consequently the pollen must be conveyed from one flower to another. The stamen-bearing (staminate) and carpel-beanng (carpellary) flowers may oc?u on ^hTsame individual-plant, as m the Hazel, Oak, and Pine. Or the two kinds of flowers may be on dirferent individual-plants, a in the Willows, in which case the stamens are borne on one tree and the carpels on another tree. ° "i";\f^^'™?.''^' '^T'""' ""''^ ^^^^^^^ ^'^ one flower rtp.n at different times; the consequence is that, though the Iljpf WIND-POIJJNATED FLOWERS yg flower possesses both stamens and nrnpk fK n stigmas arc not rca ly for noHinSn ^Mh ' ^'^ ''"" ^"^ ^^^' the stamens shed tLir pX." Hon th' "T"" '"•^" l^''^'''" receive it. thc^ flower is said to h. . ''>''"'' '' ""^^^y to family, MalW). liu Xn L .^^^ ^'''^— ^^^^ '''''^y- anthm are ah L to dehlce t !' tT"" ■ '\''^'\ '"' ''^ tero^^vnous. "^-niscc, the flower is descnl)ecl ro- pollen from the sLf flow' nol 1 ' ''", ' '" '^'^'"^^ ^^'"^■^^■^^ form of Primtl^'l'n^CiSof "' ^' '^'^^ "^ ^'^^ ^°"^-^y^^"d iloS^ri'K'cLe'o?'^^^^^^^^ °^^'^ Wind- Wind-pollinated raised above ground o tZ^^"""""'?^ ^'"^'^ "^^'^ «-^'-^ pollen to be trLspor teS thro" h Z^^U^t^ ""''''''^y ^^^ cross-pollinated. The Dollen hnfn. ^°'''^''"' ^'■^' ^^ ^e only rarely does th niant if^.if ' "P ^"^^'^'[^0 move unaided. violently ^as in t l^^l,::^ ""^Jt^J '""^ ^'^^ cross-pollinated bytheSr'h-''f- l^""'"''' ''^^'^ '•^'^ polliLed flower^. Plo'l vhth'are ''' ^'T^^'^ "^ ^^'■'''^- agency of'animals ^TalM^at'^^^ ^^^ animals which are of importance in X^tf' k "^^'" ^'^^^ °"'y of flowers are insects -^icew™^?^^^^ cross-pollination As examples of wind SmLt^edfln'''''"^^^^^^^^ «°^^-^'-«- Hazds,PoiJars,andGtL"^^^ "^^l TfT "'f ) The?: ""^^-P°^!--te^ flov^efsTittv^l be' noted ttit •'" . They are small, mconspicuous, and unseen ed * (11.) They have no nectaries ""^-centea. iV ?hf ^T"" '' P°^^'^^^y' ^"d not sticky. fre^iy^o:t':f^reio:;^^^^^^^^^^^^^^ i;i3t"^-t ^"' ^r^ or^tVreldlf ^oll T r^'^^^^^^P^d. and often feathery !l:; i J IMAGE EVALUATION TEST TARGET (MT-3) 1.0 I.I 1.25 til IM 2.5 1.4 2.2 2.0 1.8 1.6 150mm 6'

^^ >> '// y / /^PPLIED_^ IM4GE . Inc .a^ 1653 East Main Street _^=-^ Rochester, NY 14609 USA .^='.= Phone: 716/482-0300 ..:^ Fax: 716/288-5989 e 1993, Applied Image, Inc.. All Rights Reserved |\ :i>^ \ \ -''%. f ^ ■ mentioned, it w"ll be noted hat the buttercup.flow,.r may be entered f om ay ^de and the vtsittng msect may crawl about in the flower and recei^-e F I liHJI '!'i| 83 SELF-POLLINATION pollen on various parts of its body. On the contrary, the 'Bee-flower" is so constructed that its honey cannot be obtained unless the insect visits in a certain special manner ; the consequence is that the visiting insect receives pollen on a certain definite region of its body, and may unerringly convey that pollen to the stigma of the flower next visited. For mstance, in the pea-flower it is the under-surface of the bee's body which comes into contact with the pollen and stigma ; in the Foxglove, it is the back of the humble-bee which is pollen-dusted and meets with the stigma. This ar- rangement in these "Bee-flowers," therefore, not only allows the flower to economise in pollen, but it also places the pollen and honey in a position of greater safety in regard to the injurious action of rain and the inroads of marauding insects. For further illustratjions, refer to Ranunculacex (p. 121) Papihonaceae (p. 138), Labiatae (p. 155), Scrophulariace^ (P- 157). Caprifoliaceae (p. 160), Aracea (p. 180). I r t h c r( a: C( m T 1^1 SELF-POLLINATION. Although in the case of many plants' cross-pollination leads to the production of better seeds, or more seeds, than self- polhnation, yet some plants produce quite as many seeds, and those of as good quality, by self-pollination as by cross- pollination. Cross-pollination has this advantage over self- pollination, that it frequently affords- a better crop of seeds. But self-pollination is superior in one respect, it is easily secured and rendered certain: the pollen simply has to come into contact with a stigma which is ready and close at hand. The self-pollinated plant is not dependent on the presence of another individual-plant of the same kind in the im- mediate neighbourhood : furthermore, it neither demands the attendance of special insects nor the influence of wind in a certain direction to carry the pollen to another individual. Many flowers are self-pollinated, either spontaneously or by the agency of insects. Insects wandering over the Buttercup- flower frequently effect self-pollination. In Malva rottmdifolia (see page 134), and in some members of the Daisy-family, the stigmas curl down until they reach the pollei -laden anthers, so that the flower spontaneously pollinates itself. The flower of the Poor-man's Weather-glass {Anagallis), if it ;* ^ i SELF-POLLINATION g^. the sti.ma effect s, If nn r •^'''' .^?'"'"^' '"^° ^""^^^^'t >^^ith f! j i> 1 "'. li |ij III CHAPTER XII OVULE— FERTILISATION— SEED— FRUIT OVULE. An ovule (figs. 108, iii) is a more or less egg-shaped body attached^ to the placenta by means of a stalk — the fimicle (/). The main body of the ovule consists of a central egg-shaped 108 loQ ' no mass — the niicellus — which is surrounded by one or two coats — the integuments {in). Each integument is attached by its base to the nucellus, but elsewhere it surrounds the nucellus like a narrow- mouthed bag, which is open at the top. The opening at the top of the int*'gument or integu- ments is the micropyle {m) ; it allows free com- munication between the nucellus and the chamber In the nucellus itself, near the micropyle, there is a minute clear space. This is in reality a closed bladder, and is termed the embryo-sac. There are three com.mon types of ovules, whose forms are best explained by the figures given. (i) An orthotropous ovule is one in which the stalk (funicle) is in the same straight line as the straight nucellus (figs. 108, 1 1 1). (2) An atiatropous ovule is one in which the nucellus itself is straight, but is inverted, and consequently .appears to be attached by its side 84 Figs. loS-iio. — Ovules. - , Figs. 111-113.— Vertical sections through ovules. 01 the OVary. OVULE 85 FERTILISATION AND CHANGES IN THE OVULE. When a healthy pollen-grain reaches a suitable sticma ffit- s. vt*^ '.X"""f'^''M-^"'ii.g a slender tube (//) &\he c,o:™';^'^thrt;:^h^:T.v7sac°s" -'' "-^ ""^'"- .u ! '^u ^^"^^^qu^'nce of fertilisation is that the ovu/e grows and becomes a seed (compare figs. 1 14 and 1 15). The most important change in the ovule is that a minute _ new plant-the embryo- ^^ develops mside the embryo-sac. The embryo-sac grows and becomes, wholly ai or partially, filled with endosperm, which surrounds the embryo. This endosperm may be present still in the seed, and Fig. 114.— Vertical section ^^C Seed is Said ^ " through a carpel and an aiiatro- to be /'^;///jc/S^^„,/- '^^ pons ovule, showing the pollen. ^'laOSpertniC ,.. tube entering the micropyie. — e.g. Grass and '•' iS«;. Ur the endosperm formed in the ovule may be gradually absorbed by the growing embryo, so that in the ripe seed there remains no trace of it • the seed is then said to be non-endosper- mc~e.g. Bean and Wallflower (fig. j 16) In most flowering plants, whilst the em- - - --- bryo-sac, the contained endosperm, and the embryo are grow- miL™ pr ?!? Ti.T'j^i^::^ir''^ ^^ ^ ^f of . compound the mic^yle. but pushes^"! 'ZXoJ'/h S?ubstnceTf tt ouf t^^ It reaches the embrvo-sac In thf> T>;n« 5 -""^""^^ ot the ovule till grain itself reaches th'e ^L^^ ^d ttas'el^ra X"" *= ^"'"• w . Fig. 115.— Vertical sec- tion through a fruit of the Buttercup, with one anatropous seed : per = pericarp; )'j = testa ; <■«(/= endosperm ;*w^ = embryo. IP M !: I r 86 SEED ing, the nuccllus is being absorbed by them, and no trace of It remains in the mature seed. In such cases the whole of the seed within the testa represents the embryo-sac and its contents. In some plants the nucellus is not entirely absorbed, but persists and forms an endosperm-like layer within the "^ "7 ii8 Kl^\,J}^?'?--^"^'^''^ ««Ium ; /s = false sep- tum ; o = seed ; v = valve ; Jf= stigma. Fir. 121.— Siliqua of Chelidoniuin ; /-^re- plum. ('■i Fig. i2_'.- CapMile of Iris dehiscing aloriR three dorsal sutures {(is) ; 7'.t = ventral suture ; J = seed. Fir. 125. — Capsule of A nagallh dehiscing transversely: r = calyx ; ff=- seeds ; Jo or mote car/^c/s hut / i!''"^? '' '>'"^'^"y P^^'-I'ke in Shane morciarhi'/s '' « W Usual,, . J,,. ue„i,,e.„t ,r„i, A,r„,od" h^'t^ «n Ui C.ISU the- sc-iKiratc valves arc- t..oth-liku \'^y Violet, f.g. X5S; /^/,, r.g. (Y) SplittiMii along the ventral sutures, and cparat.ng from the partition wJlls of the capsule so as to leave the seeds attached to a middle axial column (e^r (8) Splitting for a certain distance along th?th ''"' '"^- ^^"^'•^^ sutures, so hat there are twice as many valves as there are carpels (especially in capsules ^^ th tooth-hke dehiscence) (.. {^') Capsule with transverse dehifcence." The ton of he capsule separates like a lid (.. . Poor-man's A\ eatlier-glass, fig. 125). ^ '''• '^^" ^ {c) Capsule opening by a number of little holes or Am- in the pericarp (..., Poppy, fig ,2°) °' (^) Capsule opening irregu)aHy. ^' ^' ^. FLESHY (Dehiscent). Some/;///^/^^ are soft and sreen whpn fj, ^ u- Has a so. p..a.p, ^r^H./^S^/oitSd \m 92 INDEHISCENT FRUITS throif rfl> , V^ ''''' ^ ""^= '''' ^ Stone-fruit, INDEHISCENT FRUITS ASie '•;;; . , ^'^- /?S.-Vert cal sections of the Sunflower fh^^^f' °> ^^"'^ = '" '^^ right-hand figure ounnower. the fnut is cut vertically through the ventral suture (r/^) .nd dorsal sutSre : in the left-hand figure the fruit is vertically cut in a plane at right angles to the pre- &ta°orseirr.:"Usw:„p--^p' One-See^e^. ""' ^^^ (Indehiscent). (i) Pericarp stone-like {e.g. Hazel, fig. 138). =Nut (2) Pericarp leathery, or hard skin-like. (a) Pericarp not adhering to the testa (e.^ Buttercup, fig. 115 ^ Daisy-famify, l^\ P^'- ''^u' •^- =Achene. (P) Pericarp adhering closely to the testa, or the testa absent {e.g. Grains of Grasses, Wheat, fig. 28). = Caryopsis. B. FLESHY (Indehiscent). (i) The inmost layer of the pericarp is stone-like =Drupe {a) The outer layer of the pericarp of a drupe is like a thin _*skin,» the middle layer is usually soft and juicy, and the inmost layer is very hard = Nut. FRUITS 93 and stone-like. The simplest drupes are composed of one carpel, with one sto^ e enclosing one seed (.,^. Cherry, fig. i^s' I lum. Apricot). The most complicated drupes are syncarpous, and have several ston^es because the walls of each of the ovary! chambers has become separately changed into a stone with one seed inside it. It must be noted that the stones fe Hawthorn oTstone- ToZt '"V'^'u ^ '"'"^ '' P^°duced from an ovule only, whereas the hard stone of a a\ Th "P""-'' ^"'^"^"^ ^y ^ ^^y^' of the ov"-v-wall (^) The pericarp is soft and fleshy throi. out L Grape, Gooseberry, Currant, Orange, Cucumi (d The fruit of the pear and apple is quite pecuS" and IS termed a Pome. The component five carpels are fused with the hollow receptade mierior (hg. 178). i he carpels are also com- bined with one another by their sides, but may be free towards their' centres (ventra su ures), thus the gyn^cium is only incom mch^'^?^l'P°"'^ ^i^' '79). In thefrufta parchment-hke membrane forms round each chamber, just as stones may form round the resH t'"'^"' °' " ^^°"^-^^"^^' ^hils? the r:i;^thr(%?^.i:-3rr^3^ SEPARATING FRUITS (SCHIZOCARPS) These all possess more than one carnpl Tu^ «« .• carpels .epa,a.e as closed one-seedrf cSV' ~"^""'^' ctiamberuj parts as there are carpels Earh m!, represents a closed carpel, and is te'med a m«i^ m n\ 1 , 1. •1 'f ! '1 i ii| jl 1; I'*' 94 FRUITS {e.g. two - carpellary fruits of the Parsley-family, fig. 185, and Sycamore) or a coccus (if the ovary consists of more than two carpels, e.g. Mallow, fig. 164) //\ Tu 4. „ , . . = Schizocarp. {0) 1 he two-carpellary fruit is divided into four one-chambered one-seeded parts which separate as little "nuts" Each "nut" therefore represents half a carpel (e.i^r, fruits of the Labiata, and many Boraginacece). COMPOUND FRUITS. The compound fruit may possess a number of follicles {e.g Pffiony, Winter Aconite), of achenes {e.g Buttercup, Rose, hg. 170, Strawberry, fig. 172), of drupes {e.g Blackberry, fig 175, Raspberry), inserted on a receptacle. But obviously it cannot possess a number of siliquae or capsules, because these are always syncarpous fruits. DESCRIPTIONS OF COMPLETE FRUITS. The classification of fruits so far given refers only to the nature and behaviour of the pericarp. A few examples will fruits application of this classification to complete car 'el ^^^' ^^^ ^'"''^ '' '™^^^ (legume) and is the ripened (2) Honeysuckle : the fruit is simple (berry), is the ripened inferior ovary, and therefore inclujjes the receptacle (3) Dandelion: the fruit is simple (achene), and consists of the ripened inferior ovary (carpels and receptacle) and pappus. (4) Raspberry : the fruit is compound; the simple fruits are' drupes ( = carpels) inserted on a receptacle, which also bears a persistent calyx. (5) Strawberry: the fruit is compound, and consists of many achenes ( = carpels), and a large fleshy receptacle bear- mg a calyx with an epicalyx. (6) Rose: the fruit is compound, consisting of many achenes ( = carpels) attached to and concealed in a hollow receptacle which bears a persistent calyx. "nuts." CHAPTER XIII THE DISPERSAL OP SEEDS. AND A SUMMARY WITH REGARD TO THE PLOWERS thousands of seeds. If every one of these seeds is to be afforded an opportunity of developing into a mature plant, means must be pro- vided to enable the seeds to reach suitable spots at some distance from the mother-plant. The seeds of flowering plants are con- veyed through the air in the same manner as the pollen, in so far that they are either violently ejected (e.g. Bal- sam, Oxalis), or are carried by the wind (e.g. Dande- lion), or borne by animals (e.g. Rose, Cherry, Galium). Explosive fruits are not common. The capsule of the Violet opens into three boat -shaped valves, each containing a double row of smoothly - polished seeds. The sides of the boat-shaped valves contract as they dry, and fling out the seeds. To understand this mechanism, we have only to remember the manner in which an orange-pip springs out when squeezed between two fingers. ill, 120.— Right-hand figure is a vertical section of infructescence of Dandelion: br = involucre. _ Left-hand figure is a vertical sec- tion of a single fruit (achene) with a pappus rrf-»)on a long beak; /c = pericarp ; //= testa the seed; c<;/=cotyIedons ; *'=radicie. Dispersal by the wind—To facilitate dispersal by the '% |!uit = capsule). Wallflower (Fruit = siliqua). Scotch Pine (is a Gym- nospenn), fig. 67. Willow, Poplar, Wilfow- herbs (Fruits are cap- sules). Fruits Dispersed (Fruits indehiscent or separating) Nutlets of Labiatae. Mericarps of many Um- belliferae (fig. 185). Samane (fig, 130) of Elm, Birch, and Sycamore. The achenes of many Composite (Dandelion, etc.) with a pappus (fig. 129). Achene of Clematis with a hairy style. Dispersal by clinging to Animals.-Many fruits possess hooks, or rough or sticky surfaces, which cause^hem to adhere theTrnJ^i ^^T^Vl '''■"'^ against them. It is usually Seeds dispersed by being transported inside Animals.- It IS to be noted that when the seeds or fruits are scattered by small ; or rge surface jit or seed, n of wings that wiicn :hizocarps) the meri- idapted to e passively t dehisces, seeds are it is they "erence to esponding dispersal 5PERSED liscent or ^g) at£E. nany Um- 185). o) of Elm, >'caniore. of many )andelion, 1 pappus \chene of ti a hairy > possess :o adhere s usually examples of many "Mm, and imala — tered by DISPERSAL OF SEEDS ,. animaLs are usually pisJsLri of !?'^ ^^ ^"">^ ™'-'-'«> "'»ide which invite a„i„';r"o notic :Xr"hJn,'' "t,'"' T^^' and inv tes the animak whTh 7? P^"^^'^P ^^^ich is succulent When, on the o Cr hand ,h ' '^"^ "^''^^''^^ ^^ '^'^ ^ruit. nospe;ms and d7h scent frufts 'Tif'' ''? "^^^"' ''' '" ^>'"^- coloured, and may We a succulen'; iW" '"^ °^^"^ '^"■^^^^^>- an/). ^ succulent mviting outgrowth (the Seeds Dispersed. {a) Fleshy aril— Seeds of Yew (Gymnosperm) I W'th, bright- red fle.hy ;'.anl," distributed by birds. ■^ . L Fruits Dispkrsed, | (rt) Fleshy pericarp— Drupes of Cherry, Blackberry, Kaspberry, distributed by birds Larger drupes of plums, etc., distributed by larger animals (Mammals). Berries of Mistle- toe, Currants, distributed by birds. ^ {b) Fleshy or coloured receptacle— J^ose-hip Strawberry, both d tributed by the agency of birds Protection of the embryo in the se^d pk food-substance inside the tesf. In ^~ ^'^ ?"'^'"y° ^"d climatic influences whih would haTn'thr'n''^"" "gainst and decay, and ' against at acks on th^ ^^7 disorganisation fungi. Theemhrvn^nH f T I *^^ P^'^ ^^ animals and by f firm hard eoa, ^S^::t:)T^^W ^^^^^^^ P-tected travel naked, the testa is thir^T^ t^''^^^' ^"^^^^ ^^^^^ Bean). When tL fSt k Hr\ ' w t'''^"^ ^'••^'■- ^^allflower, seed is protected by the SrSol'd .'b'"' ^' ^^P^^^^^"^' *'^^ the testa to be so thick ^nT.?v '^'^ '"-"^ necessity for or absent (J. Grassesr Fi"^^^^^ ^' f^^J be quite imperceptible the stonylivt ofTe tric!^^^^^^^^^ fleshy mdehiscent fruits and the testa is thin ^wh ^ ' ^'u^^^ P''°^"'"'^^ "^^ embryo, layer, so ha' the^esla of th'e T J"'""""' ^^^^^ ^^ "° ^^^"y ai me testa of the seed must be well developed 98 FUNCTIONS OF REPRODUCTIVE PARTS in order to withstand the action of the digestive iuice of animals which eat the fruits. SUMMARY OF THE FUNCTIONS OF PARTS OF FLOWERS, FRUITS, AND SEEDS. 1. The calyx usually protects the young flower bud (e.(^. Poppy). It may also serve as a means of attracting insects by Its colour (e.g. Clematis), or act as a factory (e.i,-. Mallow) or as a receptacle for honey (e.g. Wallflower). Sometimes the calyx aids in the dispersal of the seeds by the agency of the wind (e.g. pappus of Compositae). 2. The corolla serves to attract insects which will effect cross- pollmation. It may further bear nectaries (e.tr. Buttercup) 3. The androecium.— The pollen pollinates the flower and is mdispensable for the production of seed. The anther manufactures the pollen. The filaments bring the anthers into the position which will lead to cross-pollination by wind or msects, or to self-pollination. As good ex- amples, illustrating the fact that the length of the filaments IS to be explained in accordance with the method of pollina- tion, we have but to compare and contrast the flowers of the Primrose, of Grasses, and the cleistogamic flowers of the Violet. The time and direction of dehiscence also, are related' to the method of pollination; we note, for instance, the introrse dehiscence of the Violet and of Composites, the extrorse dehis- cence in the Buttercup when the fldVver opens. 4. The gynaecium.— The embryo-sac in each ovule is the region in which the embryo and its food (endosperm) arise The ovary protects the ovules. The stigma receives the pollen- grains. The style raises the stigma to the proper height so as to bring about cross-pollination or self-pollination. The size shape, and time of ripening of the stigma and style bear relation to the method of pollination (see Grasses, Compositae, Violet). . 5- Sugar.— Sugar is excreted in flowers in order to attract mseccs which will effect cross-pollination. Sugar is manufactured m many fruits, and is responsible for their sweetness of flavour, in order to allure animals (mainly birds in this country) which will disperse the seeds. 6. Pericarp.— The pericarp protects the seeds and often facilitates their dispersal. Often it is brightly colcurod so as to attract the notice of animals. It may or may not dehisce. FUNCTIONS OF REPRODUCTIVE PARTS 99 .J' '^^^ *®«** f ves to protect the embryo and food-sub- stance of the seeds. Consequently it is thin and delicate when the seeds are adequately protected by the pericarp " the disS oTfU '"'^/"''S ''' ''!-'^' ''^''"^*' ''^-^ to faciUtate me dispersal of the seeds. Sometimes the hooks or spines mav also aid ,n protecting the fruits against animals wWch would eat them and destroy the seeds. i m ;|i ill ex- PART II CLASSIFICATION OF ANGIQSPERMS f\ ill \} m a tv sli of cu m( th( sel Ji( Wl coi am Co am Th to cer Ma cul; bel( the seri^ will ing Cla M CHAPTER XIV CLASSIFICATION mm§mm certain orders Th,ZZ ' I ^" ^^"^''^ ^''^ included in will be more easuy understood SgtS thl^h^^ .ng scheme of dassifica.ion of someTthe^ngTosllt ffl'"" ANGIOSPERMS. ^"'' '■ ^nS:d°XSf' '"« ''•^%'™ ^"'^■'^'^o-- Leaves net veined, .^^loral leaves in fours and fives. 103 m If i 104 TLASSinCATION 01 niCOrVLEDONS CiAss II ; Milii^kyledons.— SeodlinK Hus mk- cotyledon Leaves para I Icl- veined. Moral leaves in threes. Class I. : DICOTYLEDONS Sun-CLASs I. : APETAL/K. Petals absent. 1. Cupuliferce. Flowers epigynous diclinous. $ flowers 'h ^u ^"""'^ indehi.scent one-seeded. Trees or 2. Salicaccce. Flowers hypogynous diclinous. $ flowers in catkins. I-ruit dehiscent with many seeds. Trees or shrubs. U- Euphorl>iace^tic posit^o of the Euphorbiacea^ ; DUi the lamily ,s j)lacecl h.-e -let. ise it is easier for becinners to identify plants belonging to it when it is classed amongst the ApetS 14. T5- CLASSIFICATION OF DICOTYLEDON- ,05 (d) 07'rn' syncarpous. Phucntation axile corolla. Anth,.. onc-lobed ^ ''"'" '" "^'-' n. Disci^ora.. Flowers hypogynous number of se.d. in each chamber '""'"-™'' "'"' " HI. Oalyemor». Rowers perigynous or epigynous. «aklyperigy„oir"LST;P'':',hTffiir"? CarpTo^"^"' °^ °- -P--e f-m 'he"othl;r rr ^Tfi:;;e,!r;;;?^;tTsr'"'^ ^'^"^-^ --"^ ^"- (b) Efigym,,!. Gy,mcium svmarpom. UmMl.fera^'. Flowers acinomorphic in umbellate in florescences. K3 or Co A5 G ,1). Fruit a schl^L;" Sun-C..ss III. . GAMOPETA..^:. Corolla gamopetalous. (a) FLOWERS HvPOGV^ous. Gyn=ecium syncarpous. (.) N,men ac- trhamtr^'-"-^''^"'^---- ^>'"" --•- ovules in 14. 15- m ill I) \'i n . 21 22. 23- io6 CLASSIFICATION OF MONOCOTYLEDONS 19. Boraginacece. Ovary four-lobed, four-chambered, with one ovule in each chamber. Fruit four nutlets. (2) Flowers zygomorphic (stamens fewer than the petals : corolla irregular). 20. Labiat(^\ Ovary four-lobed, four-chambered, with one ovule in each chamber. Scrophuhinacece. Ovary two-chambered, with several ovules m each chamber. (b) Flowers Epigyngus. Gynascium syncarpous. Caprifoliace(B. Ovary two- (three-) chambered. Leaves opposite. Cot}ipositce\ Inflorescence a capitulum. Anthers united Uvary one-chambered, with one ovule. Class II.: MONOCOTYLEDONS I. Perianth Petaloid. Ovary syncarpous. (a) Flower adinomorphic (perianth regular, ovary superior). 24. Liliacecc. Stamens six. (b) Floiver actinotnorphic. Ovary inferior. 25. AmaryllidacecB. Stamens six.' 26. Iridacece. Stamens three. (c) Flower zygomorphic. Ovary inferior. 27. Orchidacecs. Perianth irregular. Usually only one anther present ; it is gynandrous. II. Perianth small or absent, (a) Flowers ? c? on a spadix usually in a spathe. 28. Aracece. (b) Flowers usually $ in spikelets invested by chaffy bract-scales. 29. Graminece. [It will be well for young beginners to confine their attention to those families which are specially marked with the sign ° in the above list.] ^ ONS , with one )etals : with one ral ovules DUS. Leaves rs united. iperior). e anther iffy ttention ;ign ° in APETAL/E-CUPULIFER.'K DICOTYLEDONS. CUPULIPER^ (Oak Family). apetalous. Periantnmal lien n'''? "^^"' ^"^°"-^Picuous, three (rarely four or ^,\-?' ^ ' °' ''''•"''"^- ^""'l'^^^ two oi^ or thrL-chambe ed ova ' ^^^^^^^ ^"^'-^"°'-' "-dually with a tw^ Fruit one-seedeTinSscem ^C a^^T " r^d ^'^"^'^^'^- endosperm. ^ "^'- ^eeds without Type: HAZEL (C.;;,./.,. a^,//^;,^). Vegetative Characters.— Shmh ■ ^k^ up into several larger banche a " short T? '^'T ^'^""^^ ground. The main root present in th.T h ''"''^ ^^^''^ ^^^ a short time; it gives off sev.r^ ^n the seedhng grows only for -ntally close beS tfe X of'tre^J'^Th'^';"" ^^^"^ roots (or the basp nf tK^ . w °''- ^ hese horizontal adventitious shoo s4Lt..v"i^- k'^"'"^^^ P^°^"^« ^^-"der These shoots, in °urn can XTh '''/'°^. ^"^^^^^"X upwards, own at their ba"e lnd^,?Kf '"""^""^ adventitious roots of their from the motSant bv r^^'^"'"'^^ may become disconnected ing parts. XsVhe Ha.^T-''" i ' ^"'^^ °^ ''^" "^""^'^^^- Ras^berry cLes and Rose tr"Y) ""^'^^'^ '^ ^"^'^^^ ^^^I-- suc'i;roynrttirj^^^^^^^ ^T -?' - - -gorous the margin is twice ser ate if Tl '''P"'^'' ^^''^^^^ soon fall ; condition the two halves of ^ ^'i r^' "°>'^ '^'"' ^" '^^ »^"d- the mid-rib7the one half of fh^ eaf are folded together along other and overlaps tL'?au:r7n'rhe bud ^'^''^ ^"^^^ ^^^" ^^' prcSuc^^SSlltg bi:^^ ^??'^^^^^^ ^l^^-g^te. and in pairs on oppisito sid'^^ff i^ ^'^ bud-scales are arranged I '] io8 DICOTYLEDONS f * •I i f^ resting-buds are similar, but they have in addition two scale- like prophylls inserted below the remainder of the scales. Within the scales are hidden the young foliage-leaves. In February or March the plant blossoms before its vegetative buds unfold ; when the latter become active their scales drop off after being forced apart by the growing stem and by the emerging foliage-leaves (figs. 6-11). Inasmuch as these scales were set close together, after they have fallen their scars form small groups; whereas the fallen foliage-leaves, having been separated by longer internodes, are represented by scars which are widely separated along the stem. Consequently, on parts of the stem which are from one to three years old, it is easy to recognise which portions bore scales. Each such group of scale-scars represents one winter. We can, there- fore, tell the age of a tolerably young stem by counting the number of its groups of scale-scars. Thus, if we com- rnence at the apex of a resting vegetative shoot, the por- tion of the stem which connects it with the first group of scale-scars represents one year's growth. Again, travelling farther down, that part of the stem which connects this first group of scars with the next Jower group represents another (previous) year's growth, and'hence it is two years old, and so on. Inflorescences. — The stamens and carpels do not occur together in the same flowers. The staminate flowers are arranged in pendulous spike-like inflorescences — catkins. The carpellary flowers are grouped together in small bud-like inflorescences, which can be recognised by the tufts of red stigmas which protrude from their tips. Both kinds of inflor- escences are borne upon certain axillary dwarf-branches. In order to understand the arrangement of these dwarf-branches, we will follow the growth of a vegetative bud which com- mences to sprout in spring. The bud opens, the stem emerges and grows during the summer, and bears foliage- leaves. In the axils of these leaves three varieties of buds arise — vegetative buds, buds enclosing the young carpellary flowers, and buds destined to grow out into branches bearing the staminate inflorescences. The first two forms of buds are externally similar ; they are resting-buds, and remain dormant during the follnwing winter. But the third type of bud grows out at once and develops into a dwarf-branch. This wo scale- e scales, ives. In 'egetative ales drop id by the 2se scales :ars form ing been irs which on parts old, it is ch such ,n, there- counting we com- the por- group of travelling this first another old, and ot occur wers are - catkins. bud-like s of red of inflor- :hes. In tranches, ich com- he stem 5 foliage- of buds ;arpellary ; bearing buds are dormant of bud h. This APETAL.4^.-CUPULIFER^ 109 branch has no foliage-leaves, but it bears on its basal parts a number of scales, whilst its ^ terminal portion is a staminate inflorescence (catkin). In ad- dition, lateral catkins may arise in the axils of one or two of the higher scales of this dwarf- branch. The scales soon drop off. Thus, when we examint; the Hazel-trees flowering in February (see fig. 131), we find the stami:-ate catkins (c?) are arranged, usually several to- gether, on short branches of the previous year's stem: the catkins rest naked through the winter. The buds ( ? ) enclos- ing the carpellary flowers now show that they are not vegeta- tive resting-buds, a tuft of red stigmas protrudes from their tips. These buds also stand laterally on a part of the stem which was formed in the i)re- yious year; also occasionally in the axils of the basal scales of the dwarf, branch which bears the catkins. Staminate Inflorescence (fig- 131 c?). — The inflores- cence consists essentially of a number of bracts and axillary flowers, which are spirally ar- ranged on a long axis. There is one flower in connection with each bract. Two prophyll.s (fig- 132, J^r), representin;r the first two leaves on the flower- stalk, are present, but are fused with the bract (dr), for no flower-stalk occurs. The staminate flower (fig. 132) con ^i Fig. 131.— Shoot of IhwL-] bearirif in- flore.sce:h:w. 'J-he stem from ihescale-scars (..sOw.-ii; produced in the previous year. The dotted leaves have fallen oiV ; 7-= vegetative no DICOTYLEDONS in sists solely of four stamens, which are attached to the bract place of being on a flower-stalk in the axil of that bract. Each stamen is halved almost to the base of its filament, so that at first sight there appear to be eight stamens, each of which possesses only half a complete anther. The anther is crowned by a tuft of hairs. The bud branch (fig. produces the florescence is described as florescence. of the dwarf 134) which carpellary in- often loosely being the in- The bud is Fig. 132.— Staniinate i flower of Hazel inserted on bract 0r), with wliich two prophylls (/>) are fiisetl. Fig. 133.— Diagr.ini of ditto. really the commencement of a foliaged branch which terminates in an inflorescence; but the foliage-leaves do not unfold till after the flowering is over. On the axis of this bud the most elcternal and lowest leaves are two prophylls ; then succeed three to four pairs of scale -like stipules (sc), and within these two to four foliage-leaves. Thus so far the bud is like a vegetative bud; but above these foliage-leaves follows the true inflorescence. The carpellary inflorescence consists of four to eight spirally -placed bracts (dr) with axillary flowers, which are borne on a shortened axis. In the axil of each bract (fig. 135) there stand the buds of two carpellary flowers, so that the whole inflores- cence possesses eight to sixteen flower-buds. But only a few of the flower - buds develop into mature flowers. Each carpellary flower has minute, indistinctly lobedj ereen a minute, indistinctly lohedj green Fig. i34.-Vertiral srrtion of perianth (J>e), which is inserted on the ''"'' ?S H^ «' terminating in a ^ \r /J >-»»^ carpellary inflorescence. the bract lat bract, ed almost filament, ^dit there stamens, ;sses only ler. The 3y a tuft le dwarf ) which illary in- i loosely the in- bud is ement of mce ; but h sc sprtion of lating in a ;e. APETAL^:— CUPULIFER^: III ^t^-c^^'^^':!r'' '^'^yPr- ''^^ -^->- ovary thread-like stills (tr- thuTthf ' '^ '"° ^""^' purplish-rec^ b <^>^ Ks^) , thus the gynascium consists of two Fig- 13s.— Two carpellary flowers of Hazel in the axil of a bract (6r). Fig. 136.— Diagram of ditto. ^37 useless to look for ovn p. W ^ ^n-^^.) ; consequently it is of the ovary (Z) then canT.f P°"^"^^^«"- ^^^h chamber base of each^flot^r (uleZT "' °'"'^^ ^^^^ ^' ^^e insertion of the ovary) there is a little cup-hke envelope (^a/)— an involucre. It is well to note that ^^- his IS not a calyx or a perianth; J It IS a collection of bracts.* " Fruit.— After pollination the ovules are produced, but, as a rule, only one ovule in an ovary develops fully so as to form a seed. The fruit (fig. 13^) is a nut contaming the one seed. The involucre originally investing the — '• the nut is the seed; it has a thin xf ^^^ ^^'"^^ of possesses no endospe'™. "^he^ ^^^^ X^fSe^td'l' are also prophylls. The dia/rani xU^ i • ^^ree joined bracts which een/l^-'?,^ -Vertical section of re- cen ly po hnated gyna^cium of Ha/el HaJt'l^ ^^ ^'^""^^ '=''''°" of""' of I i" ' m il- Ml ' fili' i 11' iffi 112 DICOTYLEDONS constituted of the two large fleshy cotyledons (cot) of the embryo. Dissemination. — The fruits merely fall to the grovnd, or may be carried away by animals (especially squirrels) for future use. Pollination. — The flowers are wind-pollinated. When the staminate catkins have ma- tured they bend down, and, as their bracts separate, the anthers dehisce and drop pollen on to the bracts below them. The pendulous cat- kins are easily shaken by the wind, and the pollen may reach the tufts of stigmas. (i.) Note the inconspicuousness of the flowers which are not visited to any appreciable extent by insects. (ii.) That a large amount of dry pollen is produced, and easily shaken from the flowers. (iii.) The large filamentous -stigmas. (iv.) The absence of nectaries. All these are common features of wind-pollinated flowers. Fig. 139. — Two nuts of Hazel invested with cupule.^ ( -' from the, bauds'* TlU^nl°'T,^■°'." "'^ foHage-leaves emerge a fav scate .TnH i I ' °' *" '"""■■escence bears at its bate The sLnmate ( °) flower ffift, J" *" f" f '="'''> '"■^'"• ^n°'i™bra;f(:)-rd 'F'^<^^^^^^^^^^^^ and has one chamh.-r Jhil '^ . ^ "^ °™'>' <""> '' ^"'""-'d, two parietal phcem^ Th "" "'"u "'"">' °™'«^ ""^'^h'^d to a two-armed stfemaT;.'^ ^he ™gle short style forks above into the flower and Teinltserd beTorth" '''^'^'f ""' P"' "' described as i^ypZnouT T^^IJir'''^! "l? """'^ i» fruit is a two-valvercapsule ,™ch^ltw? hr'*''°''--;''^ numerous minute seed? tL I T *" *-'"="?<= °f *e and each see™ possessed of a1nft„1-'"-L^^^ ^^ *<= ""'d. the sailing mechaS °' ""'>' ''^'■=' ">>'<='' f°™'' Type II. : POPLARS (/'oM«s). catSr;lSinat'?Lt" whh'?'°"%'" ''™"« ?»<'""'- nectaries tho?mh tJ Moreover, the flowers have no P0.1inated;wIereI^tX;rafJSp;iS^^^^^^^^^ •I if ' i IjS ii6 DICOTYLEDONS Iriiiit IlfiSli |1 '■ ance with these facts we note that the catkins of the Willow are erect, its flowers produce honey, and its pollen is sticky. Ikit the catkins of the Poplar hang loosely and are easily shaken by the wind; the flowers produce no honey; the pollen is dry; and finally the stigma, being lobed to a greater extent than in the Willow, it off"ers a larger surface for the reception of the pollen. EUPHORBIACEiE (Spurge Family) Plants sometimes having a milky juice. Flowers usually apetalous, diclinous, hypogynous. Perianth small or absent, (iynxcium, syncarpous, with a lobed three- (rarely two-) chambered ovary, having one-two ovules in each chamber. Fruit a capsule. Seeds endospermic. i Type : PETTY SPURGE {Euphorbia fep/us). Vegetative characters. — An annual herb containing a white milky juice and with simple leaves. Inflorescence : the stem, which is simj)le or has two largy branches, terminates in a compound inflorescence, which is an umbel-like cyme of three Fig. 146. — Cyathium of Euphorbia feflus, branches. Each of the latter is in turn a two-branched cyme (dicUasium), the branches of which may again be forked cymes (dichasia). But throughout the whole inflorescence the actual termination of each shoot is formed by a peculiar inflorescence termed a Cyathium, which looks like a simple flower (figs. 146, 147).— The cyathium has a cup-like in- EUI'IIORiiiACEK ,,^ junction of four of these hricL r f' ' '"'' ''^ Fig. .47.-Vertical section of cyathium of ^u/Aorfiia >■//«. flower <'fiK T .s\ . K f'i'^^'L'-lol)cd o\-ary (o7>). Staminate stalk. A jo^ tL^^^^^^^^^^ T'"'' '''''''''-^ °" ^ "°^^- a^whicH t e fi.. ::i fL^i^jsr r ^i^ "^^ ^^^ ^^^"^ S and dl^n . ''°^.'^' J°'"^ ^"^ ^'^^' flower-stalk to S V' .u^ " "^ P'^"^ "^^'^h '■« closely related Thf fln ?? '^"''; ^' ^ ^^"'^^ P^^"^"th at the joint ] I he floral formula s KO CO A1 TO -n ■' stamen-like flowers are arranged in five S opposite the five bracts* (fiLTs iao tcM PoT I these radial lines of stai;in':;J^fl^o;;^rf ^ep^^^ems an inflorescence standing in the axil of a bract diagram 149). CarpeUaryflower (figs. X46 147) the sino- e renfml o-,,.,^^: _ _•./ P , ■+"' ^47; the single centra gynrecium with kl ^f Vl' ^'i^'-'inate^ flower renresents n c,',..r,i 1 , ^ ^ ^^^ ^°"g ^^alk °f Euphorbia represents a simple naked flower composed of H^'i'^ ^"^ ■'"' three carpels. In some spurges there isTd stinct ^"' "^"^ hypogynous perianth, consisting of three or S^T • \u , even n the Pettv Snum^ tv. • ^''^ penanth-leaves : The ova. ^l "^^^^ ^ ^t^^^l^^t^^ !a!fyrl " "■""'-")'«» in a large cyathium like ,ha, o, J!„M.Ma Ii8 III DICOTYLEDONS ovule (o) in each chamber. There are three forked styles '.vith stig) -IS (.s;v) on the .summit of the ovary. The iloral formula i.s KO (minute) CO AO C, (3). Fruit.— The three-lohed ovary forms a three-valved capsule. Seed.— Endospermic. We see therefore that the cyathiuni (figs. 149, 150) is a cymose inflorescence consisting of one terminal carpellary FiK. 149.— DiagMm of cy.ithium of Kupliorbia. i, 2, 3, 4, 5 .nre br.icts. Fiff. 150.— Scheme of cyathium of huplwrbia. i, 2, 3, 4, 5 are bract flower and lateral staminate inflorescences arising in the axils of five bracts which form the involucre. RANUNCULACE-ffi (Buttercup Family) Usually herbs. Leaves alternate (except Clematis). Flowers, usually showy, acyclic or hemicyclic, regular (except Monks- hood and Larkspur), hypogynous. Sepals polysepalous, often petaloid. Petals polypetalous or absent. Stamens numerous. Carpels usually more than one, apocarpous, superior. Seed endospermic. Type L : BUTTERCUPS {Ranunculus acris, R. bulbosus, R. repens). Vegetative characters.— Perennial herbs. Leaves alternate, simple, deeply divided. Stipules are absent, but there is a leaf-sheath at the foot of the petiole. In the first two species i'()L\'i-i; rAL/i<; kanunculaci: .k ...j the stem is erect, and in M. Imllmus it is swollen at the base. In /v. npcns the stem is not erect, hut forms creeping runners, which are iixed to the soil l,y adventitious roots given off from W " U-, ^"^°'««^«»c« :-cymose ; the axis ends in a In';}; .1 1 V •''';'''"'' '^r '^'^''■^^^ inflorescences are two- branched (d.chasia) or one-branched (monochasia). Note the wo small prophylls on each lateral axis of the inflorescence, s ilif' \'! '^' ^'f'^" "^ ''''' ^"^'^■^■'^ ^he leaves are simphhed; they are bracts. Flower (figs. 60, 6i).-The ^r^?l A '"•' ••''■'' T^' °^ ^""'-•^^"J^ '^^^' ^^^ ^'•'<''' th^it one genera description will suffice. The flowers are hemicyclic monoclmous ( 9 ), regular, and hypogynous. Sepals (J, sp) five, separate, green />./,^^• (.or, p) five, alternating with the epals, sej^arate. Note that there is a little pocket -the nectary (/0-at the base of the mner face of each petal. Stamens (and) mimerous (oc), hypogynous, spirally arranged, separate Carpels {}iyn) numerous ( ^), apocarpous, superior, spirallv arranged on a conical receptacle (r). Each carpel contains one basal ovule (^) ,n its one-chambered ovary; style, very short : tigma, knob-hke Fruit :-compound, consisting of numerous achenes (fig. 115) upon a common receptacle. (Each achene IS derived from one carpel.) Seed endospermic (end) with a minute embryo (e;nl>). Pollination, -The outermost stamens ripen before the inner ones and before the carpels. Their anthers dehisce towards the petals. At this early stage the flower IS practically staminate, for the stigmas cannot be pollinated because they are not ripe, but are covered by the closed anthers of the inner stamens. Gradually the rest of the stamens ripen and dehisce, but the stigmas are ready for pollination before the innermost stamens have dehisced. Ihus, when it first opens, the flower cannot be pollinated. subsequently it can be either cross-pollinated or self-pollinated Many kinds of insects (beetles, flies, bees, and butterflies) visit he flowers for the sake of the scarcely-concealed honey or for the pollen, and act as pollinating agents. Type II.: MONKSHOOD (Aconltum napdlus). The Monkshood differs from the Buttercups in the t. "^i^ y^^^^Y ■—■l^^r^orcsccjice, a terminal raceme. Calyx {J>s, as, Is) blue, petaloid; of the five sepals the posterior i 120 n I DICOTYLEDONS one (/>s) is hood-like; irregular. PeAr/^ ^.mht • tu. . posterior (//) paals arc'long-cWd n^L c^n eded undl? pa rS'l ovu r.-nth ■"■" ''P"''?,!f '•"^•■''- '■"* «ith many fol cS Th, fl "'=.°™'-J'- , J '»=/"«/ consists of three tolliclcs. Ihe flower is irregular, and is zvomorohic in ^ median plane. Pollination._Th; flower is^ZSrous; as Figs. I3T, T52.-Flower of Monkshood : <^^=bract ; ^r=prophylIs, fmol'^slhlP ^l "' °'^r P°"^". ^PP^^^^ t° ^e thus rendered Kd^f hnJrr"'"'T ^l ^^^0"^Pli«hed exclusively by flit V ^""^'^'e-bees. As the humble-bee alights on the flower, It uses the two lateral sepals as a platfo m and the consequence is that the lower surface of the bee'sSdv comes into contact with the anthers and stigmas. In freshlyCned flowers It IS the anthers against which the insect strikes ^Tu^ m older flowers the stamens have bent back, and the sdgmas b e atT Tl "ff' '^^'^^ ^'^ ^°"^^ ^"^^-^ °f the body oTthe bte at precisely the same spot as do the anthers in a younger POLYPETAL.E-RANUNCULACE^ 121 p^ w£%s^^r i.5:r ^^°^^-p°"'-^^^^^ The lowest flowers, and travels up he in fl'' ^°"^"^^^"^^e.s at the polHnation b; the poHen even nf .r'"''""''' ^" ^^^'^ "^'^^nner The long-stalked neSes are rnl ^. f"'" P'^"^ ^' ^^'^^rted. side view, nor can thdr honev h ^ '/'^^ ^°"^^^^l^^d from out- difficulty by any insec X^'th^nTu^W f^'^^'^P J^^^ ^reat hood-flower is a flower esDeciallv nHn . r"^''"''" ^^^' ^"^^o^ks- agency of these particular wl^ ^ '"^ ^r pollination by the those regions of the earTh vvhlh ' "^^^^l^^^^^^y it is absent from Com/ansou betzveentke l]/// ^'"^ ''"^°"' humble-bees. is actinomorphic, and if dl^^pi '^ ^''"°7 buttercup -flower nectaries arj feebfy conceded In. f ''"•?'• ^""^'""^^ as its with quite short toLues cl ditn '^''^L ^^^^■'^^i^le, insects The flower is therefort Sited bv^/ ''""'^ '^' ^'°"">'' of insects. These alight l''h J S's ^oTon '.'^ "'^^^^ ^^"^^^ may cause cross-pollination nr.«if n ° °" ^^^ carpels, and hood-flower is Cm^phfc and' t " ''r . ^ Its honey is carefSlly concealed nnV"?""^ '? '^^ ^^"^on- specialised insects ca^n dTscover anr, ^T"'"^' ^° ^^^^^ ^nly pollinated exclusively by one ^oun o/'"'^ ''• J^'^^ ^^^^"^^ ^s which visit in one partkukTr wav '. I "^sects-humble-bees- pollination as they go £rDran^%o i"?''^''^' ^^^^^ ^^oss- ^mpossible in the Monkshood fln ^'''^u ^elf-pollination is Buttercup-flowers tK ustmt Tf. 7^^ ^^nkshood- and shapes of flowers are as ocSed wkh tL '' -^'^ '°^°"^^ ^"^ which visit and pollinate thTse flowers %^''T''' °^ ^"^^^^« irregular zygomorphy is a mean. 7,^ i )^ ^^'° '^^ ^hat the insect to deal with the floTer l 2 T^'° '""^^ ^^^ ^^^i^ing ensure cross-pollination. Snalli^^Ce S t^'""'^ ^° ^^ ^' flowers are associated with cer ta n Hn«! f -^"^ ^ygomorphic 'he Buttercup. .i.H ™„/vS;^'?''re°:ir;isr '= f M 1 3 Jj(!l [T ARLE 122 DICOTYLEDONS M U a Honey excreted by the bases of the carpels. Transition from foliage- leaves to bracts and sepals. 2i o 3 > c rt C . Ji c XI 'J * 1) c x: < tn jo "o i Id PL, i ■4-1 a < c <5 c 0) < .§1 CU3 < tn 'C tj u "3 XI 3 ■4-1 ii > B 5 . CL 3 o G -^ ^ 71 U) 71 CU - c c 'o IS ■4-1 ■3 3 U .. Oh - 3 t/3 -.is 10 h > CD e © © © © -> 1 i 2>r J! o (^ . i O QJ ?! ~ Ui P' C m er m] witl soli two 2 + the are the Car^ {oi) plac man from of thi POLYPETAL/E-PAPAVERACE^ PAPAVERACE^ (Poppy Family) I^'jf^. "j^^i"^- ^.L--^ exstipulate. 123 usually showy, "^^lai: hypogy,:oT TelSf 1™ & carpLls, Ironi 2 to 00 , syncarpous : ovary onc-charaljered with rndoV™',?. "" '""^""' '""^-'- ^■™" dd,isce,«.n:ds TVPE I : FIELD.POPPY (P„J,ave,- r/mas)* Vegetative characters.-Annual herbaceous platit with mtlky jutce (latex) and bristly hairs. Leaves alterna^rsmlSd, Fig. I53-— Vertical section of flower of Poppy. without stipules simple, pinnately cleft. Flower (fig ir,\ solitary, termina lactiuomorphic, hypogynous. Sef^s (seJ) two, separate, falling off as the flower opens. PSaL (7) 2 + 2 separate, arranged m two alternating whorls of two eafh ' the outer wo also alternate with the two sepals. The Ss are crumpled m the bud ; each petal may have a black spo a the base of Its mner face. Stamens numerous ( oc), Y^Zgynous Carpels from eight to twelve, syncarpous, superior ^Ovarv M one-chambered, with from' eight o twelve panetd placenta (//) protruding inwards from the wall, and Cni many ovules on their faces (also fig. i c r ). StiemasTfia TcTl from eight to twelve, sessile, form'ing^'.llve^jTandf fadi^ttn'^ 11 .:'{|l ?! 124 DICOTYLEDONS from the centre of the roof of the ovary. We should expect the stigmas to lie above tlie gaps between the placentne, because a stigma usually stands above the dorsal suture (mid-rib) of the carpel to which it belongs. But in the Fig. 154. — Gynaeclum and one stamen of Poppy. F'S- 'SS- — Cross-section of ovary of Poppy. Poppy the stij;mas stand directly above the placentae, instead of alternating with them. When stigmas are thus superposed on the placentae they are said to be cotnmissiirnh Fruit (fig. T;ib) a capsule, opening by lateral pores which alternate with ihe stigmas. Seeds minute, and easily transported by the wind. Pollination : the flower has no nectaries, but is visited by insects desiring its pollen. Type II. : COMMON CELANDINE {Chelidonium majus). Herb with yellow juice and yellow flowers. Its flowers differ from those of the Poppy in that the gynaecium consists of two combined carpels, with two commissural stigmas surmounting a one-chambered ovary possessed of two parietal placentas. The fruit (fig. 121) is a siliqtia, which has no septum; conse- quently the persistent placenta {r) {repluin) forms an empty frame which bears the ovules. Uses, Peculiarities, etc. of Papaveraceae. — The latex of Papaver somniferum is the source of opium. Eschscholtzia is a familiar garden plant, with flowers tending to become perigynous. CRUCIFER.ffi (Wallflower Family) Herbs. Leaves alternate, exstipulate. Inflorescence, race- mose, usually without bracts. Flower, regular, hypogynous. I'0LYPETAL.4i_CRUCIFER^.: ,35 no endSper™''" ™"'"°"'- F™'' "--"/ aliliqua/S, TVPB I, : U-AIJ.FLOWER (CMraMus ckeinX* * .am ■56 "157 "+T''seDarSL°^Trf ''"™ 7 J""'™' ^«'eet-sce„ted. &w. whor sTtwo eaS,''^ The't'J^^'lT T^^f '" '™ ^"«™^ng whorl, and are Inserted hiilr n S' ''P^''' ^ '°"" *e inner our. median sepa^TK^er:^ Z^Tl^J^^Z llifl I . 126 DICOTYLEDONS and pouched at their bases : the little pouches act as recep- tacles to hold the honey poured out by the nectaries. Petals (/) four, separate, arranged in one whorl alternating with the four sepals. Note the blade {la) and claw (cl) of each petal (fig. 83). Stamens {f{gs. 156, 88) 2 + 4, hypogynous, separate. There are two short stamens {at) and four long ones {am). The two shorter stamens are opposite the inner (lateral) sepals, and are inserted at a lower level than the four long stamens. Therefore the two shorter stamens form an outer whorl, and the four long ones constitute an inner whorl of stamens. Nectaries (figs. 156, 88) : a green nectary {n) is situated at the base of each of the two shorter stamens. Carpels (figs. 156, 88) two syncarpous, superior. Ovary {ov) : the two parietal placentre, bearing numerous ovules, are connected by a delicate parti- tion (septum) which divides the cavity of the ovary into two chambers. When an ovary is divided into several chambers, and contains numerous ovules, the placentation is usually axile; but in the Cruciferae the ovules are attached to the walls, and not to the axial partition. It is for this reason that the partition is regarded as not originally a true part of the carpels, and is therefore termed a false septum (fig. 156). The short style is surmounted by two commissural stigma- lobes {s). Fruit (fig. 120) a pod-like siliqua. It is necessary to distinguish between the persistent placentae forming the replum {re) and the false septum, {fs). Seed (fig. 116) contains no endosperm, the embryo is bent. The seeds are compressed, and are easily carried about by the wind, and are thus able to reach the tops of walls, on which the plants frequently grow. Type II.: SHEPHERD'S PURSE {Capsella bursa pastoris). This plant is an annual little weed, in reality an ephemeral, flowering at nearly all seasons of the year. The inflorescence and flowers are constructed on the same plan as those of the Wallflower. The length of the four long stamens is such as to occasion regular self-pollination. The fruit is of peculiar shape, and is a shortened siliqua. Uses, peculiarities, etc., of Cruciferae.— Though they appear sc diff'erent. Cabbages, Cauliflowers and Broccolis, Brussels- sprouts, Turnips, Rape, and Mustard are plants all belonging to the same genus — Brassica. They are placed in one single ?OLYPETAL/E-ViOLACE^ ^ J27 genus, because the flowprc fr,„-f j The Cahhase(ZsTaZl'':i;\Tt^^^^^^^^ closely alike. Its large leaves. The Brn..!T. i . ""^^"^ ^°^ ^^^ sake of cabbage producing many wf^^; -f, ""T^y ^ ^^""^^^y of the edible portions. The cfulE ^''^i^'S ^"^' ^^'^^ form varieti^.sof\hecabbage?cui?vated for ?h"^ ^^^^f ^ ^f^ other branched inflorescence th7i ^°^th^jaJ "^ branched terminal possessing a tuberous m"f ioot'Zw r"^''''''^ '' ^ biennial The Swede is a variet^of the T. ^'^ T "^' ^' ^ vegetable, sake of its swollen tan root T^ p'P' "^ '° ^"I^ivated for the ofB. .«.../.././., and from ks sled'. ?' '%'' " ^"^t^^"- ^^"-"ty seeds of the Black MustTrd ^^l '^:°'^ x^' °^^^"^^^d- The the condiment mustard ^^f^ff^.f^^^) ^^^ ^^e source of White Mustard (BrassL JIa) Tth ^°""^. P'^"^'^ ^^ ^he this is the Mustard cultivated withV ?"lP°^'fion of salads ; cress." Cress (ZeJ^Zti^^A ' ?' ^° ^°'"^ " "^""^^^^d and The edible part of tlTnor ^R^^ ^ff ^^ '^^ Crucifer.x. the rhizome'(not the roS~itt o^^^^^^^ "''"^?^-) - stipulate. The swollen red tubprr.f ?! ^^^ ?orse-radish are fW) are formed ma nfv bvh.h^' ^'^''^ {Raphanus i^asturtuon o^anafeUhl belong fjThif 'f ' '''^'T'^^^ Cruciferae are cultivated in gaSs fo fh ''"''^- "^ ^^^ flowers: such are the <^tnnLn I °^ *^^ '"^ake of their flowers). '^' ^^°"^^' Candytuft (with zygomorphic VIOLACE^ ^Violet Family) Herbs. Leaves alternate Qfi"r,„in*. t-i irregular, hypogynousSe?'akri, ^'°T" °fe" ^^h^T, one-chambered, with three ™S,i ,''''' '>'"'''"'P™^ J °™ry ovuJes. Fruit, 'a Are ^^'el^psule;''""'" ^'"""^ many T^™- PANSY (r/,,/^/,/,^/^^) leaf-Iike. Leaves rolTe7L ^^t'ir ™ ^^ V ^"P.-'^f '"«' Inflorescence.— 'I'ho flower isToi,-,, ^R '^'^'^'^ '" "«= bud. i ' -I, I ill; I r>id Hj«] 128 DICOTYLEDONS the flower-stalk. Flower median-zygomorphic, hypogynous. Se/>ais five, separate. Note the prolongation of the sepals below their points of attachment. Fcta/s five, separate, irregular. The anterior petal is produced into a long spur Fig. 158.— Pansy. 1. Vertical section of flower : s= sepal ; //= lateral petal ; sfi=&p\it of anterior petal ; a/=appendage of one of two anterior stamens. 2. Floral diagram, 3. Flower-bud, showing aestivation: j = descending process of sepal. 4. Fruit: //= placenta. 5. Flower with calyx and corolla removed : a/ = appendages of two anterior stamens; /■= filament ; = anther ; c = continuation of connective ; j = swollen end of style ; z' = shutter of stigm.i-cup. 6. Gynaecium : /= ivo anterior ien end of ti lump (c). endosperm. acts as »ud con- Stamefis irranged nectives ). The POLYPKTAL.'E-VIOLACEyK (^^) into thT^^uroAhf .trb^Sf ^^^^^ (^^e-) onc-chaXred w nf "f? '' '"P'."°''' ^^"^bincd. Ovary (./^) on theanterio'rsur^fe e of its u'n;^^ '' \^\ a capsule splitting down the dor™ture ' l^fth^ '^f'^ contract and jerk out the smooth se^ds Seed ^i^ « '^^ endospermic, with a lump (c ca\ np^r th • ^V^ ' '58-7-8 tion.-The anthers dSe towardT hi "^^"^"P>''^'- P^Uina- time as the stigma ripens AtS ^'^^ 8^"'-^^'""^ at the same pollination is ineWtaSe and ndeed''.^ 1 '' u^'^''^'' '^''' '^^^■ place in the whitish-ydCl^rc^.^K 'j^^^^^ ( V. tricolor var. arvensi^\ R„«- ;., «.u i ^'i'^'^v or the Pansy i>sy, which vo"£^-Jl^,il^!::^T7''V'''^' °f hindered by a verv neat mirh^nf -ru" ''^ f-Po'l"w"on is little shutter or flap (fe^sf^-hr' ^ ' ^'■fc™''-™P has a A bee visiting the flo«; a&ht'sln thT "l' '•" "' '°7" ^*'=- tl^rf^o^S -r r -* ■" C™nt-S -; '"r bee's ton u^is ^uVbld To t"^^^ O^'- '", . pushed farther towards x\l HI ^"S["a-cup. As the tongue is time into contacfwith he noHen'h^ T "'?"''' "?^' ^"^ '^^ ^'^^ and in this way the fonlf belongmg to the flower itself; own poU^" When the bee haT2'' T'^ "f^ ^^^ «-^'-'« ceedi to withdraw Lton.ueth.° 1 n'^l T' ^'^^^^^ ^"^ P^^' latter closes the shutter nf /J .•^"'^'^ movement of the SSeer^OrroIerPCd"^^ *«^ ? "^^ -^' vellowish-whiteflowerfnf h i ' '•" ^^^ '"^^" y^^^^^ o^ i3.oreeasi,yac"e:SLl°f*^s:*:nir^^^^^^^^^^ I :!!<' |i: 130 DICOTYLEDONS by insects with shorter tongues (beetles and flies) as well as by bees. It IS well to note that the yellow-flowered form has more accessible honey and a wider circle of visitors than the blue- flovvered form which is a " bee-flower " ; and to compare this with the case of the yellow Buttercup and the blue Monkshood borne of the flowers of the small-flowered variety do not open but pollinate themselves. * ' The Violets belong to the same genus (Viola) as the Pansy and have their flowers constructed on the same general plan • but the structure of the stigma varies in different species' Many violets have two different kinds of flowers In the springtime they produce the familiar white or blue flowers • but later in the year they bear a second crop of flowers which are minute and bud-like, and incapable of opening. These c osed flowers pollinfite themselves and are hence said to be cleistogamtc. CARYOPHYLLACE-ffi (Pink Family) Herbs. Leaves opposite. Inflorescence cymose. Flowers regular, cyclic, hypogynous. Sepals four or five. Petals four hve (or none), polypetalous. Stamens usually eight or ten' often obdiplostemonous, usually hypogynous. Carpels from two to tive, syncarpous, superior; ovary one-chambered: ovules many, on a central placenta; styles from two to five. Seed perispermic, embryo curved. Type I. ; CHICKWEED {Stellaria media). Vegetative Characters.— Annual herb, much branched in a cymose manner (fig. 43). Note the line of hairs on one side ot each internode, continuous with a fringe of hairs on the bases of the leaves. Leaves opposite, exstipulate simple, entire; lower leaves stalked, upper leaves sessile. Inflorescence axillary, commences as a two-branched cyme ^ichasium). Flower (fig. 159) ^ regular, cyclic; small, white. I he flowers vary considerably, but a complete typical flower will be described first, and then the variations will be noted ^^/a/.y(^^) five, separate, /'.^/'a/j (^^) five, separate. Note the deep division of each petal. Stamens 5 -f- 5, hypogynous. 1 he stamens composing the outer whorl {af) are opposite to the petals : whilst the five inner stamens (as) alternate with them. The flower is therefore obdiplostemonous. Anthers POLYPETAL/K_CAR^'OI>HYr.LACE/E 131 introrse. Nectaries {„) five, very small knobs standing outsid the five ,nner stamens and, therefore, opposite tht ^ o Fig. i59.-Vertical section of (lower of Steliaria media. Cr^^A/x three, syncarpous, superior: styles three • ovirv ^..a one-chambered, with many ovules on a centril Sema^ f^l ^^\ " "'^u "'P.^"^'^'- °P^"'"^^ ^y ''^^ valves. Seed k / A i Ci '^^?,!;f y-^^^P^d' J'th perisperm. Variations ^ in" the flower.— I he sepals and carpels ® remain constant in number (ex- cepting that very rarely the sepals may be six in number). In some flowers the five stamens which should be opposite the petals are wanting : in others there are only three stamens, which are opposite three sepals : in still other flowers no stamens are present, so that the flower is carpellary. Again, in some cases the petals are wanting. Pollin- ation.— The plants are found in flower throughout the year. The honey is accessible to .-. short-tongued insects, and the flowers are cross - pollinated :"i< Fig. i6o.— FIor.-ii diagram of ^'te'liiriu media. w HH •(- : mlj ■ ., ifliS ■^m iifl n ^32 DICOTYLEDONS ;l y he agency of ma.iy knuls of insects (bees, beetles, flies, etc.). Self-po iMuit.on often takes place in open flowers n..cause the stu,'nnis come in contact with the anthers ; but k also oanirs m flowers which rcnai.i closed. These closed self pollinating ilowers are merely ordinary flowers which fail o Ks^ji^vioir "-^ ^"' ''''-' ^' -^ ^'^ ^^^^^^^ The flowers of these plants differ from those of the Chick weed more particularly in having a tubular gamosepalous cX and long-clawed petals. Their honey is conse< uently con^ cealed at the bottom of a long tube, ancJ cannot be reached by hort-tongued msects. These flowers are exclusively pollinated by insects with long tongues-/... mainly by butferfli s and mohs. J he comparison between these flowers and those of ^/.//«^/.^ gives us additional evidence for the view that the shapes of insect-pollinated flowers bear relation to the so ts of nsects which pollinate them (see pages 8r, 82 and 110 121) It IS important to note that Pinks are pollinated by but?erflies flying during the daytime, and that !hey often have a pink colour and delicious scent. Contrast this with the w1 te col.ir of the flowers of Z)r/.,«> mA^V.a, ^. hich open 2 dusk, give out their strongest scent It that time, S are pollinated by night-flying moths. The white coloir renders flowers more conspicuous at night. f«-"utrs MALVACE^ (MaUow FamUy) r..^i7^l°' '^'"^'- .^^^''"^^ alternate, stipulate. Flowers regular, hypogynous, often showy. Sepals fi e, gamosepaloSs valvate Petals five, nearly polypetalous, joined to Thrst^amens fvU n ^'? ^''T'' """^-'•O"^' filaments united. Amhers With only tvvo pollen-sacs each. Carpels from three to 0^ chSrs" ^°^^P°^^^P°-)- Ovary wilh from three to man^ Type : MALLOWS (Ma/va sylvestris and M. rotundifoltd). POLYPETAL.].:_MAIA\\CE.E ^33 Vegetative characters — ir.rh^ with »,.,.- t stipulate, simple inlm.tlv , • i , , 'i''"'- I^^'^vcs alternate, style: the s.a„,eMs and pct!I are rl=;/2ear^ '^''■•'' 'P'"'>--^ (''")' ^"^ P'->rt of epicalyx (/..). ^Flower Tfi. . f' '-"'"'"^ ^"^ ^"°^^" ^« ^'^^ showy \S.W/ Xfiv. \ ;^- ^^^^"^'^"lorphic 9, cyelic, ^../Lv. fiJe pitf on ?h >' hn ""^'^l' ^'"^"^^^ ^'" the bud by hairs on the nnr n-n ^T ?^ '^'' ^'" ^'^P''^''^' P'-o^ected five, contor ed '-n U fl ud '^^r^'^'^M ^^e petals. />.,./, another and to tL stanle '' by^h./tts'^^v"'^^"' '^ °"^ ous, united by their mamrnt. fr! f -^^^me^s numer- petalous. The nur^ m i .. ^°™. ^ ^^^^^^ W, epi- Each anther h'as ^^^^l^^ ^^^<^ ^^^ Petals, a complete anther -it k ImV?.V" u '^"<^ //prc^^ents only i,al{ (figs. i6i, i6. sewr.) c '^'"'^''P''^ ^^S- 162). Car/!>e/s 6 I, 103; several, syncarpous, superior. Ovary (ov) iii J3 7i '4\ 134 DICOTYLEDONS with several chambers, each representing one carpel and containing one ovule attached to the axile placenta. Style (st) one, which divides above into as many branches as there are carpels and ovary - chambers : each branch of the style is stigmatic on its inner and upper surface. Fruit (fig. 164) a schizocarp splitting into one-seeded cocci (cc). Pollination. — In both these species of Mallows the stamens ripen before the carpels, and their opened anthers form a group round the closed erect style-branches. As the stigmas ripen and commence to separ- ate, the filaments gradually bend backwards and outwards. In M. sylvestris the anthers are carried completely out of reach of the stigmas, so that the But in M. rotundifolia the anthers are not borne so far backwards, whilst the style- branches gradually curl over and bring the stigmas into contact with the open anthers : thus the flower can regularly pollinate Itself. I1ie flowers of M. sylvestris are more showy, and are visited more frequently by insects which cause cross-pollination. Thus we see that of these two flowers which are so much alike, the more conspicuous is more frequently visited by insects, and consequently more extensively cross-pollinated. This tends to prove that conspicuousness of flowers aids in attracting insects. On the other hand, the less conspicuous flower of M. rotun- difolia is more often self-pollinated. This fact goes to show that the more perfectly cross-pollination by insects is ensured, the more precautions are taken to avert self-pollination ; and that, on the other hand, when cross-pollination is not ade- quately secured, the flower makes provision for the formation of seeds by self-pollination. Putting both results together, we see that flowers are conspicuous in order to attract insects which shall effect cross-pollination. 164.— Fruit of Malva sylvestris : i/ = sepals ; ''''' iiower wnicii arises xiower (hg, ,6s) actmomorphic, ?, cyclic: purplish-red. : 136 DICOTYLEDONS Sepals (^) five, imbricate. Petals (/) five, separate. Stamens 5 + 5, with their filaments slightly combined at their bases. ^ The stamens {pa) forming the outer whorl are opposite the petals (obdiplostemonous) and are shorter than those {sa) op- posite the sepals ; anthers, in- trorse. Nectaries {n) five lumps opposite the sepals, and lying p between them and the five inner stamens. Carpels five, syncar- pous, superior. Ovary (ov) five- lobed, five-chambered : each chamber contains two ovules attached to the axile placenta. Style single, but dividing above r ■ « T., , ,r— i"to five branches with stis- P .g. .66.-Floral diagram of Herb Rober.. ^^^^sg). It IS important tOnOtC that the ovary-chambers and five style-branches are opposite to the petals. Thus the five carpels are opposite to the petals instead of being opposite to the sepals : this is an additional peculiarity of many obdiplostemonous flowers. Fruit (fig. 167).— The main single part of the style elongates, and becomes a strong " beak," Only one ovule in each chamber forms a seed. When the fruit is ripe, as it dries, the five carpels separate, one by one or simultaneously, from below upwards in such a manner that the five seed - containing chambers (cocci) are carried up by elastically curling strips of the " beak," and are thrown off. The fruit is a peculiar schizocarp, because the carpels do not open whilst still attached to the mother -plant. In some of the British species of Geranium the ^'s- >67-— I'ruitofHeVbRobm, .."Sg POLYPETAL^-PAPILIONACE^ ,37 OXALIDACE^ (Woodsorrel Family) iB^B?^^^ i: - --ace,. T,e are more than two ovules in each of fh^ fi ^V 9^^''" ^^^^""^^ ovary, (iii.) There are five s les Hv f "^u' ''"^'^' "V'" has no "beak." ' ^ ^•'' ^^^ capsular fruit Type: WOODSORREL (aw/. ...,,,,//,). symp'ode-^Th: Ltf ' f' '^ ^ ^^"^^^^ -^ not a leaflets. Notftherdav .nrl ^^"^ ^'S'^"'*^' '''''^ three 350). Inflorescen e i"c;^^^^^^^ "lloweTm" v? ^''f\ ''^^ petals are contorted in the bud ^ iT Th®/^''"' ^'.^ "^^^ opposite the petals, and lie between hJmanr.rT""' """^ stamens, (iii.) The nlant nrn^„o ?, ,^"^ ^^"^ ^^^ outer in addition^ 'ooA^' ^^:Z:r\^TT^^^^ capsue dehiscine- nlnni tK^ ^ , ^ "'' ^"^ ^^^^^ is a ejected viotnt^yfromTbv^^^^^^^ •''^^ '''^' ^'^ fleshy coat which envelops eal." ^r''''''°" T^ ^ ^^^^^^ outer testa. envelops each seed separately like an PAPILIONACEiE (Pea Family) pou'!,?^FLwe7ste.u^^^^^^^ --"X -m- five, gamoseTalous S weakly perigynous. Sepals standard, tr"ngs,'^:n1 a ke'ef 'It^' 'T^^^^"^ ^^ ^ perigynous; filament^ of all or of JuT'' '""' T'^^'^ eXerm?c. ^~ ^"^ -">' " ^e^n^^' sLtr.' TvPEs: GARDEN PEA (P/sum sativum): WHITE CLOVER {Tnyoiium repens). Vegetative characters.— Herbs w,>k nu stipulate leaves Th^riA,, • ' -- ^^^ern.ate compound (4. .5. .t) s;^^tz^as:^is:^:^ if'!' i.li 138 DICOTYLEDONS each. The pea is a 'imbing annual with pinnate leaves (fig- 59) and large green persistent stipules (n) ; some of the leaflets are converted into tendrils (dr). Inflorescences axillary: capitulum in the clover; peculiar, two-flowered in the pea. Flowers (figs. 96, 97) median-zygomorphic, irregular, ? , cyclic, perigynous. Se/>a/s five, combined to form a five- toothed cup. feMs five, polypetalous, irregular. The posterior petal (sd) is the largest, and is termed the standard {vexillum)) the two lateral petals {w) are termed the wings {al(£) ; whilst the two anterior petals (/&), which have separate claws, cohere by their blades, and form the boat-shaped keel {carina). The aestivation (fig. loi) is descending-imbricate (see page 73). Stamens (fig. 87) ten, weakly perigynous. The single posterior stamen {pa) is separate, but the filaments of the nine others -"ea to carpelofStraw- Numprn,i« I^Jt ' ^^^ therefore pengynous. berry, showing ^umerous apocarpous carpels are inserted on fh^ '^ ""^^^ '^"^ central outgrowth Th^ S/-/, /v\ .'"v, on tne down the ^„j T ""'•b^^*^'-"- ine ^/W/C' (af) 2s like a r na midd e. .^-^ ./l^. ^. and IS a nectary. Each carpel (fig Iv.y ^r '? l^^'^^ ^'y) attached to the Side of the ovary (ov) The ovary contains one ovule (0). rruit (%• 172). -After pollination, the central mass of the receptacl^ (re) enlarges greatly, becomes first white in colour, and finally changes into the red, sweet, juicy "strawberry'' which we eat. Each carpel remains small and forms an achene (ac) with one Of the strawberry, —ItrdtL'^^^^^^^^ Fig. I72.--Vertical section of TOmpouiid fruit of Strawberry i ( 1 1 142 DICOTYLEDONS inserted upon an enlarged fleshy receptacle, to which the calyx {sj>) and epicalyx {ep) still adln re. Dissemination.— The fruits are dispersed by birds, which eat the juicy receptacle and incidentally swallow the little dry achenes. These achenes have indigestible hard 'pericarps, and consequently pass uninjured through the bird's body. Vegetative characters (fig. 54). — Note the "runners," also the stipulate leaves with three leaflets. Types III. : BLACKBERRY {Rubus fruticosus) and RASPBERRY {Rubus idmis). The flowers (fig. 173) are structurally very like those of the Strawberry, the only important distinctions being that there is ^73 174 Fig. T73. — Vertical section of flower of Blackberry (in the figure, the terminal part of the receptacle {f-p) drawn more spherical than it is in reality). Fig. 174. — Cross-section of a ,ngle ovary of ditto. no epicalyx, and the carpel contain two ovules each (fig. 174), After pollination the behaviour is different, however. The central outgrowth {rp) of the receptacle which bears the carpels does not develop into a large fleshy mass ; it remains relatively small. But the carpels enlarge considerably and become one-seeded stone-fruits (drupes), which conceal the receptacular lump in their midst. Thus the fruit (fig. 175) of the Blackberry or Raspberry is compound : it consists of a collection of small stone-fruits {a) inserted upon a receptacle which bears also a persistent calyx {sp). Dir ^mination. — The fri Stra seed Tvp] P, flowf consi same of t.h there carpe two ( bottoi recepi {re) o; After great ( the t Pninu Rose recepti Prunu and carpel POLYPETAL^^ROSACE^ fruits are distributed bv birds in tu^ c u oy Dirds in the same manner as in the ^ 176 strawberry, bm the stony endocarps (fig. ,,6, .«^ ,„o,ect the TVPBS IV : CHERRY, PLUM, ..„ APRICOT (/•„.,„) flofr"(fii"^.',tr ''' '""'"'■ '■'"-' ^'^ ^^P*-t) has constructed on the ' ^ same plan as those of the Rose; but there is only one carpel, containing two ovules, at the bottom of the deep receptacular tube i^c) of each flower. After pollination great differences in the behaviour of Primus and of the Rose set in. The receptacle-tube of Primus drops off, and the single *''^- *77— Vertical section of flower of cherry carpel grows greatly and becomes a one-seeded stone-fruit i| »'■ f i: ■a !* f% i 14 1 t' ' ii '. 11 i 1 Ml 144 DICOTYLEDONS (drupe) (fig. 128). Thus the fruit is simple, and consists of one drupe. The stipules of Primus are not persistent, but drop off. TAni,K SHovviNt; some Distinctions between different Species ok Frunus. I . Leaves rolled [^^^ ^^uj;, '7"'^' ^'''^V\^^r..^«««jar;w«/fl in the bud. I , II. Leaves folded (conduplicate) yellow, smooth, J-Cherry {Prunus cerasus). without "bloom." J in the bud. ' ]<^^*'''";^^„'P'J'''= °;J^rt Vc^ch (Prunus J>ersica). I vplvPtv ' ^"^ y j(A smooth variety of the Peach is V vcivciy. J known as the Nectarine.) Types V.: APPLE and PEAR {Fyrus): VL : HAWTHORN (Crafcegus). The genus Fyrus includes both Apples and Pears. The flower (fig. 178) of Fyrus possesses five sepals {ex), five petals {cor\ numerous _ stamens [a), and usually five carpels (fig. 179 cp). Not only is the receptacle {re) hollowed to form a cup (as in the Rose), but the outer faces of the carpels are fused with the lining of the receptacle-tube. Thus the flower is markedly epigynous. _ The five carpels are also united to one another by their sides, and, at the most, are only free from each other along their ventral sutures and styles; consequently, a five-chambered inferior ovary is produced. In the flower of the Pear the five styles are separate, but in the Apple the styles are united at their bases. Each of the five ovary-chambers contains not more than two ovules. As the fruit (figs. 180, 181, 182) ripens, the lining of each chamber of the ovary becomes a parchment-like endocarp {cp). The portion {re) lying outside this core of five endocarps enlarges greatly, and is responsible for the production of the large, fleshy part of the Apple or Pear fruit. The fruit is a peculiar inferior fruit known as a pome. Dissemmation. — ^The fruits are adapted Fig! Figs T78.i8i.-Apple. Fig. 178.- Vertical section of flower Fie .8n n-» of frutt. F.g. x„.-Cross.sectio„ of ovary. Fig. .^:-vL^}t.T^ "" MS lii^ M. ■■ ' H ^u.^^l l^H m 146 DICOTYLEDONS I !i ... ", -82. — A parchment- like chaml)er removtd from fruit of apple, containing a see J : /,f = testa of seed ; cot- coiyledons. to invite the visits of fruit-eatin.' beasts, which inadvertently •swallow the seeds as they eat the fleshy ixirts of the fruit. The Hawt horn (0^//,/-,.^ oxyamn/Zm) has flowers very similar in plan to those of the Apple and Pear ; but the ovary consists of two carpels only, and has ^"^ two chambers. In the fruit the endocarp around each chamber becomes hard and stony (not parchment-like), so that the fruit IS a stone-fruit with two stones Birds are responsible for the distribu- tion of these red fruits, which are commonly called "haws" or Hawthorn- frnit.^ Th. 1 /^errie>* (though they are really stone- f uits) Ihe leaves (fig. 58) have large stipules (/A and in the axils of some leaves protective thorn-branches (i) arise. UMBELLIPER.ffi (Parsley Family) Herbs Leaves alternate. Inflorescence simple or compound umbel. Flower usually regular, cyclic, epigynous, small. Sepals five or none, small. Petals five, polypetalous. Stamens five Carpels two, syncarpous ; ovary inferior, two-chambered, with one ovule in each chamber; styles two. Disk, epigynous truit a schizocarp. ^ 'b/"uus. There is such a uniformity in the general habit of the Urn- bellifen-e, and in the structure of their flowers and fruits, that it is unnecessary to select any particular type. The CARROT (Daucus carota), the COW-PARSNIP {Herackum sphondyliunt) may be mentioned as easily obtainable and recognisable Vegetative characters.— The stems are hollow. The leaves are alternate, deeply divided, with broad large sheaths In- florescence a compound umbel. There is usually a eeneral inv-olucre at the base of the whole inflorescence (main umbel) and a so small involucres at the bases of the secondary (partial) "?• u •.•i" '°'"'' P^^"*' *^^ ^'^^^ °f ^" umbel ends in a flower which differs m colour from the rest of the flowers. In the Larrot this central flower is red, whereas the other flowers are white. Flower. - Usually ?, usually actinomorphic. cyclic usually white or yellow, l-'loral formula is K5 C5 A5 G(T). In nadvcrtcntly tt the fleshy oxyacanfha) Ian to those It the ovary ly, and has he cndocarp ics hard and so that the two stones, he distribu- which are Hawthorn- .'ally stone- '«), and in arise. compound all. Sepals imens five. 3ered, with epigynous. 'f the Um- iits, that it CARROT hondylium) ble. rhe leaves aths. In- a general n umbel), y (partial) n a flower >. In the lowers are ic, cyrlic, G("/. In i'OLYl'KTAL.K-UMBELUFRR F 47 rs y an ■Sf Fig. ,83.-Vert!cal section of a marginal .ygomorphlc flower of Jlerackuins/ihoiuiyliui,!. present the calyx is smarand If ;' V^^ " "^ """"^ "^^^''^ presented by Ave teeth; in some Umbel- liferre the calyx is absent. Fctals (a/, pp) five, separate, often bent inwards at th^; tips. Stamens {an) five, cpigvnous, sepa- rate a ternate with the petals, bent in- wards m the bud. CarU two, s nca - Vou., inferior; ovary two - chambera , vith one ovule m each chamber: styles )vo, short. Z?/.£_The fleshy disk ^Z lies on the roof of the ovary'chamber this d sk 'pf A^r^' '° ^"^^^^^^^ f^°"^ rvi / ■ /. ^^•'''^ ^^ ^ nectary. Fruit ... --^ — Ihe fruit (figs. l8?, l86) is a Schi/nr-irr. .f'^'-'S^.-Floral diagram cr^^■ft,•.,^ • ^ r^ "^ ^/ ^^ ^ '^cniZOCarp of zjKomorph c flower of splitting into two one-seeded closed meri ^^'''■^^''""'' W«^"v4%. carps, which remain for a time attichorl t.. fK th.n portion of the axi. (.,) O^i^i^/^^forthf ftuT'^S ,!1, • 148 § DICOTYLEDONS i w fruits have oil canals (v) in their walls which are ribbed. - — s^ The oil -canals of the mericarps 1^ of the Cow -parsnip are of a characteristic club-shape (v). Seed (sd) endospermic. PoUination.— The flowers are small, and there- fore not conspicuous, but they are crowded together in order to form a showy mass of bloom which shall serve to attract the notice Fig 185. -Fruit (schizocarp) of ?[. ^^^ects. In the Cow-parsnip /feraae«»tsMon