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No. 9. — On the Genus Lepidophloios as illustrated by specimens from the coal formation of nova Scotia and New Brunswick. BY Sir J. William Dawson, C.M.G., LL.D. [Reprinted from the Transactions of the Royal Society of Canada, Second Series, 1897-98, Vol. Ill, Section IV, pp. 57-78, with 13 Plates.] Montreal, 1898. >. ' ■»!■ m i: A i^f."*-""' -^ ■trf"- li' it,S : r;;TT-vi:'-j' Seotion IV., 180T. [87] Trans. R. S. C. II. — On the Genus Lepidophloios as illustrated by specimens from the Cnal Formation of Nova Scotia and New lirunswick. By Sir .1. William Dawsc.n, C'.M.G., LL.D., I'.R.S. (Kend June 24tli, 18)>7.) In the flora of tho Carboniferous period, nothing? is moro remarkable than the abundance and wide distriltution, as well as the magnitude and complex structure of trees allied to tho humble Lycopods or Club Mosses of our modern woods. Trees of this type appear in the preceding Erian or Devonian period, but they attain their maximum development in the time of the deposition of the productive coui-measures, and rapidly dim- inish in the Permo-Carboniferous, disappearing altogether in the Per- mian. The great size and peculiar forms and structui-es of these trees, with the fragmentary state of most of tho Hjieciraens obtained, have led to much confusion and controversy, and there are still important ques- tions in dispute respecting some of the forms, and very specially in regard to the genus Lepidophloios and its allies. As a contribution to the knowledge of these i)lants, and with the view of resolving some of the doubts entertained with respect to them, two species are here described, to which the attention of the writer has been directed for many yeai-s, and of which ho has collected and studied many specimens in diH'eront states of preservation. They are those which he had named Lepidophloios Aeadianus and L. (^liftoticnsis. It will be instructive, in tho first instance, to illustrate these by specimens from tho coal-tields of Nova Scotia and Now Brunswick, which have been placed with the rest of tho author's collections of Carboniferous fossils in the Peter iiodpath Museum of McGill University, and which nu>re or le.ss com|)letely display their habit of growth, external parts, reproduction and internal structure. Ti»e Hrst of tho species above-named, I met with about tifty years ago. In Working at that time in the beds of sandstone containing erect Cala- mites at Dickson's Mills, near Pictou, Nova Scotia, 1 found lying prostrate among the Calaraito stems a trunk, or large branch, with loaves and cones attached. It was mentioned, merely incidentally, in connection with the description of tho mode of occurrence of tho erect Calaniites in a paper in the Journal of the Geological Society of London,' and a cone and a portion of the bark, with the leaves attached, woi"e presented to the collection of the society, along with tho specimens of Calamites, rooted in situ, described in the paper. At that time, however, 1 supposed that tho plant in question was referable to tho genus I^epidodendroti, and it was noticed merely as illustrative of the occurrence of other trees in the • » Vol. VII., 1851. 4 ! ^ '■]■] i j , t ' ii.i i j wwwtwmwwl mtimittm -1-» 68 ROYAI, SOCIETY OF CANADA bmkcH of oroct Cnlamifes, then described with their roots and leavoH com- plete for the first time. I may rcmarlc hero that wliile much has i)een done more recently, by the lato Dr. Williamson and others, in developinjij the internal structure and fructitication of (\1la7nites, Nova Scotia has taken the lead in the discovery of their habit of growth, external appear- ance and relations to the accumulation of coal. The species Lepidnphloios Acadianus was not described by me till 1865, when the characters of other specimens from the Albion Coal Mines and the Soutii Joggins were yiven in my paper, " On the Conditions of Accumulation of Coal," in the Journal of the Cicological Society, vol. xxii. It was included in 18(J8, in the " Summary of the Coal Flora," in the second edition of " Acadian (ieology." The second sjiecies was discovered at a later date, and, for a reason to bo explained in the sequel, was also Hrst described as a Lepidodendron, under the name L. CUftonensc'' In the following pages I shall discuss, with the aid of specimens in my collections representing more especially these two species, the follow- ing topics : — I. The charactei"s of the genus Lepidophloios. II. The sjteciHc chuvactei-s of 7>. Acadianus and L. Cliftonensis. II [, The relations of thcfe species to others representing them else- where, and to the forms known as Bofhrodendron, Halunia, Lepidophloios, etc. IV. The relations of Lepidophloios to other genera of Carboniferous trees. V. Its connection with the accumulation of coal. I. The Ge.m's Leimdoi'iii-oios. This genus was established by Sternberg in his great "Flora dor Vorwelt,'' (1820) and its structure was illustrated by Corda (though under a now name, Jjomatophloios, in 1845. Since that time it has attracted the attention of many paheoboiauists, but owing to the IVagmentaiy nature of their material much confusion and controversy have arisen, which culminated in the summary of the characters of the fanuly Lepido- dendrea', attempted by Count Solms-Laubacb in his " Introduction to Fossil Botany," (1891) and may be appreciated by a glance at the biblio- graphy of the genus prepared by my friend, Mr. R. Kidston, to illustrate his paper on the Scottish si)ecies in the Transactions of the Royal Society of Edinburgh (18!);}). The last-mentioned paper is of great value in elucidating the diHiculties attending the study of Jjepidophloios in Europe, and especially in Great Britain, where good specimens seem to bo very rare. ' Bulletin Geological Society of America, 18U1. leaves Corn- ell has boon n developing a Scotia has oriial appoar- Lepidophloios characters of JojLjgins were Coal," in the 0(1 in 18(j8, in of " Acadian , for a reason iciiidudendron, spocinions in los, the follow- ''tonensis. lug tlicm dsc- JjC.pidophloios, Carboniferous eat "Flora dor Jorda (thouufh it has attracted lO frag men taiy sy have arisen, family Lepido- [ntroduction to CO at the biblio- on, to illustrate Royal Society great value in doios in Europe, oem to be very [sir J. w. DAW80N] ON THE GENUS LEPID0PIIL0108 89 (1) Habit of Growth and External Parts. Trees, but by no moans the largest in the coal Ibrests ; branching dichotomously but sometimes uneqiuvlly, so as to produce branches appar- ently lateral. Branches usually stout, but, in some species at least, with slender branchlots bearing the strobiles. These may either be spiral or in two ranks, or irregularly disposed, often on thick branches. Fertile branchlots or peduncles, when mature, dropping oH'and leaving rounded scars depressed in the centre and with a raised rim. Leaves very long, linear, with one rib forming a keel below. The leaves are articulated to the oblong leaf-bases by broadly rhombic surfaces pointed at the lateral ends, and with three dots, the central one of which marks the fracture of the bundle of vessels passing uj> the middle of the loaf.' The leaf-bases are strap-shaped, decurrent on the bark below, but so flat and so loosely attached above that, on the full development of the loaf, they separate at the upj)er ends from the bark and curve outward, so that the leaf-scar becomes pendant and the leaves seem to bo borne on flattened petioles bending downward from their line of attachment. When the leaves have separated, the permanent loaf-bases i-emain, giving a rugged and scaly appearance to the stem. Finally, in dead or abraded stems, the loaf-bases are entirely stripped otf, and a smooth surface of bark remains, on which are seen merely traces of the lines from which the leaf-bases have been torn off, and spirally arranged juts or elliptical spots marking the pf^iwts of entrance of the bundles of vessels of the leaves into the stem. \i •.v~"^ in this condition the branches, especially those bearing the marks of itsO cones, assume forms to which the names Halonia and Bothrodendron have been applied. The latter term has, however, been used by Grand'Eury and Zoiller for trees which seem to bo ditt'erent from Lcpidophloios, but which I have not seen, at least in well }»rcserved specimens, in the Acadian coal-flelds. The above description will serve to explain the various views which have been held as to the leaf- bases and scars of Lepidopkloios. In young and slender branches these are like those oi' Lepidodendron, but as the leaves become developed, the loaf-bases split otf from the stem and b end downward, the leaves still remaining attached, but not inverted,^ as some have supposed. Their lower parts, however, become horizontal, or even bend downward, and do not attain to an upward direction until they have spread out to an inch or more from the stem. When the old stem or branch in this condition is flattened, tho loaf-scars appear at the lower instead of the upper sides of th eaf-bases. (Fig. A., p. GO.) A flat- ' The name "cushions," sometimes applied to the leaf-bases, is quite inaccurate. They are really tlat, strap-like organs. '■* Dr. Williamson, Proceedings Royal Society, Vol. Iv., No. 334, 1894. " .i .1 ; ) ■; 1 t ( ;l ■ ti W I 60 ROYAL SOCIETY OF^CANADA tened frograont of a stem or branch without the leaves, may thus ho placed either with the scars on the upper or lower angle of the leaf-base, and they have been figured by authors in bothjpositions. The former is the position when young, the latter when old. In the former condition the plant may be referred to Lepidodendron, or to Lomatophloios of Corda. In the latter it is the adult cciiaition of Lepidophloios. This will appear more clearly in describing the species in detail. (See Plate IV.) Fig. a.— Young and old lbak-basej of Lbpidophloios enlarokd. (2) Internal Structure. Only one specimen of the species L. Acadianus has afforded to me fairly well preserved internal structure. It was figured and described in my paper of 1865, and some additional preparations have since been made, and have been micro-photographed through the kindness of Prof Penhallow, of McGill University. (Plate VI.) The specimen is a portion about two feet in length, apparently of a large branch, with two rows of cone-scars, and is slightly flattened, its longest diameter being about 4^ inches. It is mineralised with clay- ironstone, calcite and pyrite, and was obtained from the workings of the Albion Colliery in Pictou, Nova Scotia. The woody axis is scarcely an inch in diameter, and only its outer portion has the structure preserved, while outside of this a large portion of the stem, probably occupied by perishable parenchyma, has disappeared. External to the last is a ring of fine-grained quadrangular and imperfectly radiating tissue, about a quarter of an inch in thickness, and probably corresponding to what has ay thus Ihj e loaf- base, former is r condition OS of Corda. will appear V) ,AR()KI>. fforded to me I described in re since been Iness of Prof iparently of a • flattened, its id with clay- rkings of the is scarcely an ire preserved, Y occupied by last is a ring Bsue, about a g to what has [UH J. w. DAWiON] ON THE GENUd LEP1D0PHL0I08 61 in similar stems been regarded as an equivalent of corky bark. This tissue is infiltrated with pyrite, so that it can be seen only as an opaque object, and is very imperfectly preserved. The outer bark and remains of the leaf-bases are in the state of dense shining coal. (Plato VI. and figures in the text.) The axis in cross-section shows u central space without structure, and with only obscure indications of transverse partitions of the Storn- Fio. B.— Original Sections of Lepidophloios Acaoianus, I860. (1) Grosfl-section of Lepidophloios, showing (a) pith, (6) woody axis, (c) inner bark and leaf -bundles, wn, aro mcloH or I found Plato X. jii of tho torn or a uil spoci- Dt'ovorcd, ropresont my two ' by com- jom show 'hich aro tho basal roiis troos icrosporos mid much jrokon otT Dsorved in srfoct con- abundant may bo in ) aro side do of tho I tho lower boar fruit > irregular 3wn to mo [8IB J. w. DAWBONj ON THE GENUS LEI'IUOPIILOIOS 63 of terminal conos. unless wo regard tho long peduncles of X. Cliftonensis as branches, and there is no doubt that as the leaf-basos of these are fjopidodondroid in form and tho leaves short, they might, when detached, bo easily mistaken for branches of LcpidotleiKtroii bearing terminal cones II. LePIOOPIILOIOS AoADtANUS, Dawsou. (Plates I. to VIII.) .luiirniil (ieoloKical Sniicty of Loiuloti, IStlT), \v\nv KM, wilh tlKurus of hIimii iiiul Itninclii'M in (liU'uiont HtiitcN of It-iif itiid coni>, iinil of tlic Ntructnre of the nxlHof tliu Htvin. "Acadian UooloKy," socond and folluwiuK oditions, IHtlH, otc, with Mimilnr llgures and an attempt at restoration. PaKi' 457. This species, described in lH(i5, has recently been idontitiod by Mr. R. Kidston in his Catalogue of Palieozoic Plants in tho British Museum, and in his paper an Lefu'dophloio^xn the Transactions of the Royal Society of Edinburgh (18!t3), with the type species of the genus L. (arieinus of Fill. ('.— OnioiNAi. KniDHK ok riKPinopiiLoioH ArAOiANUs, 1805. (1) Impression of leaf-bases reduced. (2) Tlie same, natural size. {'•i) Surface uf middle burk. (•I) Portion of leaf. Sternberg. While admitting, however, that portions of the bark of old Hj)ecimens in a llattenod state are scarcely distinguishable from that species, I am not ))repai'ed an yet to admit this identitication, for tho following reasons : First, the leaves, cones and internal structure of the EurojHsan species cannot bo said to be certainly known, and cannot thero- tbro bo compared with tlio.se of the Acadian form. Secondly, in well preserved specimens of L. Acadianus tho leaf-buses are shorter in pro- portion to thoir width, and less completely rotlexed than in Sternberg's species, while they do not show the central keel seen in tho best tigures ■I • I ;l ;. .h I had described in " Acadian Geology" in 1868.' While collecting along the cliffs near the > Pp. 241 et aeq., 473 et aeq. Sec. IV., 1897. 5. 1 •>' 1| ly V • i 66 ROYAL SOCIETY OF CANADA quarries, I was guided by Mr, Scott, the manager of the Clifton quarry, to a spot whore a fall of rock had i-ecently taken place and had thrown down a great slab of argillaceous sandstone or coarse shale, on which was laid out. as if prepared for an herbarium, the specimen represented in Fig. D. As the mass of rock was too large to be removed entire, I made a rough sketch of the whole plant in my note-book, and cut out specimens SIS large as 1 could take away, showing the trunk, branches and cones. Other matters, however, were at the time occupying my attention, and the specimens were not described till 1888, when a short description was given in my "Geological History of Plants," at which time I regarded the plant as a Jjepidodendron, nearly allied to L. Wortheni of Lesquereux. Two years later, a collection of plants from the coal formation of New- foundland was placed in my hands by the late Mr. Murray, F.G.S., Director of the Geological Survey of Newfoundland, and his successor, Mr. Howley, F.G.S. Among these was a remarkable Lepidodendron, which r named L. Murraijanum, and which raised a number of questions as to the group to which L. Wortheni belongs, and some members of which had been described as Sigillaria>, because of the apparently vertical arrangement of the leaf-bases. The Newfoundland collection was de- scribed in the Bulletin of the Geological Society of America for 1891, and led to the re-examination of the Clifton specimen in the manner shown ill the following extract : III. The Eelation of these Species to Others. " In the coal formation of New Brunswick there is a species which I have described as L. Cliftonense from its locality,' and of which I have found very perfect specimens, it is in some respects so near to the above that I have doubted its specific distinctness, though on carel'ul com- parison there seem sufficient grounds for a difference of name. I there- fore figure this species also, more especially as it has not been beforo figured and as it shows the fruit and habit of growth. " It will be observed that this species agrees with the last in the forms of the leaf-bases and in the length of the leaves, which are, however, wider and sometimes as much as five inches in length, while the leaf- bases are transversely furrowed above as well as below the scars. The leaf-bases also are somewhat different in shape and more spirally ar- ranged, and the leaves are longer in L. Cliftonense. Additional speci- mens might, however, show them to be varieties of one species. The foliage reminds one at first sight of that of Jj. longifolium of Sternberg, but both leaves and scars are altogether dilteront in detail. I Geological History of Plants, 1888, p. 164. [sir J. w. DAWSON] ON THE GENUS LEPIDOPHLOIOS 67 ton quarry, had thrown e, on which repi'esented re, I made a it specimons and cones, tention, and icription was e I ref^arded Lesquereux. tion of New- rray, F.G.S., is successor, ndron, which nestions as to rs of which ntly vertical lion was de- for 1891, and lanner shown ER8. )ecies which I which I have A' to the above I careful com- ume. I there- )t been befoi-e st in the forms arc, however, ivhile the leaf- lie scars. The re spirally ar- Iditional speci- ! species. The I of Sternberg, "I would romtirk here that the leafy branches in Hgiiro 8 (pliite 22) are not a ' restorti ;ion,' but taken from a sketch in my note-book of a specimen exposed on a large slab of sandstone. It is the more necessary to remark this, as several bjuropean j)aleol)otani.sts have borrowed similar figures from my papers without acknowledgment, and have printed them as ' restorations.' It may also bo remarked that though the loaf- bases of L. Cliftonense are smaller in the older part of the stem than those of iy. Murrdi/amon, this difference may be more appai'cnt than real, since the specimen of the latter may be from the main trunk, and that of the former from one of the larger branches only. '' These plants raise several interesting points in regard to the Lepido- dendra. As I have el.sewhero pointed out, ' the growth in diameter of stems of Lepidodcudra took place in throe ditVorent ways : In some, as in L. Steniber(ji', the bark retains its vitality in such a manner that the leaf- bases inci'ease in size and do not become separated from each other. In others, as in L. Veltht'Mannm and L. Pictoense, the leaf- bases remain small and the intervening bark becomes torn in strips, leaving wide gashes without any scars. An intermediate type is that which vve have in li. rimosum and L. corntijatunu in which the scar.s increase only slightly in A/.*i and then become separated by rims of slightly wrinkled bark. It would appear, from the observations of Williamson and others, that the tirst condition appertains to those Lepidoilendra that possess only a very slight development of the woody axis, while the second occurs in tho.se Mpecies in which the woody zone becomes thick and strong. "The two species above referred to evidently belong to the first cate- gory ; and, as the stems found are not large, still older stems would probably show larger leaf-bases. Such species oi Lepidodendra ai»proach nearer than others to the genus Lepidophluios in the expansion of the old leaf-bases and the small develoi»mont of the woody axis ; and it is inter- esting to notice that they also resemble them in the great length of the leaves and the thickness of the branches. The Lepidodendra whose branches end in slender sprays are usually, if not always, those in which the woody axis is large and the bark of the old stems torn and wrinkled. " 1 may add that these dirterences are most im[»ortant in the discrim- ination of species of the genus Lepidodendron by the markings on the stems, though they have been too often overlooked. " Another noteworthy point is the manner in which the fruit of L, Cliftonense is borne on slender branchlets with few and short leaves, ex- tending fronx the thick branches. Such branchlets might, if alone, be readily mistaken for branches of other species. They also help to explain the scai-s of fructification often found on Lepidodendra, as well as on the so-called Ulodendra, some of which, however, ai'o not generically distinct 1 Ibid, p. Itt2 ; also Acadian Geology, 187S, p. 452. '\ -; \ ■» 1 ■ 5 ill i 68 ROYAL SOCIETY OF CANADA. 3 from the Lepidodendia, and on Lepidojihloios. In some species, especially of the latter genus, these scai-s are seen from their form to represent sessile cones, usually of large size ; but in other cases they are merely round marks, as if indicating the insertion of branches or buds. The little fertile branchlets of L. Ciftonense, which would probably die alter the maturity of the fruit, would leave such scars, and may probably account for some of the less intelligible of them. "If now we compare our two species above described with others found in America and Kurope, and most of which are characterized merely by the forms of the leaf-bases and scars, wo may exclude from consideration all those in which the leaf- bases do not expand in growth, and confine oui-selves to those having living and expanding leal-ba^ies. At first sight we might imagine that these would be the oldest, as being simpler than the others in structure ; but though some of the Erian or Devonian species are probably of this type, in the lower Carboniferous, where the Lepidodendra first became important, the species with leaf-bases separated by wiinkled bark or by expansion of the cortical tissues between the leaf-bases are apparently predominant, though others also exist, and the type which we are now considering perhaps culminates in the Coal For- mation. " We may fli-st refer to L. costatum of Lesquereux, with vertical row* of corrugated leaf-bases, but separated by distinct longitudinal spaces of wrinkled bark. This is a Lower Carboniferous species, and is compared by Lesquereux with his L. Jiritt.v' and with i. VoUanannianum, Stern- berg, of the European Carboniferous, both of which have strong points of resemblance in the characters of the leaf-bases, though differing in the scars and in the leaves, so far as known. The L. Wortheni. of Lesquereux is based on fragments closely allied in general form to our species. Sa also is L. diplostegioides, a species found in the lower coals as far west as Arkansas. None of these species are, I think, sufficiently near to be identified with our Newfoundland and Nova Scotia species, though as most of them are known only by tlie bark of old stems, this may admit of doubt. In any case, Lepidodendra of this general typo and aspect were widely distributed, both in KuroiK) and America, in the Carboniferous, and e8i»ecially in the lower portions of the Coal Formation, to which in all probability the Newfoundland specimens belong. " [ may add here that Zeiller ■ figures a species as L. Veltheivxianum, which can scarcely be that species, and may be a branch of L. Murray- anum, with which it agrees very closely. The same plant is figured by Eenault. ^ The leaf-bases of the Newfoundland species have also some resemblance to those of L. aculeatum, Sternberg, but differ in detail. "Another intei-esting question rijes here as to the limits oi Lepidodend- ron Sujillaria, as determined by their surface markings. The markings of » VeR^taux fossiles du Terrain Houiller, 1880, pi. xxll. •^ Cours de Botanique Fot-tiJe, 1^81, pi. v, fig. 2. f tsiR J. w. DAWSON] ON THE GENUS LEPIPOPHLOIOS 69 )ecially present merely The e after •obably others tcrized de from growth, ries. At simpler )evonian lere the uparated veen the and th© /oal For- ical row* s])ace8 of jompared m, Stern- points of ig in the squereux jcies. Sa ir west as 3ar to be hough as admit of pect were jniferous, hich in all umianum, . Murray- igured by also some etail. '.pidodend- irkings of the latter have usually been considered as characterized by the Iciif-scars being placed in vertical rows and often on continuous prominent ribs, and also by the fact that the lateral vascular scars uro much larger Ihun the central one ; but in such a case as Lcsquereux's species, L. lonttittim, the confluent leaf-bases in vertical rows have the ett'ect of ribs, and in a less degree the same remark applies to L. Murmyanum. \ may add that when one happens to find young stems of Sujillaria not comprc-^-ied, the leaf-bases are seen to project in the manner of those of Lepidodendron, and that in some non-ribbed Sigillaiids, as in S. eleyans, the very young branches have the seal's arranged spirally.' In connection with this I may observe that Sauveur '' has described two species of SiijilUirla, S. angtistata and »S'. undulata, which are scarcely distinguishable, so far as the old bark is concerned, from X. Murruyanum ; and Goidonberg ' has two similar species, S. aspera and S. coarctata. Goldenberg's two species are by the character of their scai-s unquestionably Sigillaria, but S. nngmtata and *S'. undulata of Sauveur, especially the former, might well have been lepidodendroid trees very near to L. Murrayannm. This, how- ever, could be certainly ascertained only if more complete specimens could be found. On the whole one might infer that as the spiral and Lepidodendroid characters of Sujillaria appear most prominently on young branches, the more Lei)idodendroid and spiral Sigillax'ia are the lowest in type and the ribbed Lepidodendra among the highest of that genus. But such a conclusion must be received us liable to many excep- tions." Sub.sequently to the appearance of this paper, in which V referi-ed only to the branches and cones, I was led, in arranging the specimens in our museum, to strip otf some of the long leaves from the largest slab in my possession, representing a portion of the trunk or a main branch, and was surprised to find that the leaves and leaf- bases wei*e arranged on the plan of Lepidophloios. My Clifton specimen thus showed characters •which combined those of Lepidodendron and Lepidophloios, and as the leaves and fruit were those of the latter genus, I have now no hesitation in referring it to this ; though it furnishes a very interesting illustration of the close approximation of the two genera, as well as an example of the possibility of referring fragments oi Lepidophloios to Lepidodendron. At the same time, a specimen from the Clifton quarries which is evidently a portion of the surface of a trunk or large branch, shows that in this species, which I think may be referred to Lepidodendron Wortheni, the character of the leaf-bases and leaf-scara, which are confined to slender branches in the associated Lepidophloios, may be persistent on the main trunk. Were it not for this specimen I would be induced to suggest that ' Acadian Geology, 1878, p. 434. ^ Fossil Flora of Belgium, 1848, pi. Ivi. and Iviii. * Brit. Mus. Catalogue, 1886, p. 151. I : iii i :• i '■: ! .;:■ « ij' 70 ROYAl. SOCIETY OF CANADA many branches of Lo])idotloncli'ii Hgurod by authoi-H, and of this type might, if better known, 1)0 found to be branches of Xf^>/(/o/i/t?08os. Yet, thougli thiH is possible, tliere is an equal possibility that they may really bo Lepidodendron. These facts, however, lead to the discussion of what is known from structure, form and fructification, of the relationships of the Lopidodendre;i- and Sigillariu'. in referring brief!}- to which subject 1 shall depend chief! 3' on Canadian examples in my own collections, as thv current descriptions and figures of fragmentary specimens by authors abroad do not always furnish reliable data for comjiarison. JV.— J{KI,AT10NS Tit Le1'IJ»()I)BN1)K()N, TTi.oDENDKON and SiajLLARIA. We have alioudy seen how easy it would be to refer fragments of Lepidopldoioti to the genus Lepidodendron^ and in regard to internal structure it is probable that branches of iyfyy/r), I was so far influenced by these apparent connections as to include under this genus not only the Jjomatophloio.s oi'Corda, which is no doubtasynonj^n, but also ihoUloden- dron of Lindley and llutton, of which tM'o species or varieties are found in Nova Scotia, and some plants with leaf-scars, similar to those oi'Lejtido- phloioti, but without the long [)endant leaf-bases, and which are now usually classed by paheobotanists with the Sigillariu'. With regard to the Vlodendron, it may bo stated that the Ulodendra and Ulodendroid Lepi- dodendra cannot be distinguished by the two-ranked cone-scai's, because those occur also on Lepidophloios, but rathei- by the fact that the cones were not stalked but sessile by a broad base,' and that the leaf-bases and leaf-scars were of different form. I illustrate this by figures of two species or varieties of Ulodendron, corrosjionding to U. majuvi and U. minus L. and H., which are found, though rarely, in Nova Scotia. (Plates XL, XII.) In one of them (Plate XIT.) the leaves are present, and are more like those of Lepidophloios than that of Lepi- dodendron, while the leaf-bases resemble in general form those of a Sitjil- laria of the Clathran'a type. The plant is like S. dixeophora of Kcenig, ' It is quite likely that were the structures of these cones perfectly known, other differences would appear. h.^ [bir J. w. DAWSON] ON THE GENUS LEPIDOPHLOIOS 71 but cannot be a scv Sitjillaria, This was named L. parvun. In point of fact tho Carboniforous fbreHts contained many species of trees belong- ing to an advanced typo of acrogenous structure, and so nearly allied that it is difficult, if not impossible, to distinguish them when in the state of imperfectly preserved fragments. The difficulties of the pahcobotanist are increased by the presence of numerous species of SujUlaria, which, while for the most part distinguishable from all tho Lepidodendrea>, yet in some of their genera ap})roach them very nearly both in external markings of tho stem and its internal structure. On the other hand, there are plants inehided among tho Sigillariie which there is at least reason to suspect belong to a higher type, akin in structure to tl»e modern cycads. In a paper on the affinities of these plants, published in the •lournal of the (ireological Society in 1871, I suggested the following scheme of their affinities, placing the Sigillaria^ as a group on tho con- tines of the Acrogons and (Tyranosperms. After the lapse of twenty-six years, and in view of the |)rogress of discovery in the meantime, this scheme must require some modification ; but we nuiy well make its amendment a basis for discussing the present asjjocts of the question. Cycadai'ecv. Favularia ? Coniferw. Dadoxylon. Palii'oxjion. Ormoxylon. Dictyoxylon. 1 .'r SiGrr.LAEiiT;. Hhytidolepis. Favularia ? (Mathraria. Syringodendron. Lej)idophloios. Le])idodendron. Lycojx/di'aced'. Oalamodendron. Calamopitus. Hornia. Calaraites. Eqid&etaceiv. Jn this tlie Sigillariu' are regarded as a central generalized group, from which, in regard to structure and affinities, various genera radiate towards Cycads and Conifers on the one hand, and Lycoj)ods and Equiset- ums on the other. The Sigillarian structure is based on that of a remarkable axis show- ing structure which I had at that time found in an erect trunk at the Soutli Joggins, and of which the details are figured in the paper above referred to. Though I have since found a still better preserved axis of different type, to be referred to in the sequel, I still hold that my original specimen represents one, and that the more advanced, Sigill- : . t' \ '^ 72 ROYAL SOCIETY OF CANADA i arian typo, and approaches very near to tisnusH of CordaLtes on the one hand and to that of Cycads on the other. Other doubtful species mentioned in the original account of Lepido- phloios Acadianiis (1865) above referred to, wore those which I named X. platysti probably two typi'H of or^'ani/.ation, ono upproacbing to tbat of Cyeadfl anil Conhiitni' and tbo otbor allied to Siijillariir. In otbor words, tbat tbo dividini^ lino Itotwoon (Ti/mnospcrmn anil Afro;/eiis or Arrhc(joniat(r iixWn within t\\o groat genus Sojillaria, an now hold by pahoobotanists.' In proof of tills f may refer to the struoturo of an axis described by me in 1871, and taken from an ereet ribbed Sii/iUnrid, undoubtedly of tbat genus, and j»robably allied to, if not identieal with, my S. lirounii. I have described tbo details of this structure in the paper referred to, and may here merely refer to the figures of the more important tissues and invito attention to their resemblance to ll»(»se of ('ordaiteu', as figured by Henault and other French botanists, and to those of modern Cycads, It may, however, bo doubted whether this axis may not have been introduced accidentally into the trunk in which it was found. This would be in the last degree improbable in the case of a trunk not tilled with foreign deliris, but containing along with sand apparently only Iragments of its own interior tissues. Farther, in many erect trunks at South Joggins there are masses of mineral charcoal on the liottom, which have fallen in before any foreign matter entered, and whidi, when pre- pared by nitric acid and examined microscopically, show similar struc- tures, as 1 have shown in my paper of 18«;0 on Vegetable Structures in Coal.^ These observations contirm the impression that this structure, much more advanced than that of any Cryptogams, recent or fossil, was that of many at least of the Sigillarian trees. Hut another and less .-idvaneed structure comparable with that of Lepidodendra is also found. Of this an excellent example was discovered by .Mr. Albert J. Hill in the coal measures of the Cumberland basin in Novji Scotia, and was described by me in 1877. it was an erect ribbed Sii/illaria. with broad ribs like ,S'. renifarmis, and twelve feet in height, tilled with sandstone. I>ut having its axis perfectly firm in cal- cite, and standing, like a jiole or the core of a ca.sting, erect in tlie stem, nearly from the base to tbo summit, tliough fallen a little to ono side. It will be soon that its structure corresponds with Di/iloxyloi of (^orda, and with those more advanced Lepidodendroid stems which have thick development of radiating tissue.^ ' .lournivl Cfcological Society of London, Vol. XXVIL '^ Quart. Journ. Geol. Soc, Vol. XV. '■' Note on a specimen of Diploxi/lon, Quart. Journ. Geol. Soc, Vol XXXIIL mutm cvi'n in tho /.at ion, ono er III lied to i/mnospennx nl»li!(lly of ,' .S. lirnunii. referird to, t tisHiu'H and H tif^iirod liy CycadH. ot have been fouml. This nk not tilled arently only ect trunks at ottom. whieh [•h, when pre- similar Htruc- Structuros in UH Htrnelure, or fossil, was witli tlmt of vas discovered berland basin was an erect d twelve feet ly lirni in cal- t in the Btcni, tie to ono side. ylon of (yorda, ich have thick [bir J. w. dawhon] on the GENUS LEriDOPHLOIOS 7B ol XXXIIL V. ReLATIONH of LEPIDOl'IMiOIOB TO THE ACCUMULATION OF CoAI,. On tliissubjoct it i» not necoesary to say much, au what is noted of the Lepidodendra in my papers on tho Accumulation of Coal, in tho Journal of tho Geological Society (IStJS), and in the chapter on that subject in Acadian Geology covers nearly all that ean be uaid of Lepido- phloios. I may merely state that such specimens as I possess, in a flattened and carbonized state, show that inordinary circumstances tho outer bark and leaf-bases have yielded a tilm of comj)act coal, perhaps ,J,oth of tho tliicknoss of tho recent stem, and that the woody axis will appear usually as mineral charcoal of tho same character as that of tho Lopidodendra The largo eones and their contained sporangia and macrosporos must have contributed to the mass oi" such material which enters into the coarser layers of foal, but can, until tho microscopic structure of these organs is better known, scarcely be distinguished from the similar parts of other Ijopidodendroid I roes. The trees ol" the gonus Lrpidu/ihloios woi'o associated in tho Carboniferous swamps with Siijillarid, Lepidoden- dron, Catamites, etc., and wore most plentiful in tho Middle and Upper Coal Formations, but do not soem to have boon so abundant as either of those genera in any locality in which \ have studied thom. ^ n! 1 r'li ■!3 1 1 M 'I i ^^f *;.i«!*ii*.M- •«•«(»«*» P [m* J. w. DAwioM] ON THE OENIIS LEPlDOPHLOTfX* DKSCRIPTION OF TIIK PLATES. USL- . Lfphlophtoloa Acndtanua—hnitrtiMlon of the lenf-bAHes on Hundiitone. Plam II. I'nrt of the name trunk, and nurface of bark immediately Iwlow the leaf-baseii, and epIdermlH nhowlng punotlform markH like Bothrodendron of Lindley and Ilutton. Plati III. Tlie same— Portion of bark with leaveH attached. Plati IV. The ftftmc— Leaf-lmNi'N of a large and old stem, above ; below, coneti or Htrobiles seen iranHversely and longitudinally, alHO a detached Hcale or Lepidophyllum, Plate V. The Hamc— Horizontal branch showing arrangement of coneNoars above and below. Plate VI. The same— TrunsvorNe section of axis, magnified, nhowing outer and Inner ring uf Bcalariform llbres (upper figure x *iU, lower figure x 4H)>wlth loaf-bundles at outer margin of axlH and spaces representing their sheaths. The same, ^or possibly the upper figure a Itwa Holhrodetulron. The lower figure a branch In the Hnlonia state, but at one spot near the right hand showing a few perfect loaf-lNises. Plate VIII. The nama— Ha Ionia state of a branch or small stem, showing very distinct cone- sears. Plate IX. LejndirphUnoa Cli/toHftuia.— Portion of stem showing rcflexed leaf-bases and the drooping position of the basal portion of the long leaves. Plate X. The same— Ifpper figure a fertile branchlet with cone. liOwer figure an ordinary branch. Plate XT. Vlodeuitron of the type of V. majum, L. and H. Half natural size. South .Toggins. Plate XII. Vloihmlron allied to U. minus, L. and H. Upper figure showing cone-scars and leaf-bases. Lower figure, reverse of same specimen, showing leaf-bases and leaves. ■i\ I : ',■> I ro I ,1 78 ROYAL SOCIETY OF CANADA Plate XIII. Lejiidophloioa ^^antimRS?.— Rough restorations showing general habit. Plate XIV. Lepidophloios CH/tonensis.—iionf^b restoration showing general habit. On same plate a fragment of bark with short leaves, perhaps of a Sigillariu of the Clathraria type. FIGURES IN THK TEXT. Fig. A.— Young and old leaf-bases of Lepidophloios Cli/fonensi,s. Fig. B.- -Original sections (1883) of Lepidophloion Acaduinus. Fig. C— Original figures of markings, etc. (186.5), of Lepidophloios Aendianus, with impressions and outlines of leaf-bases, surface of inner bark and leaf. Fig. D. — Rough sketch of Lepidophloios Ctiftoneiisin in situ on a surface of sand* stone. t. On same llaria of the (lianas, with d leaf. 'face of sand* I SIR J. w. UAW80N] Trans. 1897. Sec. IV.— PijiXB K ON THE GENUS LEPIDOPHLOIOS 79 ISIR J. W. DAWSON] TkANS. 1897. SeC. IV.— PI.A1K II. ON THE GENUS LEPinOPHLOIOS IS <'i', il' I m " < ' iHr^ f '\ I^^IPI^ir^. ' 9HHii mmm^m 81 -SMa{^%av'„..ii«*'i, ■f" I. [sin I. w. tawson] Trans. 1897. Sec. IV.— Pi.mh III. ON THE GENUS LEPIDOPHLOIOS 'ZMii^$;S''- h ^P^jfc^^BEffi i ^^H||Bk^^I^ .)ii^ J^ 'Vj^^ft ,3,, 'i t i I 83 (filB J. W. DAWHON] TuANs. 1S97. Src. IV —Plate IV. ON THE GENUS LEPIDOPIILOIOS !-i'l [sir J. w. dawron] Trans. 1897. Skc. IV.— PlatiV. ON THE GENUS LEPIDOPHLOI08 H ii i 87 ! 0lMfyvk' m^^'i imtmift: . |hi« J. w. pawbon] Trvkh. 1897. Si:r. IV.— Pi.atk VI. ON TIIK (iENlTS LKPIDOIMILOIOS 89 [wp J. w. DAWMON) Thanh. 18117. Sec. IV.— I'iatb VII. ON TUK (iKNUS I.EI'IDOI'IILOIOS ffip-v*-. i 91 (iOBBli'S^»ijaes^3ii *?'•'•''''■■*'****■' [sir J. w. DAWSON] Trans. 1897. Sec. IV.— Plate VIH. ON THE GENUS LEPIDOPHLOIOS 93 ; ( [sir ,t. w. pawsox] Trans. 1897. Pec. IV.— Plate IX. ON THE GENUS LEPIDOPHLOIOS 98 mmmm i m mmM ■ i iMMri tii »i ii. .r :.r iiiMan mn [sir J. w. dawson] Trans. 1897. Sb& IV.— Plate X. ON THE GENUS LEPIDOPHLOIOS 97 0f^rm t_. [sir J. w. DAWSON] Trans. 1897. Sec'IV.— Plate XI. ON THE (JliNUS LEPIDOPIILOIOS 99 tmit:'-^'' , l( S' I; V I iito irriai ni (SIR J. w. DAWROs] Trans. 1897. Sec. IV.— Plate XII. ON THE GENUS LEPIDOPHLOIOS . M^'m ''^M (^Ji-^,,,- ^m:^ if^ ■' .«^ lOl mumim-'iik:. {8IR I. W. DAWHON] TllANS. 1807. 8kC. IV.— I'lATH XIIl ON THK (iKNlJS LEriDOI'lILOIOS 103 mm i«iirf» ^MiH I. w. hawhon] Thanh. I8lt7. Sr,?. IV.— I'i.mk XIV. ON Tlir, (iKNl'S I.KI'IKoi-riMtlos ■I I lOS