PADGETTIA, A NEW GE~US BASED ON FERTILE IEUROP­ TEROID FOLIAGE FROM THE PEH.MIAN OF TEX \S*

SERGIUS H. MAi:vIAY .S. Geological Survey, \>Vashington 25, D.C.

s Permian become increasingly to several adnate, sef'd-like fructifications, well-known, it becomes more apparent probably imbedded in the lZLIllina, aligned A that the Permian period produced parallel to the venation on either side of the many peculiar forms that defy close midrib. comparison with of the present. Pad­ Fronds at kast once pinnat ; pinnules gettia, the new genus to be described here, is apparently isophyllous, long (12 em. or morC') represen ted by one of these morphologically and relatively narrow (to 3 cm. wide) with anomalous types of plants. entire margins and cordate bases, the bminae The material upon which this account is tapering gently to acut apices. Pinnule based was found in an assemblage of plant midribs to 3 mm. wide, finely --triated; lateral compressions collected in 1939 by Charles veins clo ely spac d, departing decurrently B. Read, U.S. Geological Survey, at a locality at an angle of approximately 30 degrees, " approximately 2 miles northwest of Pad­ arching to meet pinnule margins nearly gett ", in Young County, Texas, (U.s.G.S. perpendicularly, usually forking once within Palaeobotanical Locality Number 8967). a short distance of the midrib According to the geological map of Young Fructifications ovoid, elliptical or pyriform, County (Plummer and Fuqua, 1937), out­ from 2·5 to 9·0 mm. long and 2·0 to 5·0 mm. crops in that area lie within the Lower wide, usually borne one or two, occasionally Permian Moran formation of the Wichita several to a pinnule, being evel Iy . paced group, at an undetermined distance above in the latter instances. Fructifications the Dothan limestone of former usage. oriented lengthwise along decurrence of The abundant plant remains are preserved lateral veins, with broadest ends toward in a fine-grained, dark grey shale with well­ pinnule midrib, some in contact with midribs, developed fissility. In some specimens the and apparently attached to laminae or preservation is so fine that epidermal cell imbedded in them throughout their length; patterns are visible under high magnification; apices of some fructifications extended as in most specimens, however, only a very thin either broad or constrictecl " beaks", tt'rJDi­ film of dark brown carbonaceous matter nating truncately at pinnule margins. remains, which presents a fairly sharp colour Holotype ~ US.l\.iVI 41165 a and b contrast with the shale matrix. (counterparts): figures 3 and 4. The plant assemblage is fairly diverse, Descriphon of the .11 aterial ~ The Padgett containing representatives of Cordaites, Bow­ collection contains nearly a hundred seedlike manites, Sphenophyllum, Pecopteris, Sphenop­ fructifications, distributed among 52 pinnul s. teris, Odontopteris, and Padgett·ia. Although Most of the fertile pinnules, which in the the Pueblo formation, which underlies the sterile form have a decidedly neuropteroid Moran, is known to contain Callipteris, this appearance, have only one fructification each, Permian " guide" fossil is not recognizable but 12 have 2 each, 7 hZLve 3 or more, and in the Padgett collection. Padgettia seems one small pinnule fragment, 3 em. long and to have dominated the flo rule , and on the 1·7 em wide, has 7. The holotypc, the basis of more than fifty fertile pinnules, its counterparts of whi.ch are shown in Fig'. 3 known features are diagnosed as follows: and 4, is an incomplete pinnule 6 cm. long and 2 cm. wide, with 8 fructifications. Sterile Padgettia readi n. gen. and sp. pinnules apparently do not differ from fertile ones in regard to size, outline or v nation. Combined Diagnosis ~ Plants "vith large The fructifications are all flattened to the neuropteroid pinnules; pinnules bearing one extent that they create hardly any relief on

'Publication authorized by the Director, U.S. Geological Survey. 53 54 THE PALAEOBOTANIST the surface; in this flattened condition It is likely, however, that the frond was at they are mostly ovoid or pyriform. There is least bipinnately compound. no evidence of pedicellate attachment. Most Interpretation - The problem of morpho­ specimens occur on the laminar area between logical interpretation of the fertile pinnules the midrib and pinnule margin, but a few of Padgettia has been discussed with various have their basal ends in contact with the colleagues, and although the possibility that midrib; none of these, however, extend from the ovoid objects represent abnormaliti s of one side of the midrib to the other. unknown origin has been considered, the Most of the fructifications occur nearer to consensus favors their interpretation as fruc­ the base than the tip of the pinnule. Their tifications. My personal opinion is that orientation conforms closely with the angle Padgett1:a is a pteridosperm, and that the of decurrence of the lateral veins, so that the pinnules described here are the ovuliferous fructifications are typically situated with parts. Reasons for this interprdation are: their long axes directed apically at a wide 1. The presence in the Padgett collection angle to the midrib, with their broadest ends of a large number of the ovoid objects, and toward the midrib. Where several fructi­ their complete restriction to one species of fications are present on the same side of the plants in this reasonably diverse , seems midrib, they tend to be approximately evenly convincing evidence that they constitute a spaced and, as shown in Figs. 3 and 4, they natural growth feature of the pinnules. may also occur in opposite pairs. 2. The strict conformity of the long axes Although not all of the fructifications of the objects with the decurrence of the extend as far as the pinnule margin, many lateral veins of the supporting pinnules have beak-like apical prolongations that indicates a preferential orientation along the extend as far as, but not beyond, the pinnule ultimate vascular strands, as in linear margin. The beak may be narrow and son. In adition to this feature, the relatively constricted, giving the fructification its even spacing and opposite pairing in the few pear - or urnlike outline, or it may conti­ observable instances are also suggestive of nue unconstricted to the pinnule margin as reproductive structures rather than pathologi­ an extension of the greatest width of the cal effects, insect damage, or other artificially fructification. induced abnormalities. The outline of the fructification is delimited 3. Their shape is -like and their size is by a more or less pronounced furrow - evi­ comparable to that of any number of the dentlya compression border - in the matrix. smaller pteridospermous . They are This surrounds a small, flat, lens-like body of too large for micro.'porangia or isoporangia, sediment that can be flaked off to expose the and there is no evidence to indicate that they opposite side of the specimen; this obviously are multisporangiate sori. represents the filling by sediment of an The most unusual and perhaps morphologi­ originally hollow structure on the pinnule. cally most significant aspect of the seeds is Some of the furrows are filled with fusinized the manner in which their apical ends are carbonaceous matter, suggesting that the truncated exactly at the pinnule margins. original structure had considerable substance; Had the seeds been pedicellate or, if sessile, some specimens are almost completely cover­ had they been attached only at their basal ed by a thin film of coal, but others lack ends, it is unlikely that their apical ends this, having lost it to their counterparts would have coincided exactly with the pinnule when the matrix was split. margins in all instances. The marginal No or cuticular remains were found truncation of the seeds thus suggests that in any of the fructifications, although several they were imbedded within the lamina and specimens were sacrificed for matrix dispersal as the seeds matured, slits opened along the and examination of residues; nor was it pinnule margins to permit access of possible to determine definitely whether the to the micropyles and shedding of the matured fructifications were borne on the lower or seeds from the . The compressed upper surface of the pinnule, although they " beaks" would thus represent the fossilized generally appear to have been on the lower avenue of access between the seeds and the surface. outside of the sporophylls. The degree of frond division is not known Further support of this interpretation lies because only one specimen was found with in the evidence of complete sessility or adna­ two pinnules attached to an ultimate rachis. tion of the seeds as demonstrated by their ).!.\MA'l-PADGETTlA, Ai EW GlZ~ "S ON FE! TILlZ l"E -R PTEROTD FOLIAGE 55 consistently decurrent alignment. Had the Discussion - The taxonomic implications seeds been stalked or incompletely attached of Pad"ettia are important, becau. e in its to the lamina, some of them certainly "vould sterile stat a pinnule of thi plant i. indistin­ have been preserved in other positions relative guishable from i reuropteris foliage. In leaf to the bLrral vein~. shape and venation, Padgettia readi bear a Another point worthy of consideration is clo-e re· mblance to . europteris permiana the r lationshi p between size of s eds and S Jlarcls (1908), from the Permian of Kan.-a.-, development of the apical beak. The small st and the t"..·O .-pecies would po..-ibly be r ­ seeds arc unbeakrrl, while the be. t dev loped gardecl as conspecific if the fructifications beaks occur on the largest ~eeds, sugge. ting of the PJ.dgett mat rial wer not known. that all seeds did not mature at on 0., and It must be pointeel out, of cour. , that that the beak was not developed until th Sellards' material ma" ultimately prove to seed had matured to the stage, belong to Padgettia rather than to l\~europ­ when a point of pollen entry became neces­ teris, should it fructification rver become sary. It se ms probable that the: sporo­ known; the evidence on h::ll1u, however, phylls were shed and covered by sediment do not warrant the tel. ·onomic recombi­ after the seeds had h n pollioat d and nation. dropped from their foliar envelo!)('s, for the On the basis of the great morphological presence in most p cimens of a small lens-like diffe'renc' of the fructification of Padgettia flake of sedim nt i~ evidence that the. 0. were from Ltny known neuropterid fructifi alion, hollow structure when buri d in the mucl. aSSi lflll1lent of th Padgett material to Neurop­ This would largely explain the absence of a teris would be ju ·tifiall only from the ·tand­ mega ·pore membrane or seed cuticle in the point of sterile foliar morphology. Such a larger specim 'ns; tlll: smaller one:, on tile taxonomic choice \vould involve disr gard other hand, may have be/'n pre· -rved before of the strong probability of foliar homeo­ cuti nization of part was sllfficientl y auvanced morphy and would effect an um asonable for satisfactory preservation. extcll:ion of the circumscription of Neurop­ In the absence of tIle direct evidence teris. . eed attachment has been demonstra­ neces. ary for incontrovertible establi. hm~nt ted for the type . 0. ie', N. heterophylla of th se structur S as seeds - the pr sence of Brogniart (see KmsTo.', 1904) as well as for a m gaspore mcmbran - two alternative N. ouliquaBrongniart (KIDSTON & jO"GMANS, interpretations must b admitted, althoucrh 1911) and N. schlehani (JONGMAXS, 1954). neither of these appeals to me. If, on one In tho. 0. ·recies, the s cds are laure, pachyte­ hand, the Padgettia fronds are to be regarded staid bodi . that terminate naked extensions as pteridospermolLs microsporophyll., tli 'y of the pinna rachis, with only one seed borne are structurally unique among the Palcowic on any single rachis. .10reover, the male pteridosperms, for the male organs of those fructification 0 r f\ . schlehani has b en shown plants-in so far as they are known-are all by Jongmans (1954) to be a larg whittle­ elaminar, synangial structures of considerable seyan campanulum, so that even if there were size and complexity; the probability of homo­ evidence for interpr ting the pinnules of logy between sporophylls of Padgettia and Padaettia as microsporophyllar, there would certain of Halle's (1929) seed-bearing foliage still be no basis for identifying them with from the Permian of China (in particular, N Mf,ropteris. fronds of Emplectopteris triangularis) strikes :\1ention should be made of two other me as a much stronger one. On the other examples of pI" sumably fertile neuropteroid hand, interpretation of Padgettia as an iso­ foliage that may be more closely related to sporous fern would limit comparison to one Padgettia than to Neuropteris. Chodat (1908, with the modern Ophioglossacme, particular­ p. 404, 405) briefly described a specimen of ly Ophioglossu.m, whose sporangia are r 'garded l ..:europteris auriCHlata Brongniart, from the as being imbedded in foliar (EA~IES, Stephanian of France, which bore several 1936, p. 121). It is conceivable that a form­ sarnaroid .. sporospermes" with "more or like Padgettia, through reduction of inter­ less flattened indusia". Chodat's de ·cripti on sporangiallamina and contraction of the pin­ and illustrations are some",.. hat less than nule rachis, eventually produced;.J. f rtile spike adequate, so that suitable comparisons with like that of Ophioglossum. Howev r, such an Padf!.ett-ia are not possible; however, it seems evolutionary process cannot be demonstrated likely that the structures r ported by Chodat on the basis of the available evidence. are more similar to the m gasporophylls of 56 THE PALAEOBOTANIST

Padgettia than to the known female fructifica­ pare, the time-morphology relationships of tions of Neuropteri;;. the known ones are sufficiently striking Fontaine and White (1880, p. 47, 48, PL. 8, that it is not unreasonable to postulate that FIGS. 7, 8, 8a) figured seemingly fertile pin­ evolution of pteridospermous seed position nules of Neuropteris lu:rsuta Lesquereux from underwent a Bowerian "phyletic slide", "20 ft. below the Pittsburg coal" near analogous to that entailed in the evolution of Bellaire, Ohio. The fruiting bodies were fern fructifications, the terminal posi tion of " linear-elliptical sori, 4} mm. long and 1 mm. the oldest seeds reflecting the terminal posi­ wide at the middle ..... normally placed tion of the ancestral I silophytic . in groups of four, the sorus nearest the base It is of interest to regard Padgettia in the of the pinnule being situated near the middle light of such an evolutionary process, for it of the lamina .... each succeeding sorus of may be that Padget/ia represents a stage in the group approaching nearer to the midrib, evolving seed position even more advanced until the last one comes quite close to it, thus than the Permian forms reported by Halle. forming rows, each containing 4 sori, and Having migrated from the termini of naked each row inclined toward the midrib". These rachises to the surface of an unmodified were interpreted as fern sori, comparable to lamina, furtherance of the tendency toward those of Scolopendrium vulgare, although increased proximity of seeds to foliar lamina individual sporangia are neither described eventuaLly might have resulted in actual nor distinguishable in the illustrations. If embedment of the seed within foliar meso­ these are actually fructifications, they re­ phyl!. How this was accomplished, \vhat the semble much more closely those of Padget/ia ecological or evolutional advantage of such a than those of any species of Neuropteris and modification could have been, and what the add significantly to the already demonstrable subsequent stages in such an evolutionary artificiality of N europteris. Unfortunately process were arc difficult questions, but the the Fontaine and White material is no longer possibility of such a sequence is supported available, so that first-hand examination is to some degree by the age relationships of not possible. the fossils involved. The evolutional significance of Padgcttia The question of affinity of Padgettia to other might well be evaluated in relation to Halle's Paleozoic plants with neuroptcrid foliage is (1929, p. 18-22) well-known comments on one that must await discovery of many the position of pteridospermous seeds in rela­ more pertinent specimens. Perhaps the close tion to the fronds on which they were borne. resemblance between the pinnules of Padgettia Although only a few instances of demonstrable and foliage of Ne%roptcns is only another connection between seed and leaf were then example of homeomorphic evolution and known, Halle pointed out that the older no genetic relationship is involved. On the Carboniferous examples consisted of terminal other hand, it is possible that Padgettia seeds on much reduced foliar segments. represents a late stage in a neuropterid Younger Carboniferous forms showed a trend evolutionary sequence that began in such toward increased proximity of seed to lamina Carboniferous forms as N europteris Izetero­ and decreased heterophylJy. Finally, the phylla, with the evidence of a lineal relation­ majority of known Permian examples pro­ ship being retained only in the form of the duced seeds neither terminally nor marginally pinn ules. The latter alternative "\lould, of but actually attached to the surface of course, necessitate a drastic reduction of seed either the lamina or rachis of apparently size, concomitant with the" phyletic slide .. unreduced foliar segments. Thus, even and eventual embedment of the seeds within though there are still few examples to com­ the pinnules.

REFERENCES

CHODAT, R. (1908). Les pteropsides des temps FONTAIC'E. w :-1. & 'VHIH, 1. C. (1880). The Paleozoiques, Etude critique. Arch. des sci. Permian or l pper Carboniferous (lora of yVest physiques at nattf1'elle:i. 26(10): 394-416. Virgini<1. and S.'V. Pennsvh·ania. Srrond Goot. EA),lES, A. J. (1936). ~'Iorphology of vascu lar S"rv. PClIllsr!vallia: J?P/Jt. ofProgrcss. plants. Lower groups (Psilophytales to Fili­ H:\LLc. T. c..;. ·(1929). Sum seed-bearing plerido­ cales). lVIcGruw-Hitt Dook Co, l'[C1f1 York and sperms frolll the Permian of China. A"II[;I. London. . cJlska VetfilSk. Harldl. 3rd Series. 6(8): 3-24. lIIA.;I'LAY - PL TE 1 TilE PALAE0I30TAl'IST. YOLo 9 MAMAY -PADGETTIA, A NEW GENVS ON FERTILE NEl:ROPTEROID FOLIAGE 57

]ONG~IANS, \'1'. J. (1954). Contribution to the Dgl. A l'ch, N,'!'r!. des S·ci. F.1'actes et Nat. ser. knowledge of the flora of seam Girondelle lIIB. 1: 25. (lower part of the vVcstphalian A). Part 1. PLu~nl£R, F. D. & FUQU/I, H. B. (1937), Geologic JliJededel. Geol Stichtiug. S r CollI. 1(4)' 5-16. map of Young Coullty, Texas. Ulliv. Texas, 1\1])5'1'0:-:, ROB[':R'1' (1904). On the fructification of Dul'. Ecoll. Ceo!. Map (1930), revised 1937. Ne"1'opte1"l:s heterophylta, Brongniart. Phi!. Trans. SELLARDS, E. H. (1908). Fossil plants of the Roy. Soc. T.ondon. Ser. B. 197' 1-5. Upper Paleozoic of I<:ansas. Uniu. Geol Suru. I<:lDsToN. ROBERT & ]ONGMAl\S, W, ]. (1911). [(aI/iUS. Special report on oil and gas. 9: Sur la. fructification de NelfYOptel'is obliqua 586-00

EXPLA ATIOI OF PLATE I

1. Portion of pinnu1e of Padgettia l'eadi sho\\'­ each pinnule, both directed toward bottom of ing midrib ftt right, pinnule margin at left, and photograph. x 2. olle fructification with apex extending to margin. 3, 4. Counterparts of holotype, showing attach­ X 4. ment of several fructificalions. Note truncation of 2. Portions of t\\'o pinnulcs attached to ultimate beaks at pinl1ule margins. X 2. rig. 3: C.S.N.M. rachis. Note two fructifications, one near base of 41165a; Fi .4: 41165b.