STATE OF ILLINOIS ADLAI E. STEVENSON, Governor DEPARTMENT OF REGISTRATION AND EDUCATION

NOBLE J. PUFFER, Director

DIVISION OF THE STATE GEOLOGICAL SURVEY M. M. LEIGHTON, Chief URBANA

REPORT OF INVESTIGATIONS—NO. 142

PTERIDOSPERM MALE FRUCTIFICATIONS : AMERICAN SPECIES OF DOLEROTHECA, WITH NOTES REGARDING CERTAIN ALLIED FORMS

BY JAMES M. SCHOPF

Reprinted from the Journal of Paleontology

Vol. 22, No. 6, November, 1948

PRINTED BY AUTHORITY OF THE STATE OF ILLINOIS

URBANA, IIXINOIS

1949 ORGANIZATION

STATE OF ILLINOIS HON. ADLAI E. STEVENSON, Governor DEPARTMENT OF REGISTRATION AND EDUCATION

HON. NOBLE J. PUFFER, Director

BOARD OF NATURAL RESOURCES AND CONSERVATIO:

HON. NOBLE J. PUFFER, Chairman W. H. NEWHOUSE, Ph.D., Geology ROGER ADAMS, Ph.D., D.Sc, Chemistry LOUIS R. HOWSON, C.E., Engineering A. E. EMERSON, Ph.D., Btology LEWIS H. TIFFANY, Ph.D., Forestry GEORGE D. STODDARD, Ph.D., Litt.D., LL.D., L.H.D. President of the University of Illinois

GEOLOGICAL SURVEY DIVISION

M. M. LEIGHTON, Ph.D., Chief _

SCIENTIFIC AND TECHNICAL STAFF OF THE STATE GEOLOGICAL SURVEY DIVISION 100 Natural Resources Building, Urhana M. M. LEIGHTON, Ph.D., Chief ENID TOWNLEY, M.S., Assistant to the Chief Velda a. MiLLAKD, Junior Asst. to the Chief Elizabeth Stephens, B.S., Geological Assistant Helen E McMoRRis, Secretary to the Chief Elizabeth Wray, A. A., Technical Assistant Berenice Reed, Supervisory Technical Assistant Norma J. Parge, A.B., Technical Assistant GEOLOGICAL RESOURCES GEOCHEMISTRY Frank H. Reed, Ph.D., Chief Chemist (on leave) D.Sc, Principal Geologist Arthur Bevan, Ph.D., Grace C. Johnson, B.S. Research Assistant Coal Coal G H Cady, Ph.D., Senior Geologist and Head G. R. YoHE, Ph.D., Chemist and Head " Mechanical Engineer r" J Helfinstine, M.S., Ruth C. Wildman, M.S., Assistant Chemist Robert M. Kosanke, M.A., Associate Geologist Wm. F. Loranger, B.A., Research Assistant John A. Harrison, M.S., Assistant Geologist Tack A. Simon, M.S., Assistant Geologist^ (on leave) Industrial Minerals Raymond Siever, M.S., Assistant Geologist S. Machin, Ph.D., Chemist and Head Barnes, M.S., Assistant Geologist J. Mary E. Tin Boo Yee, M.S., Assistant Chemist Parker, B.S., Assistant Geologist Margaret Paulene Ekman, B.A., Research Assistant Kenneth Clegg, Technical Assistant Fluorspar Oil and Gas G. C. Finger, Ph.D., Chemist and Head Geologist and Head H. Bell, Ph.D., _ HoRST Schneider, B.S., Special Assistant Chemist A Engineer G. Frederick Squires, A.B., B.S., Petroleum William Frederick Buth, B.S., Special Research David H. Sv^^ann, Ph.D., Geologist Assistant Virginia Kline, Ph.D., Associate Geologist Richard Blough, B.A., Research Assistant Wayne F. Meents, Assistant Geologist Robert E. Oesterling, B.A., Special Research Assistant Petroleum En- Richard J. Cassin, B.S., Assistant gineer L. Finnerty, Special Research Assistant , A ^ J. James B.S., Lester W. Clutter, B.S., Research Assistant Nancy Cassin, B.S., Research Assistant Chemical Engineering H. W. Jackman, M.S.E Chemical Engineer and Industrial Minerals Head P. W. Henline, M.S., Chemical Engineer E. Lamar, B.S., Geologist and Head J. B. Greenwood, B.S., Mechanical Engineer Robert M. Grogan, Ph.D., Geologist J. James C. McCullough, Research Associate Raymond S. Shrode, B.S., Assistant Geologist X-ray and Spectrography Clay Resources and Clay Mineral Technology W, F. Bradley, Ph.D., Chemist and Head Ralph E. Grim, Ph.D., Petrographer and Head William A. White, M.S., Associate Geologist Physics Herbert D. Glass, M.A., Associate Geologist Kenneth B. Thomson, Ph.D., Physicist Groundwater Geology and Geophysical R. J. PiERSOL, Ph.D., Physicist Emeritus Exploration Analytical Chemistry Carl A. Bays, Ph.D., Geologist and Engineer, and *0. W. Rees, Ph.D., Chemist and Head

Head . L. D. McVicker, B.S., Chemist ^ , Robert R. Storm, A.B., Associate Geologist Howard S. Clark, A.B., Associate Chemist Merlyn B. Buhle, M.S., Associate Geologist Emile D. Pierron, M.S., Assistant Chemist M. W. PuLLEN, Jr., M.S., Associate Geologist Elizabeth Bartz, A.B., Research Assistant John W. Foster, B.A., Assistant Geologist Donald Russell Hill, B.S., Research Assistant Richard F. Fisher, M.S., Assistant Geologist Ruth E. Koski, B.S., Research Assistant Draftsman Margaret J. Castle, Assistant Geologic Annabelle G. Elliott, B.S., Technical Assistant Geologist Robert Knodle, M.S., Assistant MINERAL ECONOMICS Engineering Geology and Topographic Mapping W. H. Voskuil, Ph.D., Mineral Economist George E. Ekblaw, Ph.D., Geologist and Head W. L. BuscH, Research Associate Nina Hamrick, A.M., Assistant Mineral Economist Ethel King, Research Assistant Areal Geology and Paleontology M. H. B. WiLLMAN, Ph.D., Geologist and Head EDUCATIONAL EXTENSION Lovi^enstam, Ph.D., Geologist (on leave) Heinz A. Gilbert O. Raasch, Ph.D., Associate Geologist Ph.D., Geologist J. S. Templeton, in Charge Dorothy Ranney, B.S., Technical Assistant Geology Subsurface LIBRARY L. E. Workman, M.S., Geologist and Head Elwood Atherton, Ph.D., Associate Geologist Anne E. Kovanda, B.S., B.L.S., Librarian Paul Herbert, Jr., B.S., Associate Geologist Ruby D. Prison, Technical Assistant Donald Saxby, M.S., Assistant Geologist Robert C. McDonald, B.S., Research Assistant PUBLICATIONS Lois Titus, B.S., Research Assistant Dorothy E. Rose, B.S., Technical Editor M. Elizabeth Staaks, B.S., Assistant Editor Mineral Resource Records Meredith M. Calkins, Geologic Draftsman Ardis Assistant Geologic Draftsman Vivian Gordon, Head D. Pye, Wayne W. Nofftz, Technical Assistant Harriet C. Daniels, B.A., Technical Assistant Leslie D. Vaughan, Associate Photographer Dorothy Gore, B.S., Technical Assistant Beulah M. Unfer, Technical Assistant Dorothy A. Foutch, Technical Assistant Zora M. Kaminsky, B.E., Technical Assistant •' Acting Chief Chemist in interim of absence of Elene Roberts, Technical Assistant Chief Chemist.

Consultants: Geology, George W. White, Ph.D., University of Illinois Ceramics, Ralph K. Hursh, B.S., university of Illinois Mechanical Engineering, Seichi Konzo, M.S., University of Illinois Topographic Mapping in Cooperation with the United States Geological Survey. January 10, 1949 Digitized by tlie Internet Arciiive

in 2012 witii funding from

University of Illinois Urbana-Champaign

http://archive.org/details/pteridospermmale142scho a

Journal of Paleontology, vol. 22, no. 6, pp. 681-724, pls. 104-115, 18 text figs., November 1948

PTERIDOSPERM MALE FRUCTIFICATIONS: AMERICAN SPECIES OF DOLEROTHECAy WITH NOTES REGARDING CERTAIN ALLIED FORMS JAMES M. SCHOPF U. S. Geological Survey, Washington, D. C.

Abstract—Dolerotheca includes a group of pteridosperms (MeduUosaceae) char- acterized by very large and unusual pollen-bearing organs. Their botanical p)er- tinence to plant microfossil studies and to phyletic theories, as well as their rarity in good preservation, lends considerable interest to these fossils. The rnorphology of the polleniferous organs, or male fructifications, is reviewed preliminary to taxonomic treatment of the new American material. Three new species are described in considerable detail both as to general external form and internal organization— result possible only because of preservation in the limestone concretions in coal beds known as coal balls. The species of Dolerotheca are assembled in a new sub-tribe called the Dolerothecinae. The evidence for relating these forms with other coal- bail fossils known as Myeloxylon, and, in turn, with MeduUosa, is discussed with par- ticular reference to one species where the peduncular organ of attachment seems to be preserved. Notes are also included regarding a specimen of Dolerotheca pre- served in surface imprint in an ironstone concretion, and regarding the allied Whit- tleseyinean group classed as Codonotheca. The relationships and comparative anatomy of Dolerotheca with other pteridosperm groups that present homologous features are discussed and a tentative evolutionary interpretation presented. Hetero- theca of the Lower Carboniferous appears to represent a plausible ancestral type, combining features of both the lyginopterid and meduUosan lines of descent. The morphology of Dolerotheca suggests, however, that evolutionary modification has been by elaboration and septation of a single telomic structure rather than by adna- tion and concrescence of many.

INTRODUCTION that dififer radically from organs known in THE male fructifications of pteridosperms ferns. A more complete understanding of the are less well understood than most of characteristics and the nature of the diver- the other organs pertaining to this large sity of male fructifications in pteridosperms group of ancient plants. The fact that a will have important influence on ideas of considerable number of the Paleozoic fern- phylogeny and relationship among this like plants bore seeds and hence were not large, chiefly Paleozoic, plant alliance. true ferns, in spite of their highly dissected Among the pteridosperms the plants or pinnatifid leaves, became established classified as Dolerotheca display conspicuous about 45 years ago. Since then a number of differences with regard to their male fruc- pteridosperm seed types have become well tifications. Such fructifications of Dolerotheca known; on the other hand an equivalent have not been commonly reported, and up amount of information has not been ob- to the time specimens here described were tained about the male fructifications de- discovered, only a single fragment was spite the fact they must have been numer- known which showed well preserved tissue ous. Some of the first recognized pterido- structures. A few surface impressions and sperms seemed to have male fructifications coalified compressions of similar fructi- resembling the synangia of ferns. These fications have been recognized, but these are organs were presumed to be conservative difficult to interpret and naturally afforded and little modified in the evolutionary tran- much less conclusive information about sition from thefree-sporing to the seed habit. their structural organization than do the However it has become clear during the last specimens described below. fifteen years that certain other groups of These new fossils from coal balls have the pteridosperms possessed male fructifications cells preserved in almost perfect detail. Coal

681 38.5 mm

9.5mm PTERIDOSPERM MALE FRUCTIFICATIONS 683

balls are calcareous, siliceous, or dolomitic it may be possible to attribute certain concretions that formed in some Carbonif- varieties of coal material to certain kinds or erous peat beds, in which mineral matter to various associations of plants. Spores and solidly infiltrated, enclosed, and preserved pollens actually found in their parent plant organs and other peaty materials with fructifications indicate affinities of at least remarkable perfection. The enclosed plant some of the similar spores and pollens iso- materials were protected from subsequent lated from coal and thus facilitate a more alteration, whereas the adjacent unminer- accurate biologic classification of the abun- alized peat became much compressed and dant microfossils. Isolated spores of the was transformed to coal. Consequently it is type borne by Dolerotheca are usually iden- possible to describe the Dolerotheca fructi- tified with the genus Monoletes, in part, fications found in coal balls in considerable unless their more precise affinity can be detail and to compare their anatomical and established (Schopf, Wilson, and Bentall, tissue structure with that of more con- 1944). At present, when subsidiary infor- ventional organs of spore or pollen produc- mation about the organs that bore them is tion. lacking, the isolated spores cannot be as- This new information permits more ade- signed to a less generalized group. quate comparison with the fructifications of Dolerotheca is believed to be allied with other pteridospermous plants than was pre- the Medullosaceae as broadly defined. The viously possible and thus assists in inter- writer believes that the Medullosaceae pretation of relationships and phylogeny. includes the genera Alethopteris, Callipteris, Because only a few of the fossils that can be Myeloxylon, Medullosa, Rotodontiospermum, compared with Dolerotheca are as amply Trigonocarpus (at least in part) and some described, and because the organization of other allied genera typified by their seeds. Dolerotheca fructifications is relatively novel, Neuropteris, and some other genera typi- the writer's present phylogenetic interpre- fied by characteristics shown by leaves tation is tentative, a working hypothesis and fronds, may possibly be allied with this that later discoveries may or may not con- family, in spite of the fact that their re- firm. A full appreciation of the significance lationship to the type genus, Medullosa, has of Dolerotheca may be impossible for some not been indicated by recent studies.^ considerable time. The comparison of Dolerotheca with fructi- These descriptions of fossil fructifications fications of the Whittleseyineae tends to should also help to clarify the relationship of confirm the alliance of this subtribe within certain common types of plant microfossils the medullosan family. that are abundant in coal. The value of Halle's brillant research (1933) on the isolated spore and pollen types in identifying structure of the Whittleseyinean types was and tracing individual coal beds is a matter based largely on coalified compression of current investigation. Their effective use specimens. With some hesitation he included depends not only on knowledge of their stratigraphic distribution but also on a 1 Schopf (1937), Steidtmann (1944) and An- of natural of knowledge the groups plants drews (1945) all present evidence of alliance be- which they represent. From such knowledge tween Medullosa and Alethopteris.

Explanation of Frontispiece

External Appearance of Male Fructifications of Pteridosperms Figures (except Section Diagram D) are drawn to the same scale

A. Dolerotheca formosa, surface reconstruction showing proximal features. B. D.formosa, surface reconstruction showing distal features. C. D. villosa, surface reconstruction showing proximal features. D. Heterotheca grievii (left). Surface reconstruction showing side view; (right) cross-section, diagram- matic, black heavy dots—vascular bundles, hatch lines—sclerotic tissue, round open areas—spor- angia. Based on description, figures and meavSurements reported by Miss Benson (1922). E. Telangium scotti, surface reconstruction, according to description, figures and measurements re- ported by Miss Benson (1904). 684 JAMES M. SCHOPF

Dolerotheca as a member of the Whittlesey- acteristics they do show have in the past inean subtribe. The structure of Dolerotheca been difficult to interpret. The data to be is now shown to be sufficiently different so presented relative to their organization and that its separation as another subtribe seems microscopic characteristics may aid con- advisable; the alliance of the new subtribe siderably in facilitating recognition of such Dolerothecineae (here proposed; see p. 687) organs in various states of fossil preservation. with the Whittleseyineae can scarcely be Additional records and observations are doubted and only the taxonomic decision as needed to establish their use in stratigraphic to how this relationship should most appro- paleontology. priately be expressed can involve any differ- SUMMARY OF MORPHOLOGY AND ence of opinion. In this regard the writer has ORGANIZATION OF DOLEROTHECA followed Halle in utilizing the subtribal category because he believes the Dolerothe- Detailed information about the plants cinean group merits recognition on a par classified as Dolerotheca is lacking for all with the Whittleseyinean group. parts except the male fructification, and The Medullosaceae is an important family characteristics of such fertile parts provide which includes several genera having exten- the only basis for identification. Evidence of sive distribution in the Euro-American floral histology and association point to the very province of the Carboniferous and Permian, great likelihood that the fructifications were with some species of special stratigraphic borne on fronds of the same type as Myelox- value. It therefore seems remarkable that ylon and Alethopteris. The manner in which so little has been known in general about the the male organs were connected to the plant male fructifications of these plants. Un- is not precisely known, and only in Doler- doubtedly they were actually much more otheca reedana has a probable connective common than would appear from scattered organ (described as a peduncle (?), c.f., p. references in, the present literature. They 710) been observed. However, the peduncle may not have been recognized in some in- (?) is not in actual attachment. The evidence stances because they appear to have been at hand suggests that the organs were shed deciduous shortly past maturity and they from their connection with the plant soon may have disintegrated readily after they after maturity, and that their early abscis- dropped from their attachment on the plant. sion left a very inconspicuous scar, both on Furthermore, in their more common preser- the parent axis and on the fructification vation as compressions, the male fructi- itself. fications frequently do not show very dis- The male fructifications of Dolerotheca tinctive megascopic features and the char- are broadly bell-shaped and include numer-

EXPLANATION OF PlATE 104

Fig. 1 —Dolerotheca formosa, longitudinal section—fructification is enclosed in a dense mat oiAlethop- teris leaves. From coal ball 219Bl(tl). 2—Same as above, section from opposite side of saw kerf. From coal ball 291 CI (b 1). 3—D. formosa, transverse section (peel) of fructification across the irregular distal (dehiscence) surface. From coal ball 129 A (t 7). 4—D. formosa, transverse section of fructification taken at a higher level than figure 3, intersecting dehiscence tissue only on the left. From coal ball 129 A (t 22), scale same as figure 3. 5—Same as above, section taken at a higher plane. From coal ball 129 A (t 25), scale same as for figures 3 and 4. 6—Same as above, section at the top of fructification. The fragment of "sparganum" cortex shown in the upper center does not seem to be attached. Note horizontal sections of Alethopteris leaves showing venation. From coal ball 129 A (t 38), magnification same as figures 3 and 4. 7—D. formosa, transverse section of a different fructification at level of dehiscence tissue with associated Alethopteris leaves. From coal ball 129 A (t 38), same scale as figures 3 and 4. 8—Dolerotheca fertilis (Renault) Halle, longitudinal section of sporangium and spores, o. d, spores; b, intersporangial tissue; c, sporangial membrane (?); f, lysigenous tube ?. Copeid for comparison from Renault (fig. 1, PI. XIII, 1902). '

Journal of Paleontology, Vol. 22 Plate 104

toi^^a'^I y^ tf^^m . ^^^ qI ^^'' ^^K<|)J wm^ " JMHC^yi B^f mc KiHj^^Hi i^J } Jm m 3 cm 2 mm

'^^^J^

Schopf, Dolerotheca jormosa n.sp., D.fertilis Halle Journal of Paleontology, Vol. 22 Plate 105

Schopf, Dolerotheca formosa n.sp. PTERIDOSPERM MALE FRUCTIFICATIONS 685 ous long tubular sporangia immersed com- intrasporangial tissue, the tips are effectively pletely in tissue. The structure is large and opened to shed the spores. No instance has massive and quite unlike any of the con- been observed where an isolated sporangium ventional types of polleniferous structures has failed to open so that the full normal and (see, for example, the discussion presented mature complement of spores was still by Wilson, 1937). Because of the difficulties retained. In the Dolcrotheca campanulas of homologous comparison, the male fructi- described by earlier authors, more numer- fication of Dolerotlieca may conveniently be referred to by a noncommittal morphologic term as a campanulum? Essential features of such a campanulum are diagram matically sketched in text figure 1. The external aspects of Dolerotlieca fructifications have been re- constructed as shown in the frontispiece illustrations A, B, and C.

Dorsally, that is, on the side of attach- ment, the organ is enclosed by a differen- tiated layer here called the campanulary cover; the distal surface is evidently adapted to permit emission of spores from the sporangia. The distal side is covered by a FiG. 1 —The campanulum of DoJerotheca. Median zone, here called the dehiscence layer, tissue longitudinal aspect: Diagrammatic although no kinetic mode of sporangial de- A. Campanulary cover layer hiscence has been recognized. The dehiscence B. Dehiscence layer C. Tubular sporangia layer is more or less radially grooved and D. Inter-sporangial tissue: ground paren- slit or each ripened sporangium opens by a chyma, secretory elements, sclerenchyma, pore into the grooves of the distal surface. vascular strands. There is evidently no analogue of the pris- cells so in spor- matic epidermal common ous spores apparently were retained in the angia of cryptogamic plants which fre- sporangia, but their specimens were so in- quently are specialized to provide for expul- complete or unfavorably preserved that sion of spores. dehiscence details could not be reported. The dehiscence layer probably is perfo- The sporangia are in paired rows radiating rated when the campanulum dries at matu- from the center of the fructification, with rity. It may be that radial tensions are set up their long axes approximately parallel to the at that time to cause rupture of this layer organic axis of the campanulum. New at the distal ends of sporangia. In any event double rows of sporangia are intercalated the sporangia are completely im- although towards the periphery of the solid bell- mersed in parenchymatous and sclerotic shaped structure.

2 Refering to the external form; campanula, L., Glandular pubescence is a common at- a little bell. tribute of many pteridosp.erms and has been

Explanation of Plate 105

Fig. 1 —Dolerotheca formosa, transverse section of fructification at level of dehiscence tissue. From coal

ball 129 A (t 7). ^ 3—D. formosa, longitudinal section of fructification showing shorter sporangia at margin; note slight sigmoid curvature of longer sporangia. A transverse section oi Alethopteris leaf is shown at the bottom below dehiscence tissue. From coal ball C 1 B 1 (b 18 c), magnification same as figure 1. 3—Vascular strand from section shown in figure 2. Tissues around it are poorly preserved; at the left is tissue bounding a sporangium. 4—Vascular strand shown in figure 3 but at higher magnification showing scalariform and spiral elements. 686 JAMES M. SCHOPF

discussed by Halle (1929, p. 21-22) relative Andrews (1945, p. ^il) has inferred from to seeds, and also was described b)^ him his study of their stem anatomy, that (Halle, 1933) on the male fructifications of Medullosans may have grown in rather Goldenhergia. Relativel}'' dense short hairs dense stands. The prolific occurrence of are present on the campanulary cover of Medullosa stems and roots, Myeloxylon type Dolerotheca, and more sparse longer hairs on petioles, Alethopteris type foliage, Rotodon- the epidermis of the dehiscence layer. Their tiosperm seeds, and Dolerotheca campanulas function, if they possessed a function, is not at the one locality which provided two of the apparent, but they seem suitable for use as species described below, tends to support taxonomic criteria. Hairs also are present on this view. However, no evidence points the surface of the Codonotheca male fructi- directly at any one of the modes of fertili- fication, one other genus included in the zation suggested by Halle (1933, p. 51). Whittleseyinae. Certainly Dolerotheca has the most massive The spores produced by the campanulary male fructification of any groups Halle in- fructifications of Dolerotheca are very large, cluded in the Whittleseyinean subtribe, and sometimes longer than half a millimeter, if the prepollen was expelled by gusts of or as much as 10 times the usual dimensions wind as a general occurrence in smaller forms of isospores or microspores of cryptogamic such as Goldenhergia or Boulaya, a gale might plants. They tend to be considerably larger have been required to clear the spores from than the pollen grains known from fossil sporangia of the massive campanulas of cycads and conifers. They are, however, Dolerotheca. more primitive in organization than true Although a majority of spores evidently pollen grains and it seems evident they are had been shed in most specimens observed more advanced than cryptogamic micro- in this study, a number of prepollen grains spores. For this reason it seems desirable to persist in some sporangia of most of the refer to the spore bodies of the dispersal specimens. It appears to be a reasonable stage as prepollen, following the practice inference that the emission of spores through long ago adopted by Renault (1893-96). the distal sporangial opening was often not The size of the prepollen and the organi- complete. In spite of obvious maladaptation zation of the campanulas that bore them, im- for easy spore distribution, the writer is mediately suggests a considerable biologic inclined to favor dissemination of prepollen problem regarding the means of effecting by strong gusty wind as more inherently fertilization. Such large heavy prepollen probable than distribution by insects or obviously was not well adapted to ordinary similar agents. The prepollen is obviously wind pollination, as the pollen of many more protected from contact with small modern plants is. Insects have been sug- vagrant animals than it would be from gested as a possible vector agent for fer- the mechanical effects of sporadic air cur- tilization but there is little positive evidence rents. There can be little question that to support this idea beyond the mere pres- intermittent winds could have dislodged ence of glandular pubescence which might most of the prepollen and carried it a little have attracted insects. To carry this sort of distance after it left the sporangial openings. prepollen effectively the insects should have Information about the location of campan- been of a specialized type. ulas and seeds on the parent plants is not Plants with this kind of prepollen had a sufficiently clear to formulate any opinion relatively long span of geologic existence. as to how far the fertilizing elements would The prepollen grains are commonly found in need to be transported after they left their many Upper Carboniferous coal beds both sporangia in order to effect fertilization. in America and in Europe. The more important and demonstrable Thus there is good reason to believe that features discussed above are used to establish fertilization actually was accomplished with a new group, parallel to the Whittleseyinae relative ease, because otherwise the plants in nomenclatural status. It is clear that Dc?- could not have been as extensively dis- lerotheca differs in some important features tributed; at times they were certainly dom- from those shown by the Whittleseyinean inant elements of the vegetation. Indeed, group. It is believed that coordinate taxo- PTERIDOSPERM MALE FRUCTIFICATIONS 687

nomic ranking of the Dolerothecinae will male fructifications externally campanulate assist in unifying information about the var- or broadly campanulate in form, enclosing ious genera typified by diverse fossil speci- tubular sporangia completely immersed in mens, so that they can be brought together the campanulary tissue. Sporangia paired in more easily into a ''normal" familial group. biseriate roAvs, with additional double rows In the future it is hoped demonstrated char- of sporangia intercalated toward the mar- acteristics of the Medullosaceae will come gins; order of sporangial maturity probably to compare favorably in all essentials with slightly gradate and trending centrifugally. those of families chiefly based on modern The cover of the proximal side of the cam- material. panulum bearing a glandular pubescence of short hairs; distal dehiscence surface with Subtribe Dolerothecinae more sparse and more slender hairs and Schopf. n. subtr. epidermal papillae. Type species.— Diagnosis.— Plants of Medullosan alliance Dolerotheca fertilis (Re- possessing massive male fructifications en- nault) Halle. closing numerous elongate tubular sporangia. Halle restudied as much of Renault's Sporangia paired in rows radially disposed, material of this species as could be found in containing exceptionally large spores of the prepollen type. Prepollen grains oval, not quite bilaterally symmetrical, with a lin- counterpart Grand 'Eury illustrated and de" ear proximal suture. External surfaces of scribed under two generic assignments in 1890, fructification characteristically pubescent. i.e., Androstachys in textual description, Disco- stachys for the plate, is congeneric with the pres- Type genus.—Dolerotheca Halle. ent Dolerotheca material. Grand 'Eury's specimen is distinguished from The Dolerothecinae is evidently a reasonably well preserved compres- the Whittleseyinae by the massive campan- sion example of the type that may be more com- ulum, and the more numerous and differ- monly recognized now that it is possible to inter- pret the structure. ently disposed sporangia. It is distinguished Halle in 1933 was unable to be sure of the gen- from the Potonieinae by the character of its eric identity of the Grand 'Eury specimen and prepollen, and possibly by features of the that shown by Renault's silicified fragment of sporangia that are not as clearly defined at Dolerophyllum fertile; the latter was taken by Halle to be the generotype of Dolerotheca. The the present time. Heterotheca of the Lower present material is complete enough to show Carboniferous, which may well represent an clearly that the Androstachys-Discostachys speci- alHed ancestral group, is to be distinguished men and the silicified fragment are congeneric. by lack of tubular sporangia, by differences The popular old name "Dolerophyllum," which Renault used in the sense of a combination genus, in its spores, and its smaller size. is of course inapplicable to the fertile specimens is only genus Dolerotheca at present the that had been included in it, as Halle recognized. assigned to the Dolerothecinae. The mater- But we cannot now regard the Androstachys- ial available now enables a more satisfactory Discostachys specimen as ambiguous, as Halle suggested. One would suppose that one of the generic diagnosis to be presented. Although names proposed by Grand 'Eury, either Andro- certain features of the genotype species thus stachys or Discostachys, would have to be applied acquire added significance, it does not seem since both have a clear claim to priority over that any change in taxonomic meaning Dolerotheca. White, in fact, anticipated this pos- sibility in 1903 and suggested, with reference to "circumscription" is involved, and there- some comparable material that Androstachys fore, although the diagnostic description of should be selected "if the generic identity of the the genus is somewhat amplified, it is not sterile leaves (i.e., referring to Dolerophyllum, regarded as emended. s.s.) and the supposed polleniferous leaves is not established." The name Androstachys is, however, unavail- Genus Dolerotheca Halle.^ able since Grand 'Eury himself had used the Amplified Diagnosis.— Plants agreeing name earlier in reference to a fertile zygopterid frond. Therefore Androstachys Grand 'Eury, with the Dolerothecinae (see above), with 1890, is a junior homonym of Androstachys Grand 'Eury, 1877, and though now regarded as a syn- ^ Whether Dolerotheca is a valid name or not, is onym, such names cannot be reused according to open to some question. One of the results of this the express stipulation of Article 61 of the Inter- study has been to show that the specimen and national Rules of Botanical Nomenclature. 688 JAMES M. SCHOPF

1929, and presented the results of his obser- compressions of Dolerotheca.* A photograph vations and new photomicrographs in 1933. of a longitudinal section of D. fertilis was A line tracing from the transverse section illustrated lithographically by Renault in a Halle studied, showing arrangement of little known publication in 1902. This fig- sporangia, is reproduced here in text figure 2. ure (Renault, 1902, PI. 115, fig. 1) has been rephotographed and is presented in pi. 104, fig. 8 for comparison. Three additional fig- ures of prepollen have been copied from this same publication by Renault (1902, pi. 114, fig. 4, pi. 12, figs. 3-4) and are reproduced in pi. 108, figs. 11-13. All the structures are in evident generic agreement with the new forms described below. The most divergent structure is the ground parenchyma, de- scribed as aerenchymatous by Renault, but scarcely mentioned by Halle. Sclerenchyma seems to have been lacking in the Euro- pean forms.

NEW SPECIES OF DOLEROTHECA

Three new species of Dolerotheca are de-

problem now Is to properly incorporate this in- formation systematically. So far as factual matters pertaining to identi- fication are concerned, it does not make much difference which name is applied. The nomen- clatural types of both names leave much to be Fig. 2—Dolerotheca fertilis, transverse section of desired in the way of completeness and preserva- Line tracing Renault's holotype. from pub- tion. The writer believes, however, that prefer- lished photograph by Halle pi, 9, fig. (1933, 2), ence should be given to Dolerotheca, although it showing about 50 sporangia, most of which are was proposed later. It is a name now in current associated in paired rows. use, being mentioned in at least three recent text- books. Discostachys is in complete disuse, ap- parently has never been cited in a textbook, and It is evident that it accords with species was regarded as a dubious and confused syno- described below in having radially paired nym by both White and Halle. Hence, in the present paper the writer proposes to retain rows of sporangia. This interpretation is Dolerotheca as Halle introduced it in 1933. In more in agreement with Halle's alternative order to clear it of conflict with Discostachys suggestion (Halle, 1933, p. 48) and with G. 'E., 1890, he further proposes that Disco- the structure shown by the "Mont-Pele" stachys be regarded as a nomen confusum and that Dolerotheca be added to the list of officially conserved names, being specifically conserved over Discostachys as typified by D. cebennensis There seems no alternative to the conclusion G. 'E., 1890. that Discostachys Grand 'Eury, 1890, type D. It appears to the writer that this course is the cebennensis, as illustrated by that author in plate one most likely to promote stability in reference 7, fig. 2 A and A', in the Gard report, is a name to the group of plants involved. Any other is that may be available, with priority over Dolero- likely to lead to prolonged nomenclatural con- theca Halle, 1933. If the name had not been con- fusion that would be profitless in advancing fused with Androstachys and if a proper descrip- knowledge of these plants or any aspect of paleo- tion had appeared under the name Discostachys botany. no question would exist about the propriety of * Saporta and Marion (1885, p. 74) also men- usinp^ it in this connection. Grand 'Eury for in- tion that locules of the "Dolerophylleae" (evi- explicable reasons confused the names he ap- dently they had the Mont-Pel6 .specimens de- plied to his specimen but the descriptive facts scribed as D. berthieri in mind) are (list ribii ted in [jertinent to it are relatively clear. The chief "two contiguous rows." PTERIDOSPERM MALE FRUCTIFICATIONS 689 scribed below. One of them, distinguished as Dolerotheca formosa Schopf, n. sp. D. formosa, is represented by a somewhat Frontispiece, figures A, B; plate 104, figures indefinite number of specimens. They are 1-7; plate 105, figures 1-4; plate 106, rather common in the large coal ball aggre- figures 1, 2; plate 107, figures 1-6; gate collected from a coal bed below the plate 108, figures 1-10; text Calhoun limestone in southwestern Rich- figures 3a-d, 4-13 land County, Illinois, in 1937. A prelimi- External Characters.—Male fructification nary note (Schopf, 1938) identified the zone broadly campanulate, about 40 mm. in di- as lower than the La Salle limestone, but it ameter and 11-14 mm. thick. Point of learned since that this was in error has been attachment somewhat excentric. Proximal that its stratigraphic position is higher. and (dorsal) side convex, probably of leathery deposit is in the upper part of the Mc- The texture, somewhat irregularly indented Leansboro and has been discussed group radially, indentations diminishing toward coal ball zones in a previous relative to other margin. Proximal surface covered with publication describing an unrelated lycop- numerous glandular simple hairs, sometimes sid form, Mazocarpon oedipternum, that was capitate tipped. Distal side also slightly found in the same coal ball aggregate convex, with bifurcating radial (dehiscence) (Schopf, considerable number of 1943). A grooves 1-2 mm. deep except near the center the D. formosa fructifications are quite frag- where they become obsolete or less regular. mentary. Study has has been mainly based Sporangia are arranged in double rows be- on three essentially complete specimens. tween the grooves and open into them by About 15 other specimens in a good state slit-like perforations. Toward the center of preservation have been observed inci- of the fructification sporangial openings dentally in slices of the Calhoun material, are more pore-like since the grooves are and the general features have been checked shallower there. Distal surface covered with from them, both on sawed and etched sur- sparse simple hairs and epidermal papillae; faces and from peel preparations. the hairs consist of one to three cells and Two specimens of a much smaller form, are more slender and much less glandular here described as Dolerotheca villosa, also appearing than those on the proximal sur- were discovered in examination of coal balls face. from the same deposit. An accurately scaled reconstruction of The third species has been described un- these external features is presented in the der the name of Dolerotheca reedana, so frontispiece figures A and B. The peduncle called in recognition of Fredda D. Reed, only, in fig. A, is hypothetical since no at- Professor at Mt. Holyoke College. Professor tached specimens have been found. The pro- Reed discovered this specimen in the course portions of these figures have been carefully of her investigation of fossil plants in coal checked with sections in both planes. balls from the Harrisburg (No. coal bed 5) General Anatomy.—The tubular spo- in Saline County, Illinois. She generously rangia of D. formosa are 0.6 to 1 mm. in di- permitted the writer to include it in this ameter and vary from about 4 to 12 mm. in study when it was learned that comparable length. In a preliminary note (Schopf, 1938) material from the Calhoun locality was be- they were described as "radially related in ing investigated. D. reedana thus is from pairs of rows; sterile locules alternate with the Carbondale group of the Illinois Pennsyl- the fertile ones in each radial series." This vanian, and of considerably earlier geologic is a fair statement of the arrangement of age than the other forms described here. At sporangia and other cavities but the "ster- present it represents the oldest described ile locules" should be designated species of Dolerotheca, but future discoveries mentioned will probably extend the range of the genus by the more non-committal term, lysige- into still lower strata. nous tubes, because there is no evidence of The most obvious difference between the their sporogenous nature although this at three species is in size and character of first seemed probable. The tissue surround- pubescence, but other differences also can ing the lysigenous tubes is ragged on all be noted. edges. Aside from miscellaneous tissue frag- 690 JAMES M. SCHOPF

ments none has any contents. They may Text figure 3 a, from a section across the function as respiratory chambers somewhat middle of the fructification, shows a very as the parichoi of lycopod stems, although similar character although the double rows there seems to be no special means of com- are not so obvious. A nearly radial longitudi- munication with the exterior. Renault nal section is shown in text figure 3 d and thought the aerenchymatous tissue of D. the transverse planes corresponding to the fertilis would assist the fructification to float sections in figures 3 a-c are approximately in water. Doubtless this suggestion would indicated. apply as well to the lysigenous cavities, One of the interesting features in arrange- but the advantage of this structure is not ment of sporangia is the way new paired evident unless the plants had the growth rows are added by intercalation toward the habit of pond lilies—a suggestion which for margin. Text figure 3 c shows this best by various reasons seems far fetched. the course of the dehiscence grooves. Plate Relations of the sporangia are diagram- 105, figure 1 represents a photograph of part matically illustrated in text figure 3. The ofthis same section. In the longitudinal plane outer dark shaded zone represents the cam- the sporangia incline upwards around the panulary cover which in this species is margin of the fructification as shown in plate

about 400-800 /x thick, and extends over the 105, figure 2 until they abut on the dorsal strongly convex proximal surface as shown cover layer. Thus they are shorter than in figure 3d. The double rows of sporangia sporangia more centrally located. This are best shown in cross-section close to the feature may provide a clue to the mode of lower dehiscence surface (fig. 3 c). This sur- growth of these fructifications. It also is face is covered by an epidermis beneath worthy of note that many of the sporangia which appears the rather delicate elongate are not actually straight but have a slight cells of the dehiscence tissue. The dehiscence sigmoid curvature which is apparent in tissue covers the lower ends of the sporangia nearly all of the near-radial sections (text and the areas between. It extends deeper fig. 3 d; plate 104 figs. 1 and 2; plate 105 inside the fructification along the strong fig. 2; plate 107, fig. 1). dehiscence grooves as shown in the frontis- In regard to growth the chief question is piece figs. B. Thus a section across this lower the order of sporangial maturity, whether part of the fructification (fig. 3 c) shows the centripetal or centrifugal. One would expect free sides of sporangia clothed by the dehis- the sporangia first formed in ontogeny to cence tissue which has split opposite each be the most complete and longest. These locule to provide egress of spores from spo- evidently are the ones centrally placed in rangia. The lower surface of these fructifica- this fructification and so it seems most tions is slightly convex so that the section plausible that the fructification expanded as shown in text figure 3 c is slightly off the a capitate head with the central, i.e., the main transverse plane, more accurately most axial sporogenous tissues maturing transected by the section shown in text fig- first and marginal tissues somewhat later. ure 3 b. Near the margin of this figure the The course of maturation in this event dehiscence tissue and grooves between the would be centrifugal or opposite to that in sporangial rows again are shown. Centrally umbels and capitula of modern plants. The the sporangia are tubular and separate number of marginal rows produced and the except where septae have broken down. final diameter attained by the fructifica-

— FiG. 3 Dolerothecaformosa, sections of fructification : schematic indication of tissues. Spores are shown black, inter-sporangial tissue (ground parenchyma and sclerenchymatous strands) represented by dashed areas, dehiscence tissue is stippled, campanulary cover dark with white stippling. Drawings prepared by projection of "peel" sections at low magnification, scale of enlargement is indicated. The serial number of preparations is given for each figure. A, B, C.—Transverse sections. D.—Vertical (slightly tangential) section. Ruled lines (A-A, B-B, C-C) indicate approximate relative levels at which transverse sections for figures A, B, and C were obtained; the transverse series is from a different specimen than section D; both are from coal ball 129.

692 JAMES M. SCHOPF tion was probably dependent to some extent as shown in text figure 7. From two to four on environmental conditions which favored or five cells may adjoin the basal hair cells. or retarded growth and reproductive proces- No stomates have ever been recognized in ses in the plant. the epidermis of the cover although, in view Histology.—The proximal or dorsal side of of the spongy tissue lower in this layer, the fructification is covered by the rather their absence is noteworthy. thick more or less coriaceous campanulary Beneath the epidermal tissue is a zone of cover. It has a definite cuticularized epider- spongy parenchyma generally not well pre- mis bearing numerous short glandular ap- served, with numerous large intercellular pearing hairs. These hairs are 60-90 n long spaces. Isolated in this spongy tissue are and about 45 ju broad consisting of from two groups of nearly isodiametric sclerotic or to five cells, all of which except the terminal stone cells. These are shown most clearly in cell are broader than long. The terminal cell is the section illustrated in plate 107, figure 6, variously cone-shaped and sometimes has which was cut obliquely tangential to the divided into two cells to become capitate. cover layer and appears thicker than it All the cells have dark contents shrunken actually is for this reason. The groups of away from the cell walls, which gives the stone cells seem comparable in position to hairs a glandular appearance. The dark the sclerenchyma of the sparganum cortex material does not appear "resinous" and of Myeloxylon petioles and also to cells of the may be the remains of a dense cytoplasm sclerotesta of certain trigonocarp seeds. The containing tannin derivatives or other ma- cell shapes and the tissue occurrence differs terials. Some cells contain rounded central considerably, however, so that the histologic bodies reminiscent of nuclei. Three of the similarities are not very marked. Numerous hairs are shown sectioned vertically in text large secretory canals are also present and figure 12. A somewhat better idea of the possess characteristic opaque contents. The hairs and epidermal pattern is obtained contents often are more broken by calcite from cuticular fragments prepared by dis- intrusions than the resin rodlets^ of Mye- solving the calcite matrix in dilute hydro- loxylon petioles. This may indicate that the chloric acid. The hairs drawn in outline in contents in the two instances were somewhat text figure 9 a were obtained in this way and different in consistency and perhaps slightly the arrangement of cells around the hair different in composition when mineraliza- bases is shown from a similar preparation in tion occurred. text figure 9 b. Photographs of the same The vascular supply of the campanulum material are shown in plate 107, figures 3- of D. formosa is not prominent. It has never 5. Figure 5 was taken at a higher plane of been possible to demonstrate tracheids in focus than the others to show the upstand- the marginal region. In a few instances deli- ing tips of the hairs. These fragments pre- cate strands of small closely spiral, annular pared by hydrochloric acid treatment have or scalariform tracheids have been seen the advantage of being more translucent near the top of the fructification. These are than thin sections since much of the dark generally located internally at a lower his- cell contents has been removed. The epi- tologic level than either the secretory canals dermal cells proper are irregularly polyg- or the groups of stone cells and are appar- onal with contents similar to that of the hairs. The dark contents are not limited to 5 The term "resin rodlet" is used herein only in a descriptive sense similar to the usage in coal the hairs and epidermis but several layers microscopy. In no case is any particular chemical of deeper cells near the lower margins of the composition to be inferred from the descriptive fructification also possess similar inclusions use of this term.

Explanation of Plate 106

Fig. 1 —Dolerotheca formosa, transverse section near center of fructification about 3 or 4 mm. above level of dehiscence tissue. From coal ball 129 A (t 12). 2—Section similar to figure 1 but about 3 mm. higher, showing more compact structure. From coal ball 129 A (t 27), magnification same as figure 1. Journal of Paleontology, Vol. 22 Plate 106

lOTTlTTl

Schopfj Dolerotheca formosa n.sp. Journal of Paleontology, Vol. 22 Plate 107

ffH

i

1 m

o o > m j^"-. f

-rp \ *^

t)"-v^v # -yi^O r- a o k O • ^a^

Schopf, T>olerotheca jormosa n.sp. PTERIDOSPERM MALE FRUCTIFICATIONS 693 ently unrelated to either in their position. film. The latter is more probable because it Presumably phloem accompanies them but seems the ground tissue must have shown preservation of the tissue immediately sur- some differentiation adjoining the sporangia, rounding them is poor and the details are at least during the early stages of growth. obscure. Since differentiated perisporangial tissue is The spongy tissue of the cover merges not otherwise in evidence, the sporangial internally with the intersporangial ground membrane probably represents a vestige of parenchyma which is somewhat thicker it. walled, has larger cells and is generally well The dehiscence tissue occurs over the preserved. The cells tend to be radially distal ends of sporangia, extending up above elongated as is apparent in the longitudinal the radiating dehiscence grooves. It consists section in text figure 5, and in the trans- of undulated elongate cells with oblique and verse sections illustrated. The interspor- tapered end walls. Cells near the distal sur- angial parenchyma is the fundamental face are thin-walled and from three to five groundwork of the fructification, since it times as long as broad (cf. text fig. 9 c). chiefly encloses and in fact often seems to Deeper within the fructification the cells constitute the walls of sporangia. A rela- become longer, more tapering at the ends, tively small number of cells, chiefly in the and their walls thicker and straight. In lower part near the dehiscence area, possess short, they assume all the characteristics secretory contents. The ubiquitous resin rod- of fibrous sclerenchyma. Although they lets also occur in this ground parenchyma merge in this manner with the internal and extend down close to the dehiscence sur- sclerenchyma system (described on p. 696) face (cf. r. r., text fig. 6). only the thin-walled tissue has contact with Although ground parenchyma appears to sporangial openings. It is not assuredly es- constitute most of the wall of the sporan- tablished that specialized kinetic cells are gium without any sort of differentiation, in nowhere present to provide for the opening many sporangia there is a somewhat of sporangia, but they have not been recog- shrunken membrane which originally en- nized and no dehiscence mechanism is evi- closed the spores. This membrane is non- dent. cellular and does not seem to be of waxy So far as can now be ascertained, spores nature like cuticle although it is quite per- are shed through slits or pores produced by sistent. That it is an organic structure and mechanical fracture of the dehiscence tissue. not a pseudomorph in the calcite is shown It is not altogether clear why the fractures by its presence as a definite membrane in always coincide with the distal ends of nitrocellulose peels. There are at least two sporangia. Since no actually "motivating" possible explanations for this membrane. cells responsible for the opening of sporangia One is that it represents the remains of a can be demonstrated, the designation "de- sporangial Plasmodium. However it might hiscence tissue" may not be particularly better be taken to represent the remains of appropriate; still it appears that this thin- peri-archesporial tissue which has been walled tissue is specially modified as a transformed to a gelatinous or mucilaginous whole to permit shedding of spores. In any

Explanation of Plate 107

Fig. 1 —Dolerotheca formosa, longitudinal section similar to fig. 2, PI. 2. Note dark sclerotic strands which merge below with the dehiscence tissue. From coal ball 219 C 1 B 1 (b 9), magnifica- tion same as fig. 6. 2—D. formosa, intersporangial vascular strand. From coal ball 219 C 1 B 1 (b 18). 3, 4—D. formosa, cell patterns of proximal cover epidermis showing frequency and relative position of hairs. From hydrochloric acid maceration of coal ball 229 B 2 C. 5—Same as above, photo at higher plane of focus to show the tips of upstanding hairs. Note hair

broken from its base ; hairs similar to these are the basis of drawings in text fig. P A. 6—D. /orwo5a, longitudinal section at margin of fructification. Note groups of sclerids in the cover layer and hairs shown above it. The hairs appear disconnected because the section is oblique with reference to the surface of the fructification. From coal ball 219 C 1 B 1 (b44). —

Fig. 4—Dolerothecaformosa, transverse section showing spores (Sp.), sporangia (Spg.). lysigenous tubes (Lysig.), Sclerenchyma (Scl.). The character of the inter-sporangial tissue and of the campanulary cover also is shown. From coal ball 129 A (t 37).

Cov.

Fig. 5 Dolerothecaformosa, longitudinal section for comparison with transverse section shown in text figure 4 (lettering symbols the same; cov. == campanulary cover). From coal ball 129 (B3). PTERIDOSPERM MALE FRUCTIFICATIONS 695

event this function is the essence of sporan- as the dehiscence tissue opposite the ends of gia! dehiscence, whether by a kinetic me- sporangia. No stomates have been observed chanism or not. Sections across the sHts in but it is conceivable that the dehiscence the dehiscence tissue communicating with pores are initiated by some sort of modified sporangia are shown in text figs. 7 and 8. stomatal apparatus. The hairs are more The preservation is best in marginal areas sparse than on the dorsal cover surfaces, such as shown in fig. 7 and this also may more slender, simple, consist of 1-3 cells, indicate that maturation of the fructifica- and are less glandular appearing. No capi- tion proceeded centrifugally. If the central tate tipped hairs have been observed.

Fig. 6—Dolerotheca formosa, longitudinal section of distal part of fructification showing dehiscence tis- sue, sporangial pores, sporangia (Spg.), lysigenous tubes (Lysig.), sclerenchyma (Scl.), resin rodlets (r.r). From coal ball 129 (b3).

pores were the first to open, presumably Papillae however are extended to a variable they might become more fragmented before degree on nearly all cells not otherwise the organ dropped from the plant and had a acting as hair bases. The relation of the dis- chance to be petrified. tal epidermis to the dehiscence tissue is The definite epidermis of the dehiscence shown in text figure 9 c, and the shape of layer is of particular interest since no equiv- distal trichomes may be contrasted with alent of the usual prismatic wall of crypto- those of the integument shown in figure gamic sporangia is present. This epidermis is 9a at somewhat greater magnification. The composed of somewhat flattened cells often distal epidermis apparently is not strongly bearing hairs or papillae (cf. text fig. 9 c). cutinized and is more irregular and broken It apparently is fractured in the same way by original fractures. Consequently no suit- —

696 JAMES M. SCHOPF

able preparations have yet been obtained by bridges between them. Their arrangement is dissolving the calcite matrix. All the details evident in text figures 4 and 6 and they

reported have been observed in sections. can also be seen in pi. 107, fig. 1, and pi. Aside from the campanulary cover, sup- 105 fig. 2. Two small strands are shown in porting tissue of the large fleshy male fruc- text figure 10 deeper within the fructifica-

FiG. 7 Dolerotheca formosa, transverse section of distal part of fructification showing campanulary cover layer with sclerotic cells (Scl.), dehiscence grooves, dehiscence tissue, sporangia (Spg.), lysigenous tubes (Lysig.) and resin rodlets (r.r.). From coal ball 129 A (t 38).

tification of D. formosa is limited to the tion. A type of cell wall thickening some- fibrous sclerenchyma strands developing times also occurs in the tangential bars on above the dehiscence grooves. As mentioned, either side of the lysigenous tubes between cells of the dehiscence tissue merge with the sporangia. These cells however are not usu- sclerenchyma in these areas by a gradual ally elongate and spindle-shaped like the transition. Apparently the fibrous strands fibrous strands and probably owe their act as isolated buttresses or "stays" to sclerotic appearance to some other cause. prevent distortion as there are no sclerotic The fibrous strands are somewhat compara- PTERIDOSPERM MALE FRUCTIFICATIONS 697

ble to the sparganum strands of Myeloxylon strands, i.e., between the paired sporangia. but their distribution is different so that the The ground tissue along these radii is gener- resemblance may be mostly superficial. ally rather poorly preserved, perhaps due to The vascular bundles are noteworthy for a slight difference in its character, and dis-

2 mm

Fig. 8—Dolerotheca formosaf transverse section of distal part of fructification more centrally located than text figure 6, (lettering symbols the same). From coal ball 129 A (t 6).

their obscurity. They appear to consist of a organized humic material is present around few spiral or annular tracheids isolated in all the delicate vascular strands that can be the ground parenchyma unassociated with found. The tracheids are very small, aver- resin rodlets or sclerenchyma; they are not age about ISfi in diameter, and can be ob- numerous. They seem to be restricted to the served chiefly in longitudinal sections where radii alternating with the sclerenchymatous their annulae distinguish them. Figures 698 JAMES M. SCHOPF showing the vascular strands are shown in lar to those forming the ultimate veinlets in text figure 11 and in pi. 107, fig. 2, and pi. the Alethopteris pinnules, which are abun- 105, figs. 3 and 4. dantly associated with this material. Al- The vascular bundles are gathered at the though fructifications of D. formosa are the top, always situated rather deep within the largest of the Dolerotheca species known.

Fig. 9—A. Dolerotheca formosa, hairs of dorsal cover broken from the epidermis after dissolv- ing the calcite matrix. Fig. 10—Dolerotheca formosa, transverse section B. Same, cuticular cell pattern at the base of a septum with a characteristic sclerenchyma of two of the hairs. Magnification same for A strand between sporangia of opposite paired and B. rows (Spg.), also small lysigenous tube C. D. Formosa, line drawing of dehiscence tis- (Lysig.). The sporangial membrane (memb.) sue showing epidermis and hairs. A resin rodlet is continuous in the sporangium on the right; appears in oblique cross section in the tissue resinous inclusion (r). From coal ball 125 A above. From coal ball 219 C 1 b 1 (b 18 c). (t 25). cover layer, and branch with bundles pene- they show considerably less vascular de- trating downward between the paired velopment than either D. villosa or D. ree- locules. These bundles are hardly comparable dana described below. in size and character of the elements to those Spores or Prepollen.— It is important in associated Myeloxylon petioles. However that the difference be recognized between they appear to contain elements rather simi- the preservation of spores in coal balls since PTERIDOSPERM MALE FRUCTIFICATIONS 699 these can be dissolved out undistorted by Prepollen grains of D. formosa are 300- compression, and those which have been 350 fjL long and 200-250 fx broad by about flattened and present a somewhat distorted ISOfx thick. Proximally they are marked by a appearance in coal maceration residues. In the latter, only two dimensions may be

100

Fig. 11—Dolerotheca formosa, vascular strand from radius of paired sporangial row, showing Fig. 12—Dolerotheca formosa, detailed draw- spiral or annular thickenings. From coal ball ing of dorsal hairs and their contents. From 219 C 1 b (b 18a). coal ball 129 A (t 38). accurately observed; the depth dimension monolete suture which in nearly all shows a must to some extent be reconstructed by slight angular deflexion near the middle inference. In coal ball material all three (pi. 108, fig. 7). To the extent that this su- dimensions may be observed with an ac- ture deviates from a straight line, the spores curacy approaching that in living material. are asymmetric bilaterally. Distally, the Spores of D. formosa have been studied iso- coat has two prominent grooves which ap- lated after solution of the calcite matrix in proach close together at the two ends but addition to those obtained in sections. are spread farther apart at the center. An —

700 JAMES M. SCHOPF

almost perfect axial section across the short diameter of a prepollen grain is shown in pi. 108, fig. 4. The distal grooves are uppermost in the figure and the proximal suture is marked by a slight indention at the bottom. Shadow outlines of the distal grooves below the plane of focus are evident in an example isolated by solution of the matrix shown in pi. 108, fig. 6, and in fig. 7 the same spore is illustrated at a higher plane of focus show- ing the characteristic proximal suture. Fig- ures 8 and 9 of plate 108 show examples of other isolated whole grains where the suture has opened. Median sections across the short dimension of grains are shown in outline in text fig. 13. In no case has the umbo between the distal grooves been found separated as a germinal "operculum," or the distal grooves split, except in irrelevant cases v/here me- chanical disturbance, such as may occur in peeling nitrocellulose films, probably Fig. 13—A-F. PrepoUen or spores of Dolerotheca had formosa. Outline drawings (microprojection) of occurred. The shadow of the distal grooves specimens Still within sporangia, in approxi- appears on either side and at a lower plane mately median transverse section; C is most of focus than the open proximal suture in oblique. Proximal suture is uppermost in each, distal grooves and umbo downward. From peel the whole specimen illustrated in pi. 100, sections of campanulum in coal ball 129. fig. 8. For Dolerotheca fertilis, Renault

Explanation of Plate 108

Magnification same for figs. 1-9

Fig. 1 —Dolerotheca formosa, spore (prepollen) showing collapse of the exospore (pseudomorph shows original outline) and endosporal membrane shows pseudo-cellular structure due to collapse. Section is obliquely longitudinal and intersects only one of the distal grooves on the lower side. From coal ball 129 C (S 7) 2—D. formosa, longitudinal section of spore showing original form of exosporal coat and frayed distorted remnants of the endosporal membrane. From coal ball 129 C (S 7) 3—D. formosa, oblique longitudinal section of spore similar to fig. / showing pseudo-cellular col- lapse of endosporal membrane. Small cross composed of pyritic crystals is above the inden- tion caused by one of the distal grooves. From coal ball 129 C (S 7) 4—D. formosa, transverse section of spore showing typical configuration of layers of the spore coat. Proximal suture (pr. sut.) is at the bottom somewhat obscured by thickness of the sec- tion, dist. gr.—distal grooves; endo—endosporal membrane. 5 D. formosa, transverse sections of two spores showing distal contour and proximal sutures (pr. sut). The proximal side of the lower spore is slightly collapsed in preservation similar to that shown in fig. 1. Dist. = distal umbo. From coal ball 129 C (S 7). 6—D. formosa, isolated spore showing outline of slightly collapsed endosporal membrane. Note shadow outline of distal grooves. From hydrochloric acid maceration of coal ball 229 B 2 C. 7—Same as above but at a higher focal plane to show the proximal suture. 8—D. formosa, isolated spore with proximal suture split open. From hydrochloric acid maceration of coal ball 229 B 2 C. 9—D, formosa, spore showing proximal suture open as in fig. 8. Shadow outlines of distal grooves may also be noted in both figures. From hydrochloric acid maceration of coal ball 229 B 2 C.

10—D. formosa, spores in two adjacent sporangia. From coal ball 129 C (S 7). 11—D. fertilis (Renault) Halle, sections of two spores probably showing endosporal gametophytic tissue. Details of the spore coat obscure. From Renault (fig. 4, PI. XII, 1902). 12—D. fertilis (Renault) Halle, spore showing proximal suture—evidently not one of the distal grooves. From Renault (fig. 3, PI. XII, 1902). 13—''Aetheotesta pollen," showing endosporal gametophyte possibly different from spore (pre- pollen) of Dolerotheca. From Renault (fig. 4, PI. XI, 1902). Journal of Paleontology, Vol. 22 Plate 108

13 'X 1 I

Schopf, Dolerotheca spores Journal of Paleontology, Vol. 22 Plate 109

I

5 mm "! 1^.5X

Schopf, Dolerotheca villosa n. sp. —

PTERIDOSPERM MALE FRUCTIFICATIONS 701

(1902) cited the illustration copied here in Florin (1937) have shown beyond doubt that plate 108 fig. 12, as proof of the opening of endosporal gametophytes are present in the distal umbo as an "operculum." It seems some types of well preserved Paleozoic quite clear that this figure illustrates the spores, prepollen and pollen grains. The proximal and not the distal side, and that folded endosporal membrane within some the slit has occurred normally by way of the grains of D. formosa was at first taken as a proximal suture as in spores of D. formosa remnant of gametophytic tissue, but it discussed previously and shown in pi. 108 seems now that this probably is not the figs. 8 and 9. case. Only in the sectioned example shown in The writer is inclined to attach consider- text fig. 13 a, is there some question con- able significance to the angular deflection cerning the endosporal interpretation. In- of the proximal sutute. The sutures of mono- stances where the endosporal membrane is lete fern spores, e.g. those included in Laevi- folded to simulate gametophytic tissue are gato-sporites (see Schopf, Wilson and Ben- shown in pi. 108, figs. 1-3, and may be com- tall, 1944, pp. 36-37) are not deflected in pared with figs. 11 and 13 of the same plate this manner. The tetrads have not been ob- (which have been copied from Renault) that served in Dolerotheca but the author enter- probably do represent gametophytes. One tains the possibility they may have shown could be more confident of Renault's inter- tetrahedral arrangement and been relatively pretation if it were possible to distinguish small. The Dolerotheca spores may have en- both layers of the coat (exo- and endospore) larged greatly after the tetrad separated and as well as vesicular (gametophytic) contents. the deflection angle of the suture line may Around the spore shown in pi. 108, fig. 1, mark the trilete apex and point of departure is a calcite pseudomorph (indicated by the of the third suture ray that has become obso- dashed line) which no doubt represents the lete. former outline of the exospore before it The exosporal layer of the prepoUen coat partially collapsed during mineralization. varies in thickness from about 8 /u in the Possibly the endosporal membrane also trough of the distal grooves, to about 12 /

EXPLANATION OF PlATE 109

Fig. / Dolerotheca villosa, oblique longitudinal section through fructification; compare with text fig. 12a drawn from an adjacent peel section. The tip of an Alethopteris pinnule is associated below it. From coal ball 229 B la (t 10). 2, 3—p. villosa .oblique peel sections taken adjacent to one another around 45° corner of fructifi- tion. Associated Alethopteris pinnule in upper left. The presence of paired sporangial rows and intercalation of new rows is most evident in lower left of fig. 2. From coal ball 229 B 2 A (s & b 2), magnification as for fig. 1. 702 JAMES M. SCHOPF PTERIDOSPERM MALE FRUCTIFICATIONS 703

tion most questionable. Possibly in fossilized Hairs adorn the lower distal surfaces of de- material the walls of gametophytic cells hiscence tissue and are relatively longer and

might appear as if fused with the endo- more numerous than in D. formosa. sporal membrane. But if the membranes A reconstruction drawn to the same scale interpreted here as endosporal are in reality as that of D. formosa is shown in the frontis- gametophytic walls, the cellular arrange- piece, fig. C. ment of the gametophyte must have been General Anatomy.—The tissues are essen- very irregular, to say the least, and the tially the same as in D. formosa. The spo-

writer can see little definite evidence to sup- rangia are from 300-400 jj. in diameter and port such an interpretation. Probably the perhaps as much as 5 or 6 mm. long, or about gametophyte is the most delicate and least half as large as in D. formosa. Lysigenous preserved "spore" part. If this tissue is cavities also occur as in the other species present in any instance, the more resistant but they are proportionately smaller and spore coat layers should also be accounted less distinctly preserved. The general rela- for. tions can be followed in the thin section Type Material.—The paratypes of D. shown in pi. 109, fig. 1, and text fig. 14 a, formosa are these illustrated in pi. 104, as drawn from an adjacent peel section. Plate figs. 1-7 etc. from coal balls 219 and 129 of 109, figure 2 shows peels taken from adjacent the Illinois State Geological Survey collec- surfaces cut at right angles to o^^e another.

tion. Should selection of a holotype speci- In pi. 110, fig. 1, and text fig. 14 b, are sec- men in any event be required, the writer tions cut progressively more tangentially: would prefer to designate the one illustrated The last is far enough out so that, for the in pi. 104, figs. 1 and 2 from coal ball 219. short length represented, sporangial locules The specimens are from the coal bed just are cut in fairly good longitudinal align- below the Calhoun limestone near the town ment. The campanulary cover averages 200-

of Calhoun in Richland County, Illinois. 300 ju in thickness and contains large secre- This zone is in the upper part of the tory passages. Just below the integument is McLeansboro group of Illinois.^ a row of large pores which seem to have arisen by lysigenous break-down of sporangial DOLEROTHECA VILLOSA Schopf, n. sp. septae and other tissues. Each of the per- Frontispiece, fig. C; Plate 109, figs. 1-3 sistent septations between these enlarged Plate 110, figures 1-9, text figures 14, a-b pores contains an elongate series of tracheids cut transversely. The dehiscence tissue is External Characters.—Male fructification present in very much the same relationship about I as large in external dimensions as D. as in D. formosa. formosa and more strongly convex proxi- The species is represented by two speci- mally. Proximal surface slightly ridged ra- mens in the material studied. These are dially; covered with close set villous hairs. somewhat complementary and afford an ade- quate basis for diagnosis but nevertheless ^ Age relations of Illinois coal ball horizons of D. are given in a previous publication (Schopf, are less well preserved than those 1941). formosa. On account of the smaller dimen-

FiG. 14—A. Dolerotheca villosa, oblique median longitudinal section of fructification from coal ball 229 B la. B. D. villosa, nearly longitudinal section of same fructification near margin. Magnification, same for A and B. C. D. villosa, section of campanulary cover with hairs, secretory cavity and septum con- taining vascular strand. From coal ball 229 B 1 a (t 8). D. D. villosa, detail drawing of distal margin of longitudinal section showing epidermal hairs, dehiscence tissue (Dehis.), sporangia (Spg.), Lysigenous tube ? (Lysig.?) and resin rodlets (r.r.), in tissue above. From coal ball 229 B 1 a (t 8). E. D. villosa, hairs from campanulary cover. F. D. villosa, campanulary cover with secretory cavity (Sec.) and hairs with contents. Magnifi- cation same for E and F. 704 JAMES M. SCHOPF sions of D. villosa and its rarity it has not cover actually is less complex than in D. been possible to obtain as perfectly oriented formosa. sections as in D.formosa. Both specimens were Vascular strands seem to be limited to the cut obliquely. One is complete except that all persistent septae between the large pores spores have been shed. The other consists located just below the dorsal cover. One of only of the central sporangial tissue and en- these septae is shown in its relation to the tirely lacks the campanulary cover layer, integument in text fig. 14 c. The section although the dehiscence layer is well shown. here, as in most of the others, is cut obliquely Some of the sporangia in the incomplete ex- through the hemispheric fructification and is ample contain a number of flattened and per- approximately at right angles to the surface haps abortive spores. It seems likely that of the campanulary cover at this point, the cover from this specimen has broken which is about the highest in the section. loose from the included sporangia by the Consequently the tracheid strands which disintegration of septae which occur in par- run parallel to the outer surface are cut tial dissolution in the other example. transversely. About 20 tracheids are shown The only tissues in either specimen which in this group. Marginal walls of tracheids are in fair preservation are the hairs, the have broken down also so that probably dehiscence tissue and the vascular strands. there were a few more elements in the group Parenchyma of the cover layer and inter- originally. Smaller tracheids are seen at sporangial tissue have collapsed into a dark several places. Longitudinal sections as disorganized humic mass preserving only shown in pi. 110, figs. 7 and 8, show scalari- the external outlines and the contents of form elements with the suggestion of an secretory cavities. The tracheid rows are incipient bordered pit here and there in clear enough but all the adjoining tissues larger cells. The vascular strands seem some- are also reduced to a humic residue without what more developed and the tracheids visible cellular organization. It is difficult somewhat larger in F. villosa than in D. for- to account for the fair preservation of origi- mosa where only small strands of character- nal form under these circumstances but istic spiral and annular tracheids have been there is little or no evidence of distortion. observed. Histology.—The hairs of the dorsal sur- The association of vascular strands with face are 4-6 cells long, generally simple the mid-line of paired sporangial rows is but occasionally biseriate. None of them ap- somewhat more evident in D. villosa than in pears to be capitate as are some of those D. formosa, perhaps due to the collapse of present on D. formosa; they are much more all but the tracheid-bearing septae at the closely spaced and differently shaped. The edge of the fructifications. Allowing for bi- cells are filled with dark material and furcation of vascular strands wherever new oftentimes a globular central body is present sporangial rows are being intercalated to- in each cell. The hairs are set very close to ward the margin, it is apparent that the vas- one another forming a villous felt on the cularized septae occur regularly along the proximal surface as much as 60-70 fx deep midline of double series of sporangia, essen- near the top of the fructification but becom- tially similar to the apparent vasculariza- ing thinner toward the margin of the cam- tion of D. formosa. panulum. Individual hairs are shown in The breakdown of septae just below the text fig. 14 e. Their close arrangement is cover has not progressed so far in the margi- shown in text fig. 14 c and f ; also in pi. 110, nal region but none of the septae near the fig. 4. margin of the fructification contains tracheid The cover layer has many large secretory strands. Apparently the tracheid bundles ducts with characteristic dark contents, 20- radiate only part way down the sides of

50 fi in diameter. They generally occur in a the fructification. It seems that the vascular single series as shown in text fig. 14 c (sec.) strands served for support well as as conduc- and in pi. 110, fig. 4. No vascular strands or tion in this type of fructification, but that the stone cells are discernible within the cover margins were sufficiently rigid that they re- layer although this may be due to poor pres- quired no special stiffening. The distance ervation. However it seems likely that the for translocation of materials was not very PTERIDOSPERM MALE FRUCTIFICATIONS 705

great in this smaller fructification and did typical proximal sutures and two distal not require a more extensive vascular sup- grooves as in D. formosa. The spores have collapsed for the most part and no accurate There is no evidence of sclerotic tissue in thickness measurement is possible, but the the fructification of D. villosa, although the spore coats seem normally thick, and if they preservation is not sufficiently good to prove are abortive, this occurred in the last stages that none existed. Since the hairs and dehis- of growth. The example shown in pi. 110, cence tissue, of thin walled cells which are fig. 2, is from a peel and the distal side has not decay resistant are, nevertheless, well been partially torn away revealing the well preserved, there is fair presumptive evi- defined suture on the proximal side. In dence that thicker walled sclerotic tissue figure 3 of pi. 110 a group of more or less was at least not well developed and may collapsed spores is shown inside a sporangial have been absent. The preservation does locule. The distal grooves of the large spore not permit a definite statement. at the left are barely distinguishable in the The intersporangial tissue shows little photograph but may be observed in the histologic detail. Large secretory ducts oc- section at higher magnification by placing cur here, as in the cover layer, and pene- it over a concentrated point of light. Thus trate down to the dehiscence tissue on the in structure these spores are typical of distal side (cf. text fig. 14 d and pi. 110, fig. Dolerotheca but they are the smallest for

5, sec). There also is a large number of any species yet reported. smaller cells with similar contents scattered Type Material.—Both specimens used in throughout. It seems that cellular structure this description are from the same locality was not preserved except where less perish- as those of D. formosa previously described. able contents were present to mark more or There is no question that distinct species less accurately the outline of original cell are represented for not only do they differ forms. in size and proportions at maturity, but the Dehiscence tissue is in general disposed as pubescence and other features are distinc- in D. formosa but it does not extend as tive. The specimen which should be con- deeply along the dehiscence grooves. Since sidered as the holotype is from coal ball 229 the intersporangial ground tissue is not his- of the Illinois State Geological Survey collec- tologically interpretable, the relation of the tions. The more fragmentary specimen with dehiscence tissue to internal sclerenchyma collapsed prepollen grains is from coal ball strands cannot be made out. There is no 215. evidence of this sclerenchyma, however, Dolerotheca reedana Schopf, n. sp. and it probably was rudimentary or absent. Plate 111, figures plate 112, fig- Although sometimes obscure, an epider- 3, 4; ures 2-6; plate 113, figures 1-6; mal layer can be identified covering the plate 114, figures 1-9, 14, 15; distal surfaces as in D. formosa. This em- plate 115, figure 9;text phasizes the probability that no prismatic figure 15 specialization of the epidermis occurs on sporangia of this group of plants. The hairs External Characters.—Male fructification on the distal epidermis also are more numer- campanulate, slightly more inflated proxi- ous than in D. formosa. They are 2 or 3 mally than D. formosa. Diameter estimated cells (50-65 jLi) long, as shown in text fig. 14 d at 15-20 mm.; central thickness about 7^ and in pi. 110, figs. 6 and 9. The terminal mm. Proximal (dorsal) side glandularly cell of each hair is rather abruptly triangu- pubescent, irregular, covered with verrucosi- lar. ties of varying size and prominence, upon Spores or Prepollen.-—The specimen con- which hairs are particularly numerous.

stituting the basis for most of the foregoing Radial indentions of the integument, if description has matured and shed all its present, are rendered obscure by the sur- spores. They are present however in the face irregularities. The distal surface is second more fragmentary specimen, pre- slightly convex, with dehiscence grooves ^ viously mentioned. Prepollen spores are 130 to 1 mm. deep. As in the other species, a

to 150 M long and 100 to 120 fi broad, with definite epidermal layer covers the distal 706 JAMES M. SCHOPF surface, the cells of which serve as bases for In addition to the Dolerotheca fructifica- hairs or papillae. Distal hairs lack the dark tion and fragments and the peduncle which contents characteristic of those of the proxi- probably goes with them, a fragmentary mal cover and are slightly more slender with Myeloxylon petiole, in part well preserved, terminal cells more cone-shaped. is also present in the same coal ball. The General Anatomy.—The holotype speci- possible correlation of these on the basis of men of D. reedana is located on the edge of histologic structure is discussed later. a coal ball so that somewhat less than half of The sporangia of D. reedana occur in it is preserved; nevertheless enough is pres- paired rows and presumably they radiate ent to afford a fairly accurate and complete from the center of the fructification as in description. The largest available section is the other species. However, nearly all the that shown in pi. Ill, fig. 4. As shown in sections available are longitudinal and the that figure the lower central part (lower characteristics shown best by transverse left) is missing or poorly preserved. The sections cannot be as accurately estab- central part of the dorsal cover proper has lished. The sporangia are 350-400jU in di- been destroyed, possibly by intrusion of ameter and the longest sporangium seen is roots. A much flattened Psaronius (?) root slightly more than 6 mm. in length; a few is shown at the top of the figure on the sporangia may be slightly longer. The long- left where at least the outer part of the est sporangia seen are on one side of the campanulary cover is mising. The unusu- center of the fructification and show a slight ally thick parenchyma shown just below sigmoid curvature which is somewhat more this foreign root can be followed by a some- pronounced in shorter sporangia near the what tenuous but undeniable connection margin. with the more characteristic fructification The lysigenous tubes are clearly shown structure toward the right. The largest between sporangia of each radial series. vascular strands yet observed in Dolero- They are relatively large, measuring about theca appear in this parenchymal region and 400 by 100-200^ in diameter, with the one of them is illustrated in pi. Ill, fig. 3. shorter diameter crowded between the Probably the peduncle attachment was radially adjacent sporangia of the rows. The close to this point. The presumed peduncle cells surrounding the tubes have consider- (described later) is not attached but prob- ably thicker walls than the ground tissue ably belongs to this specimen with which it although their dimensions are similar. Pos- is closely associated. It is located above the sibly the breakdown of tissue inside the better preserved part of the cover and to the cavities has contributed to this appear- right of the root as shown in pi. Ill, fig. 4. ance. It is also illustrated in pi. 112, figs. 2 and 6. Dehiscence tissue and fibrous scleren- The tissues below the peduncle (?) are chyma are present and in general have the rather well preserved and one sporangium is same relative position as these tissues in D. cut longitudinally from top to bottom. The formosa. Spores were shed through slit-like more marginal sporangia are also poorly perforations in the dehiscence tissue as in preserved but may be observed in other sec- the other species. No specialized mechanism tions (pi. 112, figs. 2 and 6). The margin to produce dehiscence has been noted. Vas- of the campanulary cover is everywhere ob- cular strands are located on the middle ra- servable on the side of the specimen, not- dius of paired sporangial rows and alternate withstanding spotty preservation of margi- with the rows having sclerenchyma strands. nal sporangia. In D. reedana the vascular strands are more There are two other Dolerotheca fragments prominent throughout their length, than in in the same coal ball which appear to cor- the other Dolerotheca species. Possibly a respond with the type specimen. The frag- combination of fortuitous factors is more ments show some tissue structure, chiefly in responsible than any great biological differ- the transverse plane, but the most valuable ence. The radial sections of D. reedana aire information they afford is in regard to the favorable for their observation, and the spores. Spores in the type specimen are all tracheids of the bundles are larger than in D. more or less collapsed. formosa. Three of the vascular bundles are PTERIDOSPERM MALE FRUCTIFICATIONS 707

cut transversely in some of the sections in The epidermis of the campanulary cover the area near the top of the fructification consists of small rather thick-walled, nearly and they probably are only a very short isodiametric cells with dark contents (cf. distance from the point at which the pe- pi. 113, fig. 3). Subdermal tissues also are duncle was attached. These bundles are elon- secretory in appearance though also more gated in outline, 300-400ju long and 50-90^ definitely parenchymatous. A slightly denser broad (see text fig. 15). Small tracheid zone of less well preserved cells appears at a variable depth below the dermal layer. In .^.^^M''' general this zone appears more regular in outline than the surface, due to the pres- ence of the verrucose protuberances of the latter. In some respects the dark layer ap-

pears as if it were an incipient pellogen al- though no clearl}^ distinguished secondary tissue has been produced. Below the dark layer is a zone of spongy parenchyma. Intercellular spaces are evi- dent as shown in pi. 113, figs. 1 and 2. Secretory cells and resin rodlets are inter- spersed in the spongy parenchyma as in D. villosa but they are less abundant. Sclerids, isolated or in groups, also occur in the spongy tissue. Vascular strands are lo- cated near the interior of the spongy zone as shown in pi. 113, figs. 1 and 2, and may mark the internal limit of the cover Fig. 15—Dolerotheca reedana, transverse section layer. The tissue internal to the bundle of large vascular strand from campanulary cover close to the probable attachment of zone of the spongy parenchyma is of the peduncle. From coal ball H b 208 B (b 1). characteristic type which also surrounds the sporangia, i.e., the ground tissue of the strands branch from the lower edge of the fructification. The cover layer thus defined elongate bundles and penetrate downwards has a thickness of ^-1 mm. depending on between the sporangia (see pi. Ill, fig. 3, whether the end of a sporangium is adjacent and pi. 112, fig. 5). The cover layer is vascu- (causing it to be a little thinner) or whether larized nearly to its periphery by small measurement includes the thickness of one remnants of the deeply situated plate-like of the external verrucosities. strands. The intersporangial ground tissue in D. Histology. —The hairs on the proximal reedana is generally similar to that in D. cover are more numerous than in D.formosa formosa. Secretory cells and resin rodlets but they are not as closely set as in D. are present in the ground tissue as in the vtllosa. They range from 40 to SQfi in length other species; they are less abundant in D. and consist of from 3 to 5 cells. Most hairs reedana than in D. villosa although indi- are peg-like with a round tapering tip but vidually the secretory cells and rodlets are some areclavate or capitate tipped as shown slightly larger. in pi. 113, figs. 1-3. Clusters of hairs cap the As in the other two species, the tissue di- warty protuberances of the surface; some- rectly surrounding sporangia is not well pre- times this gives the illusory appearance served. Plate 113, fig. 6, shows a segment of that the hairs branch at the base, as for sporangium in longitudinal section with example, those at the right of pi. 113, fig. 1. remnants of the original sporangial wall best Dark shrunken remnants of the cell con- shown on the left side. The dark membrane tents are nearly always evident and some- is composed of two layers and apparently times dark nucleus-like bodies are present represents the remains of cells whose end like those shown in both cells of the short walls have disintegrated. Probably this also capitate hair in fig. 3. indicates the mode of origin of a sporangial —

708 JAMES M. SCHOPF membrane such as described within sporan- which must not be far removed from the gia of D.formosa. peduncle attachment. These are also il-

The dehiscence layer is essentially similar lustrated in text fig. 15, pi. Ill, fig. 3, pi. to that of the other species. The cells appear 112 figs. 3 and 5, and pi. 115 fig. 9. The shorter however with less oblique end walls. elongate form of these bundles is most char- Plate 113, fig. 4, shows the appearance of acteristic and similar to those of D. villosa. this tissue; a large resin rodlet of the ground Small elements centrally located in the parenchyma appears at the upper left of bundles may represent protoxylem. Preser- the figure. vation is not good enough to show definitely The distal epidermis also is clearly shown the location of phloem although possibly a in pi. 113, fig. 4. Cell contents are present few phloem elements were present on both and the walls appear somewhat thickened sides. Small vascular strands which pene- although this may have been caused by trate the radii between sporangia are evi- mineralization. There is no distinction be- dently given off from the lower edge of the tween "thickening" of periclinal and anti- elongate bundles as shown in pi. 112, fig. 5. clinal walls of the epidermis, and no close The main bundles of the cover layer con- comparison can be made with the prismatic tinue nearly to the margin of the fructifica- layer of cryptogamic sporangia. Nearly every tion although there they are considerably cell serves as a hair base or has a strong cen- diminished in size. One of the larger bundles tral papilla as shown in pi. 113, fig. 5, from a near the center of the fructification has been section parallel to the epidermis along a de- twisted before mineralization so that the hiscence groove. Only a few hairs are visible pitting can be observed. Part of this bundle in fig. 4 taken at right angles to a similar is shown at higher magnification in pi, 112, surface. fig. 3, to illustrate the characteristic scalari- The dehiscence tissue merges with strands form and reticulate thickenings. The tra- of fibrous sclerenchyma as in D. formosa. cheids are broader than those of D. formosa Relative to the size of the fructification the and commonly exceed 20ju in diameter. The sclerenchyma seems a little more developed vascular strands between sporangia are in D. reedana, but in the absence of good composed of tracheids of more uniform size transverse sections this is not certain. than those in the cover itself, and possess The vascular tissues of D. reedana can be similar pitting as shown in pi. 112, fig. 4. followed more adequately than in either of Spores or Prepollen.—The holotype of D. the other species despite the rather frag- reedana contains numerous spores of the mentary condition of the available speci- prepollen type which are nearly all collapsed. mens. The fragments of tissue shown at the It is evident that this is not the result of upper left in pi. Ill, fig. 4, show vascular petrifaction but was induced earlier, possibly bundles 300-400/x long and 50-90^ broad even before this particular fructification was

Explanation of Plate 110

Fig. 1—Dolerotheca villosa, oblique longitudinal section of fructification about half way from the center to the margin. From coal ball 229 B la (12), scale of magnification indicated below figure (12.5X). 2—D. villosa, spore (prepollen) from peel section showing the proximal suture. The distal side of the spore has torn away from the peel. From coal ball 215C(B1),(172X). 3—D. villosa, sporangial locule full of partially collapsed spores. From coal ball 215 C (B 1), (172X). 4—D. villosa, section of cover layer showing close-set hairs above, secretory chambers (Sec), and persistent septae with vascular bundles (V.B.) cut transversely. From coal ball 299 B la (t 6), scale of magnification indicated at right (85 X). 5 D. villosa, section of dehiscence tissue showing epidermal hairs, sporangial pores, and secretory canals (Sec.) in tissue above. From coal ball 229 B la (t 23), magnification same as fig. 4. 6—D. villosa, oblique section across edge of dehiscence tissue showing epidermal hairs. From coal ball 229 Bl a 1 (t 6), magnification same as fig. J (172 X). 7, 8—D. villosa, longitudinalsections of vascular bundles showing irregular type of scalariform ele- ments. From coal ball 229 B 2 a (S& B 2) & (S 5), magnification same as fig. 4 (85 X). 9~D. villosa, edge of dehiscence tissue showing epidermal hairs. From coal ball 229 B 1 a 1 (t 6), magnification same as fig. 3 (172X). Journal of Paleontology, Vol. 22 Plate 1 1

^4Jm^^"'

Schopf, Dolerotheca villosa n. sp. 1

Journal of Paleontology, Vol. 22 Plate 1 1

Schopf, Dolerotheca^ Codonotheca —

PTERIDOSPERM MALE FRUCTIFICATIONS 709 incorporated in the litter of the peat swamp. The prepollen spores of D. reedana range The two other Dolerotheca fragments pres- from 260 to 325/i long and from 165 to 250// ent in the same coal ball contain normal broad. Although in size they overlap the spores which are numerous both within and lower size range of D. formosa spores, in outside of sporangia. The ordinary course general they appear more broadly ovate. of events may have involved general frag- The proximal suture is distinct and generally mentation of the fructification after the marked by an angular deflection near the spores matured and fragmentary campanulas center as seen in pi. 114, figs. 1-4. This de- like these associated with the uncollapsed flection of the proximal suture seems a trifle spores may be typical. The description of more pronounced than in D. formosa. The the spores has been drawn chiefly from those two distal grooves are very prominent but in the more fragmentary specimens and not never appear to be split open by natural from the collapsed spores in the holotype dehiscence. The spore coat is 5 to 6/i thick fructification shown in pi. 113, fig. 6. There at the bottom of the grooves as shown in can be little doubt that they are specifically pi. 114, fig. 5 (Dist. gr.), and each groove is identical because, aside from preservation, marked by a definite narrow furrow in the all the significant characters agree. Many of coat as shown in fig. 8 of the same plate. the normal and uncollapsed spores were The thickness of the spore coat increases to isolated by breaking off a fragment con- 7 or 8)U outside the furrow near the axis of taining a portion of a fructification and dis- each groove and then thickens gradually to solving the calcite matrix in dilute hydro- about 12/i on the distal umbo and to as chloric arid, as was done in the case of D. much as 18^t on the thicker proximal re- formosa. gion. The distinction between the proximal The spores of D. reedana are very similar suture and distal grooves is evident by the to those of D. formosa and isolated specimens fact that in cross section the suture shows a would be very diflficult to distinguish in or- line of parting extending through the spore dinary coal maceration residues. Individual coat. The spore shown in median cross sec- isolated spores from both of these species tion in pi. 114, fig. 15, has split open along would probably be classified as Monoletes this proximal suture line. ovatus (see Schopf, Wilson and Bentall, Spore surfaces are ornamented only by 1944, p. 38) if no other information was very fine granulose punctation. In section available. Slight differences in size and shape the coats seem to show obscure radiating are detectable when spores are uncom- striation which may possibly be due to a pressed as these are of Dolerotheca, but such type of micellar organization. slight differences probably cannot be relied The endosporal membrane is well shown upon to separate them if they have previ- in many spores dissolved out of the calcite ously been compressed. matrix wherever it shrunk away from the

Explanation of Plate 111

Fig. la, b— Codonotheca caduca, group of four fructifications attached to a common fertile branch. The two fructifications best shown appear naturally bilaterally symmetrical. Both halves of a specimen from Mazon area. Will and Grundy Counties, Northern Illinois (Carbondale formation. Shale above Illinois No. 2 coal); III. State Museum Catalog No. 14326. Slightly reduced. 2— Codonotheca caduca, fructification showing surface striation and pubescence (punctate surface due to hair bases). 2a, Surface of specimen at greater magnification. Specimen from Mazon area, III. State Museum Catalog No. 3001. 3—Dolerotheca reedana, transverse section of elongate bundle near top of fructification, with smaller vascular strands diverging from it below. From coal ball Hb 208 B (b 4). 4—D. reedana, longitudinal section of fructification, with peduncle (?) above. Spores appear as dark spots or lines in the one sporangium cut in good longitudinal alignment. From coal ball Hb 208 B (b 4). 5 Dolerotheca sp. Compression from specimen, surface slightly concave. From a "Mazon type" nodule from Carterville, Williamson County, Southern Illinois, from basal McLeansboro shale above the Herrin (No. 6) coal. Ill, Geol. Surv. Catalog No. S B 79, nearly natural size. .

710 JAMES M. SCHOPF outer wall (cf. pi. 114, fig. 5). It is distinctly the structure of epidermal hairs which are seen in pi. 114, figs. 14 and 15, but appears well preserved, in part, and correspond to be discontinuous. This discontinuity is closely with those of the dorsal cover of the probably an artifact induced when the nitro- Dolerotheca fructification. cellulose peels were being prepared. The The close association of this peduncular spores of D. reedana thus far have not structure is shown in pi. Ill, fig. 4 and pi. shown any of the pseudo-cellular (?) endo- 112, figs. 2 and 6. A line diagram of the pe- sporal configurations which are prominent duncle, text fig. 16, shows its epidermal hairs in some of the spores of D. formosa. If this is at all significant it probably is due to slight diliferences in the manner of minerali- zation. Type Material.— The holotype of D. ree- dana is from Harrisburg (HB) coal ball No. 208, collected for the Illinois State Geologi- cal Survey by A. C. Noe, from Harrisburg (No. 5) coal, O'Gara No. 9 mine (open pit), located near the southeast corner of section 21, T. 9 S., R. 6 E., just south of the city of Harrisburg, in Saline County, Illinois. This coal bed lies stratigraphically somewhat above the middle of the Carbondale group of Illinois.

NOTES ON RELATED FOSSILS

The same coal ball in which D. reedana was discovered contains a Myeloxylon petiole and a small poorly preserved struc- ture which probably is the peduncle of the Dolerotheca fructification. This presumed peduncle is described first and evidence bearing on its possible correlation with the Fig. 16—Sector of Dolerotheca reedana cam- species of Myeloxylon follows. An impression panulum and probable peduncle, showing the specimen of Dolerotheca preserved in an intimacy of association in coal ball H b 208 B. ironstone concretion is described and dis- Photo tracing from section (b 6) cussed and some recent observations on the Whittleseyinean genus Codonotheca are pre- to be nearly interlocking with those of the sented. campanulary cover of the fructification be- low, and their similarity is obvious. Another Dolerotheca reedana peduncle (?) more fragmented portion which shows the Plate 111, figure 4; plate 112, figures hairs well is illustrated in pi. 112, fig. 1, and 1, 2, 6; plate 115, figures 6-8; text at higher magnification in pi. 115, fig. 6. figure 16 The description of hairs of the dorsal cover This is a small (about 2 mm. in diameter) layer of D. reedana applies equally well to originally triangular (?) structure which these. The only difference noted is in their extends about 5 or 6 mm. along the top of arrangement on the epidermis. The hairs of the D. reedana holotype. It is badly frag- the peduncle are not situated on tubercular mented for most of its length so that it outgrowths as they commonly are on the cannot be described very satisfactorily. Al- fructification. Some are very close together though it occurs in the closest possible but in general they are fewer and less closely association with this Dolerotheca specimen, spaced. there is no actual proof of its immediate The epidermis of the peduncle is quite dis- connection. Its suggested function as the tinct and shows no evidence of any irregular peduncle of Dolerotheca is chiefly based on cell divisions. The epidermal cells contain PTERIDOSPERM MALE FRUCTIFICATIONS 711 dark contents but are not obscure on this same coal ball that contains the holotype of account, as are many of the dorsal epider- D. reedana. Its identification with Hoskins' mal cells of the campanulas. There is no species is not immediately evident by com- indication of any sclerotic tissues in the parison with figures published with the peduncle. The ground tissue is parenchyma- original description. However, comparison tous and includes a few resin rodlets as with the original slides showed that M. shown in pi. 112, fig. 1 (R) and pi. 115, fig. 6. americanum is more variable than suggested It has not been possible to ascertain the by Hoskins and that the specimen under nature of the entire vascular complement consideration agrees with it in many fea- of this specimen because at least half of it is tures. Some of Hoskins' slides show a heavy poorly preserved throughout its length. The zone of radially elongated subdermal scler- vascular bundles differ considerably in form enchyma extending nearly continuously from those in the proximal part of the around the margin on one side. In other Dolerotheca fructification as may be seen by places, these sclerenchyma strands are comparing fig. 8 (peduncle) and fig. 9 tangentially elongated and less prominent. (fructification) shown at the same magni- Adjacent to the thick marginal scleren- fication on plate 115. There is considerable chyma, the sclerotic "caps" accompanying similarity in size of the elements of both and vascular bundles and secretory canals are in the pitting. Vascular bundles of both are very heavy, but they become progressively chiefly composed of scalariform tracheids. thinner toward the center of the petiole The peduncle bundles seem probably mesarc where there is almost no sclerotic bundle and may be concentric, but phloem is too sheath. Sclerotic caps of moderate develop- obscure to be confidently identified. The out- ment are irregular in marginal outline as line of the most evident bundles is shown in seen in transverse section. Resin rodlets are text fig. 16 (V.B.). Perhaps the chief vascu- fairly numerous and possess no distinct lar bundle in pi. 115, fig. 8, and other fig- epithelial layer of cells. Cells of varying size, ures may be in process of dichotomizing, but averaging slightly smaller than those of the if so, the fission requires a distance of sev- ground parenchyma, enclose the secretory eral millimeters for completion. The pat- ducts. Thin tangentially elongated epithe- tern of vascularization of the petiole is not lial cells such as those present in the Nash- clear because two or possibly three other ville myeloxyla associated with Medullosa bundles which belonged to it are discon- distelica (cf. Schopf, 1939) do not occur. nected and variously distorted. One of these Petiolar secretory canals in Nashville speci- appears at the lower left in pi. 115, fig. 8. mens are all about the same diameter. In Because of this distortion it is not certain Myeloxylon americanum there is a wide that this peduncle was essentially radial in variation in the size of the canals, many of its symmetry rather than dorso-ventral. them arc large and contain typical resin The close agreement between epidermal rodlets but others are much smaller and hairs of D. reedana and this peduncle, the some are similar in size to large parenchyma great similarity of elements of the vascular cells of the ground tissue. In fact, numerous bundles and the conjunction of other factors, evenly distributed parenchyma cells also although individually merely suggestive, appear to have secretory contents. The when taken together furnish rather con- gradation seems to be complete between vincing indication that the peduncle per- ducts of the two extremes in size. tains to that species. The Myeloxylon fragment in the Doler- otheca nodule from Harrisburg does not have MyELOXYLON, cf. M. AMERICANUM the extremely heavy sclerenchyma present (Hoskins)^ Plate 115, figures 1-5

is author A segment of a petiole probably referable this species referable to Myeloxylon. The has personally consulted the types which are part to Myeloxylon americanum is present in the of the collection of the Illinois Geological Survey, and verified the opinion originally expressed by ^ Originally described as Angiospermophyton Seward (1923). The species seems to be well americanum (Bot. Gaz. vol. 75, p. 390, 1923), represented in the Harrisburg coal balls. —

712 JAMES M. SCHOPF

in parts of the type specimen of M. ameri- BIOLOGIC CORRELATION OF THE PEDUNCLE (?) canum. It appears to agree in most partic- OF DOLEROTHECA REEDANA AND ulars with less sclerotic portions of that MYELOXYLON AMERICANUM species, however, and probably cannot be The evidence for concluding that the distinguished from it. hirsute peduncle described above belongs to One small area of the specimen associated D. reedana has been presented. It is desirable with D. reedana seems to lack subdermal also to consider further the histologic evi- sclerotic tissues entirely, even in the prox- dence which supports the correlation of imity of marginal secretory canals. A portion this structure with Myeloxylon, since some of this area is shown in pi. 115, fig. 1. The such relationship may fairly be presumed to marginal vascular bundles all possess a have existed. definite sclerotic bundle sheath, however, Although it seems probable that Medul- and the one shown in pi. 115, fig. 2, is losa, Myeloxylon, Dolerotheca and others are typical. The phloem of this bundle (Ph) is correlative genera in Pennsylvanian strata excellently preserved and unusual in this (and possibly through most of this system) respect. Generally phloem tissue is lacking there is as yet no evidence to show how, i.e., as in the bundle shown in plate 115, fig. 3. on what particular part of the plants, the The presence of a secretory duct adjacent to male fructifications were borne. They may the xylem and enclosed by the sclerotic have been attached to the ultimate rachides bundle sheath in fig. 3 is exceptional. Pro- of an Alethopteris type frond. Some evidence toxylem as identified by small tracheids is now indicates that seeds were borne in this chiefly concentrated next to the phloem as manner (Halle, 1927, Arnold, 1937). It is in the type of M. americanum. Some small equally plausible that the male fructifi- tracheids also occur which are not in prox- cations may have been borne on special imity of the phloem but it is questionable fertile branches somewhat as suggested by whether these are actually protoxylem the specimen of Codonotheca illustrated by elements. They may be merely small cells of Darrah (1938) and by the specimen shown the metaxylem which were late in develop- in PI. Ill, fig. 1 (no. 14326 of the Lang- ment and failed to enlarge fully. It is also ford collection in the Illinois State Museum, possible that they represent only the taper- Springfield). A similar fruiting habit has ing ends of normal metaxylem elements. recently been described for Lacoea seriata by The large metaxylem elements shown in Read (1946) and a comparable occurrence pi. 115, fig. 3, are gathered in two groups, is shown by Goldenhergia glomerata (Halle possibly preparatory to bifurcation. is male A large characteristic secretory canal and 1933). It also conceivable that the resin rodlet with sclerotic tissues somewhat fructification was attached directly to the separated is shown in pi. 115, fig. 4. Two main axis, arising in the axil of a leaf base smaller canals with less sclerotic develop- near the tip of the stem, or, if the fruit bud ment but situated in about the same relative was dormant for a time, its position might position in the petiole are shown in fig. 5. have been farther down the trunk. Un-

EXPLANATION OF PlATE 112

Fig. 1 —Peduncle (?) probably of Dolerotheca reedana, showing resin rodlet (R) and epidermal hairs. From coal ball Hb A (t 4). 2—Dolerotheca reedana, longitudinal section at margin of fructification with peduncle (?) above. Distal (dehiscence) surface is irregular because the section is obliquely transverse to the dehiscence grooves. From coal ball Hb 208 B (t 3). 3—D. reedana, longitudinal section of vascular bundle near top of fructification showing irregularly reticulated and scalariform elements. From coal ball Hb 208 B (B 4). 4—D. reedana, longitudinal section of vascular strand near margin of fructification. From coal ball Hb 208 B (b 2). 5 D. reedana, transverse section of vascular bundle near top of fructification showing small strands (v) given ofi^ below. From coal ball Hb 208 (b 2), magnification same as fig. 4. 6—D. reedana, longitudinal section at margin of fructification with peduncle above. From coal ball Hb 208 B (b 10). Journal of Paleontology, Vol. 22 Plate 112

V

Schopfj Dolerolheca reedana n.sp. Journal of Paleontology, Vol. 22 Plate 113

Schopfj Dolerotheca reedana n.sp PTERIDOSPERM MALE FRUCTIFICATIONS 713

fortunately there is no evidence directly and persisted only a short time whereas it bearing on the condition in Dolerotheca. seems likely that the large petioles were at The extent of agreement or disagreement least as permanent on these plants as the between structures of the Dolerotheca pe- petioles are in living cycads. duncle and large Myeloxylon petioles possibly Plate 115, figure 1 shows an area where the should not be emphasized. There is no subdermal sclerenchyma is essentially ab- known reason to assume that these structures sent. This condition is probably not should be very similar, even if they were unusual in Myeloxylon. It seems clear that parts of the same plant. They are function- the development of sclerenchyma is variable ally diverse organs of long standing no to a considerable extent and that much of matter what the structural similarities or the variation has not yet been systemati- dissimilarities may be. cally described. The normal variation due to Plate 115, figures 1-7, shows portions of relative position in the petiole, i.e., whether the D. reedana peduncle (figs. 6-7) and of ultimate, penultimate, or main divisions of Myeloxylon cf. M. americanum (figs. 1-5) at the rachis, has not been accurately ascer- the same magnification for comparison. M. tained for most species and until this is done americanum has no epidermal hairs so far as specific identifications of Myeloxylon speci- known although associated and probably mens will be of doubtful value except where correlated pinnules of Alethopteris are hir- precise homologies can be established for sute on the lower surface and some hairs are comparison. Thus it is not entirely clear also present on minor divisions of the rachis. what emphasis should be placed on the The foliar hairs are more slender and less very subordinate development of scler- glandular than these of the peduncle and enchyma in the small section represented in

present no particularly convincing points of fig. 1 except that it is rather comparable in similarity although all of them appear to be appearance to the subdermal tissue of the uniseriate. Dolerotheca peduncle. Aside from the absence of hairs the Myel- Although the vascular strands of the oxylon epidermis agrees fairly well with that fructification and peduncle of Dolerotheca of the peduncle. The epidermal cells of the offer some strong points for comparison, petiole are darker due to greater deposits of neither shows much similarity to the col- secretory (?) material than in the peduncle, lateral bundles of the Myeloxylon. The as may be seen by comparing figs. 1 and 6 of peduncle vascular strand shows no clear PI. 115. The petiole also has a distinct distinction between protoxylem and met- cuticle which is separated slightly from axylem as in the petiolar bundles and there epidermal cells in the portion shown in fig. 1. are considerable differences in the size of These epidermal differences might be dis- elements (compare fig. 7 with figs. 2 and 3 regarded as due to differences in ontogenetic of pi. 115 which are reproduced at the same age. The peduncle probably grew quickly magnification). The largest cells of the

Explanation of Plate 113

Fig. 1—Dolerotheca reedana, section of cover layer showing hairs mounted on small verrucose pro- tuberances. Note position of vascular bundle (V. B.). From coal ball Hb 208 B (b 4), 2—D. reedana, section similar to fig. 1 but somewhat better preserved. Note the numerous secre- tory cells (R. R.) below and in the vicinity of the vascular bundle (V. B.). From coal ball Hb 208 A (t 4). 3—D. reedana, section of outer part of cover layer showing hairs, one of which is capitate, epi- dermis and dark incipient phellogen (?) layer below. From coal ball Hb 208 B (t 3). 4—D. reedana, section of lobe of dehiscence tissue showing epidermis and hairs, secretory canals in tissue above. From coal ball Hb 208 b (B 18), magnification same as fig. 1. 5—D. reedana, section in part parallel to lobe of dehiscence tissue showing number and arrange- ment of epidermal hairs. From coal ball Hb 208 C (t 2). 6—D. reedana, section of a sporangium containing collapsed spores. The row of cells bounding the sporangial locule on the left is more delicate than the rest of the intersporangial tissue and may indicate the nature of the s[)orangial membrane seen in D. formosa. From coal hall Hb 208 B (B 18). 714 JAMES M. SCHOPF

peduncle bundles are about the size of desired in stratigraphic problems. This ad- protoxylem elements in the Myeloxylon. ditional specimen of Dolerotheca suggests Whether small ultimate divisions of the that the genus may not be as rare in the rachis would show more similarity to the Pennsylvanian beds of America as the scant peduncle in vascularization cannot be stated literature indicates. now although it is known that the vascular Description of the three American species elements are smaller in the ultimate petiolar of Dolerotheca has shown that the vascular branches. strands are located rather deeply within the The peduncle of Dolerotheca is similar to dorsal cover layer. This may well afford the Myeloxylon petiole in that both possess a good basis for distinguishing Dolerotheca similar secretory canals. In fig. 6, a resin rod- from seemingly perfoliate cyclopterid leaf let is situated in the ground parenchyma impressions which may superficially cor- similar to the one shown in fig. 1. Although respond in outline. The cyclopterids show they are fewer in the peduncle both have venation clearly whereas it may be doubted very similar ground parenchyma. that Dolerotheca ever does (also see Florin, Such similarities probably are insufficient 1926). An obscure radial ahgnment of evidence for biologic correlation, but the sporangial impressions appears to be most differences also are inconclusive because characteristic of impressions and compres- dissimilar organs are being compared. A sion specimens of Dolerotheca (cf. Halle, 1933, more pertinent comparison might be pos- pi. 9, figs. 5 and 6). sible between ultimate divisions of the Myel- Dolerotheca sp. oxylon rachis and the peduncle. Plate 111, figure 5; plate 114, figure 10 Dolerotheca impression Fructification nearly circular in outline, An interesting specimen of Dolerotheca about 28 mm. in diameter; the campanulary was collected by the writer in 1938 from near cover is indicated by the rim 2-3 mm. wide Carterville, Williamson County, Illinois. It around the margin. Sporangial rows are was found upon splitting one of the iron- shown by more or less definite protuberances stone concretions of the Mazon Creek type radiating from center. Prepollen grains are which occur there in grey shale overlying large, about 450ju in their longest dimension the Herrin (No. 6) coal. This coal bed is and- about 390;n in the shortest; proximal accepted arbitrarily as the top member of suture and distal grooves of the prepollen the Carbondale formation, hence the fossil are evident; the prepollen coat is finely is from the lowermost McLeansboro. Al- granulose. Anatomical details unknown. though plant preservation is similar, this The specimen has suffered considerable zone is considerably younger than the clas- compression and most of its original carbon- sical one at Mazon Creek. Anatomical fea- aceous content is gone. The cavity formerly tures being absent, it seems inadvisable now occupied by compressed tissues has been to apply a specific designation to this speci- partly replaced by a friable film of calcite men although it probably is distinct from and kaolinite in which some carbonaceous the other species. The chief point worthy of fragments still are present (pi. Ill, fig. 5). A note is the generic identification of the form, few prepollen grains are present in this a point which seems reasonably established friable semi-mineralized layer and may be in spite of the differences in preservation observed under a Greenough-type micro- existing between this and the other Doler- scope. They show no definite arrangement otheca specimens. This occurrence gives some to indicate the form of sporangia and it is basis for hope that the geologic record of evident that they had mostly been shed be- Dolerotheca and allied genera will be further fore fossilization. One of the spores remain- augmented by compression and impression ing is shown in pi. 114, fig. 10. Twenty or specimens. Coal ball petrifactions can be more spores, all of the same kind, have been counted on to provide a basis for anatomical observed and this seems sufficient evidence interpretation but such specimens are rel- to indicate that these examples are not atively scarce and, therefore, usually do not foreign to the specimen. constitute a main source for information The characteristic spores and the nearly PTERIDOSPERM MALE FRUCTIFICATIONS 715

circular form of the fructification with no resulting from burial but the author believes indication of lobes or appendages make the that a good deal of the asymmetry in cross generic identification of this fossil certain. section is original, since the Mazon nodules It may, kowever, be distinct from other spe- often preserve surficial form without much cies because its spores are somewhat larger distortion. According to this interpretation and more broadly oval. In size the fructi- the Codonotheca fructification consists of a fication is intermediate between D. reedana single loosely paired row of tubular spo- and D. formosa. With the exception of its rangia. Free ends of the sporangia penetrate larger spores, this form seems intermediate the matrix so that it is difficult to accurately between these well characterized species. ascertain the number but it seems there were Other compression specimens which may commonly six and may sometimes have been be congeneric are those described as Dau- eight in all. Sellards (1903) and subsequent breeia (in part) (White, 1903, p. 107; Sellards, authors have all considered the Codonotheca 1908, pp. 430-433),* Doleropteris pennsyl- fructification to be radially symmetrical. vanicum (Dawson 1890, p. 7), and possibly, If Codonotheca and other Whittleseyineans judging from White's (1903, p. 107) discus- were bilaterally instead of radially sym- sion, also the Plinthiotheca angularis of metrical and composed essentially of a single Lesquereux. It should be stressed that the double series of tubular sporangia, they presence of prepollen or other proof of would seem to show greater correspondence sporogenous nature is of critical importance with the structure of Dolerotheca. in identifying any of these with Dolerotheca. The author is not yet prepared to accept Thus far this has not been shown, but it may fully Halle's conclusion as to the uniseriate be if reinvestigation is undertaken using whorled arrangement of sporangia and the modern improved methods. However, the hollow interior of the Whittleseyinean forms. specimen illustrated as Daubreeia (?) by The lamina-like form of Whittleseya was Sellards (1908) in pi. 56, fig. 5 of Vol. 9 of accepted without controversy by students of the Kansas Survey is particularly sugges- fossil plants for many years and further tive of Dolerotheca. It is about 21^ by 25 evidence is needed before the view long held mm. in diameter and seems to show radiat- is completely discarded. A bilateral inter- ing sporangial rows with additional rows pretation of Codonotheca at any rate, would intercalated toward the margin. It was col- seem equally acceptable. lected from the LeRoy shale near Blue A further character of Codonotheca which

Mound in Kansas. seems to have escaped particular notice is the pubescence of the outer surfaces. Sel- CODONOTHECA lards (1903) mentioned longitudinal striae Codonotheca is one of the genera included and weaker cross lines which no doubt by Halle in the Whittleseyineae. It has been represent the impressions of epidermal cells definitely identified chiefly in nodules from and in the description of his fig. 15, pi. 8, he in the Mazon Creek area Grundy and Will stated that fig. 17 shows the "minutely Counties of Northern Illinois. Some obser- roughened or pitted surface". The pits vations have been made on a few specimens mentioned are acutally hair bases which which are of interest in the present con- appear to be more or less glandular and nection. closely set. In distribution at least, they are similar to those of Goldenbergia and Doler- Codonotheca caduca Sellards otheca. It is not unusual for the ironstone Plate 111, figures 1, 2; plate 114, matrix of Mazon concretions to preserve figures 11-13 such surface features faithfully and the The specimens are all much flattened. In specimen shown at slight enlargement in part this may be attributed to pressure PI. Ill, fig. 2 shows the ''punctate" surface ^ Specimens of Daubreeia in the U. S. National characteristically. In fig. 2a of this plate, a Museum, including three of those studied and densely pitted surface of the same specimen illustrated by Sellards, show clearly that they are is shown at greater magnification. The bases not fertile organs comparable to the Dolerotheca campanulas. They appear, at least superficially, of hairs can be seen penetrating the matrix more like Dolerophyllum (see Florin, 1925). surrounding Codonotheca but the shape of —

716 JAMES M, SCHOPF

the hair itself is not commonly exhibited. the other hand the specimen in fig. 3 of the In a few instances they appear relatively same plate shows the characteristic pubes- long and tapering; more so than the hairs cence near the basal part and is no doubt of Goldenhergia shown by Halle (1933, pi. 2, correctly identified even though no spores figs. 18-19). The Codonotheca surfaces are are visible in the three sporangia exposed. best observed by reflected illumination with Erroneous identification of specimens as the Greenough type microscope when the Codonotheca is by no means rare in collections specimens are flooded with xylol. The author from the Mazon beds of northern Illinois. regards the occurrence of these hairs as Spores or Prepollen. —The folds shown on further confirmation of Halle's assignment spores of Codonotheca caduca by Darrah, and of Codonotheca to the Whittleseyineae, and thought by him to be similar to the distal as additional evidence linking the Doler- grooves and umbo of other Dolerosporeae, othecan and Whittleseyinean subtribes. were considered by Florin (1937) to be a The recognition of a definite pubescence "single long and broad germinal furrow." on Codonotheca is useful and aids in the According to the present author's inter- identification of fragmentary or otherwise pretation this "germinal furrow" is only a questionable specimens. For example, exam- chance structure caused by incidental col- ination of the originals of illustrations la- lapse or folding. Only one spore out of the beled Codonotheca cadua in pi. 43, figs. 1 and 2, fifteen or more illustrated by Darrah shows of Bull. 52 of the Illinois Survey are shown folds definitely enough to support the pos- by this criterion to be wrongly identified. sibility of distal specialization. Since this The original of fig. 1 is more likely a tuft one spore appears to be unique even in the of lycopod leaves similar to the Lepidoden- original figures, the writer is inclined to dron rigens of Lesquereux. That shown in question whether it has any special signifi- fig. 2 is probably a whorl of inflate Annularia cance. Spores of Codonotheca are illustrated leaves which were originally deposited some- in pi. 114, figs. 11-13 and these show nothing what distorted from their usual position. On that can be interpreted either as distal

Explanation of Plate 114 •

Magnification same for figs. 1-13, scale indicated.

Fig. 1—Dolerotheca reedana, spore (prepollen) showing strongly bent proximal suture. Spore Isolated from fructification by solution of calcite matrix in hydrochloric acid. From coal ball Hb 208. 2—D. reedana, isolated spore showing proximal suture. From coal ball Hb 208. 3—D. reedana, isolated spore showing very moderate deflexion of proximal suture. From coal ball Hb 208. 4—D. reedana, isolated spore similar to fig. 2, proximal suture appears under different illumination due to the presence of a bubble of CO2 inside the spore coat. 5 D. reedana, isolated spore showing endosporal membrane in plane of focus. From coal ball Hb 208. 6, 7—D. reedana, spores showing umbo and distal grooves. From coal ball Hb 208. 8—D. reedana, spore tilted to one side showing thin area at bottom of one of the distal grooves. From coal ball Hb 208. 9—D. reedana, spore photographed to show proximal suture {9a) and at a lower plane of focus to show distal grooves {9h). From coal ball Hb 208. 10—Dolerotheca sp., large spore from compression specimen shown in PI. Ill fig. 5. P.S.—Prox- imal suture, D. gr.—distal grooves. 111. Geol. Survey Catalog No. S B 79. 11-13— Codonotheca caduca, spores showing proximal suture only. Photographed at the same magnification and other conditions as those shown in figs. 1-10. From specimen from Mazon area. III. Geol. Surv. Catalog No. S B 1006. 14—Dolerotheca reedana, peel section including (above) the tip of one spore cut transversely, dis- tal side up, and spore sectioned longitudinally (below), one of the distal grooves (Dist.) cut obliquely at the right. From coal ball Hb 208 D (B 1), magnification indicated above figure. 15—D. reedana, median transverse section of spore showing distal umbo and grooves above and spore coat split open below along the proximal suture. Dist. gr.—distal groove; Exo—exo- spore layer; End—endosporal membrane; Prox.—proximal side. From coal ball Hb 208 D (B 1), magnification same as fig. 14. Journal of Paleontology, Vol. 22 Plate 114

Schopf, Dolerothecay Codonotheca spores 5

Journal of Paleontology, Vol. 22 Plate 1 1

Schopf, Myeloxylon americanum and Dolerotheca feduncle (?) —

PTERIDOSPERM MALE FRUCTIFICATIONS 717

grooves or a "germinal furrow." In these some hypothesis of mutual relationship is spores the proximal suture and granulose called for, even though it may be held surface texture are the only distinctive tentatively and by no means regarded as features. Their shape and size correspond proved in detail. with other members of this pteridosperm The writer believes there is ample evi- alliance. It is true that incidental folds dence to indicate the lygenopterid and med- sometimes are present, but, according to the dullosan pteridosperms are monophyletically writer's interpretation, Codonotheca spores related, that is, derived ancestrally from a lack any discernible vestige of distal ap- single common stock, and the following paratus. If specimens occur which have discussion is based on this assumption. distal specialization they probably should These two groups include the pteridosperms not be identified with Sellards' Codonotheca best known and they constitute the nuclear caduca because his description obviously is material of reference for the pteridosperm accurate for those of the Mazon specimens group as a whole in the consideration of all this writer has examined. The similarity of modern authors. material examined in connection with the Since 1930, Zimmerman's telomic con- present study to Sellards' original description cept of organization of higher plants has shows that C. caduca is an accurately de- been used comparatively because of its fined species. simplicity, and because of its recognition of fertile organs as fundamental units in the PHYLOGENETIC CONNECTIONS make-up of plants, a view that has long been Up to the present time Dolerotheca has advocated by F. O. Bower and others con- occupied a somewhat isolated systematic cerned with fundamental interpretation of position because it was not known in suffici- botany. Complex fructifications may arise ent detail to permit accurate comparison. It by the aggregation of fertile telomic units so is hoped this deficiency has been largely that the result is a synangium in the strict overcome by the material that has been sense. Probably they also may arise by described above. In the paragraphs below enlargement and elaboration of a single the writer suggests a relationship for Doler- fertile telome. The structure of the Dolero- otheca with other pteridosperms. Unless one theca campanulum seems to be more readily adopts the view that the seed habit associ- explained by the latter evolutionary process, ated with pteridosperms arose spontane- and the sort of elaboration it prominently ously in several independent phyletic lines, displays is regarded by the writer as most and therefore that the group as known today easily explained by a process of septation. is a highly polyphyletic and unnatural one, Any elaborated fructification of this type

Explanation of Plate 115

Magnification same for figs. 1-7, scales indicated.

Fig. 1—Myeloxylon cf. M. americanum, non-sclerotic margin of petiole. Note cuticle and secretory duct (Se). Froni coal ball Hb 208 B (B 18). 2—M. cf. M. americanum, vascular bundle with sclerenchyma sheath moderately developed. Note phloem (Ph.) which is well preserved. From coal ball Hb 208 C (t 2). 3—Bundle similar to that in fig. 2 but lacking the preservation of phloem—a secretory duct (Se) is located next to the xylem within the sclerotic sheath. 4—M. cf. M. americanum, resin rodlet and sclerenchyma strands moderately developed. From coal ball Hb 208 C (t 2). 5 M. cf. M. americanum, area near margin of petiole showing a moderate development of sclerenchyma strands and small secretory canals (Se). From coal ball Hb 208 C (t 2) 6—Peduncle (?) probably of Dolerotheca reedana, for comparison with fig. /. R—hollow resin rod- let. From coal ball Hb 208 A (t 4). 7—Peduncle (?) probably of D. reedana, showing vascular bundles. From coal ball Hb 208 B (B4) 8—Vascular bundles shown in fig. 7, at higher magnification. Scale indicated at right. 9—D. reedana, bundle from near top of fructification for comparison with fig. 8. From coal ball Hb 208 B (B 2), magnification same as fig. 8. 718 JAMES M. SCHOPF derived by a process of telomic septation it be granted that the lygenopterid and may conveniently be called a septangium. medullosan pteridosperms, at least, have a This and other self explanatory terms have common phyletic derivation and that the been used in indicating possible lines of male fructifications in one or several of the

LYGENOPTERID PTERIDOSPERMS MEDULLOSAN PTERIDOSPERMS i

Telangium Potoniea Dolerotheca Whittleseya

Plants with Filicoid Spores

<\5

Lower Carboniferous

Devonian Pteridosperm Ancestral Lineage

Male Fructifications

deriving from the

Simple Fertile Telome

Fig. 17—Hypothetical pteridosperm relationships according to septangial interpretation of male fructifications.

evolutionary morphologic modification in constituent groups of this alliance had the chart given in text fig. 17. evolved by septangial modification, the pos- The general problem posed in this con- sibility would be presented for extending the nection may be briefly stated as follows: if inference of telomic septation to the inter- PTERIDOSPERM MALE FRUCTIFICATIONS 719

pretation of complicated sporangia in all A synangial interpretation of Dolerotheca of the pteridospermic groups. Although this is difficult because a pair of tubular spo- question is highly theoretical, it could be of rangia, rather than a single one that could be considerable importance in definition of the directly derived from a fertile telome, seems pteridosperm group as a whole. The sugges- to be the fundamental unit of structure, and tion of elaboration of pteridosperm male because the sporangial units, single or fructifications by the process of septation is double, permit no easy comparative deri- not new, since Miss Benson recognized the vation from a telomic branch system (see distinct probability of its occurrence in at Zimmerman, 1930). It would seem more least two other important genera, as dis- plausible that the campanulum has been cussed below. The writer believes the septa- derived by septation or "septangy" and tion hypothesis deserves more serious con- that the whole fructification is comparable to a sideration than it has frequently been single telome, much modified, rather than to accorded in morphologic interpretation of a synangial aggregation of fertile telomes in the pteridosperm polleniferous structures. the manner which was more strongly fa- The most surprising result of the present vored by Halle in 1933 and which he sum- study, from the standpoint of comparative marized in 1937. The process of sporangial anatomy, is that Dolerotheca shows no evi- septation is no more improbable, biologi- dence of cyclic organization or derivation. The cally, than the process of aggregation (syn- radial arrangement of paired rows of spo- angy) in the case of fertile members. A rangia is the dominating feature. Toward the basic evolutionary difference, involving margin new double rows of sporangia are synangy in ferns and septangy in pterido- intercalated; the new rows do not appear at sperms, might, in fact, be called on to explain any uniform distance from either center or why the seed habit, with its various inter- periphery, but are inserted at various po- connected modifications, was so early at- sitions as the divergence between preexisting tained by the latter group. The gymnosper- double rows affords space for their accommo- mic ovule represents an elaboration of a dation. Hence the symmetry of the Doler- fertile telome also, and some degree of link- otheca campanulum is decidedly radial in age is to be expected in male and female character and not cyclic. The symmetry is characteristics of the same plants. not very definite and the central focus of It probably is not necessary to search as rows is not necessarily the center of the far back as the Devonian to find a primitive fructification. type of male fructification with plausible an- In view of the fundamental importance cestral relationship to the Whittleseyas, which Dr. Halle has attached to cyclic ar- Dolerothecas, and Potonieas, but the primi- rangement in the Whittleseyinae, and the tive type of telome is closely approximated indisputable relationship between the Doler- in some of the Devonian plants. In the othecineans and the Whittleseyineans, the writer's opinion, the type of male fructifica- morphology and morphogenetic derivation tion borne by Helerotheca grievi Benson, of the large pteridosperm fructifications may may serve very well to illustrate a plausible require reconsideration. To the writer, Dr. ancestor for Potoniea, Whittleseya and allied Halle's alternative suggestion, stated in the forms, and Dolerotheca. footnote on p. 57 of his important contri- Heterotheca was regarded as in biologic bution on the spore bearing organs of pterido- correlation (i.e., supposed to be a part of the sperms, seems most easily reconciled with same plant) with Heterangium, a genus the present array of facts. He stated (Halle, identified by anatomical characteristics of 1933, p. 57 footnote), "It is perhaps also the stem. Primitive species of Hetera^tgium possible to imagine septation of a single are about the proper geologic age and mor- sporangium of the remarkably large type phologic type to be close to the direct an- found in some of the Psilophy tales; the cestry of both the Lyginopterid and Medul- "sporangia" of Sporogonites have a certain losan lines of pteridosperm specialization. superficial resemblance to the Aulacotheca Both Heterangium and Heterotheca are of type in shape, in their comparatively large Lower Carboniferous age from the Calcifer- size, and in their longitudinal furrows." ous Sandstone in Scotland, and this fact •

720 JAMES M. SCHOPF

makes ancestral consideration feasible in plant groups the septate derivation of their relation to more specialized Upper Carbonif- male fructifications in general (in contrast erous (Pennsylvanian) forms. to the aggregation interpretation of fern The structure of Heterotheca is most synangia) needs to be considered. Since it readily interpreted as a product of sporan- seems most essential to regard Heterotheca gial septation (see Benson 1922, pp. 128- and Dolerotheca fructifications in this light, 129). The fruiting body is slightly flattened, other genera definitely linked with Pterido- half-fusiform, and 3| to 4 mm. long. It con- sperms, such as Crossotheca and Telangium, tains numerous sporangia, 16 of which may also should be considered in the same fashion be seen in cross-section; 12 sporangia at the even though they more successfully simu- level shown in the cross section diagram, D, late the synangia of ferns. Miss Benson has of the frontispiece, are peripheral and 4 cen- presented evidence for septate origin, both tral in position. The spores are small (20- in her paper on Telangium (1904) and in her 30/x in diameter) with a trilete suture. A discussion of Heterotheca (1923). surface reconstruction of Heterotheca is also In Heterotheca the internal sporangia are shown in fig. D of the frontispiece, drawn poorly placed for the shedding of spores; the at the same scale as the Dolerotheca figures. development of elongate sporangia free of The diagrammatic cross-section is drawn one another at the distal ends appears a to a larger scale to indicate the relative loca- likely evolutionary trend which is plausibly tions of vascular bundles and sclerotic exemplified by Telangium. The frontispiece tissue. illustration, fig. E, shows a reconstruction of From such a structure as the Heterotheca the Telangium fructification drawn at the fructification, it is possible to suggest several same scale as the other figures. Other modi- lines of evolutionary specialization, as is in- fications of Telangium as contrasted with dicated in the schematic diagram in text fig. Heterotheca also are evident, but it seems 17. No attempt has been made to present a necessary to call attention only to the con- complete pteridosperm synopsis in this traction and simplification of the cover chart, and gymnosperms other than pterido- layer in Telangium, and to the elongation sperms are not included. and reduction in number of characteristi- As to the possibility of complex fructifi- cally paired sporangia. cations arising by septation of simpler fertile In the derivation of Potoniea from a type structures, as well as by aggregation, Bower like Heterotheca, it is evident that sporangia stated (Origin of a Land Flora, 1908, p. Ill) have been modified to tubular form and the "in each case of a synangium, it may be a fructification expanded. Whether they are question whether the structure results from anatomically paired or not, cannot be de- septation or from fusion." Possibly nowhere tetmined from the evidence at hand. The in the plant kingdom does homoplasty cover layer has been elaborated (rather than play a more important part than in the de- contracted as in Telangium) and evidently velopment of the male fructifications of serves as a sporangial receptacle. The pteridosperms, and if the pteridosperms are sporangia apparently are free of one another, truly one of the several large monophyletic at least for a considerable part of their length. This would represent a considerable ^ Information about Heterotheca has been improvement over the Heterotheca condition drawn entirely from Dr. Benson's publication of insofar as dispersal of spores is concerned. 1922. Reproductions of her original photographs illustrating this form do not offer very convincing The great size elaboration of the Potoniea support for the description or interpretation. fructification is a significant feature. Recently Dr. T. G. Halle, in a personal communi- Dolerotheca and Whittleseya and their cation, has emphasized the need for further infor- closer relatives are distinguished from the mation about it. The writer sincerely agrees that in this a more definitive study, if possible with the aid of pteridosperms previously mentioned modern peel preparations, should be undertaken. connection, in having prepollen rather than Until this is done the accuracy of the original fern-like types of spores. The suggestion has interpretation cannot be confirmed and opinions been made that these advanced spores may about the relationship of Heterotheca will have to be reserved to the extent, at least, of uncertainty possess a vestigial third trilete ray; if so, about the photographic illustrations. they were derived from a tetrahedral tetrad PTERIDOSPERM MALE FRUCTIFICATIONS 721 and thus may not differ as much as they present across the width of the Whittleseya would seem to at first glance, from the types "lamina." of pteridosperms with fern-like microspores. Halle regarded the "lamina" essentially

Regardless of this, prepollen is sufficiently as a tube, containing "loculi . . . arranged different from the matured androspores of in a uniseriate whorl," that owed its lami- the lygenopterid pteridosperms that an im- nate form to compression. With this view portant biological difference is indicated. the present writer is unable to agree. We are not in a position to interpret the full The first occasion for doubting the cyclic significance of prepollen as yet. A special arrangement of locules in Whittleseya fructi- pollenation mechanism seems to be implied, fications came in the realization that it was but at least the wide-spread occurrence of entirely at variance with the radial organiza- prepollen in the upper Paleozoic is well tion shown by Dolerotheca. In other particu- established. lars it seemed possible to reasonably recon- Except for the important difference in cile the new information on Dolerotheca with spores, Dolerotheca and Potoniea show a what was known about Whittleseya. It similar tendency in elaboration of sporangia, seemed strange that Dolerotheca should have and, to some extent, in enlargment of the sporangia radially arranged in paired rows, campanulum as a whole. This structure in while in Whittleseya, very similar sporangia Lacoea is larger than in Potoniea, and com- with similar spores, are arranged according pares more favorably in this respect. to a wholly different unseriate cyclic pattern. Ground tissue completely enclosing Doler- Further study and review of this matter otheca sporangia, and sclerotic tissue in the haveconvinced thewriter that theWhittleseya campanulary cover, are both quite plausibly male fructification was never hollow, or derivative from the type of structure in campanuloid in form, but in truth is a lami- Heterotheca. Dolerotheca shows more ade- nar structure as it was first interpreted. He quate provision for dispersal of spores. believes that it consists essentially of a single The morphologic comparison of Dolero- paired row of sporangia that is the morpho- theca and Whittleseya is clouded by what the logical equivalent of one of the numerous writer believes must be a misinterpretation paired sporangial rows so definitely estab- of the structure and organization in the lished for Dolerotheca. latter. The previous ideas are reviewed Such an interpretation appears to explain briefly in order to clarify the present position. adequately all the features observed in Newberry (1853) adopted the view that Halle's excellent sections (new sections the broad shovel-shaped organs (of which could hardly bear more definitely on this he had seen some thousands) were leaves of point because, as Halle stated,- loc. cit., p. uncertain affinity. He evidently did not 22, "the median carbonized zone shows no question their morphologic identity as natural longitudinal rupture nor any other leaves, but he was at a loss to relate them or indication that it has been formed by com- place them systematically. Other authors pression of two layers originally separated substantially followed Newberry, more or by a central cavity") and it likewise is in less tentatively suggesting a gymnospermic full accord with the extensive observations of alliance, until it became clear that these Whittlesey (1849), Newberry (1853), White were fertile, rather than vegetative organs. (1901) and others. Most of the specimens Kidston may have been the first to suspect have been preserved in fine grained matrix that they were the male organs of pterido- that surely would have filled any hollow sperms. A statement to this effect, somewhat central cavity in some instances, had such a unsatisfactory in details, was made by Se- cavity ever existed. The very thin inter- ward (1917, p. 129) who illustrated pre- vening shale layer Halle demonstrated at pollen Kidston had obtained from Whittle- the distal edge of the lamina is not at ail seya elegans. However, prior to Halle's commensurate with the hollow cavity he study (1933), the tubular form of the postulated, and possibly it may be related sporangia, a most important characteristic, to a dehiscence groove similar to those of was unrecognized. Furthermore, Halle dem- Dolerotheca. There is no specimen known to onstrated that two rows of sporangia are the writer, nor any that has been described, 722 JAMES M. SCHOPF

in which such a central filling is a prominent Whittlesey stated is never seen although he feature. A quotation from Whittlesey's quite evidently looked carefully for such an little-cited original description (1849) of the indication. In several respects Whittlesey's Whittleseya elegans fructification is still most discussion is more astute than that of later pertinent to the discussion: authors; he certainly was impressed with the possiblity that the organs might be fertile It was first observed by my brother, the Rev. S. H. Whittlesey, about four years ago in the structures. Halle's modern study has fully falling roof of the "Chestnut Ridge" coal mine, confirmed W^hittlesey's suspicion as to the discovered and opened by us in 1845, and which nature of the organs, but is not reconciled is situated one mile and a quarter northwest by with the general evidence as to their mor- north from the centre of Tallmadge, Summit County, Ohio. phology. All facts known now appear in It is there called "the flower," and has a strik- reasonable agreement if the view expressed ing general resemblance to one, but has no regarding the paired sporangial row is botanical resemblance to flowers or other parts adopted; further information on sporangial of fructification. If this was originally an open pod whether a dehiscence and tissue structure is not likely flower or not, there should have been seen among to be obtained until petrified specimens are several hundred specimens that I have examined, found. evidences of a circular or oval opening at the edge The morphology of these organs naturally or apex of the figure. These edges could not al- ways have been pressed together symmetrically has important bearing on their phyletic so as exactly to cover each other, and if there were morphogenesis. For the same reasons that interior them, two surfaces with organs between the writer questions the cyclic arrangement it must have occasionally appeared in that light. of Whittleseya sporangia, he also questions But in no instance is there such a separation of the serrated edges, there being but one line that such organs can be derived from "a across the apex, which is generally straight or whorl of fertile telomes fused tangentially" slightly curving, as in the drawing. (cf. Halle, 1937, p. 231). . . . The very fine but distinct curved lines or Although the Whittleseya fructification is striae, extend with great regularity, converging to a point at the base where the stem unites. Its not nearly as massive as that of Dolerotheca, space in the rock is represented by a very thin the probable correspondence in plan of or- scale of coal, the raised lines on one face of the ganization argues about as strongly for a specimen corresponding to depressed lines on the septangial interpretation of one as the other. counterpart, showing it to be a single thickness and not double. It appears that the cover layer of Whittle-

. . . On some of them may be seen fine cross seya has been persistent, but that the fructi- marking like nerves of reticulation, but in the fication has enlarged along two radii only, finest specimens these are wanting, and are prob- instead of many. Neither radial ably due to wrinkles of compression. The teeth the nor bi- at the edge are not uniform in number. I have lateral symmetry of Dolerotheca is exact, but counted from eighteen to twenty-six. The light, the Whittleseya fructification may be more slender, but well defined stem is generally want- nearly symmetrical bilaterally. The fact ing. It is never seen longer than represented in that Heterotheca fructifications the sketch, and seldom more than half an inch in are not per- length, where it terminates abruptly as though fectly half-fusiform, but show a bilateral it were broken off. There are minute straight tendency in transverse outline, suggests the lines like fibres in this stem. possibility of deriving a more strictly bi- (The fossils) . . . exist in the ordinary bluish lateral fructification gray, soft argillo-siliceous shale of the coal series, from it as well as a more and in spots are seen in immense numbers, from massive radial type. There is little question one to one and half feet above the coal. The that significant differences of long standing shale is charged with myriads of coal plants, but exist between Dolerotheca and Whittleseya, the only hint I have met with showing any rela- and it is supposed that the parent di- tion between this and the other plants, is the stocks fact that where the Pecopteris lonchitica is most verged at a fairly early date, after prepollen abundant, this is seen in greatest numbers. was an established feature, as indicated in

. . . The Carpolithus is abundant in the roof of text figure 17. the same mine. In Codonotheca the cover layer appears to It will be noted that the most striking have become contracted to expose the free feature of Halle's reconstruction (loc. cit., ends of sporangia. Such development would

text fig. 5, p. 24), viz., the duplicate distal seem a parallelism of that which took place margin of the hollow bell, is the feature earlier and more directly in the ancestry of PTERIDOSPERM MALE FRUCTIFICATIONS 723

Telangium. It is interesting that Codono- very material assistance in critically re- theca is of large size and that no reversion to viewing the manuscript. Many of the sec- the fern-simulating septangial type has oc- tions of Dolerotheca were prepared by Allen curred. Piatt under the writer's supervision. The The writer believes that although the final drawings of surface reconstructions in- phyletic relationships and postulated struc- cluded in the frontispiece, and of the de- tural modifications are highly speculative, tailed drawings from sections of the fructi- they have greater likelihood of substantia- fications were made by Daniel M. Morgan, tion, in part at least, than may frequently be now employed by the U. S. Weather Bureau the case in a "Merkmals Phylogenie" (see at Alliance, Nebraska. Robert M. Kosanke, Zimmerman, 1930). This belief is based on Paleobotanist of the Illinois Geological Sur- convergence of evidence supplied by the vey, assisted in many ways. probable biologically correlative fossils The writer wishes to express his apprecia- (stems, leaves, seeds) which can not be dis- tion to all who have assisted him, and par- cussed in this paper. Many of the relation- ticularly to M. M. Leighton, Chief, for his ships, of course, are not likely to be satis- continuing interest and support in these factorily established for many years. investigations. It appears that such matters of phyloge- REFERENCES netic relationship as have been suggested Andrews, H. N., 1945, Contributions to our may have an importance beyond their inher- knowledge of American Carboniferous floras. ent theoretic interest. The elaboration of the VII. Some pteridosperm stems from Iowa. male fructifications very probably occurred as Missouri Bot. Garden Annals, vol. 32, pp. agradual evolutionary process in many linked 323-360. Arnold, C. A., 1937, The seeds of Alethopteris, characteristics. If a "key" can be supplied and other pteridosperms from North America. to gradational evolutionary series in geologic Deuxieme Congres pour TAvancement des time, it provides a most convenient tool for Etudes de Stratigraphic Carbonifere, Heerlen, the stratigraphic paleontologist wherever 1935, Compte Rendu, vol. 1, pp. 41-45. Benson, Margaret, 1904, Telangium scotii. An- such fossils are encountered. The evolution- nals of Botany, vol. 18, pp. 161-177. ary hypotheses embodied in the foregoing , 1922, Heterotheca grievii. The microspo- discussion should be tested wherever possi- range of Heterangium grievii. Bot. Gazette, vol. ble by comparison with other better known 74 (2), pp. 121-142. Bower, F. O., 1908, Origin of a land flora, fossils, to indicate more objectively their pp. 1-727, Macmillan, London. value in stratigraphic definition. Their value Darrah, W. C, 1937, Codonotheca and Crosso- as time indices will be more evident as dis- theca: polleniferous structures of pterido- cernible stages of evolutionary develop- sperms. Harvard Univ. Bot. Mus. Leaflets, vol. 4 153-172. ment are keyed with definite stratigraphic (9), pp. Dawson, J. W., 1890, New plants from the zones. The male organs discussed here have Erian and Carboniferous and on characters the advantage (from the paleontologic and affinities of Paleozoic gymnosperms. Ca- standpoint) of a fairly determinate type of nadian Rec. of Sci.. vol. 4 (1) Jan., pp. 1-28. Florin, Rudolf, 1925, Zur Kenntnis der Pala- growth, so that in normal course of fossil ozoischen Pfianzengattung Dolerophyllum Sa- preservation, typical should be specimens porta. Svensk. bot. tidskr., vol. 19, pp. 171- mature and therefore fairly comparable 191. ontogenetically. , 1925, Zur Kenntnis einiger Cyclopteriden des Oberkarbons. Geol. foren. Stockholm ACKOWLEDGMENTS Forh., vol. 47 (2), pp. 223-244. , 1926, tJber einige Blatterabdrucke vom All this investigation was conducted and Cyclopteris-Typus aus dem Karbon und Perm. much of the manuscript written in 1939- Arkiv for Botanik, vol. 20 A (13), pp. 1-19. , 1937, On the morphology of the pollen 1941 while the author was employed by the grains in some Paleozoic pteridosperms, Svensk. IlHnois Geological Survey. writer The bot. tidskr., vol. 31 (2), pp. 305-338. is indebted to many members of the stafif Halle, T. G., 1929, Some seed-bearing pterido- of the Illinois Geological Survey for aid sperms from the Permian of China. K. svenska vetensk. akad. Handl., tredje serien 6 (8), pp. in completing this paper for publication. 1-24. Gilbert H. Cady, Head of the Coal Di- , 1933, The structure of certain fossil spore- vision, has offered encouragement and bearing organs believed to belong to pterido- 724 JAMES M. SCHOPF

sperms. K. svenska vetensk. akad. Handl., ian relationships. Illinois Geol. Survey Rept. tredje serien, 12 (6), pp. 1-103. Inv. No. 75, pp. 1-54.

, 1937, The position and arrangement of the -, Wilson, L. R., and Bentall, Ray, 1944, spore-producing members of the Paleozoic An annotated synopsis of Paleozoic fossil spores pteridosperms. Deuxieme Congres pour I'Avan- and the definition of generic groups. Illinois cement des Etudes de Stratigraphie Carboni- Geol. Survey Rept. Inv. No. 91, pp. 1-74. fere, Heerlen, 1935, Compte Rendu, vol. 1, Saporta, Gaston de, and Marion, A.-F., 1885, pp. 227-235. L' Evolution du regne vegetal. Les phanero- Grand'Eury, F. C, 1877, Flore Carbonifere du games, vol. 1, pp. 1-249, Bailliere, Paris. ddpartement dela Loire etdu centre dela France Sellards, E. H., 1903, Codonolheca, a new type Mem. presentes par divers savants a I'Acade- of spore-bearing organ from the coal measures. mie des sci. de I'lnstitut de France. Extrait du Am. Jour. Sci., 4th ser., vol. 16, pp. 87-95. Text, 1-624. Pub. Bau- Tome XXIV. pp. by J. , 1907, Notes on the spore-bearing organ dry. Atlas, 34 pls.+map. Paris. Codonotheca and its relationship with the

, Geologie et Paleontologie bassin 1890, du Cycadofilices. New Phytologist, vol. 6, pp. Houiller du Gard. Text, pp. 1-354, St.-Etienne. 175-178. Atlas, pis. 1-22, Paris and St.-Etienne. , 1908, Fossil plants of the Upper Paleozoic HosKiNS, H., 1923, Paleozoic angiosperm J. A of Kansas. Kansas Univ. Geol. Survey, vol. 9, from an American coal ball, Bot. Gazette, vol. pp. 386-480. 390-399. 75, pp. Seward, A. C, 1917, Fossil plants, vol. Ill, Cam- Newberry, J. S., 1853a, Fossil plants of the Ohio bridge Univ. Press. coal basin [a catalog listing]. Annals of Science , 1923, A supposed Paleozoic angiosperm. (Cleveland), vol. 1 (8). pp. 95-97; (9), pp. 106- Bot. Gazette, vol. 76, p. 215. 108. Steidtmann, W. E., 1944, The anatomy and af- , 1853b, New fossil plants from Ohio (1). An- finities of Medullosa noei Steidtmann, and as- nals of Science (Cleveland), vol. 1 (10), pp. sociated foliage, roots and seeds. Michigan 116-117. Univ., Mus. Paleontology Contr., vol. 6 (7), Read, C. B., 1946, A Pennsylvanian florule from pp. 131-166. the Forkston coal in the Dutch Mountain out- White, David, 1901, The Canadian species of the lier, northeastern Pennsylvania. U. S. Geol. genus Whittleseya and their systematic rela- Survey Prof. Paper 210-B, pp. 17-28, Washing- tions. Ottawa Naturalist, vol. 15 pp. 98- ton. (4), 110. Renault, Bernard, 1896, Bassin Houiller d'Au- , 1903, of fossil plants recorded tun et d'Epinac. Etudes des Gites Mineraux de Summary from the upper Carboniferous and Permian La France, fasc. IV, atlas 1893; text. formations of Kansas. U. S. Geol. Survey, , 1902, Note sur quelques Micro et Macro- Bull. 85-117. spores Fossiles. Soc. d'Histoire Nat. d'Autun 211, pp. Whittlesey, Charles, 1849, Description of a Bull., vol. 15, pp. 67-118. coal plant supposed to be new. Am. Jour. Sci., ScHOPF, J. M., 1938, A significant collection of ser., vol. 375-377. American coal balls. Chronica Botanica IV, pp. 2d 8, pp. 184-185. Wilson, C. L., 1937, The phylogeny of the sta- men. Am. Jour. Botany, vol. 24, pp. 686-699. , 1938, Spores from the Herrin (No. 6) coal bed in Illinois. Illinois Geol. Survey Rept. Inv. Wodehouse, R. p., 1935, Pollen grains. Their No. 50, pp. 1-74. structure, identification and significance in sci- medicine. Pp. 1-574, McGraw-Hill, , 1939, Medullosa distelica, a new species of ence and the Anglica group of Medullosa. Am, Jour. Bot- New York. any, vol. 26, pp. 196-207. Zimmerman, Walter, 1930, Die Phylogenie der Fischer, , 1941, Mazocarpon oedipternum and sigillar- Pflanzen. Pp. 1-454, Gustav Jena.