FERAXOTHECA GEN. N., A LYGINOPTERID POLLEN ORGAN FROM THE PENNSYLVANIAN OF NORTH AMERICA

The pollen organ Feraxotheca gen. n. is described from Pennsylvanian age coal balls from the Lewis Creek, Kentucky, locality. The fructifications consist of bilaterally symmetrical synangia composed of a basal pad supporting elongate sporangia that are laterally appressed for the entire length of the sporangial cavities. Sporangial tips extend over the center of the synangium and delimit a small open area, while the bases arise from a parenchymatous cushion that is bounded by short tracheid-like cells. Each synangium is borne on the surface of an expanded pinna tip and is surrounded by a small amount of laminar tissue that envelopes the base of the synangium. Ultimate pinnae are rectangular in transverse section, possess an elliptical vascular bundle surrounded by canals containing a yellow froth-like substance, and have a cortex of elongate cells that radiate from the center of the axis. Sporangia contain small (40–64 μm), radial, trilete spores ornamented by regularly spaced coni or blunt tipped grana. Feraxotheca is compared with the compression genus Crossotheca and some new ideas are advanced concerning the morphology of this compression genus. The obvious differences between Feraxotheca and other lyginopterid pollen organs strongly suggests that the Lyginopteridaceae, as it is currently interpreted, is an unnatural family.     

HALLETHECA RETICULATUS GEN. ET SP. N.: A SYNANGIATE PENNSYLVANIAN PTERIDOSPERM POLLEN ORGAN

A new structurally preserved synangiate pollen organ is described from the upper Pennsylvanian (Mattoon Formation) of southeastern Illinois. The specimen of Halletheca reticulatus gen. et sp. nov. measures approximately 1.5 cm long by approximately 5.0 mm in diam, and consists of five elongate sporangial tubes equidistantly arranged around a solid central column, and embedded in a thin-walled ground tissue. The vascular system consists of five terete bundles characterized by scalariform tracheids. Sporangia are thick-walled and contain pollen of the Monoletes-type. Ultrastructural studies of the pollen grain wall show it to consist of a uniform network of muri which branch and re-unite to form small lumina. A comparison of the ultrastructure of the pollen grain wall of the new fructification is made with the wall organization found in similar pollen of Dolerotheca. Relationships between the new taxon and other presumed seed fern pollen organs differing in preservation mode are discussed.     

ACAULANGIUM GEN. N., A FERTILE MARATTIALEAN FROM THE UPPER PENNSYLVANIAN OF ILLINOIS

Material described by Graham as Cyathotrachus bulbaceus is believed to represent a new genus that is a common constituent of Upper Pennsylvanian coal balls. The sessile synangia of Acaulangium gen. n. are borne in a row on either side of the pinnule midrib and are composed of four to six short, tapering, laterally appressed sporangia. The sporangia have extended tips which curve over the inside of the synangium distally and delimit a small open area inside the synangium. The outer facing walls of the sporangia are two to three cells thick throughout while the inner facing walls are uniseriate. During dehiscence the sporangia separate laterally and spore release results from the rupture of a row of elongate cells along the inner sporangium midline. Among species of Scolecopteris the new genus resembles S. illinoensis and S. minor var. parvifolia but differs in its sessile synangial attachment. The additional parenchyma present between sporangial cavities in the synangia of Acaulangium, and the tendency toward bilateral symmetry suggests an early stage in the evolution of a bivalve synangium such as is present in Marattia.     

PALAEOSTACHYA DIRCEI N. SP., AN AUTHIGENICALLY CEMENTED EQUISETALEAN STROBILUS FROM THE MIDDLE PENNSYLVANIAN OF SOUTHERN ILLINOIS

Equisetalean strobili normally are encountered as disarticulated organs. This condition has necessitated the creation of 12 form genera to accommodate the various morphological architectures and anatomical configurations. Taxonomically useful characteristics, which are discernable in permineralized specimens, are rarely distinguishable in coalified compressions due to their destruction during diagenesis and coalification. Therefore, genera established on the position of sporangiophore-trace origin, such as Schimperia Remy and Remy, are untenable when dealing with coalified compressions. Although the two largest genera of strobili, Calamostachys Schimper and Palaeostachya Weiss, may be synonymous, it is proposed that these form genera be retained when dealing with coalified compression specimens. Each genus provides a particular architectural concept for specimens which may not be assignable to the species level. Calamostachys and Palaeostachya are highly overspeciated genera. It is suggested that characteristics necessary to delimit new species include bract height, degree of bract fusion, disposition of bracts, bract: sporangiophore ratio, number of sporangia per sporangiophore, and sexual status.     

A NEW PTERIDOSPERM MALE FRUCTIFICATION FROM THE MIDDLE PENNSYLVANIAN OF ILLINOIS

Rhetinotheca tetrasolenata gen. et sp. n. is described from a Herrin #6 coal ball from Illinois. It consists of an ellipsoidal cluster of small synangia bearing spores of the Monoletes type. Although the synangia are partially connected to each other by sparse sterile tissue, evidence indicates that the synangia are immature, and it is presumed that they separated and spread apart at maturity. A small portion of a protostelic axis is present near the center of the cluster. Individual synangia consistently contain four sporangial tubes and measure 2.0–3.6 mm long by 0.7–1.2 mm in diam. A conspicuous central columella is present. When compared with compression forms, Rhetinotheca tetrasolenata compares most favorably with Aulacotheca iowensis. On this basis, arguments are advanced disputing the classical concept of whittleseyan fructifications. It is contended that none of them possessed a hollow central cavity as depicted in most reconstructions.     

TRIGONOCARPUS LEEANUS,A NEW SPECIES FROM THE MIDDLE PENNSYLVANIAN OF SOUTHERN ILLINOIS

A new species of Trigonocarpus Brongniart is described from the level of the Herrin (No. 6) Coal (Carbondale Formation, Kewanee Group) at Carterville, Illinois. The seed is three dimensionally preserved by authigenic cementation and exhibits a well preserved nucellar cast, integument and micropylar region. The specimen represents the largest pteridosperm compression-impression seed collected in North America and measures 10 cm from the apex of the micropyle to the chalazal end, and at least 5 cm in breadth. Trigonocarpus leeanus sp. n. is compared to the remaining forty-three taxa within the genus, and specifically with Trigonocarpus grandis Lesquereux, the one species with dimensions approaching it. An emended diagnosis, with designation of a lectotype, is presented for Trigonocarpus grandis. Correlation of the features displayed by Trigonocarpus leeanus sp. n. and the petrified taxa within Pachytesta Brongniart is attempted.     

VALLITHECA VALENTIA GEN. ET SP. NOV., PERMINERALIZED SYNANGIA FROM THE MIDDLE PENNSYLVANIAN OF OKLAHOMA

Vallitheca valentia gen. et sp. nov. is a permineralized, synangiate fructification of probable seed fern affinities from the Wewoka Formation (Desmoinesian) near Ada, Oklahoma. Synangia are oblong to pyriform, average 1 cm long, and contain 32 to 48 tubular sporangia embedded proximally in ground tissue. The sporangia are arranged within the synangia in a unique pattern: a ring of peripheral sporangia dehisces toward the center of the synangium and a central group of sporangia dehisces outward. This unique arrangement is unlike that of any currently recognized group.     

THE VEGETATIVE ANATOMY OF SCHOPFIASTRUM DECUSSATUM FROM THE MIDDLE PENNSYLVANIAN OF THE ILLINOIS BASIN

Schopfiastrum decussatum, a monostelic pteridosperm, has been recovered from Middle Pennsylvanian age coal balls from six localities within the Illinois Basin. Additional features of stem anatomy include the presence of horizontal sclerotic plates in the inner cortex, secretory ducts in the inner and outer cortex, and adventitious roots. The primary xylem is interpreted as bilobed, emitting massive leaf traces in a distichous manner. Five orders of frond members are described, including pinnules. All orders of the frond contain secretory ducts and tissues characteristic of Schopfiastrum stems. The rectangular, bilobed protostele, and method of leaf trace origin indicate that Schopfiastrum is more closely related to certain lower Carboniferous seed ferns than to contemporary Pennsylvanian pteridosperms.     

FURTHER OCCURRENCES OF SPENCERITES FROM THE MIDDLE PENNSYLVANIAN OF KANSAS AND ILLINOIS

New specimens of Spencerites moorei add knowledge of its sporophylls and method of sporangial attachment. The sporophyll consists of a slender pedicel which expands at its distal end into a fleshy, peltate, diamond-shaped head which bears a presumably fleshy lamina. The sporangium is attached through most of its length to the adaxial surface of the pedicel rather than distally as in S. insignis. It is suggested that the distal attachment shown in S. insignis may be derived through a phyletic shift from the pedicellate position. Additional specimens of Spencerites provisionally assigned to S. majusculus are also recorded. The spores are bilateral, monolete, and shaped like quadrants of a sphere. Two prominent wings extend along the two contact faces and the monolete mark is prominently raised, thus imparting a three-winged appearance to the spore. The axis consists of an exarch protostele and a cylinder of thick-walled outer cortex.     

RHABDOXYLON AMERICANUM SP. N., A STRUCTURALLY SIMPLE FERN-LIKE PLANT FROM THE UPPER PENNSYLVANIAN OF ILLINOIS

A new species of the genus Rhabdoxylon Holden (1960), an anatomically simple plant of presumed fern or fern-like affinities, is described from a coal ball petrifaction found in the Upper Pennsylvanian of southern Illinois. The new species, R. americanum, is based upon five specimens consisting of stems bearing spirally arranged leaves and numerous randomly distributed adventitious roots. The haplostelic stems branch by equal dichotomies and bear foliar traces which arise as unequal dichotomies of the stele. Leaf traces possess a circular outline in cross section and one adaxial protoxylem strand. The characteristics of exclusively primary tissues, diarch adventitious roots, centrarch haplosteles with simple scalariform pitting, and the nature and arrangement of the leaf traces, suggest that Rhabdoxylon represents a fern or fern-like plant rather than a representative of the Rhyniophytina or Trimerophytina. At present it is not possible to determine whether the simple structure of Rhabdoxylon has come about through phyletic reduction or represents a primitively simple condition.     

AN ANATOMICALLY PRESERVED POTONIEA WITH IN SITU SPORES FROM THE PENNSYLVANIAN OF ILLINOIS

Specimens preserved in coal balls collected from the Herrin (No. 6) Coal in Illinois reveal the internal structure of the pteridosperm pollen organ long known as the compression fossil, Potoniea. Cylindrical sporangia are concentrically arranged in a campanulate body and the end of each sporangium projects freely from the distal face of the organ. Pollen is trilete and without a distal germinal aperture. The exine is structureless and has a separable, perine-like layer adorned with orbicules.     

PHYSOSTOMA CALCARATUM SP. NOV., A TENTACLED SEED FROM THE MIDDLE PENNSYLVANIAN OF KANSAS

A new species of Physostoma is described from Kansas coal balls of Middle Pennsylvanian age. The seed is small, ovoid, and radially symmetrical. The integument consists of 6–10 rounded segments, fused in the lower half of the seed but free in the upper. Distinct spurs are formed by the segments near the base of the seed. The integument is essentially non-sclerified and has a distinct blow-off epidermis. Each segment is supplied by a single vascular trace. The pollen reception mechanism consists of a short cylindrical salpinx, a bell-shaped lagenostome, and a shallow plinth. A central column is present within the salpinx. It is suggested that the Upper Carboniferous seed genera Conostoma and Physostoma may have been derived from the Lower Carboniferous genera Salpingostoma-Euryostoma and Genomosperma-Hydrasperma, respectively.     

A NEW STRUCTURALLY PRESERVED PENNSYLVANIAN CORDAITEAN POLLEN ORGAN

Permineralized specimens of the pollen organ Gothania (Hirmer) consist of a primary axis bearing pollen cones in the axils of bracts that are four ranked. The bilaterally symmetrical primary axis consists of a uniform parenchymatous pith surrounded by up to 15 endarch-mesarch axile bundles. The cortex is two-parted and consists of an inner zone of subepidermal fibers. Bract traces arise from the ends of the ellipsoid stele. Traces to the cones are derived from the open ends of the stele, and at higher levels form a centrarch-medullated vascular system. Each pollen cone is constructed of up to 25 helically arranged scales, each vascularized by a single trace that may dichotomize. Scales are elongate and broad, and histologically composed of mesophyll parenchyma and fibrous layers. Stomata are restricted to the adaxial surface between rows of fibers. Up to 10 distal scales may be fertile, each with 4 elongate pollen sacs at the tip. Large monosaccate grains of the Felixipollenites-type are densely packed in each pollen sac. The well-preserved specimens of Gothania provide an opportunity to compare this genus with pollen cones assigned to the genus Cordaianthus, and to relate isolated plant organs to the Cordaitales.     

ETAPTERIS LECLERCQII SP. N., A ZYGOPTERID FERN FROM THE PENNSYLVANIAN OF NORTH AMERICA

The zygopterid fern Etapteris leclercqii sp. n. is described from Lower Pennsylvanian age coal balls from the Lewis Creek, Kentucky, locality. Isolated petioles extend up to 15.0 cm in length and 5.0 mm in diam; no lateral axes have been observed. The clepsydroid-shaped petiole trace is characterized by lateral arms that sharply taper and by the production of peripheral loops prior to the separation of pinna traces from the stele. Large irregularly shaped multicellular hairs are randomly scattered over the surface of the petioles. When compared with other currently recognized zygopterid ferns, E. leclercqii appears most similar to Metaclepsydropsis duplex. Based on the configuration of the leaf trace and the occurrence of peripheral loops, it is suggested that E. leclercqii may represent the most primitive species of the genus known to date.     

IBYKA AMPHIKOMA,GEN. ET SP. N., A NEW PROTOARTICULATE PRECURSOR FROM THE LATE MIDDLE DEVONIAN OF NEW YORK STATE

Ibyka gen. n. is described from late Middle Devonian compressions and petrifactions collected in eastern New York State. It is a robust plant of which three orders of branching and ultimate appendages (leaves) are known. The latter dichotomize up to five times, are arranged spirally on all orders of branching, are three-dimensional, and all orders are terete in cross section. Fertile appendages, homologous with the sterile, are terminated by sporangia. The protostele has five or six arms, the maturation is mesarch, and the protoxylem disintegrates leaving lacunae at the tips of the arms. Traces to appendages are terete and arise spirally from the tips of the arms. The primary xylem consists of tracheids only, the phloem of thin-walled cells and probable tanniniferous cells. The cortex consists of parenchyma and groups of sclereids. Secondary xylem is lacking. Ibyka is placed in a new order, Ibykales, close to the Hyeniales (protoarticulates) and to the Pseudosporochnales all three of which probably evolved from Trimerophytina.     

POROSTROBUS NATHORSTII SP. NOV.: A NEW SPECIES OF LYCOPSID CONE FROM THE EARLY PENNSYLVANIAN OF ILLINOIS

Thirty-one specimens of a small megasporangiate lycopsid cone referable to the genus Porostrobus Nathorst and abundant associated dispersed megaspores have been collected from Early Pennsylvanian strata in the Allied Stone Company quarry, Milan, Illinois. Based on other elements in the flora, the deposit is considered to be part of the Morrowan Caseyville Formation and probably of Namurian age. This is the first reported occurrence of Porostrobus in North America and the cones are recognized as a new species, P. nathorstii. The environment of deposition indicates that the cones may have been transported from the parent plant prior to preservation. Cones are preserved as coalified compressions measuring 15–36 mm long by 2.5–7 mm wide, and are characterized by an apical tuft of leaves up to 20 mm long. Sporophylls are spirally arranged on a narrow cone axis, lack a heel or keel, and have a long distal lamina. Sporangia contain a single functional megaspore tetrad. Mature megaspores are 750–1, 150 μm in diameter, have prominent trilete sutures raised to form a gula, and have numerous branched hairs confined to an equatorial band. Megaspores correspond to the dispersed form Setosisporites praetextus (Zerndt) Potonie and Kremp. Porostrobus nathorstii is the only species of the genus described to date that is monosporangiate.     

PHILLIPOPTERIS GEN. NOV.—ANATOMICALLY PRESERVED SPORANGIAL FRUCTIFICATIONS FROM THE UPPER PENNSYLVANIAN OF THE APPALACHIAN BASIN

The discovery of a new type of sporangial fructification in coal balls from the Upper Pennsylvanian of Ohio provides the basis for describing Phillipopteris globiformis gen. et sp. nov. Sporangia are borne terminally on up to two orders of branching axes. Penultimate axes branch pinnately to produce irregularly branched ultimate axes. Sporangial wall cells are of a single type and show no specialization for dehiscence. Spores are radial and trilete, and reminiscent of the sporae dispersae genus Dictyotriletes. Phillipopteris increases our knowledge of diversity among fernlike plants from the late Paleozoic, and shares several features with Sclerocelyphus Mamay.     

SULLITHECA DACTYLIFERA GEN. ET SP. N.: A NEW MEDULLOSAN POLLEN ORGAN AND ITS EVOLUTIONARY SIGNIFICANCE

The pteridosperm (Medullosaceae) pollen organ Sullitheca dactylifera gen. et sp. n. is described from middle Pennsylvanian coal balls. The proximally fused units of the obpyriform compound synangium separate and extend distally as finger-like projections. Each projection contains 4–6 vertically oriented cylindrical sporangia arranged in pairs along the radius of the unit; each unit extends from the outer cover wall toward the center. The distal portion of the compound synangium is hollow as a result of the lateral separation of the centripetally and distally directed synangial units. About 40 tubular sporangia are present in all and dehiscence occurs along a lateral slit in each sporangium. Vascular strands are disposed around the periphery of the organ in addition to a single strand paralleling each sporangium. Two- or three-cell trichomes and stomata are present on the organ surface. Pollen of the Monoletes type is present. A paired row of sporangia in Sullitheca composing a synangial unit is considered the homologue of a paired row of sporangia in the more compact and highly evolved genus, Dolerotheca.