STUDIES OF PALEOZOIC MARATTIALEANS: AN EARLY PENNSYLVANIAN SPECIES OF THE FERTILE FERN SCOLECOPTERIS

Remains of the fossil Marattiales are very rare in Lower Pennsylvanian sediments. The present report describes a new species of the fertile fern foliage Scolecopteris from the Lewis Creek, Kentucky locality (Lower or lower Middle Pennsylvanian). Scolecopteris conicaulis n. sp. has radial synangia composed of a ring of 4–7 elongate, exannulate sporangia. Most features of the synangia of S. conicaulis were previously hypothesized to be primitive in Scolecopteris based on geologically younger species. Supposed primitive characters include the large synangium pedicel with fiber core, an outer-facing sporangial wall lacking differentiation or zonation, and large spores. The anatomy of the sporangium walls, pinnule morphology, and general spore type support an association with the Minor group of Scolecopteris. The new species is similar in several important features to Scolecopteris (Cyathotrachus) altus, the only other anatomically preserved fertile marattialean known from this early time, and indicates a considerably earlier origin for fertile foliage of this type.     

Fertile and sterile frond segments of the lyginopterid seed fern Feraxotheca

Fertile and sterile frond segments of the lyginopterid seed fern Feraxotheca culcitaus are described. In both the fertile and sterile specimen three orders of frond axes are borne alternately and in the same plane. Antepenultimate and penultimate frond axes are characterized by a C-shaped vascular bundle and numerous canals containing a golden-colored material in the fossilized condition. Synangia with only four sporangia demonstrate radial symmetry; bilateral symmetry is present in larger synangia. Pinnules possess dichotomous venation, with a single vein entering each lobe of the deeply incised lamina. A single canal occurs below each vein, and vein ends have an amplified vascular bundle. Morphologically Feraxotheca compares most closely with the compression genus Crossotheca. The morphology of the vascular bundle in the largest pinna is similar to a Lower Carboniferous specimen of Rhodea.     

STUDIES OF PALEOZOIC MARATTIALEANS: THE MORPHOLOGY AND PROBABLE AFFINITIES OF TELANGIUM PYGMAEUM GRAHAM

Telangium pygmaeum Graham is known from Upper Pennsylvanian coal balls from the Calhoun coal mine (Illinois). The species was described as possessing radial synangia consisting of 3-5 sporangia fused laterally for about f13 their length. Synangia were believed to be sessile and borne terminally or laterally on a branching rachis without lamina. Examination of new coal ball material of the same age indicates that the synangia are borne abaxially on the pinnules of a compound frond with the anatomy of a Psaronius leaf (Marattiales). Synangia are sessile and borne in two rows, one on either side of the pinnule midrib, under the unbranched lateral veins. Synangia are radial, 0.6 mm in diam, and consist of a ring of thin-walled sporangia fused to near their apices prior to dehiscence, but separating on dehiscence to release spores along their inner midline. Spores are spherical, trilete, 30-48 μm in diam, with a granulate ornamentation. The new genus Araiangium is proposed for this material based on the organization of the sessile thin-walled synangia. Araiangium is compared with other marattialean genera with sessile synangia (Acaulangium, Acitheca), and with the pedicellate synangia of various species of Scolecopteris. Criteria used in the delimitation of genera in Paleozoic anatomically preserved marattialean fertile foliage are discussed.     

Anatomy of a New Species of Scolecopteris (Marattiales) from Early Stage of Early Permian in China

Scolecopteris Zenker, a kind of anatomically-preserved fertile foliage of Late Paleozoic Marattiales, has been well studied in Euramerican Flora. It is composed of 28 species which can be divided into four forms (groups) mainly based on modified or umodified pinnules, the variation of the outer facing sporangial walls, and with or without a prominent central parenchyma area. In contrast, Scolecopteris Zenker in Cathaysian Flora has been poorly studied so far, and only one species S. sinensis Zhao, was reported in 1991 which was considered as a member of Minor Group. The paper reports a second species of Scolecopteris, i.e.S, shanxiensis sp. nov., which differs from the above four groups in that its outer facing wall of the sporangia is thick at the base and top (2 ~ 3 layers of cells), and a little thinner ( 1~2 layers of cells) at the midlevel of the synangia. So a new group, Shanxiensis group, is set for the new species. The other characteristics of Shanxiensis group is comparable with Minor group. The new species comes from the coal balls in Coal Seam No. 7 in the upper part of Taiyuan Formation (early Early Permian) from Taiyuan, Shanxi, China. The identification of Scolecopteris shanxiensis sp. nov. :The fertile pinnule probably peeopterids, 5.5 ~ 6.0 mm in length and 2.0 ~ 2.2 mm in width. The lateral extensions of the lamina of the pinnule bend abaxially and above the synangia. The synangia arrange along the sides of the midrib of the pinnnle and there are about 10 synangia in each row. The synangium is elliptical in longitudinal section and radial in cross section, 0.7 ~ 0.8 mm in height and 0.6 ~ 0.7 mm in diameter. Each synangium has 5-7 (mostly 6) fusiform sporangia fused at the base and attached to the top of the synangial pedicel. The outer facing wall of the sporangia consists of 2~3 layers of cells at the base and becomes thinner at the midlevel (1~2 layers of cells), and at the top of the synangia the wall become thicker again. The cells of the outer facing wall of the sporangia are elongate in the longitudinal sections. The lateral and inner facing walls of the sporangia are one cell thick. The synangial pedicel is small. Spores in situ are small, generally 11~14 µm in diameter, spherical or rounded-triangular, trilete and smooth-walled.     

A new late Westphalian fossil marattialean fern from Nova Scotia

Sydneia manleyi gen. et sp. nov. is based on part of a fertile frond from the upper Westphalian D of the Sydney Coalfield, Nova Scotia, Canada. It has small synangia composed of laterally fused sporangia that are elongate and with a circular cross-section. The sporangia yielded variably sized monolete and trilete spores with laevigate and microspinate ornamentation; intermediate forms were also observed. The spores can be correlated with the sporae dispersae species Latosporites minutus , Punctatosporites oculus and Laevigatosporites minimus . Size distribution of the spores is variable and highly skewed, suggesting heterogeneity of the spores within the sporangium. Spore ultrastructure indicates that the fossil is part of a fern, and the morphology of the spores and synangia indicate marattialean affinities.  © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society , 2003, 142 , 199–212.     

Rhacophyton from the Upper Devonian of West Virginia

A new species of Rhacophyton, R. ceratangium , is described from Upper Devonian rocks of West Virginia, U.S.A.; this is synonymous with R. incertum (Dawson) Krausel and Weyland but reasons are cited to indicate that the latter species name is not appropriate.
The collections include: stems up to 2 cm in diameter bearing bipinnate, non-laminate vegetative fronds; abundant well preserved fertile fronds that show clearly the distinctive morphology of their sterile and fertile pinnae; fragments of axes with woody tissues petrified.
The sporangia are particularly distinctive with their long slender tip; they dehisced longitudinally and contained several hundred spores; all available evidence indicates that the plant was homosporous. All petrified axes have a slender bar-shaped strand of primary wood swollen at either end and surrounded by strongly developed secondary wood consisting of scalariform tracheids and rays.
R. ceratangium is closely related to the Belgian R. zygopteroides Leelercq. A comparison with other Devonian and Carboniferous pteridophytes suggests that Rhacophyton is probably a primitive member of the Progymnospermopsida or immediately ancestral to that group.     

Two new species of the pinnate microsporophyll Pramelreuthia from the upper Triassic of the southwestern United States

Two new species of the enigmatic gymnosperm microsporophyll Pramelreuthia, found in the Upper Triassic Chinle Formation at five localities in the southwestern United States, provide significant new evidence on key morphological characters of the genus and extend its known geographical range. These new fossils also demonstrate that the genus was polytypic and reveal the plant megafossil sources for several common and geographically widespread dispersed Upper Triassic microfossil taxa. The genus Pramelreuthia, which until this study was known only from a single specimen from the Upper Triassic of Austria, is a planar pinnate structure consisting of a slender naked axis bearing stalked synangia in opposite to subopposite pairs. Synangia of all three species of Pramelreuthia are oval to subrectangular in lateral view and are composed of two adpressed flattened valves each of which contains up to 20 or more elongate, subcylindrical, tapered sporangia that bear nonstriate bisaccate pollen. Pramelreuthia yazzi sp. nov. is slightly smaller than the type species P. haberfelneri, and its synangia contain pollen generally similar in morphology and size to several species of the dispersed pollen taxon Pityosporites, including P. chinleana, P. oldhamensis, and P. devolvens. Pramelreuthia dubielii sp. nov. is much larger than the other two species; its synangia contain pollen similar to the dispersed pollen species Protodiploxypinus americus.     

DIMENSIONAL CORRELATIONS IN DEVELOPING SELAGINELLA SPORANGIA

With length of sporangia as a developmental index, the growth relationships of sporangia during differentiation were studied in strobili of Selaginella bigelovii. The strobili usually contain two rows of megasporangia and two rows of microsporangia with a mega- opposite a microsporangium at each node. Prior to the sporocyte stage a sporangium in a megasporangiate row is larger and elongates more rapidly than a sporangium opposite it at the same node in a microsporangiate row. The number of sporogenous cells is similar in sporangia of the same length from both rows until cell multiplication ceases in sporangia of the megasporangiate row, while it continues in sporangia of the same size in the microsporangiate row. The observed growth differences between sporangia of the micro- and megasporangiate rows are interpreted as events in the differentiation of two sporangial types.     

CALLANDRIUM CALLISTOPHYTOIDES,GEN. ET SP. NOV., THE PROBABLE POLLEN-BEARING ORGAN OF THE SEED FERN,CALLISTOPHYTON

A new genus of pteridosperm pollen organ is described from Pennsylvanian age coal balls of Illinois. Individual sporangia are grouped into radial synangia which are borne in opposite pairs on the abaxial surface of slightly modified pinnules. Sporangia contain monosaccate pollen with a distinct sulcus, referable to the pollen genus Vesicaspora. Pinnules are borne on a regularly pinnate frond which is circinately coiled when young. At least a large portion of the frond is fertile and possesses anatomical features similar to those of Callistophyton. Phyletic relationships with other pteridosperm pollen organs are discussed.     

A FERTILE SPECIES OF TRIPHYLLOPTERIS FROM THE EARLY CARBONIFEROUS (MISSISSIPPIAN) OF SOUTHWESTERN VIRGINIA

The first occurrence of attached fertile structures to foliage assignable to the form genus Triphyllopteris Schimper is reported from the early Carboniferous Price Formation of southwestern Virginia. Sporangium-bearing branch systems consisting of a basal undivided foliar region and a distal much-divided fertile region are described as a new species T. uberis Skog and Gensel. Ovoid fusiform sporangia, 2.0 mm long and 0.5 mm wide and containing trilete spores, terminate ultimate divisions of the branch systems and collectively form masses up to 4 cm in all dimensions. T. uberis is compared to previously known sporangiate organs of Late Devonian and early Carboniferous age, many of which lack attached foliage. Similarities in the overall branching pattern of many of these non-synangiate, sporangiate organs of early Carboniferous age is noted. The possible mode of dispersal and affinities of the plant bearing T. uberis fertile foliage is discussed.     

Zhutheca Liu, Li et Hilton gen. nov., the fertile pinnules of Fascipteris densata Gu et Zhi and their significance in marattialean evolution

The morphology of the fertile pinnules of Fascipteris densata Gu et Zhi have been subjected to a detailed morphological investigation based on recently collected specimens from the Upper Permian of Yunnan Province, south China. These investigations have revealed that this species possesses synangia of the Asterotheca-type, situated in two or three rows either side of the midrib on a Fascipteris-type pinnule. This arrangement of Asterotheca-type synangia is extremely unusual considering that all other reports of this genus are with a single row of synangia located on each side of the midrib of a pecopteroid-type pinnule. As a consequence of this unique morphological arrangement, a new genus, Zhutheca densata Liu, Li et Hilton gen. et comb. nov. has been created to distinguish this material from other specimens of the Asterotheca and Fascipteris types. The structure and arrangement of the fertile pinnule of Zhutheca are compared with other Palaeozoic and Mesozoic marattialean taxa with which it shares certain features of its morphology. In addition, the stratigraphic, evolutionary and phylogenetic significance of Zhutheca are considered in detail.     

Paleozoic seed fern pollen organs

Paleozoic pollen organs exhibit numerous morphological forms that have been arranged in categories based on their probable organization. Progymnosperm ancestors are characterized by three dimensional branching systems bearing pairs of terminal sporangia. Early Mississippian examples of seed fern fertile branches appear little modified from the progymnosperms. These pteridosperm microsporangia are nonsynangiate and thin walled with longitudinal dehiscence. By Upper Mississippian time all forms show sporangial clustering into large or small groups, with several taxa exhibiting radially symmetrical synangia. In the Lower Pennsylvanian all pollen organs are synangiate and appear to consist of a uniseriate ring of sporangia that either surround a central hollow, or are bilaterally flattened. Sporangial dehiscence in all forms is longitudinal and toward the center of the synangium. In bilateral synangia with no central hollow, the sporangia either separate laterally or effective dehiscence areas are restricted to the free apical portions of the sporangia. Callistophytacean synangia resemble the lyginopterid type, but are abaxial on laminar foliage. This family is thought to have evolved from the lyginopterids during the Early Pennsylvanian. Middle Pennsylvanian medullosan pollen organs are all radial and may be solitary, aggregated into groups, or fused into a large compound synangium. Several pollen organ types are reinterpreted, and the possible evolutionary relationships among the various Paleozoic pollen organ forms are discussed based on synangial organization, patterns of frond branching, and pollen or prepollen morphology.     

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.     

STUDIES OF PALEOZOIC MARATTIALEANS: THE MORPHOLOGY AND PHYLOGENETIC POSITION OF EOANGIOPTERIS GOODII SP. N.

Eoangiopteris goodii sp. n. is described from Upper Pennsylvanian coal balls from Ohio (Shade locality) containing isolated pecopterid pinnules approx. 7 × 9 mm that bear up to 20 linear synangia on the lower surface. The synangia extend at right angles from the midrib to the downturned pinnule margins and measure 2.0–3.5 mm in length. Individual synangia are compact and are composed of 10–19 sporangia that have their bases embedded in an elongate parenchymatous pad. In longitudinal section sporangia measure 0.4 × 2.0 mm and have acute elongate, curved apices. Spores average 70 μm in diam and are most similar to the dispersed spore genus Verrucosisporites. Eoangiopteris goodii differs from the generitype E. andrewsii Mamay in its greater size, pinnule histology, and spore type. Sporangium wall complexity and spore type of the two presently known species of Eoangiopteris are considered to be at about the same evolutionary level as the more primitive species of Scolecopteris. Construction of the synangia in Eoangiopteris is different from that of Scolecopteris and indicates that at least two evolutionary lines are recognizable within the Pennsylvanian Marattiales.     

A NEW SPECIES OF ZOSTEROPHYLLUM FROM THE EARLY DEVONIAN OF NEW BRUNSWICK

A new species of Zosterophyllum, Z. divaricatum Gensel, is described from the late Early Devonian (Emsian) of northern New Brunswick, Canada. It is a Platyzosterophyllum type, consisting of slender sometimes bifurcating axes with laterally borne sporangia oriented to one side of the axis. The species is distinctive in that axes bifurcate within fertile regions and in sporangium shape and attachment. Aspects of the morphology of axis and sporangium cuticle, tracheids, and spores are presented and considered in relation to comparable features in other Zosterophyllum species. Associated vegetative axes exhibiting H- and K-branching patterns and also cuticular features similar to the fertile specimens are described and it is suggested that they may represent parts of the same plant. Zosterophyllum divaricatum is most similar to Z. llanoveranum, Z. fertile, and Z. spectabile, and also resembles Rebuchia ovata to some extent. Z. divaricatum offers considerable information on variation within one species concerning sporangium shape, attachment, and distribution and expands the known diversity of Platyzosterophyllum types.     

CALAMOPHYTON PRIMAEVUM: THE COMPLEX MORPHOLOGY OF ITS FERTILE APPENDAGE

Although holotype material of Calamophyton primaevum Kläusel and Weyland has not been available since the Second World War, two fertile specimens of that species are in the personal collection of Professor H. Weyland. The purpose of this paper is to disclose the complexity of the organization of the fertile appendage. Formerly it was believed to consist of one segment that had dichotomized once and that had borne two pendulous sporangia, one at each branch. Numerous degagements of sporangia have revealed a complex morphology, consisting of one main segment divided into two secondary segments. Each supports three recurved side stalks which in turn bear 2 sporangia, a total of 12 sporangia. Each secondary segment terminates in two elongated projections. The morphology of the fertile organs is compared with that of two other species, C. bicephalum Leclercq and Andrews and C. forbesii Schopf. Great similarity of organization exists between C. primaevum and C. bicephalum. The possible synonymy of these two species is discussed.     

Observations on Nothia aphylla Lyon ex Høeg

Naked branched axes associated with sporangia, originally described by Kidston and Lang (1920) as the probable fertile region of Asteroxylon mackiei, were later shown by Lyon (1964) to belong to an unknown plant which he named Nothia aphylla. The name was validated by Høeg in 1967. Nothia aphylla is described here in greater detail from new material collected from the Rhynie locality. The sporangia are lateral in terminal branched spikes. Their arrangement ranges from spiral to semiverticillate. The fertile axes terminate in clusters of 2–5 sporangia. The stalked sporangia are rather reniform with a distal transversely-extended dehiscence slit. Systematically Nothia has similarities to both Zosterophyllophytina and Rhyniophytina.     

Re-examination of specimens attributed to Sawdonia curstipa Wang and Hao (zosterophyll) from the Middle Devonian of Xinjiang, China

Specimens previously attributed to Sawdonia curstipa were re-examined. Some of the specimens are transferred to Serrulacaulis cf. S. furcatus based on axial morphology. Other specimens, including fertile axes with one or two rows of sporangia with curved stalks and sterile axes with cone-shaped spines covering the surface, are of uncertain assignment due to poor preservation. The nomenclature problem of Sawdonia custipa is also noted.     

Gumuia gyzzata A New Plant from the Lower Devonian of Yunnan,China

A new genus and species, Gumuia zyzzata is found in the Posonchong Formation of the Lower Devonian (Siegenian) from Wenshan district of Yunnan, China. It has both lateral and terminal sporangia. Successive sporangia develop on alternate sides of short axes near the hases of preceding sporangia, producing a zigzag fertile organization. The author supposes that it is a sympodium Opposite sporangia are suppositionally referred to the result from condensation of the axis between alternate sporangia. The new plant is tentatively referred to a putative zosterophyll.     

Fertile pinnules of Danaeites rigida Gu and Zhi (Marattiales) from the Upper Permian of south China

Recently collected specimens of Danaeites rigida Gu and Zhi from the Upper Permian of south China have been subjected to detailed morphological investigations in order to reveal features of their fertile pinnules. The specimens are preserved as compression/impressions and possess pecopteroid-type pinnules with a single row of synangia on either side of the pinnule midvien. Individual synangia are bilaterally symmetrical, sessile, and their bases are embedded in the tissues of the pinnules. Synangia possess 18–24 sporangia that are laterally fused to one another throughout their entire length. Sporangial dehiscence is through a longitudinal slit and sporangia contain trilete spores with a granular ornamentation, referable to the dispersed spore Cyclogranisporites. This combination of characters is unique in specimens preserved by compression/impression although they are similar to those known in permineralized marattialean fertile fronds. However, anatomical details salient to the identification of these permineralized taxa are not identifiable in impression/compression fossils such as Danaeites. The taxonomic and phylogenetic implications of these findings are considered in detail and we conclude that Danaeites has closer links with Marattia than with Danaea.