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.     

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.     

A new species of the marattialean fern Scolecopteris (Zenker) Millay from the uppermost Permian of Guizhou Province, south-western China

Several isolated marattialean synangia and sporangia are reported from coal balls collected from Coal Seam No.1 (C605) in the uppermost Permian Wangjiazhai Formation in Guizhou Province, south-western China. The synangia are radially symmetrical with diameters between 0.8 and 1.2 mm and are 1.7 mm long, consisting of 3–4 elongate sporangia that are fused basally, free distally and possess a pointed apex. The outer-facing sporangial wall is 4–5 cells thick and conspicuously differentiated. Spores are trilete, have a granular ornamentation and are nearly round equatorially with a diameter of 55–60 µm. Comparisons with other anatomically preserved Palaeozoic marattialean synangia from the Euramerican and Cathaysian floras permit their assignment to the genus of Scolecopteris (Zenker) Millay. In this species the thick, outer-facing sporangial walls and large trilete spores are features consistent with those of the Oliveri Group within Scolecopteris , a group that has previously been considered primitive within this genus. Distinctions from all other previously recognized species within the Oliveri Group lead to the creation of a new species, S. guizhouensis sp. nov. This species is the youngest of the reported species of Scolecopteris recognized from the Euramerican and Cathaysian floras, and provides important evidence on the organization of marattialean ferns from the Upper Permian strata of south China.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 151 , 279–288.     

A marattialean fern,Scolecopteris libera n. sp., from the Asselian (Permian) of Inner Mongolia,China

Scolecopteris libera n. sp. is established on partial three-dimensionally preserved materials containing both sterile and fertile fronds collected from the volcanic tuff at the top of the Taiyuan Formation at the Wuda Coalfield, Inner Mongolia, China. It is characterized by tripinnate fronds with rachises over 200 mm in diameter; and long lanceolate or falciform pinnules with thick veins. Pinnules are of the pecopterid-type, with those at the base of the ultimate pinnae usually divided into small lobes. Eight to twelve circular synangia are arranged in two rows along the midvein. Synangia are borne on a short pedicel attached to the middle of lateral veins. A synangium is composed of 7–10 fusiform exannulate sporangia with pointed apices. The sporangia are free among each other beyond the base of synangia. In situ microspores of the Cyclogranisporites leopoldii type differ from all other in situ Paleozoic marattialean spores.     

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.     

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.     

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.     

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.     

Aulacotheca collicola n.sp. (medullosaceae) from the early Pennsylvanian of the Illinois basin

Compressed synangia referable to the medullosan pollen organ genus Aulacotheca Halle have been discovered in Early Pennsylvanian sediments from Rock Island County, Illinois, U.S.A. Specimens were recovered from localized shales containing floral elements suggesting an upland environment. Based on synangial size, morphology, sporangial number, and prepollen type, two distinct forms, A. collicola n.sp. and Aulacotheca sp., are recognized. Synangia of A. collicola are 11–17 × 2.5 – 4.0 mm and have four to six sporangia. Free sporangial tips are acutely pointed and dehiscence is through a longitudinal slit to the inside of the synangium. Prepollen averages 181 × 129 μm and has a monolete suture with median deflection. Sexine on proximal and distal surfaces shows narrow, closely spaced, anastomosing inpockets; distal and lateral walls are separated by a deep, encircling fold. Synangia of Aulacotheca sp. are 21–33 × 3.8 – 5.5 mm and have 4–6 sporangia. Distally, free sporangial tips have a narrow extension, giving a mucronate appearance. Features of these species suggest that greater morphological diversity in synangial and pollen structure occurs in Aulacotheca and the medullosan pteridosperms than previously recognized.     

Anatomical Study on the Pedicels of Two Ferns

Pedicel is a stalk connecting sporangia with frond in ferns, and its structure and function are not clear. In this paper, we studied the pedicels of Dryopteris zhuweimingii and Pentarhizidium orientale. We found that the pedicels consist of three lines of cells, and the cell wall can be separated into two layers. The inner layer is secondary cell wall (S1) that spiral and cling to the outer layer. The outer layer is primary cell wall. And when we broke the pedicel into two sections, the inner layer of the cell wall could be pulled out like a spiral belt. This structure may be important to support and protect the sporangia.     

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.     

IDANOTHEKION GEN. N., A SYNANGIATE POLLEN ORGAN WITH SACCATE POLLEN FROM THE MIDDLE PENNSYLVANIAN OF ILLINOIS

Idanothekion glandulosum gen. et sp. n. is a synangiate pollen organ represented by approximately 30 specimens contained in coal balls from the middle Pennsylvanian of Illinois. Each synangium is composed of seven to nine elongate sporangia that are fused laterally for approximately four-fifths of their length, and are radially arranged about, and fused to, a short central column; the central column is restricted to the proximal one-third of the synangium. Distal to the column the sporangia surround a hollow central area. Dehiscence occurred by means of a longitudinal slit along the mid-line of the inner face of each sporangium. The outer walls of the sporangia have a complex histology involving an external epidermis, a middle presumably glandular layer containing scattered enlarged cells, and an inner layer made up of thin-walled parenchyma. Vascular tissue is present in the central column and outer walls of the sporangia. Each sporangium has a prominent, attenuate, multicellular tip. Large numbers of saccate pollen grains similar to those found in numerous fossil and extant coniferophytes as well as some Mesozoic pter-idosperms were produced in each sporangium. Idanolhekion resembles some synangia assignable to Paleozoic members of the Marattiales; however, the new genus compares most closely with pollen organs believed to have been produced by members of the Pteridospermales. It seems most likely that Idanothekion represents the pollen organ of some member of the Lyginopteridaceae that produced pollen of a type which up to now has not been known from Paleozoic seed ferns.     

STUDIES OF PALEOZOIC MARATTIALEANS: NEW SPECIES OF SCOLECOPTERIS (MARATTIALES) FROM THE PENNSYLVANIAN OF NORTH AMERICA

Two new species of the late Paleozoic fern Scolecopteris (Marattiales) are described and their relationships within the genus are discussed. Scolecopteris charma sp.n., from Steubenville, Ohio (Duquesne Coal, Upper Pennsylvanian), is similar to species in the Oliveri group, while S. gnoma sp.n. from Providence, Kentucky (Baker Coal, Middle Pennsylvanian), compares favorably with the Latifolia species group. Scolecopteris gnoma is most similar to S. fragilis but differs in its smaller synangia and spore type. S. charma appears generally similar to S. iowensis because of its large pedicel and histologically undifferentiated walls, but differs in a number of characters such as vasculature and spore type. Despite its occurrence late in the Pennsylvanian, S. charma is thought to possess a number of primitive character states (large trilete spores, vascularized pedicels, flat pinnules with downturned margins). Using the same criteria for the much older S. gnoma, we note a number of relatively apomorphic character states (small monolete spores, unvascularized pedicels, extended pinnule margins). An outgroup analysis of species-level characters of Scolecopteris gives a better concept of primitive versus derived traits in marattialean and other ferns. Genera in the Paleozoic fern orders Filicales (Ankyropteris) and Zygopteridales (Corynepteris, Musatea) were chosen as outgroups, and the comparisons support suggestions for the polarity of several important characters. Some of these agree with previously proposed evolutionary polarities based on the geological occurrence of marattialean ferns.     

A NEW LYGINOPTERID POLLEN ORGAN WITH ALVEOLATE POLLEN EXINES

A new lyginopterid pollen organ is described based upon specimens occurring in a single coal ball from the Providence, Kentucky locality. Seven to nine beaked sporangia are fused together at their proximal ends forming a common synangial chamber; synangia are joined together in clusters of two or three. In situ prepollen is similar to Cyclogranisporites and Verrucosisporites sporae dispersae. The thick exine has a lamellate nexine and a prominent alveolate sexine.     

New species of the isolated Psaroniaceous rachis from the Early Permian in China

A new kind of marattialean raches are reported from the coal balls in Coal Seam No.7 in the upper part of the Taiyuan Formation （early Early Permian） from Taiyuan, Shanxi, China and are assigned to the genus Stipitopteris Grand＇Eury （Psaroniaceae）. The present specimens are different from all six reported species of the genus, and are therefore proposed as a new species： Stipitopteris shanxiensis. The raches of the new species are generally dorsi-ventrally flattened. The main raches usually exhibit scales of different forms on their surface. Beneath the epidermis is a zone of parenchymatous cells, some of which contain tannin-like contents. Inside this is a zone of small sclerenchymatous cells. Inward are the ground tissue and vascular bundles. The vascular bundles are continuous and are in two circles： the outer circle assumes a transversely elliptical shape with the gap and pinna trace, and the inner circle assumes a shallow C.shape with inrolled ends. The ground tissue located at the inner side of the vascular bundle is composed of thicker-walled parenchymatous cells. The cells of the ground tissue are vertically elongated in longitudinal sections. Subordered raches are smaller and have simpler structures than the main raches. The parenchyma zone beneath the epidermis is thinner, usually one to two cells wide and the sclerenchyma zone is usually absent. The scales are poorly developed and there is only one C-shaped vascular bundle. The new species is comparable to the crosiers of Psaroniaceae of the Euramerican Flora in some aspects, for example, it has a dorsi-ventrally flattened rachis and scales on the surface of the rachis. However, the other features and the preservative conditions of the present specimens indicate that they are not crosiers, but fully developed or mature raches. The new species is the first well-studied anatomically-preserved rachis of Psaroniaceae from the Cathaysian Flora and bears significance not only in understanding the anatomy and taxonomy of Psaroniaceae in the Cathaysian Flora, but also in the relationship between the Euramerican Flora and the Cathaysian Flora.     

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.     

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.     

A New Species of Scolecopteris from the Upper Carboniferous of Shanxi,China and Its Significance

A new species of the late Paleozoic fern Scolecopteris (Marattiales) is described and its relationship within the genus is discussed. Scolecopteris sinensis sp. nov., from Shanxi (coal balls of Taiyuan formation, upper Carboniferous), is similar to S. saharaensis, however some differences in characters are evidenced, such as pedicel and sporal ornamentation, The anatomy of the sporangium wails, pinule morphology, and general spore type support its association with the Minor group of Scolecopteris. The phylogenetic and ecological magnitude of Scolecopteris sinensis is also discussed.     

Fimbriotheca tomentosa Zhu et Chen- a New Genus and Species from Permian of China and Its systematic position

This paper has described a new genus and species on the basis of two pieces of fertile fern pinna specimens found from Tanshanwan Coal-bearing Formation in Dawangdian, Yangxin district of eastern Hubei Province. One of the specimens described here is an upper part of a pinna which is belt- shaped, entire, about 7 cm in length and 1 cm in breadth, acuminate, tomentose. Its midrib marked with an obvious ventral furrow, rather stout, approaching lmm in breadth. Lateral veins barely distinguishable, bifurcating once, about 12 veins per 1 cm margin of pinna. Spoangium finger-shaped, slightly curved, obtuse, without annulus, about 1.2 mm in length and 0.4 mm in diameter, rough. Synangium ovate or elliptic, 0.8 mm in diameter and 12 mm in length, consists of 5–6 sporangia, bearing 5–6 longitudinal ridges and furrows similar to those of such genera as Acitheca, Asterotheca, Ptychocarpus etc., but not free on upper part. Synangia of this new genus insert in a placenta which was developed by the end of each lateral vein spreading beyond the pinna margin. Synangium slightly contiguous with each other. Judging by the nature of the synangium this new genus probably belongs to the order Marattiales, quite possibly an indirect progeny from the genus Ilfeldia which has a common ancester with the genus Scolecopteris in phylogeny. According to the feature of the fossil plant society, the authors regard the geological age of the Tanshanwan Coalbearing Formation, in which Fimbriotheca tomentosa was found, as Early Upper Permian.     

A new microsporangiate organ from the Lower Carboniferous of the Novgorod Region,Russia

A new species of the genus Telangiopsis, T. nonnae O. Orlova et Zavialova, was described on the basis of a microsporangiate organ from the Lower Carboniferous deposits of the Novgorod Region. The morphology of branching fertile axes, synangia, and sporangia was thoroughly studied. The three-dimensional system of fertile axes branches monopodially; ultimate axes bear numerous connivent bunches of synangia, which consist of three to six basally fused elongated ovate sporangia. The morphology and ultrastructure of prepollen grains were studied, which were extracted from the rock matrix surrounding the sporangia. The two-layered exine includes a well-developed endexine and an alveolate ectexine, with one-three rows of large thin-walled alveolae. The new species was compared with other Early Carboniferous microsporangiate organs.