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.     

Una nueva especie de Weltrichia (Bennettitales) del Jurásico Medio de la Formación Tecomazuchil (Oaxaca, México)

A new species of Weltrichia (Williamsoniaceae: Bennettitales) is described from the Middle Jurassic of Oaxaca. The specimens come from the Tecomazuchil Formation in the Ayuquila region, at the border between the Oaxaca and Puebla states. Fossils are preserved as impressions and compressions, in a fine-grained sublitharenite sequence deposited in a fluvial environment. Preserved diagnostic characters include: large size; a cup-shaped receptacle showing seven radially arranged and basically fused microsporophylls bearing synangia. Microsporophylls are ornamented with longitudinal striations and fine brittled hairs on the edge of their wide base, and taper into a narrow distal tip. In the adaxial part of the microsporophylls seven to nine synangia are observed. These characters differentiate the new species Weltrichia mixtequensis from all previously recorded species from Mexico or elsewhere. The presence of this new species in the Middle Jurassic strata of the Ayuquila region add to the scarce fossil record of microsporangiate structures in the Jurassic flora of Mexico.     

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.     

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.     

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.     

Morphogenesis of Male Sporangiophores of Zamia amblyphyllidia D. W. Stev.

Abstract: Morphology, development and anatomy of the male cones of Zamia amblyphyllidia are studied here to amass additional information to develop a more convincing concept of the evolution of seed plants. The male sporangiophores of the cycads are usually regarded as simple sporangiophores with synangia on the abaxial side. Our developmental study of the male sporangiophores of Zamia amblyphyllidia, by scanning and light microscopy, suggests that the sporangiophores are pinnate, with synangia on reduced leaflets. This indicates that a significant difference between female and male sporangiophores in cycads, as previously stated, does not exist. Comparisons of male sporangiophores of cycads with those of conifers show that they are not homologous. Rather, the synangia of the cycads may better be homologised with the radial synangia groups in some pteridosperm taxa. Although several authors assume that the cycad precursor displayed entire, fertile and sterile leaves, our interpretations of the male sporangiophores indicate that cycads originated from a pinnate pteridospermous ancestor with radial synangia groups. These hypotheses may point to the Medullosaceae, although this remains to be substantiated.     

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.     

AN UNUSUAL FOSSIL FRUCTIFICATION FROM THE JURASSIC OF OAXACA,MEXICO

A fructification with unusual branching arrangement, Perezlaria oaxacensis gen. et sp. nov., is described from the Middle Jurassic Zorrillo Formation of Oaxaca, Mexico. The sporangial heads are similar to the pollen-bearing organs of several Mesozoic pteridosperms. The association of P. oaxacensis, as well as some isolated organs resembling the synangia of Caytonanthus, with glossopteroid foliage is noted.     

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.     

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.     

本内苏铁类雄性生殖器官Weltrichia属一新种

报道了本内苏铁类雄性生殖器官Weltrichia属的一个新种--Weltrichia daohugouensis sp.nov.,标本发现于内蒙古宁城山头乡道虎沟村附近的中侏罗统海房沟组.它是一个分离保存的本内苏铁类单性雄球花(球穗花序),在侧向压缩的平面上展开,呈扇形.基部球花梗未保存,下部由11个窄楔形的裂片融合成漏斗状或杯状,上部裂开成数目相等的游离的小孢子叶.每个小孢子叶的上部有两列花粉囊.文中对新种进行了详细地描述和讨论.并对W.huangbanjigouensis Su et Zheng的鉴定特征进行了修订.     

New male reproductive organs of gymnosperms Permotheca colovratica sp. nov. from the Lower Permian of the Ural Mountains

A new species of male gymnosperm reproductive organs, Permotheca colovratica sp. nov. from the upper part of the Kungurian Stage (Lower Permian, Irenian Horizon, Koshelevskian Formation) of the Middle Cis-Urals and from the Kazanian Stage of the southern Cis-Urals and Volga River Basin, is described. These organs are rosette-like synangiate aggregations of microsporangia consisting of four sporangia fused at their bases. The adaxial surface of the synangia has a disc of attachment. The in situ pollen grains are of Falcisporites type. The morphologically similar genera Falcisporites Leshik emend. Klaus, Alisporites Daugherty emend. Nilsson, and Vesicaspora Shemel emend. Wilson et Venkatachala are analyzed. The morphogenetic trend in the evolution of the androphores Permotheca is discussed.     

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.     

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.     

Diversity and significance of late cretaceous permineralized plant remains from Hokkaido,Japan

Middle to Late Cretaceous permineralized plants hitherto described from Hokkaido, Japan are summarized. The fossil flora comprises fungi, ferns, gymnosperms and angiosperms. Many modern fern families have been recognized including Anemiaceae, Cyatheaceae, Dennstaedtiaceae, Gleicheniaceae Loxsomaceae, Lygodiaceae and Matoniaceae. Gymnosperms are most abundant in the flora. Some recently-found materials are tentatively introduced with brief comments emphasizing their morphological and taxonomical significance. A bisporangiate flower ofCycadeoidella japonica Ogura shows fine internal anatomy and provides evidence that the cycadeoidalean ovule was a cupulate, unitegmic structure. Vascular tracheids in the synangial wall support the evolution of cycadeoidalean synangia from Paleozoic seed-fern synangia. A new gymnosperm female fructification has a thick envelope comparable to an angiosperm carpel around a large seed. The angiosperms contain various morphologies that require further extensive study.     

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.     

Morphogenesis of the reproductive shoots of Welwitschia mirabilis and Ephedra distachya (Gnetales), and its evolutionary implications

For decades, Gnetales appeared to be closely related to angiosperms, the two groups together forming the anthophyte clade. At present, molecular studies negate such a relationship and give strong support for a systematic position of Gnetales within or near conifers. However, previous interpretations of the male sporangiophores of Gnetales as pinnate with terminal synangia conflict with a close relationship between Gnetales and conifers. Therefore, we investigated the morphogenesis of the male reproductive structures of Welwitschia mirabilis and Ephedra distachya by SEM and light microscopy. The occurrence of reduced apices to both halves of the antherophores of W. mirabilis gives strong support for the assumption that the male ‘flowers’ of W. mirabilis represent reduced compound cones. We assume that each half of the antherophore represents a lateral male cone that has lost its subtending bract. Although both halves of the antherophores of Ephedra distachya lack apical meristems, the histological pattern of the developing antherophores supports interpreting them as reduced lateral male cones as well. Therefore, the male sporangiophores of Gnetales represent simple organs with terminal synangia. Although extant conifers do not exhibit terminal synangia, similar sporangiophores are reported for some Cordaitales, the hypothetical sister group of conifers. Moreover, several Paleozoic conifers exhibit male cones with terminal sporangia or synangia. Therefore, we propose that conifers, Cordaitales and Gnetales originated from a common ancestor that displayed simple sporangiophores with a terminal cluster of sporangia.     

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.     

Lunzia austriaca – a bennettitalean microsporangiate structure with Cycadopites-like in situ pollen from the Carnian (Upper Triassic) of Lunz,Austria

Based on new evidence obtained from freshly collected fossils, we here provide an emendation of Lunzia and Lunzia austriaca with an updated interpretation of the organ architecture, function and affiliation. The specimens reveal that Lunzia austriaca is a pollen organ resembling structures assigned to Weltrichia. Lunzia austriaca comprises cup-shaped pollen organs that develop up to about ten, basally fused lobes carrying appendices. The appendices are arranged pairwise and inserted laterally to a rachis-like structure, in a pinnate architecture on their adaxial side and are interpreted as prominent segments or fertile pinnae that bear numerous synangia identifying them as microsporophylls. The nature of the rachis-like structure is not straightforward. The rachis-like structure could either be fused with a bract – this fused structure then constituting the lobes – or itself been modified depicting a foliate appearance. The microsporophylls are narrow at the base and involute apically or with a sterile apical cowl. Numerous synangia with contracted bases are arranged on the inner (adaxial) side of the microsporophylls in long rows. The synangia consist of presumably four pollen sacs (microsporangia), are oblong and dehisce longitudinally. The pollen is monosulcate, elliptical and with a smooth exine (psilate). It is identified as Monocolpopollenites (=Cycadopites); from the size range, it fits best into Cycadopites accerimus. The architecture and the epidermal anatomy of Lunzia austriaca is discussed and its structure is compared with several contemporary bennettitaleans; sterile foliage and ovulate structures most likely associated with Lunzia austriaca are Pterophyllum filicoides and Westersheimia pramelreuthensis, respectively.     

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.