SPORES OF BOTRYOPTERIS GLOBOSA AND BOTRYOPTERIS AMERICANA FROM THE PENNSYLVANIAN

A study of spores from fertile pinnae of Botryopteris from middle and upper Pennsylvanian coal balls from Iowa, Illinois, and Kansas indicates that there are two distinct species, Botryopteris globosa and B. americana. The organization and attachments of fertile pinnae and the sporangial morphology and dimorphism are identical in the two species. Data are given on fertile pinnae dimensions, attachments of six fertile pinnae, spore counts from individual sporangia, and spore morphology. The ornamentation of B. americana spores is verrucate to rugulate with verrucae fusing to a variable extent to form bars and convolute ridges; B. globosa spores are vermiculate or fossulate to densely rugulate with scattered verrucae. Comparisons are made with B. forensis and a re-interpretation of the spore forms of B. forensis is suggested.     

Rotafolia songziensis gen. et comb. nov., a sphenopsid from the Late Devonian of Hubei, China

A sphenopsid from the Upper Devonian (Famennian) Xiejingsi Formation, south-western Hubei Province, China, previously named as various species in Sphenophyllum , Hamatophyton , Bowmanites and Sphenophyllostachys , is now reinvestigated and assigned to a new taxon, Rotafolia songziensis gen. et comb. nov. Its ribbed axes are anisotomous and possess slightly expanded nodes. Lateral axes are inserted at nodes on main axes. Whorls of much divided vegetative leaves are attached at nearly right angles to nodes of basal axes, and at acute angles to nodes of terminal axes. There are six leaves per whorl. The terminal strobilus includes a central axis and verticils of fertile units. Each fertile unit consists of a bract and numerous sporangia. The margin of the elongate-cuneate bract bears a distal and many lateral elongate segments. Clusters of elongate sporangia are abaxially attached to the base of the bract at the same level. The axis has an actinostele, composed of a three-ribbed, exarch primary xylem and radial secondary xylem. Although Rotafolia songziensis closely resembles Hamatophyton verticillatum in axis character, leaf morphology and primary xylem type, they are quite different in strobilar structure. Taxonomically, Rotafolia is placed in the order Sphenophyllales by three well-defined characters: 1) whorled appendages; 2) ribbed protosteles; 3) exarch primary xylem maturation.  © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society , 2005, 148 , 21–37.     

ON THE STRUCTURE OF CALAMOSTACHYS BINNEYANA FROM THE LOWER PENNSYLVANIAN OF NORTH AMERICA

The discovery of specimens of Calamostachys binneyana in Lower Pennsylvanan petrifaction material in North America has provided additional information about the structure of this calamitean fructification. The cones consist of regularly spaced alternating whorls of bracts and sporangiophores. Bracts are fused in a disc except at the margin where the individual units become free. Sporangiophores are inserted at right angles to the cone axis and bear four axially directed sporangia. The vascular system of the North American specimens differs from that in other reports of the taxon in the presence of twelve vascular bundles in the cone axis. Each sporangiophore is supplied by a single vascular trace that departs from one axial bundle. There appears to be no constant relationship between the number of vascular bundles and the number of bracts. Spores are spherical, thin-walled, and of the Calamospora type. Relationships with other structurally preserved members in the genus are discussed in light of the diversity in structure demonstrated by the new specimens.     

VEGETATIVE AND FERTILE STRUCTURES OF CYATHOTHECA VENTILARIA FROM THE UPPER PENNSYLVANIAN OF THE APPALACHIAN BASIN

Permineralized stems, leaves and a fertile structure assignable to Cyathotheca Taylor are described from the Late Pennsylvanian Duquesne Coal of eastern Ohio. The new material, C. ventilaria sp. nov., provides the first evidence of vegetative structures for the genus. Vegetative parts are referred to the fertile fragments based upon distinctive vascular morphology, common histological features, and close association. Stems are up to 5.0 mm in diam and have an apparently endarch dictyostele with scalariform metaxylem tracheids. Secondary xylem consists of tracheids with bordered pitting and uniseriate, parenchymatous rays 1–9 cells high. Leaves are arranged in a 3/8 pattern. They are small, pinnately-lobed, and vascularized by an U-shaped bundle. Distal to divergence, one of the apparent leaf traces becomes radial to resemble the base of a fertile structure. This implies a mode of attachment for the fructification and suggests evidence to interpret its homologies. The fertile specimen consists of laminae that diverge from a short stalk, and bifurcate distally. Laminae bear sporangia 0.6–0.7 mm in diam attached adaxially by vascularized pedicels. Spores average 36 μm in diam and are of the Kewaneesporites type. The combination of features now known for Cyathotheca exclude it from assignment to a currently-recognized major group of vascular plants, thus emphasizing that the Pennsylvanian coal swamp flora included a greater diversity than commonly is interpreted.     

TAXONOMIC CHARACTERISTICS OF SPHENOPHYLLALEAN CONES

The range of variability in the taxonomic characteristics traditionally used to establish genera and species of Sphenophyllum cones is studied from specimens of Bowmanites dawsoni, B. trisporangiatus, B. bifurcatus, Litostrobus, and Sphenostrobus. Taxonomic criteria examined include configuration of the cone stele, number of sporangiophores per bract, anatropous vs. orthotropous sporangium attachment, number of appendages per node, and spore morphology. Because of the large degree of variability observed, these characteristics do not appear to adequately differentiate between the genera Litostrobus and Sphenostrobus, so these genera are combined under Sphenostrobus. A new combination, S. iowensis, is proposed for specimens previously described as L. iowensis, L. paulus, and B. moorei. It is suggested that species currently placed in the genus Bowmanites may represent several distinct natural genera of sphenophyllalean cones.     

“Lycostrobus” chinleana,an equisetalean cone from the Upper Triassic of the southwestern United States and its phylogenetic implications

Detailed study of the cone Lycostrobus chinleana Daugherty shows that the fossil was incorrectly attributed to the Lycopodiales by the author and to the quillworts by Retallack and that it actually should be assigned to the Equisetales. The cone, which occurs in the Upper Triassic Chinle Formation at several localities in the southwestern United States, is ∼2.5 cm wide and nearly 6 cm long and consists of a stout axis bearing whorls of peltate sporangiophores. Each sporangiophore is composed of a slender stalk and a hexagonal disk, which typically bears a single, generally long, lanceolate, forward-directed leaf-like umbo tip on the outer surface and several recurrent sporangia on the inner surface. Small round to oval trilete spores occur in the sporangia. Since the leaf-like umbo tip is similar to the sterile leaves found in certain calamite cones and the recurrent sporangia are equisetalean-like, it appears that the cone may represent a intermediate stage between Calamites and modern Equisetum. According to this hypothesis, the nonbracteate Equisetum cone could have developed from a bracteate calamite cone, through reduction and fusion of the bracts and the sporangiophores, rather than by the loss of whorls of bracts of the Calamites cone as suggested earlier by others. As a result of this study the cone is assigned to the new Equisetalean genus Equicalastrobus and redescribed under the name E. chinleana (Daugherty) Grauvogel-Stamm and Ash, n. comb.     

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.     

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.     

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.     

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.     

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.     

Morphogenesis of leaves and cones of male short-shoots of Ginkgo biloba L.

Although the subject of several studies, the phylogeny of Ginkgo biloba is still ambiguous. Most of the morphological and some palaeontological studies assume a close relationship to conifers, but other palaeontological studies regard the origin of Ginkgo biloba in groups that exhibit a pinnate bauplan like Peltaspermales or Dicranophyllales. This divergence has led to controversial interpretations of male sporangiophores and leaves. Attempting to resolve this, here we have investigated the male cones and leaves of short-shoots by SEM and light-microscopy. Our results indicate that the male sporangiophores are simple structures, and the observed formation of thickened cell walls at the sterile adaxial side of the sporangiophores, similar to the endothecium of the sporangia, gives weak support for a precursor of Ginkgo-sporangiophores that displayed simple male sporangiophores with radial arrangement of the sporangia. Thus, our interpretations of the male sporangiophores of Ginkgo biloba allude to a relationship with Coniferales, Gnetales and Cordaitales and reject a close relationship of Ginkgo biloba with pinnate groups like Cycadaceae, as assumed by some molecular studies. In contrast to previous studies on long-shoot leaves, our results on short-shoot leaves give no indication for a compound character of Ginkgo leaves. Moreover, we infer that Ginkgo leaves could be derived from a simple bauplan, by two modifications of the basic growth pattern of conifer leaves, assuming that the dissection of Ginkgo leaves is secondary. Although more comparative investigations are necessary, our results support a coniferophyte origin of the Ginkgoales.     

A new method for heterokaryon formation in Phycomyces

Summary An efficient method is described for obtaining heterokaryons in Phycomyces by grafting stage I sporangiophores of two strains to one another. The grafts are successful in over 70% of the cases and success may be ascertained after 10 hours. The successful grafts in almost all cases regenerate one or more sporangiophores and sporangia, and about 85% of the regenerates are heterokaryotic.     

A PENNSYLVANIAN CALAMITEAN CONE WITH ELATERITES TRIFERENS SPORES

In 1943 L. R. Wilson described some scattered elater-bearing spores found in a Middle Pennsylvanian coal ball from What Cheer, Iowa, as Elaterites triferens. The spores, averaging 60 μ in diameter, with a trilete scar on the proximal surface and three conspicuous elaters attached to their distal surface, have now been found in a fragment of a cone from the same locality. The cone is similar to Calamostachys in having whorls of sporangiophores, each with four adaxial sporangia, and some secondary xylem at the nodes, but it possibly differs in lacking sterile bracts.     

AN UNUSUAL BOTRYOPTERID SPORANGIAL AGGREGATION FROM THE MIDDLE PENNSYLVANIAN OF NORTH AMERICA

A new fertile species of Botryopteris (Botryopteridaceae: Filicales) is described from four incomplete Middle Pennsylvanian specimens. Fertile pinnae of B. cratis sp. n. consist of branched frond members bearing numerous globose sporangia. Surrounding the sporangial aggregations are larger sterile frond members (0.5-1.5 mm diam). Fertile pinnae are oval in transverse section and possess an eccentrically developed cortex composed chiefly of fibers. Some frond members show the typical botryopterid xylem configuration with three protoxylem strands. Spherical sporangia are loosely aggregated on the smallest pinnae by short, broad stalks. The annulus is band-like, two cells high, and extends transversely across the lower half of the sporangium for approximately half the circumference. Spores are oval, trilete, verrucate, and covered by a thin separable layer. Sporangium morphology is like that of Botryopteris antiqua, but the spores closely resemble those of B. globosa. The new species is unlike previously described fructifications of Botryopteris in exhibiting a small pinna system which surrounds smaller pinnae bearing sporangia in an aggregation. The new form is considered to be less specialized than previously described globosoid forms because the sporangia are much less crowded. Isolated frond members, believed to belong to the new species, have a large central arm in the pinna xylem trace that resembles the Stephanian taxon B. renaultii. Small stems attached to the adaxial surface of frond members are radial, protostelic, centrarch, and have a three-zoned cortex. The inner cortical zone contains large elongate cells with distinctive layered deposits. Stems are covered with uniseriate multicellular hairs on multicellular bases. Stems compare closely with B. mucilaginosa in histological features.     

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.     

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.     

Mucor circinelloides a destructive hyperparasite of Rhizopus nigricans

In vitro studies on hyphal interactions between phyllosphere and phylloplane fungi revealed Mucor circinelloides to be a destructive hyperparasite of Rhizopus nigricans. The mycoparasite penetrated the host hypha and formed sporangiophores and sporangia on different parts of Rhizopus nigricans.     

TETRAXYLOPTERIS SCHMIDTII: ITS FERTILE PARTS AND ITS RELATIONSHIPS WITHIN THE ANEUROPHYTALES

The fertile branching system of Tetraxylopteris is composed of successive “nodes” bearing opposite and decussately arranged, upcurved sporangial complexes. By means of the transfer technique the morphology of the sporangial complex was revealed. It consists of a main stalk which dichotomizes twice producing four major branches. Each of the four branches is further subdivided three times, the subdivisions being arranged alternately and pinnately. The ultimate divisions bear the sporangia singly and terminally. The sporangial complexes decrease in size distally and are more tightly curved at the apex. The sporangia are oblong-oval with an acute apex. The spores are identical to the dispersed spore taxon Rhabdosporites langii, Richardson. They are spherical, trilete and pseudosaccate with a fine granular ornament on the pseudosaccus. They are 75–176 μ in diameter and show developmental stages from young tetrads to separated, fully mature spores depending on the age of the sporangium from which they were obtained. This is the first account of spores in sporangia of Tetraxylopteris. The diagnosis of the genus and species are emended to include the new information and the order Aneurophytales is redefined.     

SPERMOPTERIS,A NEW GENUS OF PTERIDOSPERMS FROM THE UPPER PENNSYLVANIAN SERIES OF KANSAS

Cridland , Arthur A., and John E. Morris . (Kansas U., Lawrence.) Spermopteris, a new genus of pteridosperms from the Upper Pennsylvanian Series of Kansas. Amer. Jour. Bot. 47(10) : 855–859. Illus. 1960.— Spermopteris gen. nov., based upon seed-bearing specimens of the formgenus Taeniopteris, is described from the Lawrence Shale, Pennsylvanian System, of Kansas. The single species S. coriacea (Göppert) comb. nov. is known. Comparison is made with other fertile and supposedly fertile Paleozoic specimens of Taeniopteris and with specimens of T. spatulata from the Rhaetic of Tonkin.