PALEOZOIC LYCOPSID FRUCTIFICATIONS. III. CONSPECIFICITY OF BRITISH AND NORTH AMERICAN LEPIDOSTROBUS PETRIFACTIONS

A study was made of 30 apparently similar microsporangiate cone specimens of the lycopsid fructification Lepidostrobus found in coal balls of Middle Pennsylvanian age from Illinois and Kansas. None of these specimens was a complete cone, but at least 19 were large enough and well enough preserved to provide information regarding variation both within one cone and among several specimens. The data obtained substantiated the original assumption that all 30 specimens represented one species. Attempts to equate this one species with any of the similar, previously described North American taxa, Lepidostrobus coulteri, L. pulvinatus and Lepidocarpon magnificum-microsporangiate form, and the British taxon Lepidostrobus oldhamius, including the forms (α), (β), (γ) and pilosus, revealed that no significant differences existed among any of these taxa. Furthermore, all characteristics described for these taxa were referable to, and well within the range of variation of, the one species here analyzed. Differences among the taxa were found to represent only differences in maturation or normal variation. All these taxa are, therefore, conspecific and are assigned to one species which by priority is named Lepidostrobus oldhamius. The common association of the megasporangiate Lepidocarpon lomaxi with all these miorosporangiate cones, now recognized as representing the single taxon Lepidostrobus oldhamius, is strong evidence for the probability that Lepidocarpon lomaxi and Lepidostrobus oldhamius were produced by the same parent plant species.     

THE ULTRASTRUCTURE OF PALEOZOIC FERN SPORES: I. BOTRYOPTERIS

The spores of four species of the Paleozoic filicalean fern Botryopteris are examined at the ultrastructural level. Spores of B. cratis, B. forensis, B. globosa, and an unnamed species from the Lower Pennsylvanian, are compared on the basis of sporoderm stratification and the presence or absence of a sculptine layer. The species examined differ widely as to the type of reproductive unit in which they are borne and include forms that range throughout the Pennsylvanian. In all species the exine is homogeneous, lacking cavities and lamellae. A thin nexine is present in the Middle and Upper Pennsylvanian taxa, but is absent in the Lower Pennsylvanian spores. Only one spore type (B. cratis) possesses a clearly defined sculptine layer. Features of the sporoderm are compared with those of extant, homosporous pteridophyte spores.     

STIGMARIAN PETRIFACTIONS FROM THE PENNSYLVANIAN OF COLORADO

The designation Stigmaria ficoides is restricted to casts and impressions. Petrifactions of Stigmaria arnoldii sp. n. occur in Pennsylvanian age strata in Trout Creek Pass, Colorado. The rootlet gaps of this species appear narrow and elongate in both cross and longitudinal sections. Rootlet traces are contiguous with the secondary xylem to its outer margin and are surrounded by a small parenchyma sheath in the middle cortex. The outer cortex consists of an inner layer of primary tissue and a relatively thick zone of periderm. S. arnoldii most closely resembles material described as S. ficoides from England. Various stigmarian characters are evaluated with regard to their systematic or ontogenetic significance.     

STEM-ROOT TRANSITION OF AN UPPER PENNSYLVANIAN WOODY LYCOPSID

Anatomically preserved specimens of a woody lycopsid showing the transition from the stem to the rooting region are described from the Upper Pennsylvanian Duquesne Coal of Ohio. Specimens have exarch protosteles that are apparently medullated at distal levels and exhibit abundant secondary xylem. Cortical tissues accompanying the stems have periderm, and show leaf bases or cushions. Although features of the stems are compatible with those of the arborescent Lepidodendrales, the plants have a rounded cormose rooting region, rather than the much-branched and elongated stigmarian system usually associated with the order. Specimens of this type expand our knowledge of the diversity among Paleozoic lycopsids and document the occurrence of representatives with an Isoetes-like base in Pennsylvanian strata.     

STUDIES OF PALEOZOIC FUNGI. I. THE STRUCTURE AND ORGANIZATION OF TRAQUAIRIA (ASCOMYCOTA)

Traquairia is one of the several unusual fungal structures occurring in Pennsylvanian coal balls. Specimens were initially described from European sediments and are now known from the Pennsylvanian of North America. Although Traquairia was originally believed to be a protozoan closely related to the radiolarians, its structure and organization suggest affinities with members of the fungal group, Ascomycota. Specimens are irregularly shaped and up to 1.0 mm in diameter. Each cleistothecium bears prominent radiating spines that are continuous with a peripheral mat of extensively branched, delicate hyphal filaments. A complex wall encloses a central cavity which may contain a number of asci with ascospores. Among extant fungi, Traquairia is most similar in form to members of the Eurotiales and Erysiphales.     

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

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

中泥盆世草本石松植物原始鳞木属的命名问题

草本石松植物原始鳞木属（Protolepidodendron）一名,最初由Krejci根据波希米亚泥盆纪地层中一种具叶的茎干标本所建立,当时为了强调其与石炭纪鳞木属（Lepidodendron）石松植物的相似性,取名为Proto-Lepidodendron。后来,这种以具有二分叉的叶为特征的草本石松植物相继在捷克、德国、比利时、美国、中国、哈萨克斯坦、俄罗斯等地的早、中泥盆世地层中被发现。值得一提的是,对该属及模式种的命名问题存在一定的争议,同时存在多种作者引证,甚至还存在不同拼写的种本名。根据国际植物学命名法规,对化石植物的命名必须依据模式标本。目前,Protolepidodendron的模式标本保存在捷克共和国首都布拉格的国家博物馆。通过对模式标本进行的重新观察,并发现Gothan（1921）首次根据模式标本明确了Protolepidodendron的属征,是该属最早的合格发表作者;后来,模式标本又经过Krausel和Weyland（1929）的研究,唯一合法的种P．scharyanum被确立为模式种,并提出了种征。对Protolepidodendron属及其模式种,尽管后来有大量研究和报道,但都不是基于原始的模式标本。因此。根据国际植物学命名法规,该属及其模式种的合法名称应为Protolepidodendron Krejci ex Gothan和P．scharyanum Krejci ex Krausel et Weyland。     

陕北中三叠世一种石松植物的大孢子研究

本文研究陕西中三叠世二马营组底部所产一种脊囊属(Annalepis Fliche)石松植物的原位(in situ)大孢子和散布于其围岩中的分散(dispersal)大孢子。两者显示连续的大孢子变化系列。据此,作者提出了该植物大孢子的主要发育阶段,并解释了化石石松植物大孢子多型性的原因:不仅与大孢子自身的发育正常与否以及其保存状态有关,更重要的在于大孢子不同发育阶段上的变化。     

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

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

ENVIRONMENTAL MODELS FOR PALEOZOIC COMMUNITIES

Nearshore communities in Paleozoic epeiric seas occur in two distinct lateral patterns which parallel shorelines — an expanded pattern of five and a compressed pattern of three laterally adjacent communities. The two community patterns are correlated with two distinct environmental models which are a product of local tectonics. Model 1 (tectonically stable) develops in low slope transgressing epeiric seas. Model 2 (tectonically active) develops in high slope prograding epeiric seas commonly with abundant terrigenous clastic influx. Environmental variables and organic evolution change community constituents, but the broad community patterns recur at least through the early and middle Paleozoic.     

EQUISETUM CLARNOI,A NEW SPECIES BASED ON PETRIFACTIONS FROM THE EOCENE OF OREGON

Equisetum clarnoi is described from four silicified stem fragments and numerous small roots from the Eocene Clarno Chert of Jefferson County, Oregon. Stems are up to 8.0 mm in diam and have sunken stomata arranged vertically in a single line flanking each of the external biangulate stem ridges, features that clearly ally this species with the subgenus Hippochaete. External stem ridges are equal in number to the carinal hypodermal bands. The hypodermis is composed of fibers and has prominent carinal bands up to 0.75 mm long and shorter vallecular bands. Cortical parenchyma cells enclose prominent vallecular canals which are lined by specialized thick-walled parenchyma cells. The double, common endodermis has prominent casparian strips. Vascular bundles are composed of four to seven metaxylem tracheids flanking each side of the phloem and protoxylem tracheids which occur singly on the internal surface of the small carinal canals. Leaf sheaths in cross section have an adaxial fibrous layer and an external or near external fibrous bundle. Roots are up to 2.0 mm in diam and have paired cuboidal epidermal cells from which root hairs arise. The stele of the root is central and shows exarch primary xylem maturation. Equisetum clarnoi most closely resembles the extant Equisetum hyemale var. affine.     

STUDIES OF PALEOZOIC FUNGI. III. FUNGAL PARASITISM IN A PENNSYLVANIAN GYMNOSPERM

Evidence of fungal parasitism is found in the Pennsylvanian gymnospermous cone, Lasiostrobus polysacci Taylor. Indication of fungal activity is found in the outer cortical region of the axis of the cone and in the fleshy microsporophylls. Specimens exhibit severe tissue disruption, thick-walled, branched, septate hyphae, and possible reproductive structures. Parenchymatous cortical cells may also contain rounded bodies which are continuous with the cell wall. Similar structures are formed in many extant taxa in response to fungal invasion, and are termed wall appositions or callosities. Although their role in extant plants is disputed, they are clearly the product of a living host cell. Such spherical bodies, however, are not restricted to the cell periphery but in some cases occlude the cell lumen. In appearance they resemble resinous remains similar to those found in other coal ball plants. The blockage of entire cells or groups of cells may have served to retard hyphal growth or isolate infected cells. The occurrence of such structures in a Carboniferous plant provides the best evidence to date of parasitism during the Paleozoic.     

新疆准噶尔盆地西缘晚泥盆世一种新的石松类植物

描述新疆和布克赛尔晚泥盆世洪古勒楞组中的一种石松类孢子囊穗,该孢子囊穗二歧分叉一次,长纺锤形叶座紧密螺旋排列于穗轴上,每轮6枚;孢子叶披针形,具叶柄,单脉,叶缘具细齿;孢子囊近轴处着生,长椭球形,囊内有4枚大孢子;大孢子圆球形,表面光滑,直径为900－1200μg。通过对比研究,将当前孢子囊穗定为新属、新种,即Hefengistrobus bifurcus gen.et sp.nov.,同时讨论该孢子囊穗在石松类演化上的意义。     

MILLAYA GEN. N., AN UPPER PALEOZOIC GENUS OF MARATTIALEAN SYNANGIA

Anatomically preserved fertile marattialean pinnules from the Lower Permian (Wolfcampian) Bursum Formation in Tularosa, New Mexico, and isolated synangia from the Upper Pennsylvanian (Missourian) Stanton Formation near Tyro, Kansas, are described. The sessile synangia are partially sunken into the pinnule lamina and arranged abaxially in a single row on each side of the midrib. Comparisons are made with other fossil and modern marattialeans and the evolutionary significance considered.     

中国晚古生代轮藻化石组合

本文综述了数十年来中国晚古生代轮藻化石研究成果。与全球其它地区相比较,中国古生代轮藻化石较为丰富,可归纳为九个轮藻化石组合及三个轮藻化石层位。依据轮藻植物组成特点、演化特征以及伴生其它门类化石,论证各组合的地质时代,其中两个组合地质时代相同,属于不同的生物地理区系。     

STUDIES OF PALEOZOIC FUNGI. IV. WOOD-DECAYING FUNGI IN CALLIXYLON NEWBERRYI FROM THE UPPER DEVONIAN

An extensive fungal infection is present in silicified specimens of Callixylon newberryi (Dawson) Elkins and Wieland from the Upper Devonian of Indiana. Fungi are represented by branched, septate filaments with both terminal and intercalary chlamydospores. Clamp connections were not observed. Tracheids of the secondary xylem, decayed in varying degrees, show erosion troughs, cavities, and extensive lysis of tracheid walls. The pattern of decay is most similar to modern-day white rots, which are typically caused by basidiomycetes, while hyphal features are characteristic of either ascomycetes or basidiomycetes. The presence of wood decay coupled with a septate mycelium suggests the presence of higher fungi in the Devonian and indicates a more diverse Devonian mycoflora than has previously been recognized.     

ON A NEW STRUCTURALLY PRESERVED ARBORESCENT LYCOPSID FRUCTIFICATION FROM THE LOWER PENNSYLVANIAN OF NORTH AMERICA

Bisporangiate lycopsid fructifications are described from petrifaction material of Pottsville (lower Pennsylvanian) age collected in eastern Kentucky. The largest specimen of Lepidostrobus schopfii sp. n. is 8.0 cm long and approximately 1.3 cm in diam; it is not complete at either apex or base. Basal megasporangia, each containing a variable number (12-29) of megaspores, and apical microsporangia are adaxially positioned on pedicels bearing reduced lateral laminae. Features of the cone axis and pattern of vascularization are described. Of particular interest is the occurrence of well-preserved endosporic megagametophytes showing archegonia and rhizoids. The new species is compared with other structurally preserved bisporangiate lycopsid fructifications of equivalent age.     

A WOODY LYCOPSID STEM FROM THE NEW ALBANY SHALE (LOWER MISSISSIPPIAN) OF KENTUCKY

A lycopsid axis from the New Albany Shale (Sanderson Formation) of Kentucky is described. The stem, which branches dichotomously, is 45 mm in diameter and is characterized by a relatively narrow parenchymatized protostele, a 3.0 mm-thick cylinder of secondary xylem, a tripartite cortex, and a periderm that is more than 5.0 mm thick. The secondary xylem is composed of uniseriate and biseriate vascular rays and narrow tracheids with scalariform wall thickenings on both radial and tangential walls. The periderm is characterized by elongate, thick-walled cells, some of which broaden tangentially in the outer part of the tissue forming zones that appear wedge-shaped in cross section. Surface features of the axis, including leaf bases, are not preserved. The stem is tentatively regarded as a member of the Lepidodendrales in accordance with the numerous anatomical characters that it shares with more recent representatives of the order. Because the external morphology is not known, however, the possibility exists that the axis corresponds to a protolepidodendralean taxon currently known only from compression and/or impression remains or some other nonlepidodendralean plant that produced secondary xylem. The extremely narrow profile of the secondary xylem tracheids (relative to other arborescent lycopsids) is interpreted as evidence that the plants grew in a habitat that was substantially drier than the Upper Carboniferous coal swamps.