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1.
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. 相似文献
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Numerous anatomically preserved ovules assignable to the genus Mitrospermum have been discovered in Upper Pennsylvanian sediments of Eastern Ohio. Although basically similar to Mitrospermum compressum, the newly discovered specimens exhibit several consistent differences. Ovules are strongly platyspermic, up to 4.2 mm long, 4.0 mm wide, and 0.6 mm thick. In the minor plane, ovules are broadest at the base and taper toward the micropyle. The integument exhibits three topographic regions: endotesta, sclerotesta, and sarcotesta. The sarcotesta is extremely broad in the major plane, where it forms two membranous wings. A single terete vascular bundle enters the base of the ovule, traverses the integument, and divides to form two integumentary bundles and a conspicuous nucellar platform. Integumentary bundles extend toward the tip of the ovule at the margin of the sarcotesta and sclerotesta. A pollen chamber with a prominent nucellar beak is delimited at the tip of the nucellus. Consistent differences in vascularization, size, nature of the seed base, features of the pollen chamber, and the Late Pennsylvanian age demonstrate that the specimens represent a distinct species. The discovery of these ovules extends the stratigraphic range of Mitrospermum to the Upper Pennsylvanian of Ohio. 相似文献
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New specimens of Spencerites moorei add knowledge of its sporophylls and method of sporangial attachment. The sporophyll consists of a slender pedicel which expands at its distal end into a fleshy, peltate, diamond-shaped head which bears a presumably fleshy lamina. The sporangium is attached through most of its length to the adaxial surface of the pedicel rather than distally as in S. insignis. It is suggested that the distal attachment shown in S. insignis may be derived through a phyletic shift from the pedicellate position. Additional specimens of Spencerites provisionally assigned to S. majusculus are also recorded. The spores are bilateral, monolete, and shaped like quadrants of a sphere. Two prominent wings extend along the two contact faces and the monolete mark is prominently raised, thus imparting a three-winged appearance to the spore. The axis consists of an exarch protostele and a cylinder of thick-walled outer cortex. 相似文献
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Sergius H. Mamay 《American journal of botany》1959,46(7):530-536
Mamay , Sergius H. (U. S. Geological Survey, Washington, D. C.) A new bowmanitean fructification from the Pennsylvania of Kansas. Amer. Jour. Bot. 46(7): 530–536. Illus. 1959.—A new sphenophyllaceous fructification, Bowmanites moorei sp. nov., is described on the basis of coal ball petrifactions from the Fleming coal in southeastern Kansas. One of the simplest species of Bowmanites, B. moorei has only 3 sporophylls in a whorl. Each sporophyll has 3 lobes, the median one fertile, the 2 lateral ones sterile. Each fertile lobe subtends 2 sporangia, resulting in 6 sporangia in a whorl. The sporangia are inverted, being distally attached to separate sporangiophores that arise in pairs, in axillary positions. The sporangial epidermis and epidermis of the lower surfaces of the sporangiophores are characterized by relatively large, thick-walled cells. The spores are small, spherical, and trilete, without distinctive ornamentation of the exine. B. moorei adds to the morphological variation known in Bowmanites, but contributes little toward a phylogenetic interpretation of this morphologically complex genus. 相似文献
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Robert A. Gastaldo 《American journal of botany》1981,68(10):1306-1318
Equisetalean strobili normally are encountered as disarticulated organs. This condition has necessitated the creation of 12 form genera to accommodate the various morphological architectures and anatomical configurations. Taxonomically useful characteristics, which are discernable in permineralized specimens, are rarely distinguishable in coalified compressions due to their destruction during diagenesis and coalification. Therefore, genera established on the position of sporangiophore-trace origin, such as Schimperia Remy and Remy, are untenable when dealing with coalified compressions. Although the two largest genera of strobili, Calamostachys Schimper and Palaeostachya Weiss, may be synonymous, it is proposed that these form genera be retained when dealing with coalified compression specimens. Each genus provides a particular architectural concept for specimens which may not be assignable to the species level. Calamostachys and Palaeostachya are highly overspeciated genera. It is suggested that characteristics necessary to delimit new species include bract height, degree of bract fusion, disposition of bracts, bract: sporangiophore ratio, number of sporangia per sporangiophore, and sexual status. 相似文献
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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. 相似文献
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Heterangium kentuckeyensis sp. nov. is described from Lower/Middle Pennsylvanian sediments of eastern Kentucky, based on permineralized stems, petioles, frond members, laminar foliage, and roots, including several organs in attachment. Stems 2.2 to 5.8 mm in diameter are known in several developmental stages. The considerable variability in stelar and cortical histology within this one species emphasizes the need to reassess variability within previously described taxa. Fronds of H. kentuckyensis are at least twice pinnate and bear primary pinnae alternately at approximately right angles. Laminar pinnules have dichotomous venation, are at least 2-lobed, and comparable to foliage of the Sphenopteris-type. Stomata possess 6–7 subsidiary cells with abaxial papillae. The characters used to distinguish the subgenera of Heterangium are evaluated and found to be unreliable. Moreover, suggested phylogenetic schemes both within Heterangium and between this taxon and other lyginopterid pteridosperms based on these features are inconsistent with stratigraphic data. Until reproductive features are known, the classification of Heterangium species is best based on characters of the vegetative sporophyte, including stelar organization (particularly protoxylem architecture), cortical histology, and frond morphology. 相似文献
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The zygopterid fern Etapteris leclercqii sp. n. is described from Lower Pennsylvanian age coal balls from the Lewis Creek, Kentucky, locality. Isolated petioles extend up to 15.0 cm in length and 5.0 mm in diam; no lateral axes have been observed. The clepsydroid-shaped petiole trace is characterized by lateral arms that sharply taper and by the production of peripheral loops prior to the separation of pinna traces from the stele. Large irregularly shaped multicellular hairs are randomly scattered over the surface of the petioles. When compared with other currently recognized zygopterid ferns, E. leclercqii appears most similar to Metaclepsydropsis duplex. Based on the configuration of the leaf trace and the occurrence of peripheral loops, it is suggested that E. leclercqii may represent the most primitive species of the genus known to date. 相似文献
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在对中国东北辽宁本溪中三叠统林家组的化石研究中,发现了木贼目瓣轮叶属一个新种——林家瓣轮叶(Lobatannularia linjiaensis sp. nov.)。该种叶轮小,明显分成两瓣,每瓣叶数约10–12枚。叶线形至倒披针形,叶长差别大,叶联合长度占叶长约1/3–3/4。自1927年Kawasaki建立瓣轮叶属以来,该属已至少发现了33种,其中大部分报道于二叠纪,少数见于三叠纪。瓣轮叶属作为晚古生代华夏植物群孑遗分子之一,当前该属新种的发现不仅丰富了瓣轮叶属的分类多样性,而且拓展了对二叠纪-三叠纪之交生物大灭绝及之后复苏过程中瓣轮叶属演化趋势的认识。 相似文献
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Arthur A. Cridland 《American journal of botany》1959,46(10):709-712
Cridland , Arthur A. (Kansas U., Lawrence.) A new species of Arthroxylon (Calamitaceae) from the Pennsylvanian of Kansas. Amer. Jour. Bot. 46(10): 709–712. Illus. 1959.—Arthroxylon resinaceum sp. nov. is described from 3 specimens found in a coal-ball collected at West Mineral, Kansas. The tracheids have 1 or 2 rows of pits on the radial walls and the pith cells adjacent to the protoxylem canals are filled with brown contents. Fungus spores are present in the tissues of 1 specimen. 相似文献
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A new angiosperm fructification, Caloda delevoryana, is described from the Cenomanian age Dakota Formation of central Kansas. It consists of a long, narrow, main axis with numerous secondary axes arranged helically around the main axis. These secondary axes are each terminated in a small receptacle bearing numerous conduplicate carpels. No evidence of a perianth or androecium was found. This fructification bears some similarity to a number of different modern orders, such as the Hamamelidales, Alismatales, Najadales, and Piperales, and families, particularly the Platanaceae and the Aponogetonaceae, but cannot definitely be assigned to any modern taxon within the angiosperms. C. delevoryana exhibits several characters traditionally assumed to be primitive in the angiosperms, and several other features of this fossil are proposed as primitive in the evolution of angiosperms. This floral axis, with its compact mass of numerous secondary axes bearing very small fruits and seeds, may be the product of reduction through diminished growth of internodes and carpels, and elaboration through increased repetition of floral modules. This record adds to the rapidly growing body of paleobotanical data on early angiosperm reproductive structures, which should prove important in the assessment of the extent and direction of angiosperm evolution. 相似文献
15.
Archaeocalamites lazarii, sp. nov., is based on a few vegetative compressions from the mid-Lower Permian Leonard Series near Fulda, north-central Texas. It is a minor component of a rich biota that includes sphenophylls, pteridophylls, conifers, conchostracan crustaceans, eurypterids, arachnids, insects, xenocanth sharks, and coprolites attributed to tetrapods. Biota and sedimentology indicate deposition in a small freshwater body on a deltaic floodplain. Leaves of A. lazarii differ in size and posture from those of the widespread and characteristically Mississippian aggregate species A. radiatus; nonpreservation of rooting and reproductive organs prevents interpretation of its phylogenetic relationship with other equisetaleans. The main significance of A. lazarii is that it extends the recorded stratigraphic range of the Archaeocalamitaceae from the lowermost Pennsylvanian (Namurian B) to the mid-Lower Permian (Artinskian), leaving a hiatus in records of approximately 55 Ma. This Lazarus taxon also occurs with possibly the youngest recorded eurypterid. 相似文献
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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. 相似文献
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Robert L. Dennis 《American journal of botany》1968,55(8):989-995
A new species of the genus Rhabdoxylon Holden (1960), an anatomically simple plant of presumed fern or fern-like affinities, is described from a coal ball petrifaction found in the Upper Pennsylvanian of southern Illinois. The new species, R. americanum, is based upon five specimens consisting of stems bearing spirally arranged leaves and numerous randomly distributed adventitious roots. The haplostelic stems branch by equal dichotomies and bear foliar traces which arise as unequal dichotomies of the stele. Leaf traces possess a circular outline in cross section and one adaxial protoxylem strand. The characteristics of exclusively primary tissues, diarch adventitious roots, centrarch haplosteles with simple scalariform pitting, and the nature and arrangement of the leaf traces, suggest that Rhabdoxylon represents a fern or fern-like plant rather than a representative of the Rhyniophytina or Trimerophytina. At present it is not possible to determine whether the simple structure of Rhabdoxylon has come about through phyletic reduction or represents a primitively simple condition. 相似文献
18.
Lawrence C. Matten 《American journal of botany》1968,55(7):773-782
A new genus from a Middle Devonian locality near Cairo, N. Y., is described. Actinoxylon gen. nov. is based upon pyritic petrifactions. Three orders of branching are present: penultimate branch, ultimate branch, and leaf. The penultimate branch bears spirally arranged ultimate branches and leaves, the leaves apparently replacing the branches in the spiral. The ultimate branches bear opposite to subopposite and decussate leaves. The leaves are non-planated, unwebbed structures which show at least three dichotomies. Each segment of the leaf is terete as are all other axes. Internally the penultimate branch has a six-lobed actinostele with mesarch protoxylem areas, one or two per lobe. Secondary xylem is visible in the oldest parts of several specimens. The xylem has helical-reticulate, reticulate, scalariform and circular-pitted elements. The presumptive areas of phloem are occupied by cells with dark contents. The cortex is composed of a parenchymatous inner region and a sclerenchymatous outer region. The ultimate branch traces are at first three-lobed protosteles, later becoming four-lobed. Several ultimate branch traces also possess secondary xylem while within the cortex of the penultimate branch. The leaf traces are terete strands. Below each forking of a leaf segment there is a corresponding forking of the vascular strand. Actinoxylon is compared with the progymnosperms Actinopodium, Svalbardia, Archaeopteris, Siderella, and Tetraxylopteris. The anatomy of the penultimate branch of Actinoxylon is similar to that of Actinopodium, Archaeopteris macilenta, and Siderella. The ultimate branch traces of Archaeopteris and Actinoxylon are similar. The ultimate branch stele and pattern of trace formation in Actinoxylon is similar to the stelar configuration and trace formation in the r + 2 axes of Tetraxylopteris schmidtii. The unwebbed leaves are similar to those of Archaeopteris fissilis, Svalbardia, and the terminal units of the Aneurophytales. 相似文献
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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. 相似文献
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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. 相似文献