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1.
Dwarf shoots and needle leaves of Pinus triphylla Hollick and Jeffrey and P. quinquefolia Hollick and Jeffrey have been discovered recently in a Late Cretaceous age clay deposit on Martha's Vineyard Island, Massachusetts. Detailed study of these fossils provides further information on the internal construction of the two taxa. This new information permits both species to be compared easily with similar fossil forms from the Upper Cretaceous of Japan as well as with dwarf shoots and needles of modern species of Pinus. As a result, the relationships between Cretaceous pines and the extinct genus Prepinus are found to be less than previously believed. Moreover, the dwarf shoots and needles of Cretaceous members of the genus Pinus appear to be most like those of present-day species included in the subgenus Pinus.  相似文献   

2.
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.  相似文献   

3.
The new genus Pycnococcus Guillard is based on several clones from the western North Atlantic and Gulf of Mexico. The type and only described species, Pycnococcus provasolii Guillard, sp. nov., is typified by clone Ω48-23 from the North Atlantic. Cells of Pycnococcus provasolii are solitary, spherical, 1.5–4.0 μm in diameter, have a resistant cell wall lacking sporopollenin, and have the ultrastructural characteristics of green algae. With the light microscope they are scarcely distinguishable from cells of other coccoid planktonic organisms. In pigmentation P. provasolii resembles Micromonas pusilla, Mantoniella squamata, and Mamiella gilva in having chl a, much chl b, Mg 2,4-divinylphaeoporphyrin a5 monomethyl ester (presumably), and prasinoxanthin as a major xanthophyll. The pyrenoid of P. provasolii has a cytoplasmic channel, which is unique among species closely related to it. Flagellates, occurring rarely in culture, are similar to but distinguishable from known Pedinomonas species by size and shape. Pycnococcus provasolii is referred to the new family Pycnococcaceae Guillard, in the order Mamiellales of the class Micromonadophyceae (Chlorophyta). Clones of Pycnococcus provasolii are oceanic in nutritional characteristics, require only vitamin B12 in culture, and are well adapted to growth under blue or blue-violet light of low intensity.  相似文献   

4.
Two new dasycladalean algae are described from the Gosau Group of the Northern Calcareous Alps in Austria. The tiny spicules of Acicularia? weisswasserensis n. sp. were found in foraminiferal wacke- to packstones associated with rudist limestones of the Weisswasser locality (Middle Coniacian), Lower Austria. The small globulous Terquemella? microsphaera n. sp. occurs in marls to marly limestones of the Pletzachalm locality (Upper Turonian), Tyrol, and Russbach locality (Upper Santonian), Lower Austria. The Terquemella-Acicularia group requires taxonomic revision; the two forms described herein, however, are clearly distinct from other species, and belong to the smallest representatives of these genera. In addition, Acicularia? aff. magnapora Kuss and morphologically similar forms interpreted as gametophores of unknown larger dasycladales are described.  相似文献   

5.
The occurrence of filamentous, branching, catalase-negative bacteria as a numerically predominant microflora of various soils was demonstrated by using a dilution frequency isolation procedure. The major characteristics of these organisms were those of the order Actinomycetales. However, they could not be placed in any of the present genera of this order and, therefore, a new genus, Agromyces, was proposed for these organisms. This genus includes catalase-negative, nutritionally-fastidious microorganisms whose cells produce a true branching mycelium that fragments into coccoid and diphtheroid forms. Also, they have an oxidative metabolism, are microaerophilic to aerobic, and contain neither diaminopimelic acid nor lysine as major constituents of the cell wall glycopeptide. The type species would be Agromyces ramosus, gen. n., sp. n. The possible importance of these organisms in clarifying certain phylogenetic relationships of the Actinomycetales is discussed.  相似文献   

6.
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.  相似文献   

7.
Charliea is a new genus (type-species: C. manzanitana), based on pinnately compound leaf material from the richly fossiliferous Virgilian (Upper Pennsylvanian) shales of the Kinney Brick Company quarry near Albuquerque, New Mexico. In several features Charliea resembles Russellites or a zamioid cycad. It has linear-oblong pinnae with broad, oblique attachment and a truncate tip, which is deeply incised to form two to four nearly equal lobes. The venation is simple, parallel, and sparingly dichotomous, each vein ending at the distal margin. The Kinney beds also contain Plagiozamites planchardi, another zamioid form with parallel-veined pinnae, differing from Charliea chiefly in having rounded tips and veins ending in the denticulate margins. An unnamed third form (genus B) in the Kinney beds has long, narrow pinnae with parallel veins and blunt tips; this strongly resembles the Mesozoic conifer Podozamites, but may just as well represent a cycadophyte. Another unnamed taxon (genus A), from an Upper Pennsylvanian deposit in Jack County, Texas, resembles genus B or Russellites in general shape and venation, but the critical distal margins are unknown. In their single-ordered parallel venation, these four foliar types contrast sharply with the two-ordered pinnate venation of most Pennsylvanian fern-like leaves, and seem to foreshadow Mesozoic morphologies. This tendency toward precocious evolution of parallel-veined foliar form in North America is also expressed by a single occurrence of the Asiatic, Permian genus Tingia in the Lower Pennsylvanian of Utah, and by the presence of the predominantly Triassic cycadeoid genus Pterophyllum in the Lower Permian of Texas.  相似文献   

8.
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.  相似文献   

9.
Vegetative cells and zoospores of Hormotilopsis gelatinosa Trainor & Bold, H. tetravacuolaris Arce & Bold, Planophila terrestris Groover & Hofstetter, and Phyllogloea fimbriata (Korchikov) Silva were examined by transmission electron microscopy. All cells had pyrenoids traversed by cytoplasmic channels. Zoospores were quadriflagellate and had essentially cruciate flagellar apparatuses. Scales were present on free-swimming zoospores. These features are essentially identical to those of Chaetopeltis sp. and are dissimilar to those of other described green algae. The new order Chaetopeltidales is created to accommodate the genera Chaetopeltis, Hormotilopsis, Planophila sensu Groover & Hofstetter, Phyllogloea, Dicranochaete, and Schizochlamys, organisms previously scattered among the orders Tetrasporales, Chloro-coccales, Chlorosarcinales, and Chaetophorales. Members of the order are closely related to the ancestral chlorophycean flagellate genus Hafniomonas, may be ancestral with respect to other Chlorophyceae, and may also be closely related to the ulvophycean order Ulotrichales.  相似文献   

10.
Protosalvinia has a large thallus on which P. arnoldii and P. ravenna forms develop. Light and scanning electron microscopy of Upper Devonian compression forms of Protosalvinia arnoldii, P. ravenna and P. furcata from the Ohio Shale of Kentucky and Ohio, statistical analyses of their cellular dimensions and patterns, and mathematical constructs of thallus shapes and sizes indicate that P. ravenna and P. furcata forms could be ontogenetically derived from a P. arnoldii stage. Tetrads, interpreted as the meiotic sporangial products, are morphologically identical for the three forms; tetrads contain a sporopollenin fraction and occur singly in closed, hypodermal conceptacles. Solitary, multicellular, stalked clavate structures occur in similar closed chambers. Fossil thalli are composed of hydrocarbons with some lignin-like compounds interpretable as cuticular in nature. P. ravenna and P. furcata are morphological forms of a single species showing phenotypic plasticity within an onshore-offshore paleoecological gradient. The form of thallus and the resistant spores are interpreted as adaptations to a littoral environment. The morphology and mode of reproduction of Protosalvinia suggest a heteromorphic diplobiontic life-cycle, similar to the Heterogeneratae (Phaeophyta).  相似文献   

11.
Chrysolepidomonas gen. nov. is described for single-celled monads with two flagella, a single chloroplast, and distinctive canistrate and dendritic scales. The type species, Chrysolepidomonas dendrolepidota sp. nov., is described for the first time. The canistrate scales bear eight “bumps” on the top surface, and the dendriticscales have a tapered base with a quatrifid tip. These organic scales are formed in the Golgi apparatus and storred in a scale reservoir. The scale reservoir is bounded on two sides by the R1 and R2 in microtubular roots of the basal apparatus. The cyst (=stomatocyst, statospore) forms endogenously by means of a silica deposition vesicle. The outer cyst surface is smooth, and the pore region is unornamented. Two other organisms bearing canistrate and dendritic scales, previously assigned to the genus Sphaleromants, are transferred to the genus Chrysolepidomonas. They are C.angalica sp. nov. and C. marine(Pienaar) comb. nov. The distinguishing features of Chrysolepidomonas and Sphaleromantis are discussed. A new family, Chrysolepidomonadceae fam. noc., is described for flagellates covered with organic scales.  相似文献   

12.
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14.
A new genus of Pfiesteria‐like heterotrophic dinoflagellate, Luciella gen. nov., and two new species, Luciella masanensis sp. nov. and Luciella atlantis sp. nov., are described. These species commonly occur with other small (<20 μm) heterotrophic and mixotrophic dinoflagellates in estuaries from Florida to Maryland and the southern coast of Korea, suggesting a possible global distribution. An SEM analysis indicates that members of the genus Luciella have the enhanced Kofoidian plate formula of Po, cp, X, 4′, 2a, 6″, 6c, PC, 5+s, 5?, 0p, and 2″″. The two four‐sided anterior intercalary plates are diamond shaped. The genus Luciella differs from the other genera in the Pfiesteriaceae by a least one plate in the plate tabulation and in the configuration of the two anterior intercalary plates. An SSU rDNA phylogenetic analysis confirmed the genus as monophyletic and distinct from the other genera in the Pfiesteriaceae. The morphology of Luciella masanensis closely resembles Pfiesteria piscicida Steid. et J. M. Burkh. and other Pfiesteria‐like dinoflagellates in size and shape, making it easily misidentified using LM. Luciella atlantis, in contrast, has a more distinctive morphology. It can be distinguished from L. masanensis and other Pfiesteria‐like organisms by a larger cell size, a more conical‐shaped epitheca and hypotheca, larger rhombic‐shaped intercalary plates, and an asymmetrical hypotheca. The genus Luciella is assigned to the order Peridiniales and the family Pfiesteriaceae based on plate tabulation, plate pattern, general morphology, and phylogenetic analysis.  相似文献   

15.
Rhoicosphenia Grun. is a relatively isolated genus among the biraphid diatoms. Morphological changes in an isopolar member of the genus, Rh. genuflexa (Kütz.) Medlin, were investigated using light and scanning electron microscopy. The fully raphid valve showed changes in its flexure that could be correlated with size reduction during its life history from the initial cells to the smallest cells found in the population. Bands showed changes in number (from three to one) related to size reduction. Rh. genuflexa is morphologically similar to Rh. abbreviata (C. Ag.) Lange-Bert. (=Rh. curvata (Kütz.) Grun.), although the two are distinct taxa. These observations support previous contentions that Rhoicosphenia is a natural taxonomic grouping.  相似文献   

16.
There are few studies dedicated to species of the Order Parmales all over the world. All 12 taxa described are part of the marine ultraplankton (less than 5 μm). Analysis of filtered samples from the Gulf of Tehuantepec yielded specimens of two taxa of the group. One is a new species, belonging to the genus Tetraparma. Tetraparma insecta sp. nov. is solitary and spherical (2.8–3.8 μm diameter), and all plates lack ornamentations or knobs, the walls are smooth, and only the plate junctions are seen. The shield plates are convex and show a conspicuous rim, some of them with an indentation. This species shows superficial similarities with Tetraparma pelagica, the other species described of the genus, and is very similar to siliceous forms, previously found, with no formal name. The other species is the taxon Triparma laevis form mexicana (Kosman) stat. nov., earlier described for Mexican waters, which has an irregular ala, the shield plates have knobs at the center, the triradiate plates show a “Y”‐shaped keel, and the walls of plates and ala show minute granules. Tetraparma insecta was distributed widely in the study area and was relatively abundant, reaching a density of 4 × 104·L?1, with an evident preference for subsurface waters (10–20 m depth), whereas T. laevis form mexicana was rare and scarce. Both species seem to be restricted to tropical–subtropical waters. We discuss the taxonomy of Parmales, especially concerning the category of subspecies within the group. Parmales is a widespread group in cold and tropical waters.  相似文献   

17.
Eggert , Donald A. (Yale U., New Haven, Conn.) Studies of Paleozoic ferns: Tubicaulis stewartii sp. nov. and evolutionary trends in the genus. Amer. Jour. Bot. 46(8): 594–602. Illus. 1959.—Tubicaulis stewartii, a new species of the order Coenopteridales is described. The specimen was derived from the Upper Pennsylvanian of Berryville, Illinois, and is characterized by having a lacunar middle cortex, a well-developed integumentary system bearing uniseriate hairs, and xylem parenchyma organized into vertically anastomosing strands. In addition, multiseriate (somewhat transitional to reticulate) bordered pitting is present in the petiolar metaxylem elements, while those of the stem stele are multiseriate scalariform. The habit is intermediate between that of a form such as Osmunda and a tree fern, having an upright tapering stem which gives off prominently decurrent petioles in a 2/5 divergence. A reinvestigation of the type specimen of the most closely allied species, T. multiscalariformis, of Upper-Middle Pennsylvanian age, has shown that it has similar features in the cortex, metaxylem, and integumentary layers. Tubicaulis multiscalariformis and T. stewartii form a distinct group in the 6 species now known, whose evolution has most likely involved the retention of a more primitive form of pitting (multiseriate scalariform) with parenchymatization of the xylem. The remaining species of the genus have not developed xylem parenchyma but have developed circular bordered pitting. The relationships of the genus to other genera in the Coenopteridales remain obscure.  相似文献   

18.
19.
The ontogeny and ultrastructure of Tragia ramosa and T. saxicola are described. The stinging emergence of T. ramosa and T. saxicola consists of a central stinging cell and three lateral cells. The stinging cell possesses a compound crystal in the apical region which is held in place by cell wall extensions. The stinging cell cytoplasm is characterized by a large central vacuole which contains a proteinaceous substance as determined histochemically. Upon contact, the stinging cell wall is pushed back over the crystal, exposing it to penetrate an individual. This stinging mechanism is unique among stinging emergences. The stinging cell is subepidermal in origin whereas the three lateral cells are epidermal in origin. The morphology, ultrastructure and ontogeny of the stinging emergence of T. ramosa and T. saxicola appear to be identical.  相似文献   

20.
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