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1.
A review of the history of the genus Psilophyton is presented. Two new species with sporangia in organic connection, P. microspinosum and P. dapsile, are described. They are compared with Psilophyton-like plants from Maine and other previously described fertile species of this genus. Evidence from several species in the Trout Valley flora confirms the concept of this taxon as presented by Hueber and Banks. Data based on all sporangium-bearing species of Psilophyton are outlined, certain evolutionary trends within the taxon are tentatively presented, and recommendations for the treatment of the numerous fragmentary species and future new species are suggested.  相似文献   

2.
Stenokoleos is a genus for petrified axes from the Mississippian New Albany Shale to which an Upper Devonian occurrence in New York is added. Two orders of branching were known and the plant was thought to be related to coenopterid ferns. The new petrified axes from New York reveal three orders of branching. A pair of rachides emerges from one side of the stem at each node. Their position alternates at successive nodes (distichous). Each rachis bears alternately arranged pinnae. The shape of the xylem strand and the number of protoxylem areas are variable. Traces to the pairs of rachides arise either as two separate strands or as a single strand that is presumed to divide while still within the cortex of the stem. Traces to pinnae are ellipsoid or clepsydroid. Tracheids are scalariform and uni- or biseriate, circular-bordered pitted. Peripheral loops are present in all orders of branches. Protoxylem strands are numerous and maturation is mesarch. Cortex is parenchymatous where it is preserved but outer cortex is missing. Stenokoleos and Reimanniopsis are placed in a new family, Stenokoleaceae. This is classified as Incertae Sedis among Pterophytina in Tracheophyta. It is suggested that the plant is related more closely to the Mississippian pteridosperms Tristichia and Tetrastichia than to the coenopterid ferns.  相似文献   

3.
Two new species are recognized in the rhodomelacean genus Tayloriella Kylin: T. divaricata sp. nov. and T. abyssalis sp. nov. These two taxa are distributed in the northeastern North Pacific, the former ranging from Amchitka Island in the Aleutians through southcentral Alaska to northern British Columbia, and the latter ranging also from Amchitka Island through southcentral Alaska and British Columbia into northern Washington. A characteristic of these two species shared with the type of Tayloriella is that the abaxial lateral always overtops the monopodially developed axes in every order of branching. The laterals have little congenital fusion with the parent axes. A common feature in these two species is that the laterals are terminated in a relatively long monosiphonous portion (usually 6 or 7 cells). The relationship of Tayloriella to Pterosiphonia and Pterosiphoniella is discussed.  相似文献   

4.
ABSTRACT

A new species of the genus Polysiphonia from the Mediterranean Sea is described. It is an ecorticate species, with 4 pericentral cells, showing prostrate axes from which erect axes arise. Rhizoids are formed by pericentral cells in a median position remaining in open connection with them. Erect axes are straight, simple throughout or pseudodichotomous at the base then simple or with one (rarely two-three) orders of branching; trichoblasts and scar cells not observed. Only tetrasporangial plants were found. They show ellipsoid tetrasporangia borne in short straight series, often interrupted by sterile segments. The new species is also characterized by a peculiar habit consisting of prostrate axes, adhering to lower faces of Peyssonnelia spp. by means of rhizoids growing upward, from which erect upright axes perforating thalli of the supporting species arise. A comparison with the related species of Polysiphonia was also carried out.  相似文献   

5.
Several axes of the coenopterid fern Stauropteris are described from permineralized peat associated with Lower-Middle Pennsylvanian coal deposits of southeastern Kentucky. This represents the first documented report of the genus in North America. The specimens are regarded as representatives of a new species—S. biseriata—based on the distinctive branching habit. Three branch orders are described, and in each case, branches are singular and distichous, arranged in a two-ranked pattern. This is in contrast to other species of Stauropteris in which the branches are paired and form a quadriseriate pattern. A pair of vascularized aphlebiae subtend each branch through all branching orders. Aphlebiae associated with first- and second-order branches are three-parted at the point of insertion; those that subtend third-order branches are singular. Stauropteris and a number of Devonian fern-like plants are compared on the basis of certain morphological similarities.  相似文献   

6.
Acrosymphyton firmum sp. nov., is described from the northeastern coast of North 1., New Zealand. Gametophytes are spring–summer annuals which grow subtidally on cobbles. Thalli are uniaxial; each axial cell bears a whorl of four indeterminate and one determinate branchlets. Indeterminate branchlets are alternately arranged giving the thallus a distichous and feather-like appearance. Numerous corticating rhizoidal filaments are produced from the periaxial and lower whorl branchlet cells. These rhizoids entwine and obscure the main axis as the thallus develops until in the mature plant the axes have a firm consistency and lubricous texture. The carpogonial branch bearing short lateral filaments and auxiliary cell branch with terminal auxiliary cell place this new species in the genus Acrosymphyton Sjöstedt. Of the three described species in the genus, A. firmum is most similar to A. taylori. This is the first report of the genus Acrosymphyton and the only confirmed report of the family Dumontiaceae in New Zealand waters.  相似文献   

7.
Two new fungi in a small family of zoosporic phycomycetes, the Blastocladiaceae, are described. Both are included in the Brachyallomyces category, as sexuality has not been found in either one thus far. Microallomyces dendroideus from Costa Rica represents a new genus distinguished by its occurrence on animal or plant substrata rich in protein, its branched thallus in which pseudosepta are entirely lacking but growth is renewed by sympodially formed hyphal tips, and its small size. Allomyces reticulatus from California is the first species in this well-known genus to exhibit reticulately sculptured resistant sporangia. Its robust thallus is also unusual in that, despite the presence of the characteristic pseudosepta and branching with sympodially renewed hyphal tips, growth is ordinarily not unlimited as it is in all other species of the genus. The addition of these two new water molds to the Blastocladiaceae poses some basic questions regarding generic distinctions in the family. These problems are discussed and a working key to the genera is provided.  相似文献   

8.
The new genus Yushanograptus described in the present paper is a monotypic genuswith Yushanograptus separatus gen.et sp.nov.as the genotype which is represented by5 specimens securd by one of the writers(Han)in the summer of 1961 from the NingkuoShale at the locality near Lijiapeng of the Yushan district,northeastern Jiangxi(Kiangsi)Province(Field No.F61001).The marked features of the new genus are the two long and slender primary stipesand the Goniograptid type in branching.The young forms of this new graptolite bear astriking resemblance to the slender Didymograpti,such as Didymograptus gracilis T(?)rn-quist,D.cognatus Harris et Thomas etc.The same is the case in Zygograptus,particul-arly in Zygograptus irregularis Harris et Thomas.In the mode of branching of the  相似文献   

9.
A new species of Zosterophyllum, Z. divaricatum Gensel, is described from the late Early Devonian (Emsian) of northern New Brunswick, Canada. It is a Platyzosterophyllum type, consisting of slender sometimes bifurcating axes with laterally borne sporangia oriented to one side of the axis. The species is distinctive in that axes bifurcate within fertile regions and in sporangium shape and attachment. Aspects of the morphology of axis and sporangium cuticle, tracheids, and spores are presented and considered in relation to comparable features in other Zosterophyllum species. Associated vegetative axes exhibiting H- and K-branching patterns and also cuticular features similar to the fertile specimens are described and it is suggested that they may represent parts of the same plant. Zosterophyllum divaricatum is most similar to Z. llanoveranum, Z. fertile, and Z. spectabile, and also resembles Rebuchia ovata to some extent. Z. divaricatum offers considerable information on variation within one species concerning sporangium shape, attachment, and distribution and expands the known diversity of Platyzosterophyllum types.  相似文献   

10.
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   

11.
A new species of the genus Telangiopsis, T. nonnae O. Orlova et Zavialova, was described on the basis of a microsporangiate organ from the Lower Carboniferous deposits of the Novgorod Region. The morphology of branching fertile axes, synangia, and sporangia was thoroughly studied. The three-dimensional system of fertile axes branches monopodially; ultimate axes bear numerous connivent bunches of synangia, which consist of three to six basally fused elongated ovate sporangia. The morphology and ultrastructure of prepollen grains were studied, which were extracted from the rock matrix surrounding the sporangia. The two-layered exine includes a well-developed endexine and an alveolate ectexine, with one-three rows of large thin-walled alveolae. The new species was compared with other Early Carboniferous microsporangiate organs.  相似文献   

12.
Two new propagule-farming red algae from southern Australia, Deucalion levringii (Lindauer) gen. et comb. nov. and Anisoschizus propaguli gen. et sp. nov., are described and defined largely on their development in laboratory culture. Deucalion is included in the tribe Compsothamnieae on the basis of its subapical procarp and alternate distichous branching. It differs from the other genera included in that tribe in that it produces 3-celled propagules, polysporangia, a subapical cell of the fertile axis which bears 3 pericentral cells, and an apparently post-fertilization involucre which develops from the hypogenous and sub-hypogenous cells of the fertile axis. Its gametophyte morphology has been elucidated in culture, as only sporophytes are known from the field. Gametophytes do not appear to produce propagules. Anisoschizus is provisionally included in the tribe Spermothamnieae on the basis of its subdichotomous branching, possession of a prostrate system and the production of polysporangia. It differs from the other genera of the tribe in the production of 2-celled propagules. Observations on the germination of the “monosporangia” of Mazoyerella arachnoidea and Monosporus spp. indicate that they are analagous to the propagules of Deucalion and Anisoschizus. The nature of these propagules and their role in recycling the parent plant are discussed and contrasted with true monosporangia. It is recommended that Monosporus be maintained as a form genus containing representatives from more than one tribe, as exemplified by plants from Lord Howe I. provisionally identified as M. indicus Boergesen which have both prostrate and erect, as opposed to only erect, axes.  相似文献   

13.
Two new species of the genus Tolypella (Characeae)–T. boldii Sawa sp. nov. and T. canadensis Sawa sp. nov.–were discovered in Texas, U.S.A., and Ontario, Canada, respectively. The species are recognized as additional members to the section Acutifolia because of the small and conical branchlet end cell and the oospore with a single basal impression. However, they differ from all the members previously described in the genus by the frequent and unique development of a terminal antheridium at the fertile branchlet node. A new and unexpected chromosome number of n = 8 for the genus was determined in both species, which, renders additional support to the conclusion that they represent a new taxonomic group in the section. The plants are described in detail in order to clarify some important morphological features which have been loosely interpreted by previous workers. Relationships between the new species and other members of the section are analyzed.  相似文献   

14.
A new species of Maianthemum (Liliaceae) was discovered in a tropical montane bog at an elevation of 2,500 m in central Costa Rica. The leaf bearing stems and inflorescences are supported by a stiff, erect, branching sympodium that consists of the persistent lower portions of older shoots. This lower portion corresponds in morphology and anatomy to the horizontal subterranean rhizome that is characteristic of all previously described species of Maianthemum. An erect woody habit is rare in the Lily family; an upright aerial rhizome is unique within the genus.  相似文献   

15.
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   

16.
Sphenophyllum was an important and long-surviving sphenopsid genus in the Paleozoic floras, with a worldwide distribution. A new species, Sphenophyllum changxingense sp. nov., is described from the Upper Devonian Wutong Formation of Changxing County, Zhejiang Province, China. This plant is characterized by two orders of slender axes and wedge-shaped leaves borne in whorls. The axes bear short spines and show longitudinal ridges and furrows on surface. Three to eight isophyllous leaves, with one, two, or no second-order axes, are attached at each node of first-order axes. Leaves bear spines and show a bilobate morphology; the two leaf lobes divide distally to form several marginal segments, each segment with a leaf vein. Sphenophyllum changxingense represents an early and primitive species within the genus, in light of the absence of heterophylly and specialized hook-like leaves. Like some Carboniferous and Permian species, it appears to have formed dense mats with mutually supportive axes. This plant adds to the known diversity of early sphenopsids in the Late Devonian.  相似文献   

17.
Limnobium spongia produces upright vegetative axes and prostrate stolons. The upright axes bear new stolons, whereas the stolons bear new upright axes and fertile and sterile branching systems. Upright axes and fertile and sterile branching systems are all interpreted to have sympodial growth. However, it was not determined whether growth of stolons is monopodial or sympodial. Both stolons and upright axes branch in alternate plastochrons, and branching is achieved solely by the bifurcation of apical meristems. Each meristematic bifurcation is interpreted to represent the formation of a precocious lateral bud. The upright axes develop from presumed precocious lateral buds on stolons, whereas such buds on upright axes produce renewal shoots. Limnobium spongia exhibits a marked degree of mirror-image symmetry.  相似文献   

18.
During the study of the distribution of cellular slime molds in Swiss forest soils, three new species were isolated and studied in culture, namely, Dictyostelium fasciculatum, Dictyostelium polycarpum and Polysphondylium filamentosum. The first is cosmopolitan, the latter two are known only from Switzerland. Dictyostelium polycarpum is a very delicate species and is the first species reported which is restricted to a high altitude environment. It is characterized by a coremiform habit, reminiscent of D. polycephalum, and relatively long reniform spores. Dictyostelium fasciculatum is a larger species which resembles D. mucoroides in gross morphology but is much closer to Polysphondylium in its life cycle pattern and behavior. Polysphondylium filamentosum is only the third well-defined species of the genus to be described. It produces filamentose principal and lateral axes. Optimum temperature for all three is around 20 C, somewhat below that of most other species in the family.  相似文献   

19.
Meicai Wei 《Insect Science》1997,4(4):295-305
Abstract A key is given for the known Palaearctic and Oriental genera of the family Argidae including a new genus from China. Ortasiceros gen. nov. with five new species, O. nigriceps sp. nov., O. zhengi sp. nov., O. breoicornis sp. nov., O. curvata sp. nov. and O. elevata sp. nov. are described and figured. A new tribe, Ortasicerini trib. nov., is erected for the new genus and Copidocerus Forsius 1921. The type specimens are deposited in the Insect Collection of Central South Forestry University, Zhuzhou, China.  相似文献   

20.
Abstract This paper deals with the genus Mindam Koch from China. The phylogeny of the genus is discussed. M. keteleerifoliae is regarded as the most advanced species, M. obliquus and M. piceasuc-tus are more advanced than M. abietinus, M. japonicus and M. victoria. The origin centre of the genus may be in Europe and the differentiation centre of the genus may be in Hengduan Mountains Region of China. Geological distribution of the genus shows island-shaped pattern. Five species from China was described in this paper, including one new species, M. piceasuctus Zhang and Qiao, one new subspecies, M. abietinus triprimesensori Zhang and Qiao and one newly recorded species, M. abietinus abietinus Koch 1856. A key to the Chinese species of Mindarus is given. The specimens of five species from China are deposited in the Institute of Zoology, Academia Sinica.  相似文献   

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