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1.
Sphagnum magellanicum has been viewed as being a predominantly circumpolar species in the northern hemisphere, but it occurs in the southern hemisphere and was originally described from the southern parts of Chile. It is an ecologically important species in mire ecosystems and has been extensively used as a model to study processes of growth, carbon sequestration and peat decomposition. Molecular and experimental studies have, however, revealed genetic structure within S. magellanicum, and morphological differences associated with these genetic groups. Here we describe Sphagnum divinum in Sphagnum subgenus Sphagnum (Sphagnaceae, Bryophyta) as a new species, based on molecular and morphological evidence. Sphagnum medium is reinstated as a distinct species and is epitypified. Consequently, a new species concept of S. magellanicum is presented including an epitypification. Important morphological characters to separate these three species in the field and under the microscope are presented. Ecology and distribution differ among the species; S. divinium has a wide habitat range including mire margin, forested peatlands and moist heaths, and a circumpolar distribution around the northern hemisphere. Sphagnum medium seems to be more restricted to ombrotrophic mire expanse habitats and shows an amphi-Atlantic distribution in the northern hemisphere. Sphagnum magellanicum has a very broad ecological niche in peatlands and is found in most mire habitats in Tierra del Fuego on the southern tip of South America.  相似文献   

2.
Haplodontium zangii X.R.Wang &; J.C.Zhao, a new moss species from Xizang, China, is described and illustrated. Previously, specimens of H. zangii have been identified as Mielichhoferia himalayana Mitt. However, H. zangii is distinctly different from M. himalayana in having excurrent costae with short awns (vs long denticulate awns), short-pyriform capsules, 0.8–1?mm (vs long-pyriform capsules, 2.5–3?mm), and densely papillose exostome teeth (vs smooth or vertically striped exostome teeth). Haplodontium zangii is similar to H. macrocarpum (Hook.) J.R.Spence, which was traditionally placed in Mielichhoferia Nees &; Hornsch. as M. macrocarpa (Hook.) Bruch &; Schimp. The main differences between H. zangii and H. macrocarpum are in the morphology of the leaves, capsules, guide cells, and stomata. Mielichhoferia himalayana and another Chinese species of Mielichhoferia, M. sinensis Dix., are also transferred to Haplodontium Hampe, a new genus in the bryoflora of China, as H. himalayanum (Mitt.) X.R.Wang &; J.C.Zhao and H. sinensis (Dix.) X.R.Wang &; J.C.Zhao. A morphological comparison and a key to the three species of Haplodontium in China as well as to H. macrocarpum, a species that is likely to be found in China, are provided.  相似文献   

3.
A previously undescribed species of Euglena, E. myxocylindracea, sp. nov., is described from soil in a garden and in a while pine woods in Pike County, Pa. In addition to the, type, an organism (No. 457) in the Culture Collection of Algae. Indiana University, hitherto designated E. viridis var. terricola. is transferred to E. myxocylindracea as var. terricola. Differences such as the usual absence of an emergent flagellum, or the presence of an extremely short one (ca. 3.5–4 μ), and the dominance of a palmelloid state in a variety of liquid and solid culture media in which the cells secrete dichotomously branching slimy cylinders distinguish the new species from E. viridis.  相似文献   

4.
A. Vilenkin 《Biopolymers》1977,16(8):1657-1675
A new technique is presented for treating the ground state of an heteropolymer with a random sequence of components. An exact system of equations is found for determining the ground state energy E which is equal to the polymer free energy f in the lowest-order approximation in T/V (V/2 is the large “surface” energy arising at the boundaries between coiled and “helical” sections: V ? T, Uk; U1 and –U2 are the free energies of the components counted from the corresponding coiled state energies). These equations are essentially simplified at certain fixed values of the ratio U1/U2. For integer values of U2/U1 and U1/U2 a solution is obtained with an accuracy exp(–V/Uk). The ground-state energy as a function of U1 and U2 is shown to be highly irregular: its derivatives have jumps at an infinite number of points. These jumps provide a fine structure of the melting curves. A smoothed over the jumps function E′ is found by way of analytic continuation from the integer values of U1/U2 and U2/U1. The accuracy of the approximation fE is estimated and the correctional term of order T/V is determined.  相似文献   

5.
A theory of diffusion control within hollow fiber catalysts is derived for three different types of coordinate geometries: Cartesian, cylindrical, and spherical. Effectiveness factors are calculated and formulas for reactant conversion in both a fixed-bed and a contimunuous-feed stirred-tank reactor are derived. The apparent Michaelis constant, Km′, is a measure of the amount of diffusion control within the catalysts. When Km′ is equal to Km, the true Michaelis constant, there is no diffusion control. In all other cases Km′ is greater than Km. Hollow fibers are attractive alternatives to spherical microcapsules for the encapsulation of enzymes.  相似文献   

6.
Summary The plasmid pBC16 (4.25 kbases), originally isolated from Bacillus cereus, determines tetracycline resistance and can be transformed into competent cells of B. subtilis. A miniplasmid of pBC16 (pBC16-1), 2,7 kb) which has lost an EcoRI fragment of pBC16 retains the replication functions and the tetracycline resistance. This plasmid which carries only one EcoRI site has been joined in vitro to pBS1, a cryptic plasmid previously isolated from B. subtilis and shown to carry also a single EcoRI site (Bernhard et al., 1978). The recombinant plasmid is unstable and dissociates into the plasmid pBS161 (8.2 kb) and the smaller plasmid pBS162 (2.1 kb). Plasmid pBS161 retains the tetracycline resistance. It possesses a single EcoRI site and 6 HindIII sites. The largest HindIII fragment of pBS161 carries the tetracycline resistance gene and the replication function. After circularization in vitro of this fragment a new plasmid, pBS161-1 is generated, which can be used as a HindIII and EcoRI cloning vector in Bacillus subtilis.Hybrid plasmids consisting of the E. coli plasmids pBR322, pWL7 or pAC184 and different HindIII fragments of pBS161 were constructed in vitro. Hybrids containing together with the E. coli plasmid the largest HindIII fragment of pBS161 can replicate in E. coli and B. subtilis. In E. coli only the replicon of the E. coli plasmid part is functioning whereas in B. subtilis replication of the hybrid plasmid is under the control of the Bacillus replicon. The tetracycline resistance of the B. subtilis plasmid is expressed in E. coli, but several antibiotic resistances of the E. coli plasmids (ampicillin, kanamycin and chloramphenicol) are not expressed in B. subtilis. The hybrid plasmids seem to be more unstable in B. subtilis than in E. coli.  相似文献   

7.
A new chemolithotrophic nitrite-oxidizing bacterium, for which the name Nitrospira marina is proposed, was isolated from the Gulf of Maine. N. marina is a Gramnegative curved rod which may form spirals with 1 to 12 turns. Cells have a unique periplasmic space and lack intracytoplasmic membranes and carboxysomes. N. marina is an obligate chemolithotroph, but best growth is obtained in a mixotrophic medium. N. marina may be one of the most prevalent nitrite-oxidizing bacteria in some oceanic environments. Type strain is field with American Type Culture Collection (ATCC 43039).  相似文献   

8.
The taxon currently known as Isothecium myosuroides var. brachythecioides (Dixon) Braithw. is reinstated as a species, I. interludens Stirt., the name originally assigned by Stirton when it was first described. The morphological characters separating I. myosuroides s.s. and I. interludens are summarised. The sporophytes of I. interludens, described here for the first time, differ in shape, and pattern of exothecial cells from those of I. myosuroides. A molecular analysis based on variation of the ITS region shows that I. holtii Kindb. and I. alopecuroides (Lam. ex Dubois) Isov. are not monophyletic, calling for a re-assessment of these species, whereas the monophyly of the other species, including I. interludens, cannot be rejected. The analysis failed, however, to yield molecular synapomorphies for I. interludens and other species within I. myosuroides s.l., which we interpret as the incomplete sorting of alleles among recently evolved species. Isothecium interludens is a European endemic with a hyperoceanic temperate distribution. Its nested position within a clade including the two Macaronesian endemics I. prolixum (Mitt.) M.Stech and I. montanum Draper, Hedenäs, M.Stech, T.Lopes & Sim-Sim is suggestive of a Macaronesian origin, in line with the idea that the European Atlantic fringe flora assembled during the course of the last interglacial from Macaronesian ancestors. Isothecium therefore offers a model of prime importance for the study of ongoing speciation in mosses.  相似文献   

9.
Chassalia magnificens, a new species from the Albertine Rift in eastern Democratic Republic of Congo, is described and illustrated. The species is recognised inter alia by its large stipules and montane habitat. Chassalia chrysoclada is a new combination for a widespread, but hitherto overlooked, central African species originally described in the genus Psychotria. Chassalia chrysoclada is related to C. pteropetala (K. Schum.) Cheek but lacks the bicostate twigs and dorsally winged corolla lobes of that species.  相似文献   

10.
Curcuma pygmaea?korni?k. & ?ída f. (Zingiberaceae), a new species from Vietnam, is described and illustrated. Notes on its closest allies in Curcuma subgenus Hitcheniopsis, C. parviflora Wall. and C. thorelii Gagnep., are provided and a lectotype of C. thorelii is designated.  相似文献   

11.
Two new methanogenic bacteria, Methanocorpusculum sinense spec. nov. strain DSM 4274 from a pilot plant for treatment of distillery wastewater in Chengdu (Province Sichuan, China), and Methanocorpusculum bavaricum spec. nov. strain DSM 4179, from a wastewater pond of the sugar factory in Regensburg (Bavaria, FRG) are described. Methanocorpusculum strains are weakly motile and form irregularly coccoid cells, about 1 μm in diameter. The cell envelope consists of a cytoplasmic membrane and a S-layer, composed of hexagonally arranged glycoprotein subunits with molecular weights of 90000 (Methanocorpusculum parvum), 92000 (M. sinense), and 94000 (M. bavaricum). The center-to-center spacings are 14.3 nm, 15.8 nm and 16.0 nm, respectively. Optimal growth of strains is obtained in the mesophilic temperature range and at a pH around 7. Methane is produced from H2/CO2, formate, 2-propanol/CO2 and 2-butanol/CO2 by M. parvum and M. bavaricum, whereas M. sinense can only utilize H2/CO2 and formate. Growth of M. sinense and M. bavaricum is dependent on the presence of clarified rumen fluid. The G+C content of the DNA of the three strains is ranging from 47.7–53.6 mol% as determined by different methods. A similar, but distinct polar lipid pattern indicates a close relationship between the three Methanocorpusculum species. The polyamine patterns of M. parvum, M. sinense and M. bavaricum are similar, but distinct from those of other methanogens and are characterized by a high concentration of the otherwise rare 1,3-diaminopropane. Quantitative comparison of the antigenic fingerprint of members of Methanocorpusculum revealed no antigenic relationship with any one of the reference methanogens tested. On the basis of the distant phylogenetic position of M. parvum and the data presented in this paper a new family, the Methanocorpusculaceae fam. nov., is defined.  相似文献   

12.
SYNOPSIS. A previous study with P. de Puytorac on O. bacterocaryon(3) has shown the methods of studying this Ciliate and has specified the general and buccal morphology, the morphogenesis, and the biology of vegetative individuals (theront, trophont, tomont, tomites) of this species. Three species we are describing now offer numerous common features with O. bacterocaryon. We consider them as the proper characters of genus Ophryoglena and we only insist on the specific particularities of O. gelifera, O. mucosa and O. multimicronucleata. O. gelifera is a large Ophryoglene differing from the others by a slightly asymetric, curved, spindle-shaped theront; the ellipsoidal tomont secretes abundant and clear jelly. The theront possesses one thick spindle-shaped macronucleus, one voluminous spherical micronucleus, fitting with the macronucleus. Its somatic infraciliature is dense, its buccal infraciliature is characteristic, especially in the shape of peniculus P1. This species cannot be mistaken for O. pectans Mugard(2) although it is rather near it. O. mucosa is a very small Ophryoglene. The theront has one thick elliptical macronucleus, one small micronucleus; the buccal orifice is not kidney-shaped, but quite pointed in front; there is no tragus; the somatic infraciliature is not close; the peniculus P1 is characteristic. The tomont is ellipsoidal and surrounded by a thick mucous gangue. The tomites are not close together. O. mucosa is very different from O. gelifera and O. pectans Mugard(2). O. multimicronucleata. Near to O. polymicrocaryon Mugard(2), this Ophryoglene differs from it by the small size of all its vegetative elements and especially by its nuclear-apparatus. The latter includes numerous (5 to 6) bulky spherical micronuclei and one macronucleus looking like blackpudding which can be compared to that of O. singularis Canella and Trinchas(1). The theront is spindle-shaped and of a dark-grey colour. The spherical tomont secretes a mucous gangue which is not very thick. Besides, the somatic infraciliature and buccal in fraciliature of the theront (peniculus P1 especially) make O. multi micronucleata quite distinct from O. polymicrocaryon Mugard(2).  相似文献   

13.
One new species, Rhododendron subroseum Xiang Chen & Jiayong Huang, and one new variety, R. denudatum var. glabriovarium Xiang Chen & Xun Chen (Ericaceae), from the Guizhou Province, China are described and illustrated. Rhododendron subroseum is most similar to R. morii from which it differs mainly by having glandular branchlets, a subcordate leaf blade base and a mucronate leaf blade apex, a less floriferous inflorescence, a campanulate to broadly‐campanulate corolla, and a glandular‐hairy style. Rhododendron denudatum var. glabriovarium differs from R. denudatum var. denudatum mainly by having a glabrous ovary. Both of the new taxa are quite rare and therefore their protection is highly desired.  相似文献   

14.
15.
Androecial development of 13 species belonging to six tribes ofFlacourtiaceae has been investigated. While inScolopieae andFlacourtieae the stamens develop centrifugally, inErythrospermeae, Oncobeae andPangieae they are initiated in a centripetal sequence or a sequence that is neither distinctly centripetal nor centrifugal. The distribution of these developmental patterns coincides with the distribution of other characters (e.g. cyanogenic compounds, salicoid leaf teeth) and therefore supports a split of the family intoFlacourtiaceae s. str. (containing theScolopieae, Homalieae, Prockieae, Flacourtieae, Casearieae andBembicieae) andKiggelariaceae (withErythrospermeae, Oncobeae andPangieae) and is in accordance with results of recentrbcL studies.  相似文献   

16.
Michelia sonlaensis Q.N. Vu, a new species of Michelia from Son La province, northern Vietnam is described. The new species is assigned to the genus Michelia (separated from Magnolia), subfamily Magnolioideae based on general morphology. It is closely similar to M. xianianhei and M. mannii, but differs mainly in having a leaf‐lamina that is elliptic, thinly leathery, larger, with lower surface yellowish white villous (easily visible by eyes and feeling by hand), brachyblasts and outside bracts yellowish‐white sericeous, flowers light green to cream white in colour, and nine tepals with the outside of all tepals silky hairy at base.  相似文献   

17.
18.
Pleospora drammondii spec. nov. and its anamorph Stemphylium drammondii spec. nov. The causal organism of a leaf spot disease on Phlox drummondii is described as Pleospora drummondii spec. nov. and its anamorph Stempbylium drummondii spec, nov. — in contrast to earlier reports from the USA, in which the fungus was identified as S. botryosum.  相似文献   

19.
20.
Curcuma pygmaea?korni?k. & ?ída f. (Zingiberaceae), a new species from Vietnam, is described and illustrated. Notes on its closest allies in Curcuma subgenus Hitcheniopsis, C. parviflora Wall. and C. thorelii Gagnep., are provided and a lectotype of C. thorelii is designated.  相似文献   

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