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1.
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   

2.
Summary Reciprocal crosses were performed between Rumex tuberosus and two other taxa belonging to the Acetosa group: R. acetosa and R. thyrsiflorus. All three taxa are dioecious with the same chromosome numbers, XX + 12A, XYY+12A, but they differ from one another in the morphology of some autosomes. R. tuberosus and R. thyrsiflorus are similar in external morphology, while R. acetosa differs greatly from the other two taxa in external morphology as well as ecological characteristics.The F 1 and F 2 hybrids were fully vigorous and viable but their fertility was greatly reduced. Meiotic irregularities were observed in hybrids derived from all crosses. The most remarkable meiotic irregularity was diad formation after first meiotic division. The unreduced gametes derived from diads were responsible for the high frequency of polyploidy observed among the F 2 hybrids. In the cross R. tuberosus × R. acetosa the whole F 2 generation was tetraploid.It is concluded from the analysis performed that R. tuberosus, R. acetosa and R. thyrsiflorus are separate species, closely related to one another but already isolated by genetic and ecological barriers.  相似文献   

3.
ABSTRACT

A new Anchusa species was discovered in the massif of Mt. Lattias in South-Western Sardinia. This species, here described as A. formosa, shows a sharp phenotypic differentiation from the other Sardinian endemic taxa of Anchusa, especially in habit, leaf shape and size, inflorescence and calyx morphology. Ecological traits are also peculiar, the plant being restricted to siliceous debris that accumulates in small depositional areas of dry stream beds. A. formosa is likely to represent a paleogenic schizoendemism originated through isolation and genetic drift from the same genie pool of the other Corso-Sardinian endemic taxa of Anchusa. SEM analyses provide additional information on the micromorphology of the stigma and its papillar pattern, pollen grains, mericarp coat surface and trichomes. The anatomical structure of stem, root and leaf were also analysed. Due to its extreme localization and ecological specialization, A. formosa needs total protection in its natural habitat and should be added to National and International Red Lists of plants at risk of extinction.  相似文献   

4.
We performed a series of in situ batch culture experiments to assess the resource requirements of common diatom taxa in alpine lakes of the central Rocky Mountains of North America. While physiological data are available on the resource requirements of some of these taxa, it is unclear whether intraspecific generalizations can be made across aquatic systems due to the potential development of ecotypes. In these experiments, we used amended lake water for a culture medium and natural diatom populations. Growth kinetics were determined for Asterionella formosa Hassall, Fragilaria crotonensis Kitton, Staurosirella pinnata (Ehr.) Williams and Round and Tetracyclus glans (Ehr.) Mills. Staurosirella pinnata, a historically abundant alpine diatom, had very low N and P requirements. Asterionella formosa and F. crotonensis, generally considered meso- or eutrophic species, exhibited low P requirements if N and Si were in moderate supply. Tetracyclus glans had the highest Si requirement. These experiments reveal that the recent changes in diatom community structure in these alpine lakes may be driven by changes in nutrient supply. We suggest that local diatom taxa and a natural culturing medium should be used to obtain more representative algal physiological data from a particular area.  相似文献   

5.
Morphological and karyological investigations as well as crossing experiments were carried out withR. cacuminis, R. crenatus, andR. alpestris. A key is presented including all 6 taxa of theR. alpestris-group. Ecological and geographical data for the Balkan Peninsula are also presented.R. cacuminis is diploid with 2n = 16 chromosomes as all taxa of the group, its karyotype exhibits no statistically significant differences to those from the 5 other taxa. In crossing experiments betweenR. cacuminis andR. alpestris, no hybrids could be obtained, whereas those betweenR. cacuminis andR. crenatus were slightly successful. According to its morphology, geographical distribution, and crossing behaviour,R. cacuminis is closely related toR. crenatus, and probably has originated fromR. crenatus by quantum speciation.  相似文献   

6.
A new species, Ranunculus giordanoi, belonging to the R. auricomus complex is described from Latium, central Apennines (Italy). It grows in damp meadows on Monti della Laga (National Park of Gran Sasso and Monti della Laga), the largest sandstone massif of central Italy. The new species differs from the closely related R. silanus, endemic to Sila (Calabria, southern Apennines), by leaf aperture, shape of the basal leaves, entire or sometimes deeply lobed cauline leaves, gynoclinium without intervallum and longer carpellophores.  相似文献   

7.
《Journal of bryology》2013,35(3):153-155
Abstract

The taxonomy of Anomobryum julaceum and allied species with axillary bulbils in Europe and Asia is reviewed. A. concinnatum is regarded as a distinct species, occurring in W. and C. Europe, SW., N. and C. Asia and N. America. A. bavaricum has often been confused with A. concinnatum, but differs in its more numerous, small, reddish bulbils and in leaf shape; it is known only from the European Alps. The Asian A. nitidum also has numerous small reddish bulbils but it differs from A. bavaricum in leaf shape and bulbil form. A lectotype is designated for A. nitidum, of which A. gemmigerum and other nominal taxa are regarded as synonyms. Information is presented on geographical ranges and habitats of the four valid species.  相似文献   

8.
The skeletal morphology of Paraorthacodus jurensis, a Late Jurassic neoselachian from Nusplingen, is described based on the incomplete holotype and a newly discovered almost complete specimen. For the first time, the postcranial skeleton could be investigated. Paraorthacodus is characterized by a monognath dental heterodonty and tearing‐type dentition. The number of lateral cusplets in the lateral teeth differs between the holotype and the new specimen, possibly indicating sexual dimorphism. Clasper organs are not preserved in either of the two specimens. The notochord is sheathed by about 123 well‐calcified vertebral centra. The posterior‐most caudal vertebrae are lacking. The transition from monospondylous thoracic to diplospondylous abdominal vertebrae occurs at centra 48 and 49. The origin of the caudal fin is at the 80th centrum. Most conspicuous is the presence of a single spineless dorsal fin. In this respect, Paraorthacodus differs from most palaeospinacids, but resembles Macrourogaleus. Palidiplospinax possibly is sister to a group comprising Synechodus, Paraorthacodus, and Macrourogaleus (the Palaeospinacidae). A reinterpretation of dental and skeletal characters of synechodontiform taxa indicates that Synechodontiformes and Palaeospinacidae are monophyletic groupings of basal neoselachians. Synechodontiformes is probably sister to all living elasmobranchs.  相似文献   

9.
Aims: The aims of the present investigation were to characterize and identify serovars of Riemerella anatipestifer and Riemerella‐like isolates genetically and to test the specificity of PCR tests reported for the identification of R. anatipestifer. Methods and Results: A total of 50 isolates from poultry tentatively classified with Riemerella anatipestifer were characterized genetically by partial sequencing of rpoB and by nearly full sequencing of the 16S rRNA gene for selected isolates. The results obtained were compared with the data from 13 reference strains by phylogenetic analysis. A total of 41 isolates were identified as R. anatipestifer, three as Wautersiella falsenii like, a single isolate as Pelistega europaea, while five isolates were classified as new, unnamed taxa. None of the reported PCR tests for identification of R. anatipestifer were found specific. Conclusions: Characterization of R. anatipestifer and related bacteria by traditional methods is often inconclusive because of inconsistent reactions and phenotypic diversity. For the same reason, gene sequencing and phylogenetic analysis are essential to allow proper classification and identification as demonstrated in the present study. Significance and impact of the Study: The present investigations demonstrated that isolates of R. anatipestifer are often misidentified, and that new serovars should not be accepted unless they have been properly characterized by relevant genetic methods such as gene sequencing. In addition, we showed that the published PCR tests are not specific for this species. Finally, two new taxa were outlined, the final taxonomic positions of which remain to be identified.  相似文献   

10.
The life history pattern, behavior, and distribution of the mysid crustacean,Heteromysis formosa, was studied in a temperate salt marsh. This mysid occurred in epibenthic sled collections every month, but was most abundant from June through November. Marsh creeks with irregular bottoms supported the largest populations, although some individuals occurred in other estuarine habitats and shallow ocean areas.Heteromysis formosa remains hidden on the bottom during the day and swims over open bottom at night. Many young fishes feed onH. formosa, especially at night. Seasonal changes in mysid abundance were related to the life history pattern. Reproduction was continuous from April through October. Overwintering populations of immature mysids were small. FemaleH. formosa were capable of reproducing more than one time. The number of young per brood ranged from 7 to 32 and was related to total adult body length.  相似文献   

11.
12.
A new deepsea monognathid species,Monognathus berteli, is described based on one specimen collected pelagically in the northwestern Indian Ocean at 1440–1018 meters of depth. LikeM. taningi andM. bertini, it belongs to the short-skulled species-group and has very long pectoral fins, but differs from these species by several meristic characters. The described specimen has a very long caudal filament (53% SL) which is not known from otherMonognathus. However, the fragile filament is not used as a diagnostic character since it could easily be broken.  相似文献   

13.
Chromosome numbers are reported for 156 collections representing 100 taxa of Umbelliferae. Approximately two thirds of the collections are from Mexico, Central and South America and indicate a high percentage of polyploid species in certain genera found in this area. Chromosome numbers for plants belonging to 78 taxa are published here for the first time, previously published chromosome numbers are verified for 18 taxa and chromosome numbers differing from those previously published are reported in seven instances. No chromosome counts have been previously published for nine of the genera included here. Further aneuploidy and polyploidy were found in Eryngium, and Lomatium columbianum has been found to be a high polyploid with 2n = 14x. Every chromosome count is referable to a cited herbarium specimen.  相似文献   

14.
Comparative landscape genetics has uncovered high levels of variability in which landscape factors affect connectivity among species and regions. However, the relative importance of species traits versus environmental variation for predicting landscape patterns of connectivity is unresolved. We provide evidence from a landscape genetics study of two sister taxa of frogs, the Oregon spotted frog (Rana pretiosa) and the Columbia spotted frog (Rana luteiventris) in Oregon and Idaho, USA. Rana pretiosa is relatively more dependent on moisture for dispersal than R. luteiventris, so if species traits influence connectivity, we predicted that connectivity among R. pretiosa populations would be more positively associated with moisture than R. luteiventris. However, if environmental differences are important drivers of gene flow, we predicted that connectivity would be more positively related to moisture in arid regions. We tested these predictions using eight microsatellite loci and gravity models in two R. pretiosa regions and four R. luteiventris regions (= 1,168 frogs). In R. pretiosa, but not R. luteiventris, connectivity was positively related to mean annual precipitation, supporting our first prediction. In contrast, connectivity was not more positively related to moisture in more arid regions. Various temperature metrics were important predictors for both species and in all regions, but the directionality of their effects varied. Therefore, the pattern of variation in drivers of connectivity was consistent with predictions based on species traits rather than on environmental variation.  相似文献   

15.
Distinguishing individual Russula species can be very difficult due to extensive phenotypic plasticity and obscure morphological and anatomical discontinuities. In this study, we use the internal transcribed spacer (ITS) and 28S nuclear ribosomal large subunit (LSU) markers to identify and study the genetic diversity of species in the Russula subgenus Compacta in Korea. We focus on two morphologically similar species that are often misidentified for each other: R. nigricans and R. subnigricans. Based on molecular phylogenetic analyses, we identify three subgroups of R. nigricans, with two from Asia and one from Europe/North America. Surprisingly, we find Korean R. subnigricans are more closely related to R. eccentrica from North America than the type specimen of R. subnigricans from Japan. These molecular data, along with habitat data, reveal that Korean R. subnigricans had previously been misclassified and should now be recognized as R. eccentrica. Both ITS and LSU exhibit high interspecific and low intraspecific variation for R. eccentrica, R. nigricans, and R. subnigricans. These markers provide enough resolutional power to differentiate these species and uncover phylogeographic structure, and will be powerful tools for future ecological studies of Russula.  相似文献   

16.
Ctenogobiops is a genus of Indo-Pacific gobies that form obligate, mutualistic associations with shrimp in the genus Alpheus. This study provides a molecular phylogenetic analysis of eight Ctenogobiops species: C. aurocingulus, C. crocineus, C. feroculus, C. formosa, C. maculosus, C. mitodes, C. tangaroai, and C. tongaensis. We recover two clades within the genus, one consisting of C. feroculus and C. aurocingulus, the second including the remaining species arrayed as follows: (C. tongaensis (C. mitodes (C. formosa (C. maculosus (C. crocineus, C. tangaroai))))). Recovery of C. maculosus and C. crocineus as distinct taxa suggests that these species are not synonymous, although sampling in this study is limited. Species of Ctenogobiops are morphologically very similar to each other, with generally consistent meristic character states present throughout the genus. Recognition of species is based primarily on slight variations in color pattern, shape of the dorsal fin, and size of the gill opening. Comparison of our specimens of C. mitodes with accounts of C. pomastictus confirms that color pattern variations and lateral scale counts are more reliable indicators of species identity than relative dorsal fin spine length, particularly for smaller specimens. We evaluate the distribution of morphological characters in the context of the new phylogenetic hypothesis, and provide a summary of distinguishing characters for Ctenogobiops species. In this case, as in other instances of diverse reef-dwelling fish taxa, molecular data are ideal for inferring phylogenetic relationships, whereas morphological data remain the most expedient way to identify species.  相似文献   

17.
Speciation can be described as a reduction, and the eventual cessation, in the ability to interbreed. Thus, determining how gene flow differs within and between nascent species can illuminate the relative stage the taxa have attained in the speciation process. Aquilegia formosa and A. pubescens are fully intercompatible, yet occur in different habitats and have flowers specialized for pollination by hummingbirds and hawkmoths, respectively. Using 79 SNP loci, we genotyped nearly 1000 individuals from populations of both species in close proximity to each other and from putative hybrid zones. The species shared all but one SNP polymorphism, and on average, allele frequencies differed by only 0.14. However, the species were clearly differentiated using Structure, and admixed individuals were primarily identified at putative hybrid zones. PopGraph identified a highly integrated network among all populations, but populations of each species and hybrid zones occupied distinct regions in the network. Using either conditional graph distance (cGD) or Fst/(1‐Fst), we found significant isolation by distance (IBD) among populations. Within species, IBD was strong, indicating high historic gene flow. IBD extended approximately 100 km in A. pubescens and 30 km in A. formosa. However, IBD between the species was very weak and extended only a few km beyond hybrid zones, suggesting little recent gene flow. The extensive sharing of SNP polymorphisms between these species suggests that they are very early in the speciation process while the low signal of IBD suggests that they have largely ceased gene exchange.  相似文献   

18.
Anton Igersheim 《Grana》2013,52(6):321-326
Pollen of 20 species of Rondeletia, covering three subgenera and seven sections or “species groups” of the genus, was studied using light and scanning microscopy. Rondeletia, characterized by binucleate mature pollen grains like numerous other Rubiaceae, was found to be eurypalynous. The pollen is isopolar and small-sized (average equatorial diameters 11.4–22.8 μm) and 3-colporate (rarely 4-colporate). In equatorial view, the pollen grains are mostly ± spheroidal (rarely suboblate); in polar view (ambitus), they are mainly circular or semiangular (intersemiangular in one species only). Three different exine types are distinguishable: exine with 1) tectum minutely perforate, perforations usually isodiametric, 2) tectum with comparatively large, not isodiametric perforations or 3) coarsely reticulate; supratectal sculpturing elements are lacking; the width of the perforations and lumina is either equal or different at the apo- and mesocolpia; in a few species rod-like luminal processes are present. Palynological features of most of the investigated taxa tend to overlap so that palynology is not very helpful in supporting the subgeneric division of Rondeletia. It was, however, noted that pollen morphology, to some extent, supports the sections of subgen. Arachnothrix. Palynologically, the subgen. Rogiera was found to be heterogeneous in that each of the three investigated species is characterized by a different exine type; one of these, R. strigosa, differs from all other Rondeletia species investigated in having a coarsely reticulate exine. R. odorata (subgen. Rondeletia) differs from all other investigated species in its intersemiangular pollen shape.  相似文献   

19.
Systematics of the red algal order Rhodymeniales was investigated using combined large‐subunit nuclear ribosomal DNA (LSU) and elongation factor 2 (EF2) analyses. These data were subjected to distance, parsimony, and Bayesian analyses, and the resulting phylogenies were largely congruent with previously published SSU results in that the four currently recognized rhodymenialean families (Champiaceae, Faucheaceae, Lomentariaceae, and Rhodymeniaceae) were resolved as monophyletic lineages (with the exception of Coelothrix, which is here transferred to the Champiaceae from the Rhodymeniaceae). In addition, taxa presently considered as incertae sedis consisted of two lineages (Fryeella lineage and Hymenocladia lineage). Based on these results, two new families are proposed: (i) the Fryeellaceae fam. nov. to accommodate the genera Fryeella, Hymenocladiopsis, and a new taxon from Tasmania, Australia; and (ii) the Hymenocladiaceae fam. nov., to accommodate Asteromenia, Hymenocladia, and Erythrymenia. In addition to resolving familial relationships, these analyses resolved some novel interspecific affinities, and we propose a new genus, Neogastroclonium gen. nov., for Gastroclonium subarticulatum, a species that differs significantly in both morphology and molecular data from genuine species of Gastroclonium. Relationships among additional faucheacean and lomentariacean taxa were investigated using LSU data only, and these results are discussed. The familial classification of the Rhodymeniales proposed herein is discussed in light of vegetative and reproductive anatomy, most notably the ontogeny of the tetrasporangia.  相似文献   

20.
We investigated the spectral sensitivity and response to light intensity of Encarsia formosa (Hymenoptera: Aphelinidae), which is a key natural enemy of the greenhouse whitefly, Trialeurodes vaporariorum, and the tobacco whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae). To do so, we used 15 monochromatic lights (emitting various specific wavelengths from 340 to 649?nm) and white light. E. formosa adults, which are diurnal insects, showed a positive phototaxis to a broad spectrum of light, with peaks of sensitivity at 414, 340, 450, and 504?nm. These results show that this parasitoid is generally more sensitive to short wavelength lights than long wavelength lights across all spectral ranges tested. Furthermore, E. formosa adults showed an increased phototactic response at low intensities and a decreased response at high intensities, for both ultraviolet light and violet light. Thus, E. formosa showed both colour and intensity preferences. This experiment provides a scientific basis for the development of colour traps for insect pest management and improves understanding of the ecological significance of colour vision by E. formosa.  相似文献   

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