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1.
The alpine zones of Ladakh are floristically and geobotanically very interesting. In the past these were poorly known botanically because of the ruggedness and inaccessibility of the area. The varied climatic conditions and habitat types have a main role to play in establishing the vegetation of these zones. A total of 122 taxa were identified from collections made during the summer months (July, August and September) of the year 1976. These areas fall in an altitudinal range of 4000 to 5000 m. Fifteen taxa are reported as new records for this region. Six different habitat types were recognised on the basis of local distribution of these taxa, viz. 1. Rocky and gravelly sites; 2. Alkaline swamps; 3. Silty and clay sites; 4. Stream sites; 5. Meadow and shrub fields and 6. Cultivated field sites. A comprehensive inventory of the flowering plants of this region is given in the paper.  相似文献   

2.
Comparisons between floral scent-based and DNA-molecular-based taxonomies are rare, yet such comparisons indicate that scent can provide useful taxonomic information. Here, we correlate the phytochemical differentiation in floral scent to the DNA-molecular-based differentiation in the genus Sorbus. Inflorescence scent patterns of the apomictic and endemic Sorbus latifolia microspecies Sorbus franconica, Sorbus adeana, and Sorbus cordigastensis originated by hybridization as well as their parental taxa Sorbus aria agg. and Sorbus torminalis were investigated with the dynamic headspace method. The scent data (presence/absence of compounds) were used to construct an UPGMA tree, to calculate a similarity matrix, and to correlate them with the published amplified fragment length polymorphism (AFLP) data of the same individuals, populations, and taxa. Flow cytometry was used to estimate the DNA-ploidy level of the taxa. Scent analyses showed a total of 68 substances, among them aromatic compounds, terpenoids, aliphatics, and nitrogen-containing compounds. The scent patterns were taxon-specific, and the number of scent components differed among taxa. The correlations with the published AFLP data on population and individual level are highly significant, indicating that the scent and AFLP data are highly congruent in the plants studied. Scent therefore provides useful taxonomic characters in Sorbus.  相似文献   

3.
The biogeographic affinities of the Cretaceous and early Tertiary angiosperm floras of the North American area (which includes Meso-America, and the Greater Antilles) have been the subject of considerable interest. Although recent treatments of isolated taxa have shown affinities between North American, European, east Asian and Neotropic floras, the relationships have not been quantified. This study compiles the records of fossils whose familial relationships seem secure. This provides a carefully culled, and uniformly presented review of the Cretaceous and Paleogene record from 1950 to 1989 and supplements LaMotte (1950). A subset of these records, which showed compelling evidence of subfamilial relationships, was analyzed to quantify the relationships of the Cretaceous, Paleocene, Eocene and Oligocene floras to other regions. The analysis suggests that for the entire period 24% of the fossil species had affinities with extant taxa from the Northern Hemisphere; 10% with taxa from the Northern Hemisphere that have a few species in South America; 17% with taxa from Eurasia; 3% with taxa with a disjunct Eurasian-South American pattern; 19% with taxa from South America and/or Africa; 8% with taxa from South America and/or Africa that have an important sister group in southeast Asia; 5% with taxa from the Old World; and 13% with taxa having other distribution patterns. Those fossils with affinities to Laurasian taxa are mostly found in the northern and western portions of the North American area. The fossils with affinities to South American and/or African taxa are found in the southern portions of North America, Meso-America, and the Greater Antilles. The taxa with disjunct distributions show both patterns. These patterns suggest that during this time there were wide-spread temperate elements, found throughout Laurasia; Boreotropical flora elements, distributed in North America, Europe and along the Tethys seaway to southeast Asia; and West Gondwana elements which show dispersion from South America across the proto-Caribbean. The paleobotanical data are compatible with current geological, paleontological and biogeographical studies.  相似文献   

4.
Of the many types of freshwater bodies across Iceland (e.g., lakes, springs, rivers, and ponds), greater effort has been invested in researching the freshwater Crustacea (Cladocera, Copepoda) of more permanent, larger, and deeper water bodies than on smaller or more ephemeral sites. To address this, we described the fauna of 12 shallow freshwater bodies distributed from the coast to the central highlands of Iceland. We identified 16 species in 11 genera belonging to six families of Cladocera, and 12 species in eight genera belonging to four families of Copepoda. Five of the species we identified (Alona werestschagini, Cyclops vicinus, Daphnia cristata, Diacyclops abyssicola, and Heterocope borealis) represent new distribution records for Iceland, increasing the number of species now known from this region to 34 Cladocera and 38 Copepoda taxa. Additionally, we discuss the taxonomy of some species with doubtful taxonomical status. Six crustacean taxocenes are described, each characterized by the dominance of different taxa, with bottom sediment characteristics best explaining species assemblage structure. We evaluated the relationships between Icelandic Cladocera and Copepoda faunas and those of the adjacent Svalbard, Faroe, and Shetland Islands, Greenland, and the mainland Norway. The taxonomic composition of the Icelandic fauna is dominated by widely distributed Holarctic, and secondarily Palaearctic and Nearctic species, and is more similar to the faunas of the major North Atlantic islands (64.2–71.8 % similarity) than it is to that of continental Norway.  相似文献   

5.
The deep-water macroalgal community of the continental shelf off the east coast of Florida was sampled by lock-out divers from two research submersibles as part of the most detailed year-round study of a macroalgal community extending below routine SCUBA depths. A total of 208 taxa (excluding crustose corallines) were recorded; of these, 42 (20.2%), 19 (9.1%), and 147 (70.7%) belonged to the Chlorophyta, Phaeophyta, and Rhodophyta, respectively. Taxonomic diversity was maximal during late spring and summer and minimal during late fall and winter. The number of reproductive taxa closely followed the number of taxa present; when reproductive frequency was expressed as a percentage of the species present during each month, two peaks (January and August) were observed. Most perennial species had considerable depth ranges, with the greatest number of taxa observed from 31 to 40 m in depth. Although most of the taxa present also grow in shallow water (i.e. <10 m), there were some species whose distribution is limited to deeper water. The latter are strongly dominated by rhodophytes. This community has a strong tropical affinity, but over half the taxa occur in warm-temperate areas. Forty-two new records (20% of the taxa identified) for Florida were listed; this includes 15 taxa which previously had been considered distributional disjuncts in this area. The phaeophyteHalopteris filicina is a new addition to the flora of the western Atlantic. Although more studies are needed, it appears that the deep-water flora may be relatively continuous over a large portion of the tropical and subtropical western North Atlantic. The traditional practice of considering Cape Canaveral as a biogeographical boundary may only be appropriate for shallow water. This study demonstrates the need for additional floristic work on macroalgal communities, especially from deep water, before more detailed biogeographical analyses can be performed and suggests that deep-water species could be important in experimental approaches to macroalgal biogeography.  相似文献   

6.
Today, class Demospongiae is the largest of phylum Porifera but its fossil record, especially for “soft” demosponges, is rather scarce. This study documents exceptionally preserved isolated opaline spicules, unique for the Bartonian of Italy. Interpretation of morphological types of spicules by comparison with living species lead to their attribution to five orders (Astrophorida, Hadromerida, Haplosclerida, Poecilosclerida, “Lithistida”), seven families (Geodiidae, Placospongiidae, Tethyidae, Petrosiidae, Acarnidae, ?Corallistidae, Theonellidae) and five genera (Geodia, Erylus, Placospongia, Chondrilla, Petrosia, ?Zyzzya). All the described genera are first reported from the Eocene of Europe. This study expands the geographical range of these taxa and fills a chronological gap in their fossil record. The spicules are often fragmented and bear signs of corrosion. They show two types of preservation: glassy and translucent. X-ray powder diffraction analysis confirms that both types are opal-CT with probable presence of original opal-A. Despite this, using a scanning electron microscope the texture of freshly broken surfaces is different. Milky spicules show a porous structure with incipient lepispheres. This feature, together with surface corrosion and the constant presence of the zeolite heulandite/clinoptilolite, point to a certain degree of diagenetic transformation. Macro and micro facies analysis define the sedimentary environment as a rocky shore succession, deepening upward within the photic zone. The spicule-rich sandy grainstone represents the deepest facies and was deposited in a middle-outer carbonate ramp environment, in part in a fairly high energy environment close to storm wave base.  相似文献   

7.
Names for two subspecies and 7 species are validated, in a supplement to the author's account ofAlchemilla for the Flora of Slovakia and the Flora of Czechoslovakia. Aspects of the taxonomy, variation, ecology, and geographical distribution of the taxa published as new are considered briefly.  相似文献   

8.
The species composition of centric diatoms from Lake Frolikha (Transbaikal area) has been studied. The lake is located on the eastern shore of Lake Baikal and connected with it by a river. Twenty-three species of Centrophyceae from 7 genera (Aulacoseira, Cyclostephanos, Cyclotella, Discostella, Handmania, Pliocaenicus, and Stephanodiscus) have been found. The most represented genus is Aulacoseira (11 species). Fifteen species and 4 genera are new for the lake record. All revealed species are known in other lakes of the Baikal region; however Baikal endemics are absent in Lake Frolikha. The flora of centric diatoms in Lake Frolikha can be divided into two groups. The first group includes taxa common in Lake Baikal, and the second group includes taxa not typical for Lake Baikal. The level of differences between flora in Lake Baikal and Lake Frolikha is high (43%) despite the close location and connection to the river. An analysis of distribution of interesting species in Asia is presented.  相似文献   

9.
Projects involving citizen scientists have greatly increased over the last decade and understanding errors associated with such projects has been identified as an important step. NatureWatch NZ is a biodiversity recording system accessible to members of the public. The “NZ wasps, ants, bees and parasitoids (Hymenoptera) project” was initiated within NatureWatch NZ in December 2012, and comparisons were analysed between these records and the known Hymenoptera fauna of the New Zealand region. Over the course of 1 year 25 members contributed 360 records from 186 taxa, including the discovery of several introduced species new to New Zealand. There was a strong geographical bias to the records, with the majority being based around the major cities. Aculeates (stinging wasps) were significantly over-represented in the NatureWatch records. Only half (55 %) of taxa were identified to species level, with a further 28 % at genus level, and 17 % identified above genus level (family, order). Furthermore, the majority (65 %) of taxa were recorded only once, and only a few taxa were recorded >5 times (top records were “Ichneumonidae”, “Hymenoptera”, Anthidium manicatum, and Apis mellifera). It is probable that these same biases also exist for many other taxonomic groups in projects operated by citizen scientists lacking set protocols. Caution should be exercised on the subsequent use, compilation, and analysis of citizen science, especially without prior examination of records and potential biases.  相似文献   

10.
47 names and combinations are published as new, chiefly from the elaboration ofAlchemilla byA. Plocek inL. Bertová (ed.), Flóra Slovenska 4/3, Bratislava (in press). The populations recognized as varieties and species new to science (12 and 29, respectively) come from the summits of W. Beskids (9 taxa), Belianske Tatry (12), other parts of Tatra (8), Fatra (5), elsewhere in the Central Carpathians in Slovakia (4), the Low Beskids in E. Slovakia (1), W. and E. Carpathians (1), N. Moravia (1). In addition, three epithets are published in a new combination, and the names for two new subseries and a new forma are proposed.  相似文献   

11.
Microfossils, stromatolites, and chemical biosignatures indicate that Earth became a biological planet more than 3.5 billion years ago, making most of life''s history microbial. Proterozoic rocks preserve a rich record of cyanobacteria, including derived forms that differentiate multiple cell types. Stromatolites, in turn, show that microbial communities covered the seafloor from tidal flats to the base of the photic zone. The Archean record is more challenging to interpret, particularly on the question of cyanobacterial antiquity, which remains to be resolved. In the late Neoproterozoic Era, increasing oxygen and radiating eukaryotes altered the biosphere, with planktonic algae gaining ecological prominence in the water column, whereas seaweeds and, eventually, animals spread across shallow seafloors. From a microbial perspective, however, animals, algae, and, later, plants simply provided new opportunities for diversification, and, to this day, microbial metabolisms remain the only essential components of biogeochemical cycles.We live on a planet that records its own history, encrypted in the physical and chemical features of sedimentary rocks (Knoll 2003). Part of this history is biological; as appreciated by every child who has visited a natural history museum, bones and shells furnish a remarkable chronicle of animal evolution, complete with dinosaurs, trilobites, and other evocative taxa. The fossil record of animals extends nearly 600 million years into the past, but comparative biology makes it clear that diverse microorganisms populated our planet long before animals first evolved. The Earth itself is >4.5 billion years old, and the known sedimentary record begins with highly metamorphosed sedimentary rocks deposited ∼3.8 billion years ago. To what extent do Earth''s older sedimentary rocks provide a direct and informative record of our planet''s deep evolutionary history?  相似文献   

12.
Isozyme variation in 94 accessions of Mexican maize (Zea mays ssp. mays) and 37 collections of Mexican annual teosinte (Z. mays ssp. mexicana and var. parviglumis) are compared. Variety parviglumis (a predominantly wild plant) shows a closer genetic relationship to maize than does ssp. mexicana (a weedy teosinte often found in maize fields). The isozyme data suggest that maize and Z. mays var. parviglumis share a more recent common ancestor than either of these taxa share with other members of the genus Zea. In this sense, the isozyme data support the theory that maize is a domesticated form of teosinte. Isozyme data provide no evidence for independent origin of Mexican maize races from different taxa of teosinte. Isozyme analysis suggests that gene flow between maize and ssp. mexicana exists, but that it is highly restricted and more probably goes from weed into crop. Maize and var. parviglumis are isozymically too similar and too variable to allow patterns of gene flow between them (if any) to be discerned. The maize- teosinte complex does not fit a model applied to some other crops in that (I) weedy teosinte (ssp. mexicana) does not appear to be a hybrid of the wild form (var. parviglumis,) and maize and (2) the weedy form does not act as a genetic bridge between wild form and crop.  相似文献   

13.
Meteorites, particularly type II carbonaceous chondrites, provide natural, tangible evidence for chemical evolution, but they do not appear to contain any evidence for biological evolution. On the other hand, some of the oldest sedimentary rocks of the earth have yielded good evidence for early biological evolution; whatever evidence there may be for chemical evolution in these old rocks is generally obscure. Carbonaceous chondrites (types I, II, and III) have been examined for thier content of various kinds of organic compounds. Amino acids have been reported to be present in the three types, but only in type II carbonaceous chondrites (Murray and Murchison) has an indigenous suite of amino acids been found which is apparently free of most terrestrial contaminations. These indigenous compounds are thought to have resulted from extraterrestrial, abiotic, chemical syntheses, and the presence of the amino acids in meteorites provides strong support for the theory of chemical evolution. The geological record of the Swaziland Sequence and Bulawayan System of Southern Africa contains morphological and chemical fossils which indicate that early biological evolution was taking place at least 3.0 to 3.3 aeons ago. Interpretation of the significance of the chemical fossil record has proven to be difficult. At present the occurrence of simple compounds in these very ancient rocks is believed to have little or nothing to do with biochemical processes three aeons ago. The bulk of the reduced carbonaceous material in these rocks, however, probably represents the residue of three billion years old and older organic matter. Isotopic studies of this carbonaceous material may provide chemical evidence for early biological evolution.  相似文献   

14.
Scanning electron microscopy was used to examine foliar surface features such as trichome types and the micro-relief formed by cell contours, cuticular patterns, and epicuticular wax in the genusCarya. The fourteen taxa native to Mexico and eastern United States were sampled throughout their geographical ranges, and are represented here by specimens that include segregate taxa, interspecific hybrids, and mature and immature leaves of each. Six trichome types are recognized in this survey: acicular, fasciculate, multiradiate, solitary, capitate-glandular, and peltate scale. There are no consistent differences between representatives of either the two Sections of the genus or the two ploidy levels. Although there is significant inter- and intra-specific variation, the use of scanning electron microscopy provides few taxonomically useful characters or character-states beyond those already available through light microscopy. Foliar surfaces of the fourteen taxa and three hybrids are illustrated.  相似文献   

15.
A list of 226 vascular plant type specimens, representing 220 basionyms, found during the incorporation of the DePauw University Herbarium (DPU) into the New York Botanical Garden Herbarium (NY), is presented. Included are the types from Truman G. Yuncker's numerous expeditions to Honduras and the South Pacific. Lists of the types found in the Piperaceae, Cuscutaceae, and cryptogamic collections are being published elsewhere or have already appeared.  相似文献   

16.
The three subtribes which are recognized within the tribe Vandeae are represented in the tropical African and Malagasy regions. All taxa of the Vandeae have a monopodial growth habit. The first subtribe, Sarcanthinae, is mainly Asian-Australasian, but a few of its species occur in Madagascar and in Africa. The other two subtribes. Angraecinae and Aerangidinae, are both represented in the latter two regions. The Angraccinae is characterized by the presence of a short rostellum, but this is elongated in the Aerangidinae. According to earlier authors there is a correlation between presence of the short rostellum and a basic chromosome number of x=19 in the Angraecinae, and between the presence of an elongated rostellum and a basic number of x=25 in the Aerangidinae. The results presented in this paper are placed in perspective with the chromosome numbers recorded by other authors. From the resulting chromosome number survey it appears that only part of the Angraecinae (Aeranthes, several species of Angraecum, Cryptopus and Jumellea) have a basic number of x=19; some members of the Angraecinae (other species of Angraecum) were found to have a basic number of x=21, 24 and 25. The Aerangidinae is not characterized by a single basic number of x=25 but by a series ranging from x=23 to x=27, of which x=23, 24 and 25 are the most frequent. The genus Calyptrochilum, although having a distinetly elongated rostellum, is characterized by a basic number of x=19 and its position within the Aerangidinae may therefore be questioned. The present evidence suggests that too much weight has been attributed to a single character, i.e. the shape of the rostellum, in distinguishing the two subtribes. As there appear to be two groups according to basic number in Angraecum, it appears questionable whether Angraecum, as presently conceived, is a ‘natural’ genus. Further chromosomal and other taxonomic evidence is needed to substantiate the challenge to the present views in respect of Angraecum. Taxa with x=19 appear to be frequent in Madagascar and the other islands in the Indian Ocean, whereas taxa with x=21 to 27 mainly occur on the African continent. The predominance of x=19 in the Malagasy flora suggests a link with the monopodial taxa of the Asian and Australasian floras, which are exclusively based on x=19.  相似文献   

17.
The age and geographical distribution of fossil cercopithecids in China   总被引:2,自引:0,他引:2  
Cercopithecids did not arrive in China until the latest Tertiary, relatively late in their evolutionary history. Cercopithecines are represented in the Chinese fossil record by two genera,Procynocephalus andMacaca, both of which made their appearance in the Late Pliocene or Early Pleistocene, but only one of which,Macaca, was widely distributed throughout the Quaternary and remains in the country today. The much less well known genusProcynocephalus disappeared from China in the late Early Pleistocene, but is of considerable interest because it appears to have been part of a radiation of large terrestrial cercopithecines that extended throughout portions of southern and eastern Asia. Colobines are poorly represented in the fossil record of China. Aside from a few scattered occurrences ofRhinopithecus in the Middle and Late Pleistocene records of southern China, the subfamily is represented by only one other intriguing specimen. This is the large and nearly complete mandible now classified as «Megamacaca lantianensis» from the Gongwangling locality of Lantian, Shaanxi Province. The specimen was retrieved from sediments of late Early Pleistocene age and was associated with elements of a typical southern,Ailuropoda — Stegodon fauna. The distribution of cercopithecids, especiallyMacaca, in China followed the southern and eastern retreat of subtropical habitats during the course of the Pleistocene.  相似文献   

18.
The IUCN Red List of threatened species is biased towards vertebrate animals, a major limitation on its utility for overall biodiversity assessment. There is a need to increase the representation of invertebrates (currently 21 % of species assessed on the List; <1 % of all invertebrates). A prioritisation system of terrestrial and freshwater groups is presented here, categorising taxa by species richness, assessment practicality, value for human land use and bioindication, and potential to act as conservation flagships. 25 major taxonomic groupings were identified as priorities, including the Annelida, Arthropoda, Mollusca, and Onycophora. Of these, the high-level taxa that emerge as highest priorities are Odonata (dragonflies and damselflies), Araneae (spiders), Mantophasmatodea (heelwalkers), Plecoptera (stoneflies), non-marine Mollusca (Bivalvia and Gastropoda), Trichoptera (caddisflies), Coleoptera (beetles), Lepidoptera (moths and butterflies), Oligochaetes (earthworms), Orthoptera (grasshoppers and crickets), Decapoda (crayfish, crabs, shrimps) and Diptera (flies). Of these Red Listing is well advanced for Decapoda, freshwater Mollusca and Odonata. This leaves eight higher taxa with currently a minimum or patchy Red List assessment coverage. We recommend that Red List assessments in future focus on these groups, as well as completion of assessments for terrestrial Molluscs and Odonata. However, we also recommend realism, and as some of groups are very large, it will be necessary to focus on subsets such as certain functionally important or charismatic taxa or on a sampled subset which is representative of a larger taxon.  相似文献   

19.
Previously published data on flowering phenology and pollination of neotropical families are reviewed and compared with new observations, in order to evaluate some trends of pollination strategies in neotropical savannas and forests. Central American forestBignoniaceae apparently diminish competition between sympatric species with identical pollination strategies by alternating flowering. On the other hand, in theBignoniaceae of Brazilian cerrado savannas coincident flowering is more common, suggesting different pollination strategies. Bees specialized in nectar robbery are associated withBignoniaceae, particularly mass-flowering species. These nectar robbers stimulate pollinator movements between flowers and thus increase pollen-flow. The flowering phenology of theMalpighiaceae from forests and savannas apparently follows the phenology of theAnthophorinae (mainlyCentridini)-bees, on which this plant group almost exclusively depends for pollination in the Neotropics. As the flowers of different genera and species are very uniform, the bees quite indiscriminately pollinate coexistingMalpighiaceae taxa. In theMalvaceae, the more primitive tree or shrub habit and an allogamous reproduction system is quite significantly associated with an ornithophilous pollination mode. Hummingbirds in the Neotropics have probably influenced the origin of the primitive bird-pollinatedMalvaceae flower. In conjunction with the diversification of theMalvaceae and their migration into more open regions, pollination by bees has apparently become more prominent. ChiropterophilousMalvaceae seem to have developed more recently from ornithophilous ancestors within the neotropical forest regions. As a result of this ecological radiation, parallel modifications of the basic ornithophilous flower principle can be traced in different groups of theMalvaceae. Dynastinae-beetles are pollinators of South and Central American species ofAnnona, Cymbopetalum, Caladium, Talauma, Philodendron, Victoria, Nymphaea, Cyclanthus, Bactris and others. In many cases the relationship between flowers and theirDynastinae visitors is not very specific, principally reflecting differences in the faunistic spectrum of diverse regions and vegetation types. The attraction of these beetles as flower visitors in several unrelated groups of Angiosperms must have occurred repeatedly. It is suggested that the flower visiting species of this beetle group may have acquired their preference for certain pungent or aromatic flower odours by their feeding habits during the larval stage.  相似文献   

20.
Computerization of the Edward Lee Greene Herbarium at Notre Dame is described. Reasons for the justification of such a project and the steps involved in data accumulation and data processing are presented. Results are or will be available in two forms: 1) formal publications containing summary information, including information on the more than 4400 taxa that Greene named; and 2) a computerized data bank that today can provide answers to questions from individual systematists about the 65,000 specimens. Problems in automation are discussed, as are the relation of this project to similar ones. Finally, an invitation is extended to readers to query the data bank without cost.  相似文献   

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