首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 0 毫秒
1.
2.
3.
Four different cytotypes have been reported for Senecio jacobaea L. ssp. jacobaea throughout Europe, with the most common occurrence of tetraploids (2 n  = 40). Here we present a survey of previously published chromosome number data on this subspecies and its geographical distribution, and focus on populations from Pannonia and the Carpathians. Two ploidy levels have been determined in the study area, using chromosome counting and flow cytometry: tetraploid (2 n  = 40) and octoploid (2 n  = 80). Fifty-one populations originating from Slovakia, Austria, the Czech Republic, Hungary, Ukraine and Romania have been analysed. Multivariate morphometric analyses have been performed on 39 populations to study morphological differentiation between these two cytotypes. Despite slight morphological tendencies expressed on the level of populations, tetraploid and octoploids cannot be reliably distinguished morphologically and they are not taxonomically classified formally here.  © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society, 2007, 153 , 231–242.  相似文献   

4.
The taxonomic status of Centaurea section Acrocentron in Iran is briefly reviewed. A critical study of 251 herbarium specimens, and an additional 37 accessions collected specifically for this research, led to the discovery of a new variety, Centaurea irritans var. longispinosa Montazerolghaem , and the revival of another, C. persica var. subinermis, a taxon previously treated as a synonym for about 25 years. A key to all Iranian species of Centaurea section Acrocentron is provided. © 2010 The Linnean Society of London, Botanical Journal of the Linnean Society, 2010, 163 , 99–106.  相似文献   

5.
A new species of the genus Chresta Vell. ex DC. (Vernonieae, Asteraceae) from the Brazilian state of Bahia is described and illustrated. The new species resembles Chresta pinnatifida (Philipson) H.Rob. but differs in having solitary glomerules, leaf bases clasping the stem and 35–40 capitula per glomerule. It can be distinguished from Chresta harleyii and Chresta martii , the other two species of the genus with pinnately lobed leaves, by the type of pubescence, leaf blade bases and florets number. In addition, a key to distinguish all the species of the genus is presented. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society , 2008, 157 , 587–590.  相似文献   

6.
7.
A new species of Centaurea L., C. kizildaghensis (Cardueae: Asteraceae), is described and illustrated from south Anatolia. It is restricted to the serpentine rocky slopes of Kızıl Dağ (C3 Konya–Derebucak, Çamlık), and is closely related to C. pseudokotschyi Wagenitz and C. drabifolioides Hub.-Mor., from which it differs in stem, leaf, and phyllary appendage characters. The diagnostic morphological characters are discussed. A new key is produced for Group G species for the flora of Turkey.  © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 153 , 61–66.  相似文献   

8.
9.
During a stay at the Kirstenbosch Research Centre in Cape Town (South Africa), several groups of Asteraceae were studied. One of these was the genus Marasmodes (tribe Anthemideae). After a careful taxonomic study of additional material, including the first species described by A. P. de Candolle, the author has concluded that eight collections should be considered as new species. These new species are described and their relationships with the most similar species of the genus are discussed. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 159 , 330–342.  相似文献   

10.
11.
A new species Scorzonera gokcheoglui O. Ünal & R. S. Göktürk sp. nov. from south Anatolia is described and illustrated. Its relationships with S. argyria and S. pisidica are discussed. A map showing the distribution of the species and other related species is given.  © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society , 2003, 142 , 465–468.  相似文献   

12.
A new species, Bellium artrutxensis (Asteraceae: Astereae), is described from the therophytic pastures of southern Minorca (Balearic Islands). The analysis of nuclear ribosomal internal transcribed spacer (ITS) sequences showed that the new taxon was closely related to Bellium bellidioides , but differed with regard to the annual lifespan, the absence of epigeal stolons, and the presence of a patent eglandular indumentum on the leaves. The new taxon shows morphological features that are well suited for the colonization of dry environments with a marked summer drought, and may be of adaptive significance. The new species is diploid (2 n  = 18) and shows up to two accessory chromosomes in root tissues. B chromosomes have not been reported previously in other species of Bellium .  © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 154 , 65–77.  相似文献   

13.
14.
A new species, Psephellus turcicus A.Duran & Hamzaoğlu (Asteraceae) in sect. Psephelloidei (Boiss.) Wagenitz & Hellwig is described and illustrated from Anatolia, Turkey. The species grows on limestone crevices in Kazankaya Canyon (A5 Yozgat) in central Anatolia. A neo-endemic confined to Kazankaya Canyon, it is closely related to Psephellus psephelloides (Freny & Sint.) Wagenitz. Diagnostic morphological characters from closely similar taxa are discussed, and arranged in a key of Turkish similar Psephellus Cass. The ecology, biogeography and conservation status of the species are also presented. Achene surface morphology of P. turcicus and P. psephelloides are examined by SEM. The geographical distribution of the new species and other related species is mapped.  © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society , 2005, 148 , 495–500.  相似文献   

15.
16.
HUGHES, L. & RICHARDS, A. J., 1989. Isozymes and the status of Taraxacum (Asteraceae) agamospecies. Genetic identities I and Similarity Indices SI are calculated between 12 samples of Taraxacum, on the basis of 40 isozymes at 15 loci for 10 enzyme systems. Samples included three polyploid agamospermous populations from northern England (group 1), three sexual diploid populations from south-central France (group 2), and six accessions of ‘primitive’ diploid self-compatible sexual taxa from southern Europe and Australia. Samples could be assigned to eight species, classified in seven sections of the genus. Two clusters of high relationship were evident. All the group 1 and group 2 species were very closely related, with pairwise comparisons for I in excess of 0.93. The three group 3 accessions identified as T. bessarabicum showed pairwise comparisons for SI in excess of 0.71. Comparisons for SI between the other group 3 species, and between all the group 3 species and the group 1 and 2 species were all very low, not exceeding 0.45. It is concluded that dissimilarity between samples as assessed by isozymes is probably related to the time of evolutionary divergence of those samples. Although allopolyploid, and morphologically very diverse, the group 1 agamospecies may have very recently diverged asexually from a common stock. The group 2 diploids may have resulted from rediploidization and regained sexuality from the same originally agamospermous stock. In areas of Europe in which such ‘modern’ sexuality is common, it is probable that all ‘modern’ Taraxaca, including at least five sections of the genus, should be included within a single taxon. In contrast, ‘primitive’ self-compatible sexual species in group 3 appear to have diverged from each other several million years ago, and with the exception of the disjunct accessions of T. bessarabicum, are genetically highly distinct. Such species should be maintained in the taxonomies of all areas. It is probable that an agamospecies classification of ‘modern’Taraxacum will continue to convey much useful information in areas, such as northern Europe, in which sexuality is absent.  相似文献   

17.
18.
Mitotic or meiotic chromosome numbers for 42 accessions belonging to 39 species of different genera of Asteraceae were determined. First chromosome counts are reported for one genus ( Gymnocoronis ), 14 species, and one variety. These are as follows: Solidago chilensis var. megapotamica (2 n  = 2 x  = 18), Chromolaena barbacensis (2 n  = 3 x  = 30), Chromolaena christieana (2 n  = 3 x  = 30), Chromolaena hirsuta (2 n  = 4 x  = 40), Chromolaena verbenacea ( n  = 20 II, 2 n  = 4 x  = 40), Disynaphia multicrenulata (2 n  = 2 x  = 20), Gymnocoronis spilanthoides var. subcordata (2 n  = 2 x  = 20), Mikania thapsoides (2 n  = 4 x  = 68), Stevia commixta (2 n  = 2 x  = 22), Porophyllum brevifolium (2 n  = 4 x  = 44), Viguiera rojasii (2 n  = 2 x  = 34), Pterocaulon angustifolium (2 n  = 2 x  = 20), Gochnatia haumaniana (2 n  = 4 x  = 44), Senecio ostenii (2 n  = 4 x  = 40), Senecio pinnatus (2 n  = 8 x  = 80), and Lepidaploa amambaia (2 n  = 2 x  = 28). Chromosome numbers differing from those reported previously in the literature were found in Campuloclinium macrocephalum (2 n  = 2 x  = 20), Melanthera latifolia (2 n  = 4 x  = 60), Chrysolaena flexuosa (2 n  = 2 x  = 20), and Cyrtocymura cincta (2 n  = 4 x  = 40). The relevance of the results is discussed in relation to the available data for each of the analysed taxa. © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society, 2007, 153 , 221–230.  相似文献   

19.
Saussurea balangshanensis, based on populations from Balang Mountain in the Hengduan Mountains region, SW China, is described and illustrated as a new species of Asteraceae. It can be distinguished from other species in Saussurea by its concolorous leaves, swollen and hollow upper stems, articulate hairs and stipitate glandular hairs, laciniate margins of uppermost stem leaves, numerous and sessile capitula, and narrow involucre. Based on nucleotide sequence data from the internal transcribed spacer (ITS), phylogenetic analyses also support the recognition of these populations as representing a new species. The new species is known only from a single location in Balang Mountain, at elevations of 4500–4700 m. Its habitat can be easily disturbed or destroyed by a tourist arterial highway and the over grazing. We propose that the species should be listed as Critically Endangered based on the International Union for Conservation of Nature Red List Categories and Criteria B2a.  相似文献   

20.
A new species of Tripleurospermum Sch.Bip., Tripleurospermum ziganaense Inceer & Hay?rl?oglu‐Ayaz (Asteraceae, Anthemideae), is described and illustrated. The species grows in open places, on rocky slopes and on roadsides in north‐east Anatolia, Turkey. The diagnostic morphological characters that distinguish it from closely related taxa are discussed, and its conservation status is indicated. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158 , 696–700.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号