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1.
Three sections of Calceolaria (Scrophulariaceae) in NW South America are revised, viz. sect. Urticopsis (8 species in the area), Lobatae (4), and Micranthera (2). Sect. Urticopsis is characterized by herbaceous, ovate, petiolate leaves and white to buffish pubescence. Sect. Lobatae is characterized by lobate, petiolate leaves and white to greyish white pubescence. Sect. Micranthera comprises small herbs with a weedy habit, characterized by small anthers and unusually long filaments. Three new species are described, viz. C. obtusa, C. trichanthera , and C. adenocalyx (all in sect. Urticopsis) , and one new combination is made, viz. C. penlandii ssp. puraceensis (sect. Urticopsis). Chromosome numbers (all 2n = 36) are reported for C. lamiifolia, C. obtusa, C. penlandii ssp. penlandii , and C. dichotoma.  相似文献   

2.
Sect. Calceolaria (= Aposecos) of Calceolaria (Scrophulariaceae) in NW South America is revised, and the other species of the section are briefly discussed. The section comprises annual herbs with somewhat succulent stems and leaf–blades that are usually pinnately dissected (pinnatifid). Four species are recognized in the investigated area, viz. C. mexicana, C. tenuis, C. tripartita , and C. chelidonioides , and their chromosome numbers are reported (2n = 32, 60, 64, and 60 respectively). The basic number in sect. Calceolaria is x = 8. Two new combinations are made, viz. C. mexicana ssp. prostrata (Kränzlin) Molau and C. mexicana ssp. perijensis (Pennell) Molau. The species of sect. Calceolaria are intersterile and facultatively autogamous, and each species comprises numerous pure lines, some of which may be morphologically discernible.
In the appendices, chromosome numbers are listed and the occurrence of elaiophores in all NW South American species of Calceolaria is indicated. The chromosome numbers of C. crenata ssp. australis, C. adenanthera, C. gossypina, C. semiconnata, C. stricta, C. sericea , and C. comosa (all 2n = 36) have not previously been reported. A revised key to the sections of Calceolaria in NW South America is also provided.  相似文献   

3.
Sect. Zygophylla of Calceolaria (Scrophulariaceae) in NW South America is revised. It is characterized by connate leaves with winged petioles, and most of the species have intercalary inflorescences. Fourteen species are recognized in the investigated area, one of which is described as new, viz. C. zamorana. Two new combinations are made, viz. C. nevadensis ssp. meridensis (Pennell) Molau and C. purpurascens (Kranzlin) Molau. The chromosome number 2n = 36 is reported for six of the species, viz. C. calycina, C. dilatata, C. grandiflora, C. lanata, C. lojensis , and C. trilobala. The species of sect. Zygophylla are completely interfertile, and sympatric species are isolated by external barriers, e.g. pollination and habitat ecology. Several cases of natural hybridization and introgression are reported.  相似文献   

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6.
The karyology ofCentaurea sect.Acrocentron is surveyed. 19 chromosome counts on 8 species are reported; those onC. acaulis, C. crocata, C. galianoi, C. pubescens, andC. malinvaldiana are new. The basic chromosome numbers of the section are x = 11 and x = 10. Karyological arguments have been used to show that evolution was from x = 11 to x = 10. This is supported by biogeographical data. Two main centres of diversification of sect.Acrocentron were studied from that point of view: the East and the Southwest Mediterranean region.  相似文献   

7.
拟鹅观草属3种植物的核型研究   总被引:4,自引:0,他引:4  
对禾本科小麦族拟鹅观草属物种Pseudoroegneria geniculata、P.geniculata ssp.scythica和P.geniculata ssp.pruinifera的核型进行了研究.结果显示:P.geniculata和P.geniculata ssp.scythica为四倍体物种,P.geniculata ssp.pruinifera为六倍体物种;P.geniculata、P.geniculata ssp.scythica和P.geniculata ssp.pruinifera的核型公式分别为2n=4x=28=18m(2sat)+10sm(2sat)、2n=4x=28=28m(2sat)和2n=6x=42=36m(6sat)+6sm(2sat);P.geniculata和P.geniculata ssp.pruinifera为2A核型,而P.geniculata ssp.scythica为1A核型.研究表明:3种植物的核型存在差异;P.geniculata ssp.pruinifera的核型为首次报道,其核型明显不同于P.geniculata和P.geniculata ssp.scythica.  相似文献   

8.
( 1 ) Some taxonomical problems of the genus Clematis mainly about misidentifications are discussed, and some treatments including the reinstatement of Clematis montana var. brevifoliola Kuntze, C. apiifolia var. biternata Makino, C. subumbellata Kurz, C. goudotiana Planch. & Triana, C. insidiosa Baill., C. kockiana Schneid. and C. longicauda A. Rich., and the reduction of subsect. Africanae M. Johnson, C. umbellifera Gagnep., C. pubescens Benth., C. rhodocarpa Rose, C. edentata Baker, C. stoltzi Engler, C. tibetana ssp. vernayi var. dentata Grey-Wilson, C. clarkeana var. stenophylla Hand.-Mazz., C. subfalcata Pei ex M.Y. Fang, C. angustifoliola W. T. Wang, C. dasyandra var. polyantha Finet & Gagnep. etc are given. (2) The new diagnoses for the two subsections of the sect. Meclatis are provided; C. sericea H.B. K. ex DC. and C. grossa Benth. are treated as two varieties of one species; and a new classification of the infraspecific taxa of C. hirsuta Perr & Guill. is made. (3) one subsection, one series, eight species and one variety are described as new. (4) The new occurrences of C. montana var. brevifoliola Kuntze in southern Xizang, China, Nepal, Bhutan and northern Myanmar, C. burmanica Lace in southwestern Yunnan, C. armandii Franch. in Assam, India and northern Myanmar,and C. yui W. T. Wang in northern Myanmar are reported.  相似文献   

9.
The genus Zea is here divided into the Sect. Luxuriantes Doebley & litis sect. n., including the perennials Z. diploperennis (2n = 20) and Z. perennis (2n = 40) and the annual Z. luxurians (2n = 20); and Sect. Zea , including the wild Z. mays ssp.parviglumis and Z. mays ssp. mexicana (both 2n = 20), and Z. mays ssp. mays (2n = 20), the highly domesticated and tremendously variable derivate of the latter. This division is verified by a multivariate analysis of a large number of morphological characters of the male inflorescence. Cytogenetic and chemotaxonomic evidence supports the morphological conclusions. A consideration of the phylogeny of Zea within the conceptual framework offered by this new sectioning of the genus points convincingly to annual teosinte (Z. mays ssp. mexicana) as the ancestor of cultivated maize.  相似文献   

10.
  • 1 . Folgende Centaurea-Sippen aus der Sektion Acrocentron werden cytologisch untersucht: C. spruneri ssp. minoa (2n = 110), C. spruneri ssp. guicciardii (2n = 110), C. raphanina ssp. raphanina (2n = 20) und C. raphanina ssp. mixta (2n = 20). Die Chromosomenzahl von C. spruneri ssp. minoa wird erstmals mitgeteilt
  • 2 . Die Phylogenie innerhalb der C. spruneri-Gruppe wird kurz diskutiert
  相似文献   

11.
Chromosome numbers of 25 taxa of flowering plants from northern Norway and Svalbard are reported. Four species and one subspecies, Carex halophila F. Nyl. (2n = ca. 78), C. stenolepis Less. (2n = ca. 80), Salicorniapojarkovae N. Sem. (2n = 36), Alnus incano (L.) Moench ssp. kolaensis (Orlova) Love (2n = 28), and Saxifraga svalbardensis D. O. Øvstedal (2n = ca. 64), have not been studied karyologically before. Chromosome numbers of four additional species are reported for the first time from Norway; those of another six species for the first time from northern Norway. The hybrid Salix herbacea L. (2x) x 5. polaris Wahlenb. (6x) is proved tetraploid and may be fertile. A possible hybrid between Saxifraga hyperborea R. Br. and S. rivularis L. was revealed.  相似文献   

12.
13.
Pennisetum sect.Brevivalvula is a species complex characterized by polyploidy and apomixis. Ploidy level was assessed by DAPI-flow cytometry for 304 plants of the section, originating from Burkina Faso, Benin and southern Niger. The results were confirmed for 54 plants based on chromosome counts. The samples show four euploidy levels (with x = 9) distributed among five species:P. hordeoides (2n = 36, 54),P. pedicellatum (2n = 36, 45, 54),P. polystachion (2n = 18, 36, 45, 54),P. setosum (2n = 54), andP. subangustum (2n = 18, 36, 54). The geographical distribution of these ploidy levels seems related to major vegetation zones present in Africa. Diploid populations ofP. polystachion andP. subangustum were found in the Banfora area, in Burkina Faso.  相似文献   

14.
杨亲二   《广西植物》1995,15(4):354-357
本文对鸭跖草科的穿鞘花Amischotolypehispida(LessetA.Rich.)Hong进行了核形态研究。其静止核和有丝分裂前期染色体分别属于复杂中央染色微粒型和中间型;染色体数目为2n=36,核型公式为2n=4m+28sm+4st。本种的核型为首次报道。  相似文献   

15.
While researching Cardamine (Brassicaceae) in the Pyrenees, putative hybrid plants were found at two natural sites. Pollen grain viability, AFLP, and multivariate morphometric analyses were performed in order to assess the plants' presumed hybrid origin, establishing that natural hybridization between the diploids C. crassifolia and C. amara ssp. pyrenaea had occurred. A new diploid nothospecies, C. × enriquei (2 n = 2x = 16), is described. Examination of 18 morphological characters showed the intermediacy of the hybrid between the parental taxa in most characters. AFLP analyses of C. amara ssp. amara , ssp. austriaca , ssp. olotensis and C. raphanifolia , demonstrated the close position of the hybrid to C. crassifolia , and revealed that the highest number of markers were shared with the parents. Polymorphism found in the AFLP pattern of the hybrid suggested recurrent origin, segregation and/or backcrosses, although assessment of pollen viability indicated high male sterility. The hybridization event reported here represents the second documented case between the C. pratensis group and C. amara . An account of the nomenclature of C. crassifolia is also presented, including lectotypification of relevant names.  © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 139 , 275–294.  相似文献   

16.
A taxonomic revision of Psathyrostachys (Poaceae)   总被引:1,自引:0,他引:1  
  相似文献   

17.
Somatic chromosome numbers have been determined for the followingCerastium taxa:C. eriophorum (2n = 36),C. alpinum (2n = 72),C. transsylvanicum (2n = 108),C. arcticum (2n = 108),C. latifolium (2n = 36),C. carinthiacum (2n = 36),C. banaticum (2n = 36),C. arvense subsp.glandulosum (2n = 36),C. arvense subsp.arvense (2n = 72) andC. fontanum (2n = 144). Karyotypes of three diploid species (C. eriophorum, C. banaticum andC. latifolium), belonging to three different taxonomic groups, were analysed and found to be similar. The relative nuclear DNA contents of all taxa were determined by flow cytometry and, for five species, also by Feulgen cytophotometry. The values obtained by the two methods are similar. A comparison of nuclear DNA contents among diploids shows that values differ significantly between different taxonomic groups, and are correlated with average chromosome size. Within closely related polyploid groups nuclear DNA amounts increase from 2x- to 4x- and 6x taxa as 1 : 1.4 : 2.4 in theC. alpinum complex, whereas DNA amounts are doubled comparing 2x- and 4x-subspecies in theC. arvense complex.  相似文献   

18.
C. Rose Beoome 《Brittonia》1976,28(4):413-426
A revision ofCentaurium based on field, herbarium, and greenhouse studies shows that five species are native to Central America: C.guitense (H.B.K.) B. L. Robinson (n = 21, 22),C. pauciflorum (Mart. & Gal.) B. L. Robinson (n =36),C. brachycalyx Standley & L. O. Williams (n = ca. 36),C. setaceum (Benth.) B. L. Robinson (n = 21), andC. martinii Broome (n = 21), a new species. One population of a European species,C. minus Moench subsp.minus has been discovered in Costa Rica.  相似文献   

19.
Im Zuge unserer cytotaxonomischen Untersuchung der Gattung SaxifragaL. werden Sippen der S. exarata-moschata-Gruppe untersucht. S. exarata ssp. exarata aus den Seealpen ist diploid mit 2n = 20. S. exarata ssp. leucantha (Thomas) Br.-Bl. aus dem Unterwallis (Vernayaz) ist tetraploid mit 2n = etwa 48 bis 52 und gehört unseres Erachtens zu den intermediären Formen zwischen S. exarata und S. moschata. Für S. moschata liegen weitere Zahlenangaben aus den Alpen und den benachbarten Gebirgen vor: 2n = 26 (Allgäu, ötztaler Alpen, Waadtländer Alpen), 2n = 24 (ötztaler Alpen, Hohe Tatra), 2n = 32, 34, 36 (Kantabrien). Intermediäre Formen zwischen S. exarata und S. moschata mit 2n = etwa 48 bis 52 wurden im Wallis, Zentralalpen, untersucht. Bei zwei Pflanzen einer Population oberhalb Saas-Fee wurden 2n = 48 bzw. 2n = 52 Chromosomen gefunden. Diploide und tetraploide Pflanzen lassen sich nur nach der Pollengröße unterscheiden (2x = 20 bis 22 ?; 4 × = 22 bis 24 ?). Neben einer Punktkarte der Verbreitung fast aller bis jetzt cytologisch untersuchten Sippen im Alpengebiet werden Chromosomenbilder, Blattumrisse mit den jeweiligen Behaarungstypen und Ausbildung der Nervatur gebracht.  相似文献   

20.
Alatalo, J. M. & Molau, U. 1995. Effect of altitude on the sex ratio in populations of Silene acaulis. — Nord. J. Bot. 15: 251–256. Copenhagen. ISSN 0107–055X.
Predicted increase of female frequencies in gynodioecious Silene acaulis was tested along an altitude gradient in northern Sweden. Average female frequencies for the four sites increased with altitude from 42% to 59% within a short geographical distance. This follows the outcrossing hypothesis, that female frequencies should be positively correlated with selfing rates of hermaphrodites in populations. More adverse environmental conditions should favour gynodioecy in areas where reproduction to a greater part relies on vegetative reproduction or selfing. Further, a significant difference in corolla width was found between females and the larger hermaphrodites, but not between sites. Cushion size and the number of flowers per cushion decreased with attitude.  相似文献   

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