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1.
(1) In the overwhelming majority of genera of the family Ranunculaceae, includ ing its primitive genera, Caltha, Calathodes, and Trollius and the primitive genus of trib. Anemoneae, Anemone, the sepals are spreading and the stamens are glabrous. So, the as cending or upright sepals and hairy stamens of the sections Meclatis, Tubulosa, Viorna, and Atragene of the genus Clematis are secondary, and are accordingly considered as advanced characters, and those sections and the genus Archiclematis, closely related to Sect. Viorna Subsect. Connatae, more or less advanced groups. (2) In the sections Cheiropsis, Fruticella, and Viticella, which have glabrous stamens,some species have spreading sepals, and the others have ascending or upright sepals. In Sect. Clematis, all the species have spreading sepals and glabrous stamens, except for Clematis pinnata, which has ascending sepals and usually hairy stamen filaments. In Sect. Lasiantha with 2 species restricted to western U. S. A., C. lasiantha has glabrous stamens, while C. paucifiora has stamens hairy on fliaments. In Sect. Naraveliopsis with spreading sepals,the majority of species have glabrous stamens, but one species, C.liboensis, endemic to Guizhou Province, China, has hairy stamens. These facts just mentioned indicate that the evolution of sepals and stamens took place in several lineages independently in Clematis. (3) In Clematis, glabrous stamens of C.apiifolia, C.grata, and C.montana with linear filaments and oblong anthers, are similar to those of Caltha, Calathodes, Trollius, and Anemone. Thus, the linear filaments and oblong anthers are considered primitive characters in Clematis. On the other hand, lanceolatelinear filaments of C. tangutica and C. aethusifolia or oblanceolate -linear filaments of C. courtoisii and C. loureiriana and linear anthers of C. meyeniana and C. uncinata, and narrow-linear anthers of C. courtoisii and C. lanuginosa are considered advanced ones. In ease of stamens with hairs, stamens of C. henryi with densely villous filaments and those of C. kweichowensis with both filaments and anthers densely pubescent show more advanced condition than those of C. pinnata, C. heracleifolia, and C. tangutica, with sparsely puberulous filaments and glabrous antbers(Fig. 1 ). (4)The pedunculate, 2-bracteate dichasial cyme with several flowers may represent the primitive type of inflorescences in Clematis. Manyflowered panicle-like cymes as in C.gouriana and C. tsaii, or few-l-flowered cymes as in C. henryi and C. repens, and cymes lacking peduncles and bracts as in C. montana and C. pogonandra are all considered advanced. Besides, the fact that flowers arise from axillary buds of old branches shows also an advanced condition. (5)Sect. Clematis subsect. Pinnatae, with leaflets, inflorescence ramification, and stamens similar to those of C. heracleifolia, is considered intermediate between Sect. Clematis and Sect. Tubulosa. (6) Subsect. Clematis and Subsect. Rectae, and Subsect. Connatae and Subsect. Crispae are so closely related to each other respectively that it is difficult to ascertain the systematic position of some intermediate species between the two subsections of each pair in the absence of seedlings. So, in the present paper, following the classification of Clematis proposed by Tamura in 1967, I put Subsect. Clematis and Subsect. Rectae in Sect. Clematis, and Subsect. Connatae and Subsect. Crispae in Sect. Viorna. (7)According to the evolutionary tendencies mentioned above, a realignment of the sections and the infrasectional taxa of the Chinese Clematis is made. (8) Six subsections, 6 serise, 2 species, and 4 varieties are described as new, and 5 new combinations, 4 new ranks, and 2 new names are given. (9)The specific rank of C. tenuipes W.T. Wang, reduced to varietal renk in 1980, is restord. C. taiwaniana Hayata, reduced to synonomy of C. grata Wall. in 1991, is considered distinct from the latter in hairy adaxial surface of sepal and narrower achene with tapering apex. C. kerriana Drumm. & Craib and C. laxipaniculata Pei are proved to be conspecific to C. subumbellata Kurz and reduced to syn-onymy.  相似文献   

2.
Shre.  KK 《植物分类学报》1997,35(5):396-433
Cyananthus Wallich ex Bentham, the only genus of Campanulaceae with superior ovary, is revised to clarify infrageneric relationships and phylogeny of the genus. Evidence obtained from the comparative gross morphology, anatomy, palynology, and karyomorpho-logy recommends a new infrageneric classification of the genus, recognizing 23 species, belonging to two subgenera, four sections and four subsections. One subgenus(Subgen. Mi-cranthus), one section(Sect. Suffruticulosi) and two subsections(Subsect. Flavi and Sub-sect. Lichiangenses)are described as new taxa. New combinations at sectional (Sect. Annui) and subsectional(Subsect. Stenolobi) ranks are also proposed. The genus Cyananthus is strictly distributed in the high mountains of China(Xizang, Yunnan and Sichuan), extending to Bhutan, Nepal and India (Kumaon-Garhwal, Assam and Sikkim), with altitudinal ranges from 2500 ~ 5300 m. It is observed that 13 species are endemic to SW China and only three species are endemic to the Himalayas( two species in Ne  相似文献   

3.
王文采   《广西植物》2007,27(1):1-28
(1)对毛莨科铁线莲属Clematis的铁线莲组sect.Viticella进行了分类学修订,确定此组包含13种,1亚种和2变种(包括2新种和1新变种等级),写出此组的分类学简史和地理分布;将此组划分为3亚组,4系,写出区分组下各级分类群的检索表,以及各种植物的形态描述,地理分布,生长环境等,并附有多幅插图。(2)特产我国东部的单型毛萼铁线莲亚组subsect.Hancockianae(花具4枚平展,不展宽的萼片,雄蕊无毛)被认为此组的原始群。铁线莲亚组subsect.Floridae(花具5-8枚平展,强烈展宽的萼片,雄蕊无毛,花粉具散孔)和湖州铁线莲亚组subsect.Viticellae(花具4枚渐升,多少展宽的萼片,雄蕊花丝常被缘毛,花粉具3沟)可能均由毛萼铁线莲亚组衍生而出。(3)在我国东部集中分布此组的3亚组,3系的8种,1亚种和1变种,这里是此组的分布中心,也可能是此组的起源中心。  相似文献   

4.
The geographical distribution of Aconitum in the Sino-Himalayan subregion is analysed in the present paper on the basis of taxonomy and relationship between the infrageneric taxa. Asaresult, some conclusions may be arrived as follows: 1. The Sino-Himalayan subregion is the frequency centre and the diversity centre of the genus. For analysis, the distribution area of the genus are assigned to three floristic regions, viz. 1) the East-Asian floristic region, consisting of the Sino-Himalayan subregion and SinoJapanese subregion, 2) the Euro-Siberian region and 3) the North-American region (Table 1). In the East-Asian floristic region, the Sino-Himalayan subregion comprises 3 subgenera, about 5 sections, about 13 series and nearly 180 species. However, the Sino-Japanese subregion has only 2 subgenera, 2 sections. 6 series and about 50 species. The Euro-Siberian region has 2 subgenera, 2 sections, about 9 series and nearly 70 species. The North-American region has 2 subgenera (one of the 2 subgenera has only 1 species), 1 section, 1-2 series and about 26 species. Obviously, the Sino-Himalayan subregion is the richest in taxa. 2. The Sino-Himalayan subregion is not only the preservation centre of the primitive groups and species, but also an actively differentiating region. Largely in the Sino-Himalayan subregion occurs primitive or more primitive tava in the genus, such as Sect. Fletcherum, Sect. Alatosperum and Sect. Sinaconitum, Ser. Tangutica and Ser. Brunnea etc.: A fletcherianum, A. novoluridum, A. chrysotricum, A. brevicalcaratum, A. polycarpus, A. nagarum, A. tanguti cum, A. hookeri, A. naviculare, A. violaceum, etc. On the other hand, the Sino-Himalayan subregion also has the most or relatively advanced taxa, represented by the annual monotypic subgenus Gymnaconitum, A. spiripetalum, A. hamatipetalum and A. bulbitiferum ect. About 50 infraspecific taxa occur in the subregion. For example, A. hemsleyanum has 8 varities, A. franchetii has varities and A. nagarum 1 varity and 2 forms, ect. 3. In the region under discussion the genus Aconitum shows remarkable endemism. The endemic taxa include 3 sections (Sect. Fletcherum, Sect. Alatosperum and Sect. Sina conitum), 3 series (Ser. Brevicalcarata, Ser. Crassiflora and Ser. Bullatifolia) and nearly 150 species, among which primitive and advanced ones are both present. 4. The pattern of geographical distribution of the genus Aconitum shows remarkable relationship between latitude and altitude. The majority of species of this genus prefer habi tats with a cool and more or less constantly moist climate. In the Sino-Japanese subregion, with a higher latitude, the genus has an altitude range of 500-1500 m, whereas in the Sino-Hima-layan subregion the range is 2900-5000 m. To sum up, the Sino-Himalayan subregion is the diversity centre, the frequency centre, the differentiation centre, the preservation centre of the primitive taxa and the centre of endemism of the genus Aconitum, and its development in this subregion has probably been accelerated by the lift of the Himalayas and the complicated environmental conditions.  相似文献   

5.
6.
论猕猴桃属植物的分布   总被引:27,自引:1,他引:26  
梁畴芬   《广西植物》1983,(4):229-248
<正> 作者通过中国植物志猕猴桃科的编写,完成猕猴桃属前人有关志述的研读考订和国内各大标本室所藏本属标本的鉴定整理。截至目前为止,统计本属的种和种下分类群,共得53种,56变种,15变型,从作者所看过的不完整标本而无法确定的情况说,本属的分类群肯定不只此数,但这个数字可认为是本属的绝大多数了。  相似文献   

7.
王文采 《广西植物》2016,36(Z1):231-232
该文描述了自青海南部发现的罂粟科绿绒蒿属一新种,短丝绿绒蒿。此种可能隶属琴叶绿绒蒿亚属,滇西绿绒蒿组,滇西绿绒蒿系,与此系其它种的区别在于此种的披针状条形花瓣,较少、较短的雄蕊(花丝长1~5 mm),无花柱的雌蕊,和被具短毛的硬毛的子房。  相似文献   

8.
Clematis sect. Atragene is revised in this paper based on the examination of a large number of herbarium specimens, extensive field observations, and morphometric analyses. Brief taxonomic history and geographical distribution of the section are given, the relationships among the species are discussed, and the evolutionary trends of some characters in the section are evaluated. The staminodes of the plants in this section may have evolved from the outer stamens with petaloid filaments and gradually disappearing anthers. Subsequently, they may have evolved in two different ways. One possibility is that the staminodes elongate and become lanceolate, as long as sepals, and their apices turn into attenuate. The other is that the staminodes are spathulate, but not elongating, as long as stamens, and their apices turn into retuse from obtuse and rounded. The evolutionary trend of sepals may be from thin to thick in texture, and the veins from non-prominent to prominent. As a result, five new series are established and nine species, two subspecies and nine varieties (including three new ranks) are recognized in this section. An identification key is provided, and each taxon is described and illustrated. Clematis sibirica and Clematis ochotensis are treated as subspecies of Clematis alpina due to their subtle differences and lack of, or few, overlapping distributions. Clematis fusijamana and Clematisfauriei are recognized as varieties of C. alpina ssp. ochotensis for the continuous variation of the velutinous strips on the sepal margins. Clematis iliensis is treated as variety of C. alpina ssp. sibirica for the continuous variation of leaf division types. Extensive variations in sepal color and basal caruncle size support degrading Clematis chiisanensis as a variety of Clematis koreana. The North American ser. Occientales may be primitive, whereas ser. Macropetalae may be the most advanced taxon in this section. Ser. Alpinae and ser. Koreanae are closely related to each other. However, the systematic position of ser.  相似文献   

9.
栝楼属花粉形态研究及其在分类学上的意义   总被引:5,自引:0,他引:5  
本文收集了国内外栝楼属Trichosanthes 31种1变种,在光学显微镜和扫描电镜下,进行了花粉粒形态的比较观察。该属花粉粒为3孔沟型,外壁表面纹饰可分为四个类型,即:疣状或皱波状(小苞组),粗网状(大苞组),细网状或光滑(叶苞组),近光滑或皱波状(王瓜组)。这四个类型的划分与植物形态分类基本一致,可作为分组及分种的依据之一。花粉特征支持将叶苞组分为叶苞亚组和柔毛亚组,如叶苞亚组有明显的沟,而柔毛亚组没有。  相似文献   

10.
嵩草属植物硅酸体系统的研究   总被引:1,自引:0,他引:1  
邓德山 《广西植物》2002,22(5):394-T003
对国产狭义嵩草属 (K obresia,Cyperaceae) 3个组 2 7种植物进行了硅酸体系统分析研究 ,同时结合近缘的苔草属 (Carex) 2个组的植物硅酸体特征 ,深入探讨了植物硅酸体系统分析研究在莎草科苔草族 (Cariceae)中的系统分类学意义。认为 :(1 )嵩草属及其临近类群在属间、种间及种下水平的系统分类学比较研究都可以借助植物硅酸体系统研究的证据。 (2 )穗状嵩草组 (sect. Elyna)的硅酸体系统特征具有较高的一致性 ,除矮嵩草 (K.humilis)及其近缘种同其他穗状嵩草组的种类有所不同 ,它很可能有一个不同于穗状嵩草组其他类群的嵩草组(sect. K obresia)的亲缘。 (3 )从植物硅酸体系统特征的研究来看 ,拟苔草组 (sect. H emicarex)的一些种接近于穗状嵩草组 ,如高山嵩草 (K . pygmeae) ;而另一些种接近于嵩草组 ,如禾叶嵩草 (K . graminifolia) ;也有一些种类的硅酸体系统特征更接近苔草属 ,说明这个组很可能是多源的 ,即本组的单一花穗和果囊形态特征由不同类群的复合花序种类趋同演化而出。(4 )嵩草组的硅酸体系统特征具有较高的一致性 ,说明嵩草属原始类群在硅酸体系统特征方面与外部形态特征演化的某些相关性。  相似文献   

11.
A revision of Hebeloma sect. Indusiata in the Nordic countries has been undertaken. The type species of the genus, Agaricus fastibilis , is interpreted as being a non-veiled species, and therefore sect. Indusiata is the correct name for the section comprising the veiled, non-rooting species of Hebeloma. Subsect. Amygdalina subsect. nov. is proposed for species in sect. Indusiata possessing amygdaloid, dextrinoid spores. The following new taxa and combinations are proposed: Hebeloma mesophaeum var. crassipes var. non., H. mesophaeum var. lacteum nom. et stat. nov., H. polare sp. nov., H. sordescens sp. nov., H. atrobrunneum sp. nov., H. monticola sp. nov. and Agrocybe elatella comb. nov.  相似文献   

12.
为弄清广西境内马褂木( Liriodendron chinense)天然群体的遗传多样性及分布情况,该研究运用ISSR分子标记,对广西境内现存的6个野生马褂木种群进行遗传多样性分析及评价。结果表明:广西马褂木群体具有较丰富的遗传多样性,6个参试群体的平均(及总体)有效等位基因数( Ne)、Nei’ s 基因多样度( H)和Shannon信息指数(I)分别为1.4541(1.6337)、0.2576(0.3633)和0.3786(0.5293);群体间存在基因流动但水平有限( Nm=1.2184),使群体间存在较高遗传分化( Gst =0.2910);聚类分析( UPGMA)将6个天然群体分为东部(全州QZ、资源ZY及融水老堡RS ̄L)、西部(融水安太RS ̄A、环江HJ及乐业LY)两组,其中东部组具有较低遗传多样性及较高的遗传分化,可能受到较强的人为干扰;Mantel检验表明群体间符合距离隔离模式( R=0.545, P=0.043),表明人为破坏导致的生境碎片化是造成广西马褂木天然群体遗传分化的重要原因。针对广西马褂木天然群体较丰富的遗传多样性及较高的遗传分化,除了考虑对遗传多样性较高群体(如RS ̄A及HJ)进行原地保护外,宜对各群体采集种子或穗条,统一营建基因资源收集区,以供后续育种及生产利用。  相似文献   

13.
Pollen grains from 30 taxa, mainly from the Western Mediterranean area belonging to the perennial sections of the genus Veronica (Scrophulariaceae), were studied by LM and SEM. A close relationship was found between pollen size and ploidy level. Palynological characters cannot be regarded as essential taxonomic tools within the groups studied, although they have systematic value in some specific cases. The monophyly of Veronica subsect. Multiflorae is supported by a common and exclusive sculpture of exine. Delimitation of the genus is discussed and hypothetical evolutionary trends concerning pollen characters are addressed.  相似文献   

14.
The evolutionary relationships among members of the red algal genus Hildenbrandia have not been well understood for several reasons. For example, the genus contains both marine and freshwater representatives, all of which are non-calcified and crustose, and few have definitive morphological characters for classification. Hildenbrandia is also assumed to be completely asexual (reproduction by tetrasporangia in marine forms and by gemmae in freshwater populations), and characters of the female gametangial system and post-fertilization structures are not available for comparative studies. Currently there are 14 marine and five freshwater species and infraspecific taxa recognized within the genus. We used phylogenetic analyses (parsimony, distance and maximum likelihood) of DNA sequences of commonly employed genes ( rbc L and 18S rRNA) to examine the evolutionary relationships among representatives of many of these taxa. In addition, we employed morphometrics (principal co-ordinates and cluster analyses) of several measured characters of these same representatives, as well as all available type specimens, to determine the number of morphologically-delimited entities within the genus. Thus far our results indicate that some characters traditionally used to distinguish species of Hildenbrandia , such as tetrasporangial division pattern, may not be useful in some cases, and a revision of the taxonomy of the genus will be necessary. Although the marine and freshwater species of Hildenbrandia appear to be well separated in our molecular analyses of European specimens, this trend was not observed for North American specimens. High sequence divergence values were calculated for both the rbc L and 18S rRNA genes of Hildenbrandia , compared to other red algal genera.  相似文献   

15.
Two taxa of cupulate magnoliid fossil flowers, Cronquistiflora and Detrusandra, are described from the Late Cretaceous (Turonian, ∼90 million years before present [MYBP]) Raritan (or lower Magothy) Formation of New Jersey. The fossil taxa are represented by flowers at various stages of development, associated fragments of cup-shaped floral receptacles with attached anthers, and isolated anthers. Both taxa have laminar stamens with adaxial thecae and valvate dehiscence. Pollen is boat-shaped and foveolate in anthers associated with Cronquistiflora and spherical with reticulate ornamentation in Detrusandra. Cup-shaped receptacles are externally bracteose in both taxa. The receptacle of Cronquistiflora is broader than the campanulate one of Detrusandra. Cronquistiflora also has more carpels (∼50 in a spiral vs. ∼5 in a whorl or tight spiral). In Detrusandra the carpels are surrounded by dorsiventrally flattened structures (pistillodes?) that are remote from the attachment of the stamens near the distal rim of the receptacular cupule. Detrusandra stigmas are rounded and bilobed, while those of Cronquistiflora, although bilateral in symmetry, are somewhat peltate. The fossil taxa share prominent characters with extant cupulate magnoliids (e.g., Eupomatia, Calycanthus), but also share characters with other magnoliids including Winteraceae. These fossils represent taxa that are character mosaics relative to currently recognized families. Inclusion of these fossils in existing data matrices and ensuing phylogenetic analyses effect changes in tree topologies consistent with their mosaicism relative to modern taxa. But such analyses do not definitively demonstrate the affinities of the fossils other than illustrating that these fossils are generalized magnoliids. Additional analysis of modern and fossil magnoliids is necessary to fully appreciate the phylogenetic significance and positions of these fossil taxa. However, the results of the phylogenetic analyses do introduce the possibility that extinct taxa of Magnoliales with cupulate floral receptacles were transitional between basal angiosperms and those with tricolpate pollen. The fossils provide insights into the timing of evolution of character complexes now associated with coleopteran pollination.  相似文献   

16.
This revision deals with the system, evolution, distribution, cytotaxonomy and taxonomic treatment of the genus Aristolochia Linn. from E. & S. Asia, which covers Japan, USSR (Far East), China, Viet Nam, Laos, Cambodia, Thailand, Burma, India, Bhutan, Nepal, Sikkim, Bangladesh and Pakistan. Total 2 subgenera, 7 sections, 4 series, 68 species and 1 variety (cultivated species not included) are recognized in this treatment, of which 3 sections and 2 species are described as new. In addition, 13 new synonyms and some new records to this region are also included. Ystem Having estimated all the works dealing with the subdivision of the genus by the previous authors, the system of O. C. Schmidt (1935) is chosen as the basis, with a change of the sequence of the subdivisions. The subgenus Pararistolochia (Hutch. & Dalz.) O. C. Schmidt, which has indefinite stamens and gynandrous lobes, seems to be better considered as the most primitive one in the genus, while the subgenus Siphisia (Raf.) Duch., which has definite stamens and gynandrous lobes, anthers arranged in 3 pairs and more modifications of the perianth, seems to be the most advanced one. The perianth of the subgenus Siphisia has differentiated into several types, and it is more rational using this character to classify sections than lobes of the gynostemium. In this way, three new sections has been established. A suggested system of the genus is summarized as follows: Subgen. 1. Pararistolochia (Hutch. & Dalz.) O. C. Schmidt Subgen. 2. Aristolochia: Sect. 1. Aristolochia (2 series), Sect. 2. Gymnolobus Duch. Subgen. 3. Siphisia (Raf.) Duch.: Sect. 3. Pentodon Klotz, Sect. 4. Odontosiphisia J. S. Ma, Sect. 5. Leptosiphisia J. S. Ma, Sect. 6. Nepenthesia Klotz., Sect. 7. Obliquosiphisia J. S. Ma, Sect. 8. Siphisia (2 series). Evolution According to the character analysis of the genera of Aristolochiaceae, the evolutionary trends of the family are proposed as follows: 1, the perianth from double to single, from cup-like to tubular, 2, stamens from indefinite to definite, from separate from pistil to united into a gynostemium with pistil, which is a major evolutionary line in the family, 3, ovary from half-superior to inferior, and 4, fruit from a follicle to a capsule. It is evident that the genus Aristolochia, with a tubular perianth, stamens 6, a gynostemium, an inferior ovary and a capsule, is in highly advanced position in the family. The subgenus Pararistolochia, which has more stamens and more lobes of gynostemium, is very similar to the genus Thottea Rottb. and thus better considered as the most primitive subgenus in the genus. The subgenus Siphisia, which has definite stamens (6) in 3 pairs and 6 lobes of gynostemium as well as the polyploid feature (2n=4x=28), is the most advanced subgenus. As a result of the character analysis, the evolutionary trends of the subgenera in the genus, which are in accordance with those of the family, are proposed as follows: 1. stamens from indefinite to definite, and 2. gynostemium lobes from more to less. Distribution The more primitive subgenus Pararistolochia is only distributed in West Africa (except 1 species in Malesia), the subgenus Aristolochia in the tropical and subtropical regions, rarely in the temperate one, and the most advanced subgenus Siphisia occurs mainly in E. Asia, occasionally in N. America. The result of this work shows that the Hengduan Mountains is the second center of distribution after South America. The second center of distribution is of following features: 1. complex composition of taxa, among 3 subgenera and 8 sections, 2 subgenera and 7 sections have been recorded here, 2. rich in species, more than half of the total E. & S. Asian species, i.e. about 42 species have been found in this region, and 3. numerous endemics, more than 85 percent of the total number of species in the region, i.e. about 35 species, are endemic. Cytotaxonomy and taxonomic treatment The known chromosome numbers in 43 species, with 34 reported by Gregory (1956) and Fedorov (1969), together with 9 species newly reported in this work, show that Subgen. Aristolochia with 2n=2x=14, rarely 12, is apparently more primitive than Subgen. Siphisia with 2n=2x=28.  相似文献   

17.
The law of the unspecialized states that specialized taxa have evolved from more generalized ancestors. Moreover, it is usually assumed that ecological specialization is irreversible and hence leads to extinction. This study aims to test these assumptions using a phylogenetic framework in a case study within the springtail genus Willemia and its diverse life habits. This genus is represented mostly by loam-dwelling species (generalized condition), but some species are psammophilous, living in sandy habitats (specialized condition). Fifty-two morphological characters were examined in 34 of the 36 species of the genus and in three outgroups. The cladistic analysis yielded two most parsimonious trees (tree length 124 steps; consistency index 0.56; retention index 0.86). The evolution of psammophily versus loam-confined life is compared to the cladogram: unexpectedly, psammophily is not an evolutionary innovation that occurred once in a monophyletic group; the evolutionary scenario that parsimoniously fits the phylogeny suggests that psammophily is ancestral to the genus Willemia and reversed twice to loam-confined life. These results demonstrate that habitat generalists can evolve from habitat specialists and therefore that habitat specializations are not necessarily an evolutionary dead end. Many other seemingly specialized characters may be shown to be equally malleable.  相似文献   

18.
秋海棠属是世界有花植物第六大属,是被子植物分类困难的类群之一,亟需增加形态性状的比较研究,以便于今后对该属开展分类学修订。该研究选取国产秋海棠属中较为常见的侧膜组、秋海棠组、单座组和二室组共21种,应用扫描电镜观察花粉微形态,探讨花粉形态对秋海棠属植物的分类学意义。结果表明:秋海棠属植物的花粉多为单粒花粉,辐射对称,等极,三孔沟,超长球形到长球形。选取9个稳定的花粉特征进行无序和不加权的性状编码,应用非线性多维标度分析对花粉特征矩阵进行聚类分析,结果支持这些组都不是单系类群需要重新修订,其中花粉边缘形状、极面观轮廓、萌发沟和花粉的外壁纹饰具有一定分类学意义,特别是塞缘特征具有重要的分类意义。根据塞缘特征可以将研究类群区分为2个类群:(A)无塞缘或塞缘光滑;(B)塞缘颗粒状。类群B中具规则颗粒状和精细颗粒状塞缘的种类聚在一起,而具粗糙颗粒状塞缘的种类位于类群A和B的中间,很可能是2个类群的过渡性状,这需要增加取样做进一步的研究。  相似文献   

19.
The morphological characters in the genus Orobanche were evaluated from the taxonomic point of view. The author finds that the plants of this genus are relatively similar to each other in respect to characters of vegetative organs, fruits and seeds. But the differences in the floral structures can be served as a basis for delimitating infrageneric taxa. The seed coat of 18 species and pollen grains of 6 species were also examined under scanning electron microscope (SEM). They seem to have little significance for distinguishing species. The result supports G. Beck’s (1930) division of the genus Orobanche into 4 sections, of which 2 occur in China, based on the characters of the inflorescence, bracteoles and calyx. The author considers that some characters, such as anther hairy or not, upper lip of corolla entire or not, lower lip longer or shorter than the upper one, the state of corolla-tube inflec tion and the hair type of filaments and plants, are important in distinguishing Chinese species. A key to the species of Orobanche in China is given. This genus consists of about 100 species, and is mostly confined to Eurasia, with over 60 species found in Caucasus and Middle Asia of USSR, where may be the mordern distribu tional centre. Orobanche L. in China is represented by 23 species, 3 varieties and l forma. As shown in Table 1, most species (12 species) are found in Xinjiang, which clearly shows a close floristic relationship between this region and Middle Asia of USSR. 6 species are endemic to China, of which 4 are confined to the Hengduan Mountains (Yangtze-Mekong-Salwin divide). The relationships between this genus and related ones of Orobanchaceae are also discussed. The author holds the following opinions: the genus Phelypaea Desf. should be considered as a member of Orobanche L. Sect. Gymnocaulis G. Beck, the monotypic genus, Necranthus A. Gilli endemic to Turkey, is allied with Orobanche L. Sect. Orobanche, the monotypic genus, Platypholis Maxim, endemic to Bonin Is. of Japan, is far from Orobanche L. in relation and should be regarded as a separate genus. The 11 OTU’s, including all the sections of Orobanche L. and 7 genera of Orobanchaceae, and 15 morphological characters were used in the numerical taxonomic treatment to test the above-mentioned suggestions. After standardization of characters, the correlation matrices were computerized. The correlation matrices were made to test the various clustering methods. At last the UPGMA clustering method was chosen and its result is shown in a phenogram. The result of numerical analysis is basically in accordance with the suggestions.  相似文献   

20.
中国麻黄属的地理分布与演化   总被引:8,自引:0,他引:8  
中国现有麻黄属植物15种,2变种和1变型,这些种属于膜果麻黄组和麻黄组中的麻黄亚组,没有原始类型藤麻黄亚组的代表。我国除长江中下游及珠江流域的省区处,其他省区都有分布。麻黄花粉的化石-麻分在地层中的分布说明,麻黄在过去曾遍布我国各地,发现的最早时期是在侏罗纪,到白垩纪-早第三纪时,种类较现在丰富,将近50种,根据麻黄粉在世界各地地层中的分布和时期,结合大陆飘移和海底扩张板块构造学说推断,原麻黄在各  相似文献   

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