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1.
2.
The present paper deals with four species belonging to three genera, in which a genus (Paraletabo gen. nov.) and four species are described as new to science, a genus (Sophianus Distant) is recorded for the first time from China. The type specimens are deposited in the Department of Biology, Nankai University. The new genus and new species are briefly diangnosed as follows.  相似文献   

3.
Thirty species belonging to 13 genera of three families in the Hippolytidae Bate, 1888(sensu lato) are reported in the present paper, including two new species and two newly recorded ones from the China seas. The two new species are named as Thinora leptochelus sp. nov. and Thor singularis sp. nov. Thinora leptochelus sp. nov. differs from the only knwon species of the genus, Thinora maldivensis(Borradaile, 1915), by the developed supraorbital tooth and the slender and cone-shaped chelae of the first 2 pereopods. Thor singularis sp. nov. can be dinstingershed from the other members of the genus Thor by the first 2 pereopods with epipods. The two newly recorded species from China seas are Eualus kikuchii Miyake & Hayashi, 1967 and Heptacarpus commensalis Hayashi, 1979.  相似文献   

4.
Cytological characters of four species in Syncalathium (Asteraceae: Lactuceae), a small genus with six identified species endemic to alpine scree of the Sino-Himalayan region, are surveyed in this report. Three species (Syncalathiumpilosum, Syncalathium chrysocephalum, and Syncalathium disciforme) are examined for the first time. Combined with our previous counts, five species have been cytologically investigated from the genus and the results indicated that all species are diploid with the basic somatic chromosome number of x=8. The karyotype asymmetry of Syncalathium souliei is 2A, distinct from the other four species of 1A, and the remaining species are divided into two subgroups with different karyotypes, consistent with their morphological features. The significance of the cytological evolution of Syncalathium is briefly discussed.  相似文献   

5.
Phylogeny of Chinese Allium (Liliaceae) using PCR-RFLP analysis   总被引:5,自引:0,他引:5  
Eighteen representative species were selected from all the nine sections of Chinese Allium on the basis of the classification of morphology and cytotaxonomy. The trnK and rpL16 gene fragments of chloroplast DNA were amplified from 18 species by PCR method. The two cpDNA fragments were digested by 26 restriction enzymes, and 303 polymorphic restriction sites were found, of which 163 were informative. The restriction site data were analyzed with PAUP (version 3.1.1) and MEGA (version 1.01) as well as PHYLIP. As a result, the genus Allium could be classified into six subgenera. The recognition of Sect. Anguinum in the Flora of China is reasonable, Sect. Rhizirideum, Sect. Haplostemon and Sect. Cepa are not monophyletic. The infrageneric system of this genus was also discussed.  相似文献   

6.
In the present paper, 9 species of the genus Fleutiauxia are reported from China, ofwhich one species is transferred from the genus Platyxantha, and four are described asnew to science. The diagnosis of the genus and the key to the known species of China aregiven. The type specimens are kept in the Institute of Zoology, Academia sinica (IZAS)and the Entomological Museum of Northwestern Agricultural University (EMNAU),Yangling, Shaanxi, separately.  相似文献   

7.
The very peculiar spinose psyllids Togepsylla with only two species were described from China and Japan by Satoru Kuwayama (1931, 1949), R. Takahashi (1936) and Y. Miyatake (1970). Two more species discovered by the authors from China (Fujian and Tibet) are described as new, and a new genus is added. The type specimens are deposited in the insect collections of Beijing Agricultural University. Genus Togepsylla Kuwayama 1931 Type sp.: T. takahashii Kuwayama.  相似文献   

8.
In a survey of endophytic fungi associated with medicinal plants, two species of the genus Sporormiella Ellis & Everh. were isolated in 2005. So far only one species S. minimoides was reported in China (Wang & Guo, 2004). The two species are found to be new records in China, and they are redescribed and illustrated herein.  相似文献   

9.
10.
The genus Byssosphaeria from China was briefly reviewed based on specimen examinations and literature work. Taxonomic and nomenclatural problems are discussed. Among the previously recorded taxa of the genus, a new combination, Byssosphaeria hainanensis, is made and a new Chinese record, B. alnea, is reported. A key to the known species of the genus in China is provided.  相似文献   

11.
The genus Cyananthus is distributed in the Himalayan Floristic Subregion. In the early years, it was treated as a member of Polemoniaceae, but it is now generally regarded as a natural group of Campanulaceae. Made in this paper were a comprehensive comparative morphological study, a biometrical analysis of quantitative characters and an analysis of distribution pattern. The systematic position of the genus is discussed based on the evidence from pollen morphology, chromosome number and external morphology. Finally the classification of the genus is revised. As a result of the character analysis, the evolutionary trends of the characters in Campanulaceae are suggested: superior ovary is a primitive state; the pollen grains have evolved from long-multicolpal to short-colpal, then to multiporate; the basic chromosome numbers have changed from 7 to 8 or 9, from which the groups with x=17 are derived (see Fig. 2), Fig. 2 illustrates that Cyananthus is the most primitive genus in the Gampanulaceae, closely related to Codonopsis, Platycodon, Leptocodon and Campanumoea. All these genera are relatively primitive in the family. The genus Cyananthus is distributed in S. E. Gansu (Zhugqu), W. Sichuan, S. and E. Xizang, S. Qinghai and N. W. Yunnan, extending westwards to Kashmir along the Himalayas. Therefore, the genus is strictly limited to the Hengduan Mountains and the Himalayas. That is to say, it occupies the whole Sino-Himalayan Floristic Subregion (Fig. 3). This is of great importance for determining the limits of the floristic subregion, and for drawing a more acurate line between the Sino-Japanese Subregion and the Sine-Himalayan Floristic Subregion. The analysis of distribution patterns of species shows that the Hengduan Mountains is the distribution centre of the two major groups of Cyananthus, Sect. Stenolobi Franch. and Sect. Annui (Lian) Hong et L. M. Ma. In these two groups, only four out of 12 species, i. e. C. incanus Hook. f. et Thoms., C. macrocalyx Franch., C. hookeri C. B. Cl. and C. inflatus Hook. f. et Thoms., extend their areas westwards to Sikkim and Nepal. The other section, Sect. Cyananthus also exists in the west of the Hengduan Mountains. Although in the Himalayas occur three major groups of the genus, only the last-mentioned group-Sect. Cyananthus is mainly distributed in the area (Fig. 4). According to the fact, we tend to infer that the Hengduan Mountains is both the frequency and diversity centers of the genus Cyananthus. The genera of Campanulaceae, which are relatively primitive and the closest relatives of Cyananthus, all occur in SW China and the adjacent regions. Therefore, the region may well be the preserved center of the primitive genera, or even may be the original center of the Campanulaceae. All data accumulated demonstrate that the genus is very old but still under intensive differentiation. With few diagnostic qualitative characters, the characters used in classifications are mostly quantitative ones. The following characters were usually used for classification of the genus: habit, plant size, leaf shape, leaf size, hairs on the leaf, corolla colour, petiole length, corolla length and hairs on the calyx, etc. Among them, only habit, corolla colour and hairs belong to qualitative characters, and all of the others are quantitative ones. Because variation ranges of quantitative characters have never been thoroughly studied in the previous classifications, some named taxa are artificial. An extensive statistical analysis of quantitative characters were carried out in the work to reveal their variation ranges. Based on this, 5 specific names are reduced as synonyms: C. microrhombeus C. Y. Wu is reduced to C. delavayi Franch.; C. argenteus Marq. to C. longiflorus Franch.; C. pseudo-inflatus Tsoong to C. inflatus Hook. f. et Thoms.; and both C. neurocalyx C. Y. Wu and C. leiocalyx (Franch.) Cowan to C. macrocalyx Franch., while C. montanus C. Y. Wu and C. Petiolatus Franch. are treated as subspecies in C. flavus Marq. and C. incanus Hook. f. et Thoms. respectively. As a result of the revision, 19 species and 2 subspecies are recognized in the present paper, with 7 species names and 15 variety names reduced. The genus is divided into three sections according to habit, corolla lobes and hairy types on calyx: Sect. Cyananthus, Sect. Stenolobi Franch. and Sect. Annui (Lian) Hong et L. M. Ma. In the present paper the chromosome number of the genus Cyananthus is reported for the first time, C. inflatus Hook. f. et Thoms. from Yadong, S. Tibet, being found to have 2n=14. And pollen morphology of the genus Leptocodon was first examined under SEM and is shownin Plate 1.  相似文献   

12.
Discussed in the present paper are evolutionary trends of important morphological characters of Deutzia, systematic position of several closely related genera, geographical distribution and characteristics of floristic elements. Finally the classificatory revison of the genus is made and a key to species is given. As a result, evolutionary trends of the important morphological characters in Deutzia are suggested; petals from imbricate to valvate, stamens from indefinite to definite, filaments from edentate to dentate, ovary from half-inferior to inferior. Therefore, the section Neodeutzia with valvate corolla and infinite stamens with edentate filaments should be included in this genus. The sections Neodeutzia and Mesodeutizia seem to be better considered as primitive taxa, while the section Deutzia advanced one. There are 52 species of Deutzia in China , which are grouped into two sections ( Sect. Mesodeutzia, Sect. Deutzia), four subsections (Subsect. Deutzia, Subsect. Grandiflorae, Subsect. Stenosepalae, Subsect. Cymosae)and 17 series. Sixty- five species are so far recognised in the genus Deutzia. They are mainly distributed in E. Asia and disjunctively in N. America. China is therefore an area the richest in species of Deutzia in the world, making up 80% of the total species of this genus. The greatest concentration area is in Sichuan (23 species), Yunnan (21 species), Hubei (12 species) and Shanxi (10 species), this is boundary area between Sino-Himalayan subregion and Sino-Japanese subregion, where occur abundant species (including 39 endemic species) and diverse taxa (2 section and 4 subsection). Based on these facts it is proposed that the present center of distribution and differentiation of Deutzia be in the southern part of the Hengduan Mountains, the Qingling Range and C. China.  相似文献   

13.
Chromosome numbers and the morphology of members of 24 populations representing 15 species of the Sino-Himalayan endemic genus Cyananthus(Campanulaceae) were studied using karyological and numerical taxonomic techniques. The chromosome numbers of these taxa are 2n = 10, 12, 14, 24, 28, and the basic chromosome numbers for the genus are x = 5, 6, 7. All species except C. inflatus Hook. f. & Thoms. and C. microphyllus Edgew. were examined for the first time and a new ploidy level (tetraploidy) is reported in the genus. Chromosome measurement data were analyzed using cluster analysis. The relationships between three sections within Cyananthus and evolutionary trends within the genus are discussed in the light of karyological data. The cytological data suggest that Cyananthus is a relatively primitive genus in Campanulaceae and there is significant division within the genus, and polyploidization may have played an important role in the chromosome evolution and speciation of Cyananthus in the Himalayan–Hengduan Mountains.  相似文献   

14.
The genus Rubus is one of the largest genera in the Rosaceae, consisting of more than 750 species in many parts of the world, of which 194 species have been recorded in China. In the present paper the Rubus is understood in its broad sense, including all the blackberries, dewberries and raspberries, comprising the woody and herbaceous kinds. So it is botanically a polymorphic, variable and very complicated group of plants. The detailed analysis and investigation of the evolutionary trends of the main organs in this genus have indicated the passage from shrubs to herbs in an evolutionary line, although there is no obvious discontinuity of morphological characters in various taxa. From a phylogenetic point of view, the Sect. Idaeobatus Focke is the most primitive group, characterized by its shrub habit armed with sharp prickles, aciculae or setae, stipules attached to the petioles, flowers hermaphrodite and often in terminal or axillary inflorescences, very rarely solitary, druplets separated from receptacles. Whereas the herbaceous Sect. Chamaemorus L. is the most advanced group, which is usually unarmed, rarely with aciculae or setae, stipules free, flowers dieocious, solitary, druplets adhering to the receptacles and with high chromosome numbers (2n = 56). Basing upon the evolutionary tendency of morphological features, chromosome numbers of certain species recorded in literature and the distribution patterns of species, a new systematic arrangement of Chinese Rubus has been suggested by the present authors. Focke in his well-known monograph divided the species of Rubus into 12 subgenera, while in the Flora of China 8 sections of Focke were adapted, but some important revisions have been made in some taxa and Sect. Dalibarda Focke has been reduced to Sect. Cylactis Focke. In addition, the arrangement of sections is presented in a reverse order to those of Focke’s system. The species of Rubus in China are classified into 8 sections with 24 subsections (tab. 3) as follows: 1. Sect. Idaeobatus, emend. Yü et Lu(11 subsect. 83 sp.); 2. Sect. Lampobatus Focke (1 sp.); 3. Sect. Rubus (1 sp.); 4. Sect. Malachobatus Focke, emend. Yü et Lu (13 subsect. 85 sp.); 5. Sect. Dalibardastrus (Focke)Yü et Lu (10 sp.); 6. Sect. Chaemaebatus Focke (5 sp.); 7. Sect. Cylactis Focke, emend. Yü et Lu (8 sp.); 8. Sect. Chamaemorus Focke (1 sp.). In respect to the geographical distribution the genus Rubus occurs throughout the world as shown in tab. 2, particularly abundant in the Northern Hemisphere, while the greatest concentration of species appears in North America and E. Asia. Of the more than 750 species in the world, 470 or more species (64%) distributed in North America. It is clearly showm that the center of distribution lies in North America at present time. There are about 200 species recorded in E. Asia, of which the species in China (194) amount to 97% of the total number. By analysis of the distribution of species in China the great majority of them inhabit the southern parts of the Yangtze River where exist the greatest number of species and endemics, especially in southwestern parts of China, namely Yunnan, Sichuan and Guizhou (tab. 3. 4.). It is interesting to note that the centre of distribution of Rubus in China ranges From northwestern Yunnan to south-western Sichuan (tab. 5), where the genus also reaches its highest morphological diversity. In this region the characteristics of floristic elements of Rubus can be summarized as follows: it is very rich in composition, contaning 6 sections and 94 species, about 66% of the total number of Chinese species; there are also various complex groups, including primitive, intermediate and advanced taxa of phylogenetic importance; the proportion of endemic plants is rather high, reaching 61 species, up to 44% of the total endemics in China. It is noteworthy to note that the most primitive Subsect. Thyrsidaei (Focke) Yü et Lu, consisting of 9 endemic species, distributed in southern slopes of the Mts. Qin Ling and Taihang Shan (Fig. 4). From the above facts we may concluded that the south-western part of China is now not only the center of distribution and differentiation of Rubus in China, but it may also be the center of origin ofthis genus.  相似文献   

15.
(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   

16.
In this paper the classification of the genus Bergenia Moench is provided, its geographic distribution analysed, and the phylogeny also traced. Based on an analysis of morphological characters such as leaves, ocreas, branches of inflorescences, Pedicels, hypanthium, sepals, and glandular indumentum, thi genus is divided into 3 sections: 1. Sect. Scopulosae J. T. Pan, sect. nov., 2. Sect. Bergnia, 3. Sect. Ciliatae (A. Boriss.) J. T. Pan, stat. nov. The Sect. Scopulosae J. T. Pan may be considered as the primitive one, while Sect. Ciliatae (A. Boriss.) J. T. Pan may be regarded as the advanced one, with Sect. Bergenia in between. So far, the genus Bergenia Moench comprises 9 species in the total. Southeast Asia and North Asia (south and east Siberia, USSR) each have only 1 species, West Asia (Afghanistan) has 2, Central Asia (Kirghizia-Tajikistan-Uzbekstan area, USSR) 3, South Asia 4 (Nepal has 4, India, Pakistan and Kashmir area each has 3, Bhutan and Sikkim each has 2), East Asia 6. In East Asia, Mongolia and Korea each have only 1 species, but China has 6 (including endemic species 2 and new species 1). Sichuan Province and Xizang Autonomous Region each have 3, Yunnan Province 2, Shaanxi Province (Qinling Mountains) and Uygur Autonomous Region of Xinjiang each have only 1. Thus the distribution centre of this genus should be in the region covering Sichuan, Yunnan and Xizang. Moreover, it is noteworthy that Bergenia scopulosa T. P. Wang in Sect. Scopulosae seems to have retained primitive characters, for example, non-ciliate leaves and ocreas, glabrous pedicels, hypanthium and sepals, and this primitive species is found in Qinling Mountains and Sichuan. According to the distribution of the primitive species, the author suggests that the centre of origin of this genus be in the region covering Qinling Mountains and Sichuan.  相似文献   

17.
The genus Swertia is one of the large genera in Gentianaceae, including 154 species, 16 series and 11 sections. It is disjunctly distributed in Europe, Asia, Africa and N. America, but entirely absent from Oceania and S. America. According to Takhtajan’s (1978) regionalization of the world flora, Swertia is found in 14 regions. Eastern Asiatic region with 86 species, of which 58 are local endemics, 13 series and 9 sections, ranks the first among all the regions. The highest concentration of the taxa and endemics in Eastern Asiatic region occurs in SW China-Himalayan area (Sikang-Yunnan P. , W. Sichuan, W. Yunnan-Guichou Plateau of China and NE. Burma, N. Burmense P. , E. Himalayan P. and Khasi-Manipur P. ). In this area there are 74 species (48 endemics), 12 series, and 9 sections; thus about half species of the world total, three quarters of series and 82% of sections occur in this small area. Besides, the taxa at different evolutionary stages in Swertia also survive here. It is an indication that SW. China-Himalayan area is a major distribution centre of the genus Swertia. In addition, Sudan-Zambezian Region in Africa, with 22 species, 4 series and 2 sections, is a second distribution centre. The primitive type of the genus Swertia is Sect. Rugosa which consists of 2 series and 23 species. It is highly centred in the mountains of SW. China (Yunnan, Sichuan, Guizhou and SE. Xizang) where 2 series and 16 species occur. Among them 15 species of Ser. Rugosae were considered as the most primitive groups in this genus. From our study, the outgroup of Swertia is the genus Latouchea Frahch. , which is distributed in Yunnan, Sichuan, Guizhou, Hunan, Guangdong, Guangxi and Fujian. The two groups overlap in distribution in SW. China. According to the principle of common origin, the ancestor of two genera ap peared most probably in this overlapping area. It was inferred that SW. China Was the birth-place of the genus Swertia. Four sections of Swertia have different disjunct distribution patterns: Sect. Ophelia is of Tropic Asia, Africa and Madagascar disjunct distribution; sect. Swertia is of north temperate distribution; sect. Spinosisemina is in Tropical Asia (Trop. India to S. China and Philipines); sect. Platynema also is in Tropical Asia (Java, Sumatra, Himalayas to SW. China). These disjunct patterns indicate that the Swertia floras between the continents or between continent and islands have a connection with each other. From paleogeographical analysis, Swertia plants dispersed to Madagascar before the Late Cretaceous, to SE. Asian Islands in the Pleistocene, to North America in the Miocene. The distribution of Swertia in Madagascar might be later than that in Asia. Therefore the origin time of the genus Swertia was at least not later than the Late Cretaceous, and might be back to the Mid-Cretaceous. The genus Swertia first fully developed and differentiated, forming some taxa at different evolutionary stages (Rugosa, Swertia, Poephila, Ophelia and Platynema etc. ) in the original area, and these taxa quickly dispersed in certain directions during the Late Cretaceous-Middle Tertiary when the global climate was warm and no much change. There seem to be three main dispersal routes from the origin area to different continents; (1) The westward route i. e. from SW. China, along the Himalayas area to Kashmir, Pakistan, Afghanistan and Iran, and then southwestwards into Africa throuth Arabia. Four sections (Poephila, Macranthos, Kingdon-Wardia and Ophelia) took this dispersal route. Most species of sect. Ophelia dispersed along this route, but a few along southern route and north ern route. Sect. Ophelia greatly differentiated in Africa and the African endemic sectionSect. Montana was derived from it. The two sections form there a second distribution center of Swertia. (2) The southward route, i. e. towards S. India through the Himalayas, and towards SE. Asian islands through C. and S. China, Indo-China. Along this dispersal route sect. Platynema, Sect. Spinosisemina and a few species of Sect. Ophelia dispersed; (3) The northward rout, i. e. northwards across N. China, C. Asia to a high latitude of Euasia, and also through E. Asia into N. America. The following groups took this route: sect. Rugosa, sect. Swertia, sect. Frasera, sect. Heteranthos and sect. Ophelia ser. Dichotomae. Therefore, it seems that the genus Swertia originated in SW. China and then dispersed from there to N. and S. Asia, Africa, Europe and North America and formed the moderndistribution pattern of this genus.  相似文献   

18.
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   

19.
中国梅花草属校订   总被引:1,自引:0,他引:1  
本文研究了中国梅花草属的外部形态,结合地理分布和生境条件,对国产梅花草属植物的分类、演化和地理分布均进行了研究。作者以退化雄蕊的特征为分组的依据;以雄蕊花药药隔的变异为划分亚组的依据;以花瓣边缘不同和基生叶数目为分系依据。据此归纳为9组2亚组和9系。同时作者认为我国西南部山区是梅花草属植物现代分布和分化中心,也可能是起源中心。  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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