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1.
 Xizang (Tibet) is rich in Leguminosae flora, comprising 41 genera and 254 species so far known, exclusive of the commonly cultivated taxa (including 11 genera and 16 species). There are 4 endemic genera (with 8 species), 10 temperate genera (with 175 species) and 19 tropical genera (with 46 species) as well as the representatives of those genera whose distribution centers are in East Asia-North  America, Mediterranean and Central Asia.       1.  There are altogether 4 endemic genera of Leguminosae in this region. Accord- ing to their morphological characters, systematic position and geographical distribution, it would appear that Salweenia and Piptanthus are Tertiary paleo-endemics, while Straceya and Cochlianths are neo-endemics. Salweenia and Piptanthus may be some of more primitive members in the subfamily Papilionasae and their allies are largely distributed in the southern Hemisphere.  The other two genera might have been derived from the northern temperate genus Hedysarum and the East Asian-North American genus Apios respectively, because of their morphological resemblance. They probably came into existanc during the uplifting of the Himalayas.       2. An analysis of temperate genera       There are twelve temperate genera of Leguminosae in the region, of which the more important elements in composition of flora, is Astragalus, Oxytropis and Cara- gana.       Astragalus  is a  cosmopolitan  genus comprising 2000 species, with its center distribution in Central Asia. 250 species, are from China so far known, in alpine zone of Southwest and Northwest, with 70 species extending farther to the Himalayas and Xizang Plateau.       Among them, there are 7 species (10%) common to Central Asia, 12 species (15.7%) to Southwest China and 40 species (60%) are endemic, it indicates that the differentia- tion of the species of the genus in the region is very active, especially in the subgenus Pogonophace with beards in stigma. 27 species amounting to 78.5% of the total species of the subgenus, are distributed in this region.  The species in the region mainly occur in alpine zone between altitude of 3500—300 m. above sea-level. They have developed into a member of representative of arid and cold alpine regions.      The endemic species of Astragalus in Xizang might be formed by specialization of the alien and native elements. It will be proved by a series of horizontal and vertical vicarism of endemic species.  For example, Astragalus bomiensis and A. englerianus are horizontal and vertical vicarism species, the former being distributed in southeast part of Xizang and the latter in Yunnan; also A. arnoldii and A. chomutovii, the former being an endemic on Xizang Plateau and latter in Central Asia.      The genus Oxytropis comprises 300 species which are mainly distributed in the north temperate zone. About 100 species are from China so far known, with 40 species extending to Himalayas and Xizang Plateau.  The distribution, formation and differ- entiation of the genus in this region are resembled to Astragalus.  These two genera are usually growing together, composing the main accompanying elements of alpine mea- dow and steppe.      Caragana is an endemic genus in Eurasian temperate zone and one of constructive elements of alpine bush-wood. About 100 species are from China, with 16 species in Xi- zang. According to the elements of composition, 4 species are common to Inner Mon- golia and Kausu, 4 species to Southwest of China, the others are endemic. This not only indicates that the species of Caragana in Xizang is closely related to those species of above mentioned regions, but the differentiation of the genus in the region is obviously effected by the uplifting of Himalayas, thus leading to the formations of endemic species reaching up to 50%.      3. An Analysis of Tropical Genera      There are 19 tropical genera in the region. They concentrate in southeast of Xizang and southern flank of the Himalayas. All of them but Indigofera and Desmodium are represented by a few species, especially the endemic species. Thus, it can be seen that they are less differentiated than the temperate genera.      However, the genus Desmodium which extends from tropical southeast and northeast Asia to Mexio is more active in differentiation than the other genera. According to Oha- Shi,s system about the genus in 1973, the species of Desmodium distributed in Sino-Hima- laya region mostly belong to the subgenus Dollinera and subgenus Podocarpium.  The subgenus Dollinera concentrates in both Sino-Himalaya region and Indo-China with 14 species, of which 7 species are endemic in Sino-Himalaya.  They are closely related to species of Indo-China, southern Yunnan and Assam and shows tha tthey have close con- nections in origin and that the former might be derived from the latter.      Another subgenus extending from subtropical to temperate zone is Podocarpium. Five out of the total eight species belonging to the subgenus are distributed in Sino- Himalaya and three of them are endemic.      An investigation on interspecific evolutionary relationship and geographic distribu- tion of the subgenus shows that the primary center of differentiation of Podocarpium is in the Sino-Himalaya region.      Finally, our survey shows that owing to the uplifting of the Himalayas which has brought about complicated geographic and climatic situations, the favorable conditions have been provided not only for the formation of the species but also for the genus in cer-tain degree.  相似文献   

2.
我国悬钩子属植物的研究   总被引:1,自引:0,他引:1  
 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 axill- ary 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, dru- plets adhering to the receptacles and with high  chromosome numbers  (2n = 56). Basing upon the evolutionary tendency of morphological  features,  chromosome nu- mbers 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 im- portant 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 south- western parts of China, namely Yunnan, Sichuan and Guizhou (tab. 3. 4.).  It is in- teresting to note that the centre of distribution of Rubus in China ranges From north- western 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 distribu- tion and differentiation of Rubus in China, but it may also be the center of origin ofthis genus.  相似文献   

3.
木兰科分类系统的初步研究   总被引:10,自引:0,他引:10  
A new system of classification of Magnoliaceae proposed.  This paper deals mainly with taxonomy and phytogeography of the family Magnoliaceae on the basis of external morphology, wood anatomy and palynology.  Different  authors have had different ideas about the delimitation of genera of this family, their controversy being carried on through more than one hundred years (Table I).  Since I have been engaged in the work of the Flora Reipublicae Popularis Sinicae, I have accumulated a considerable amount of information and material and have investigated the living plants at their natural localities, which enable me to find out the evolutionary tendencies and primitive morphological characters of various genera of the family.  According to the evolutionary tendencies of the characters and the geographical distribution of this family I propose a new system by dividing it into two subfamilies, Magnolioideae and Liriodendroideae Law (1979), two tribes, Magnolieae and Michelieae Law, four subtribes, Manglietiinae Law, Magnoliinae, Elmerrilliinae Law and Micheliinae, and fifteen genera (Fig. 1 ), a system which is different from those by J. D. Dandy (1964-1974) and the other authors.      The recent distribution and possible survival centre of Magnoliaceae. The members of Magnoliaceae are distributed chiefly in temperate and tropical zones of the Northern Hemisphere, ——Southeast Asia and southeast North America, but a few genera and species also occur in the Malay Archipelago and Brazil of the Southern Hemisphere. Forty species of 4 genera occur in America, among which one genus (Dugendiodendron) is endemic to the continent, while about 200 species of 14 genera occur in Southeast Asia, of which 12 genera are endemic.  In China there are about 110 species of 11 genera which mostly occur in Guangxi, Guangdong and Yunnan; 58 species and more than 9 genera occur in the mountainous districts of Yunnan.   Moreover,  one  genus (Manglietiastrum Law, 1979) and 19 species are endemic to this region.  The family in discussion is much limited to or interruptedly distributed in the mountainous regions of Guangxi, Guangdong and Yunnan.  The regions are found to have a great abundance of species, and the members of the relatively primitive taxa are also much more there than in the other regions of the world.      The major genera, Manglietia, Magnolia and Michelia, possess 160 out of a total of 240 species in the whole family.  Talauma has 40 species, while the other eleven genera each contain only 2 to 7 species, even with one monotypic genus.   These three major genera are sufficient for indicating the evolutionary tendency and geographical distribution of Magnoliaceae.  It is worthwhile discussing their morphological  characters  and distributional patterns as follows:      The members of Manglietia are all evergreen trees, with flowers terminal, anthers dehiscing introrsely, filaments very short and flat, ovules 4 or more per carpel.  This is considered as the most primitive genus in subtribe Manglietiinae.  Eighteen out of a total  of 35 species of the genus are distributed in the western, southwest to southeast Yunnan. Very primitive species, such as Manglietia hookeri, M. insignis  and M. mega- phylla, M. grandis, also occur in this region. They are distributed from Yunnan eastwards to Zhejiang and Fujian through central China, south China, with only one species (Manglietia microtricha) of the genus westwards to Xizang.  There are several species distributing southwards from northeast India to the Malay Archipelago (Fig. 7).      The members of Magnolia are evergreen and deciduous trees or shrubs, with flowers terminal, anthers dehiscing introrsely or laterally, ovules 2 per carpel, stipule adnate to the petiole.  The genus Magnolia is the most primitive in the subtribe Magnoliinae and is the largest genus of the family Magnoliaceae. Its deciduous species are distributed from Yunnan north-eastwards to Korea and Japan (Kurile N. 46’) through Central China, North China and westwards to Burma, the eastern Himalayas  and northeast India.  The evergreen species are distributed from northeast  Yunnan  (China)  to  the Malay Archipelago.  In China there are 23 species, of which 15 seem to be very primi- tive, e.g. Magnolia henryi, M. delavayi, M. officinalis and M. rostrata, which occur in Guangxi, Guangdong and Yunnan.      The members of Michelia are evergreen trees or shrubs, with flowers axillary, an- thers dehiscing laterally or sublaterally, gynoecium stipitate, carpels numerous or few. Michelia is considered to be the most primitive in the subtribe Micheliinae, and is to the second largest genus of the family.  About 23 out of a total of 50 species of this genus are very primitive, e.g. Michelia sphaerantha, M. lacei, M. champaca,  and  M. flavidiflora, which occur in Guangdong, Guangxi and Yunnan (the distributional center of the family under discussion)  and extend eastwards to Taiwan  of  China, southern Japan through central China, southwards to the Malay Archipelago through Indo-China. westwards to Xizang of China, and south-westwards to India and Sri Lanka (Fig. 7).      The members of Magnoliaceae are concentrated in Guangxi, Guangdong and Yunnan and radiate from there.  The farther away from the centre, the less members we are able to find, but the more advanced they are in morphology.  In this old geographical centre there are more primitive species, more  endemics  and  more monotypic genera. Thus it is reasonable to assume that the region of Guangxi, Guangdong and Yunnan, China, is not only the centre of recent distribution, but also the chief survival centreof Magnoliaceae in the world.  相似文献   

4.
 1.  Having analyzed the external morphology of the genus Microula, the author has proposed a series of criteria as bases for the construction of a classification scheme of this genus.  The most important ones are as follows:      1)  The normally developed stem is primitive, and the strongly abbreviated stem more advanced.      2)  The small inconspicuous bracts are more primitive than the large suborbicular densely arranged ones, which almost entirely cover the flowers and the fruits.      3)  Nutlets with small dorsal pit  are more primitive than those with larger pit on one hand or those without it on the other.      4)  The dorsal pit with simple margin precedes that with double margins.      5)  Nutlets with subbasal areola precede those with lateral or apical areola.      6)  Nutlets without glochids precede those with glochids.      2.  Basing upon these criteria the genus Microula may be divided into six sections. The section Schistocaryum may be the primitive one, and the others may be evolved from it respectively.  The possible affinities between them are demonstrated in figure no. two.      3.  The genus Microula, containing 30 species,  is  mainly  distributed  in  the Chinghai-Tibetan plateau and the majority of its species concentrates in the eastern border of the plateau, and of the 30 species 26—that is 90 percent—are endemic to China, and the remaining 4 are distributed elsewhere in China, too, and extending southward and westward to Bhutan, Sikkim, Nepal and Kashmir respectively.  In the region between Heishui, Province Szechuan, and Chinghai Lake there are 9 species, which, curiously, represent all the six sections of Microula, hence this region seems to be the center of maximum variation of this genus.  M. ovalifolia whose nutlets have small dorsal pit and subbasal areola may be considered the most primitive species. Thus the author is of the opinion that the western part of province Szechuan, to which M. ovalifolia is endemic, may probably be the center of origin of the genusMicroula.  相似文献   

5.
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   

6.
海菜花属的分类、地理分布和系统发育   总被引:1,自引:0,他引:1  
 The genus Ottelia is one of the great genera of Hydrocharidaceae.  About 25 spe- cies distributed in the Palaeotropics, extending from Africa through India and SE. Asia to Korea and Japan, Australia and New Caledonia, 1 species in Brazil; centres of specific devolopment are found in Central Africa and SE Asia.      The present study is mainly based on the materials collected during the field ex- plorations in the lakes of Yunnan and observations on the structure of the spathe and flowers, the variation of leaf of the plants cultivated in Kunming Bot. Garden. Instead of the wings of the spathe used by Dandy, by the characters such as uni-or bisexual flowers, this genus is divided into two subgenera, which by the number of the flowers in spathe and the number of the carpus in ovary again subdivided into 4 sections.  They are as the following:      A. Subg. Ottelia.  Flowers bisexual.      Sect. 1. Ottelia.  Spathe with 1 flower; ovary with 6(—9) carpus.      Sect. 2. Oligolobos (Gagnep.) Dandy. Spathe with many flowers; ovary with 3 car- pus.      B. Subg. Boottia (Wall.) Dandy.  Flowers unisexual; the male spathe with 1-many flowers, the female spathe with many flowers.      Sect. 3. Boottia.  The male spathe with 1 flower; ovary with 9(—15) carpus.      Sect. 4.  Xystrolobos (Gagnep.) H. Li.  The female spathe with (2-) many flow- ers; ovary with 3 or 9 carpus.      The Chinense species of ottelia is in great need for revision.  All of the species in China previousely described under Ottelia Pers, Boottia Wall., Oligolobos Gagnep, and Xystrolobos Gagen. are here combined into 3 species.  They are O. alismoides, O. cor- data, O. acuminata with 4 variaties.      After a study of the geographic distribution and infer relation-ships among the floristic elements it has been proved that Ottelia is certainly an ancient genus, and the primitive types came into being and widely dispersed before the separation of Laurasia from Gondwana.      During a considerable period of time the elements of the genus Ottelia in fresh- water environment of different continents have been separately differentiated and evolv- ed into more or less derived types.  The structure of flowers in all of the asian species shows the following evolutionary tendenoes: 1. In this genus the plants with unisexual flowers have evolved from plants with bisexual flower; 2.  In the groups with bisexual or unisexual flowers the number of stamens and styles reduced to 3-merous, but the number of flowers in spathe increased. So that the subgenus Ottelia is more primitive than the subgenus Bottia; While in the subgenus Ottelia O. alismoides is a more primi- tive than O. balansae and in the subgenus Boottia O. cordata is the most primitive, butO. alata seems to be the most advanced.  相似文献   

7.
 The genus Solms-Laubachia of Cruciferae was established by Muschler in 1912 on the basis of the Chinese species Solms-Laubachia pulcherrima of Yunnan Province. Since then, nine species, two varieties and two forms have been recorded.  They are almost all endemic in China except one species—Solms-Laubachia retropilosa Botsch. which was discovered in Sikkim.      We described in this paper thirteen species, three varieties and one form, of which, we suppose, three species, one variety and one combination have never been reported before.  Most species grow in the mountainous regions of Szechuan, Yunnan, Tibet,Ching-hai and Sinkiang in China.  相似文献   

8.
9.
半蒴苣苔属的研究(续)   总被引:1,自引:0,他引:1  
The genus Hemiboea is a curious genus of the tribe Didymocarpeae (Cyrtandroi- deae), characterized by its peculiar pistil with one fertile carpel and its follicle-like capsule. This genus has not yet been thoroughly studied since its establishment by C. B. Clarke in 1888.  In the present paper, the taxonomic history is briefly reviewed; the external morphology, leaf his- tology, pollen morphology and geographical distribution are discussed; a key to the 21 species recognized by the author is provided; and the economic uses reported in various publications are summarized.       I.  Morphology       (1)  Sclereids  The foliar sclereids, occurring in this genus and defined by their forms, fall into two types.       (A) Vermiform selereids  This type of sclereids is noted in 15 species and may be clas- sified into two groups according to their positions in leaf tissues.  Those of the first group are interspersed in the ground tissue around the vascular bundles of leaves and noted in 12 species, i.e.H. longisepala, H. cavaleriei, H. bicornuta, H. fangii, H. omeiensis, H. gracilis, H. glandulosa, H. mollifolia, H. pingbianensis, H. parviflora, H. strigosa and H. gamosepala, and those of the second group are dispersed in the mesophyll, occurring in H. subcapitata, H. henryi and H. latisepala.       (B) Astrosclereids The sclereids of this type are discovered for the first time in Hemiboea, dispersed in the mesophyll of a single species, i.e.H. lungzhouensis.      No foliar sclereids are found in the remaining 5 species, i.e.H. integra, H. flaccida, H. longgangensis, H. subacaulis and H. follicularis.      The differences in forms and positions of the foliar sclereids and their absence or pre- sence are of great help in understanding the relationship between the infrageneric taxa.    (2)  Pollen grains  The pollen grains of 19 species were examined with LM and SEM. They are 3-colporate, subglobose or prolate, 20-38.8×22-28μm.  The exine  is  1.3-2μm thick and the sculpture is foveolate (e.g.H. cavaleriei) to reticulate (e.g.H. omeiensis).  In Sect. Subcapitatae the pollen grains are subglobose or prolate, while those of Sect. Hemiboea are prolate.       No pollen grains are observed in anthers of 13 speciemens of H. subacaulis var. subacaulis and var. jiangxiensis.        (3)  Seed-coat Under SEM the seed-coat exhibits considerable diversity in the genus, fur- nishing useful characters for explaining the relationship between the two sections.       2.  Geographical distribution  The genus Hemiboea ranges from the eastern border of the Xizang Plateau and Yunnan Plateau eastwards to Ryu Kyu Islands, and from the southern slope of the Qinling Range southwards to northern Vietnam.  The karst region of S. E. Yun- nan and W. Guangxi is the centre of maximum variation of the genus and is probably its origin centre, where the most primitive taxon exists, and where more species (13 species, i.e. 61.9 per cent of the sum total) and more endemic species (8 species) are found than elsewhere.       3.  Classification  The genus consists of 21 species and 6 varieties which are classified into 2 sections.  The Clarke's classification is accepted, but emended here as follows:       Sect. 1. Subcapitatae Clarke Sepals free or posterior ones connate.  Muri of the seed-coat laevigate or rugose; bottom of meshes flat, smooth or with few verrucae.  Pollen grains subglo- bose or prolate.       Sect. 2. Hemiboea Sepals connate.  Muri of the seed-coat tuberculate or aliform-tuberculate; bottom of meshes flat or concave, with dense verrucae.   Pollen grains prolate.       Based on the analysis of external and internal morphological characters, the main evolu- tionary trends in the genus are discussed and enumerated, and a hypothesis indicating the re- lationships between the two sections is given.  相似文献   

10.
 A numerical taxonomic study of Chinese jasminum is presented. The 57 OTUS includemost taxa of the genus in China. Sixty eight characters, of which 30 were quantitative and 38 were qualitative, were used in the numerical analysis. The methods used here are cluster analysis and principle component analysiis (PCA). In cluster analysis, product-moment correlations secured from standardized data were clustered by the unweighted pair-group method using arithmetic average linkage (UPGMA). From the evidence presented the genus is divided into two sections which correspond to the two groups proposed by Taylor in 1945, rather than the four sections established by De Canolle (1844). By techniques of numerical taxonomy, some doubted taxa such as J. humile L., J. girddii Diels, J. ligustrioides Chia, J. hemsleyi Yamamoto J. cinnamomifolium var. axillare Kob.  … are re-examined and the treatment of these taxa are further discussed.  相似文献   

11.
本文对蓝钟花属Cyananthus及整个狭义的桔梗科Campanulaceae(s.str.)的花粉、   染色体和形态性状作了深入的系统研究,表明蓝钟花属是该科的最原始类群,它的亲缘属有党   参属Codonopsis和细钟花属Leptocodon。  对蓝钟花属中各个种及它的亲缘属的地理分布分   析,揭示了该属是典型的中国-喜马拉雅区系的成分,横断山地区是该属的频度和多样性中心;   认为中国西南部及其邻近地区至少是桔梗科原始属的保留中心,甚至可能是该科的起源中心。   作者最后对蓝钟花属各个种的性状作了生物统计分析,在此基础上对全属进行了全面的分类   修订,把原有的26个种9个变种归并为19种(包括2亚种);对该属的次级分类也作了修订。   首次报道了该属的染色体数目和细钟花属的花粉形态。  相似文献   

12.
    本文分析溲疏属的重要形态特征的演化趋势,讨论亲缘属的系统位置和地理分布及区系特点,分类系统的修订和补充,并编写了分种检索表。认为雄蕊不定数,花瓣覆瓦状排列,花丝无齿,子房半下位的是属于原始性状,而雄蕊定数,花瓣镊合状排列,花丝具齿,子房下位的是进化性状,因此新溲疏组应包括在溲疏属内,该组与中间溲疏组是原始类群,而溲疏组是进化类群。国产52种被分为2组,4亚组和17系。溲疏属基本上是属于北温带分布类型,而我国的横断山脉至秦岭南部和华中一带为本属的现代分布和分化中心。  相似文献   

13.
中国毛茛科植物小志(廿二)   总被引:2,自引:0,他引:2  
 (1)揭示了铁线莲属以下演化趋势:萼片由开展到直立;雄蕊由无毛到有毛;雄蕊花丝由条形演 化到披针状条形或倒披针状条形;花药由长圆形演化到条形或狭条形;药隔不突出到在顶端突出;在雄 蕊被毛时,毛由少而短到多而长;此外花序由具花序梗和苞片到花序梗和苞片消失,以及由自当年生枝 叶腋生出转变到自老枝腋芽中生出。主要根据上述演化趋势,本文将我国铁线莲属各组及组下分类群做出新的排列。(2)描述了6新亚组,6新系,2新种,4新变种,给出了5新组合,4新等级和2新名。  相似文献   

14.
本文根据植物类群的系统发育和地理分布统一的原理,讨论了獐牙菜属植物的起源、散布和分 布区的形成。獐牙菜属包括11组16系154种,间断分布在亚洲、欧洲、北美洲和非洲。中国西南部- 喜马拉雅地区汇集了大多数种类、不同演化水平的类群以及形形色色的特有类群,成为该属的多样化 中心和多度中心。该属的原始类群和外类群也集中分布在中国西南山地,极有可能是该属的起源地。该 属的分布区类型中出现了各式的间断分布,根据有该属植物分布的大陆间及大陆与岛屿间分离和连接 的时间推测,该属的起源时间至少不会晚于晚白垩纪,也许更早,可追溯到中白垩纪。通过分类群间亲 缘关系和现代分布分析,显示出该属植物从起源地向周围和一定方向散布,形成了三个主要散布途径。在散布过程中植物本身也发生演化和就地特化,形成新的类群。  相似文献   

15.
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, hypan- thium, sepals, and glandular indumentum, thi genus is divided into 3 sections: 1. Sect. Scopu- losae 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 (Afghanis- tan) 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 (includ- ing 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 Autono- mous Region of Xinjiang each have only 1.        Thus the distribution centre of this genus  should be in the region covering Si- chuan, Yunnan and Xizang. Moreover, it is noteworthy  that Bergenia scopulosa T. P. Wang in Sect. Scopulosae seems to have retained primitive characters,  for exa- mple, 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   

16.
本文通过对东亚和南亚马兜铃属的研究,修改了马兜铃属的分类系统,补充论证了演化趋势;并   在分析该属地理分布的基础上提出马兜铃属分布与分化的第二个中心——中国的横断山区。  本文确   认2亚属、7组、4系、68种和1变种,其中有3新组、2新种及13个新异名。  相似文献   

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