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1.
A new subtribe of the family Urticaceae, Sphaerotylinae C. J. Chen, a new genus, Sphaerotylos C. J. Chen and its type species S. medogensis C. J. Chen from south-eastern Xizang (Tibet) in China are described and illustrated. The subtribe is regarded as a primitive group in the tribe Boehmerieae. The ring-shaped stigma and the ball-like connective are the first discovery in the family Urticaceae. The types of the stigma of the family, their taxonomic significance and their evolution are also discussed in the present paper.  相似文献   

2.
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. According 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 Caragana. 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 differentiation 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 differentiation of the genus in this region are resembled to Astragalus. These two genera are usually growing together, composing the main accompanying elements of alpine meadow 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 Xizang. According to the elements of composition, 4 species are common to Inner Mongolia 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 OhaShi,s system about the genus in 1973, the species of Desmodium distributed in Sino-Himalaya 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 connections 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 distribution 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   

3.
黄土高原蕨类植物区系特点的初步研究   总被引:3,自引:3,他引:0  
对黄土高原的蕨类植物区系组成、分类及其特点进行了研究。结果表明,黄土高原有蕨类植物26科、53属、184种及3变种,种类较多的科有蹄盖蕨科(30种)、鳞毛蕨科(26种)、水龙骨科(20种)、铁角蕨科(12种)、卷柏科(12种)、中国蕨科(11种)及裸子蕨科(10种)等。这7科的种类共计121种,占本地区总种数的64.71%。种类较多的属有鳞毛蕨属(13种)、郑柏属(12种)、耳蕨属(11种)、铁角蕨属(11种)、蹄盖蕨属(10种)、瓦韦属(10种)、铁线蕨属(9种)及岩蕨属(9种)等。这8属的种类共计85种,占本地区总种数45.46%,黄土高原蕨类植物区系属的地理成分可划分为15个分布区类型。热带、亚热带分布类型的有18属,占总属数的41.86%,北温带及寒带分布类型的有22属,占总属数(世界分布属除外)的51.16%,其中,亚洲分布类型的最多,计有16属,占总属数的37.20%,表明黄封同原蕨类植物区系是温带类型,区系地理成分以华北区蕨类植物为主,同时也集中了华中、华东、东北、西北以及西南的蕨类植物。而中国特有的分布属只有1属。  相似文献   

4.
青藏高原跳甲亚科昆虫区系研究   总被引:3,自引:0,他引:3  
讨论青藏高原(包括横断山区)的跳甲亚科昆虫区系。该区已知47属228种。1)据属级阶元的分布类型分析,以东洋属和南型属种显占优势,是区系主体,显示该区跳甲区系的热带渊源,其中高山属种赋予该区以高山区系特征;2)该区物种分化活跃,是某些多种属中国种类的分布中心和分化中心;3)联系中国跳甲亚科区系,在地理分布格局上显示西-东分布,如Hespera属的分布和西南-东北分布或西南-东北的间断分布格局,如Pentamesa和Stenoluperus属的分布。这种地理分布格局反映青藏高原的隆起给中国昆虫区系带来重要影响。  相似文献   

5.
西藏佩枯错种子植物区系研究   总被引:1,自引:0,他引:1  
郭文文  屈兴乐  任毅华  罗大庆 《广西植物》2018,38(11):1428-1439
为了丰富西藏高原植物区系地理研究资料,深入开展该区域植被生态学研究、生物资源开发利用与保护,该研究通过野外调查、标本采集以及查阅相关的文献资料,对西藏佩枯错种子植物区系进行了统计分析。结果表明:(1)植物种类较贫乏。佩枯错共有种子植物31科77属115种,仅占西藏种子植物的18.90%、6.73%、2.17%。其中裸子植物2科2属2种,被子植物29科75属113种;被子植物中双子叶植物有23科58属91种,单子叶植物6科17属22种。(2)优势科明显,单种科占绝对优势。所有科中有5个科至少含有7种种子植物,占该研究区总种数的39.13%,是该区系的主要组分;同时科数中有11科仅含1种植物,该类科占一定优势。(3)种子植物的区系成分较复杂,划分为3个科分布区类型和10个属分布区类型,其中温带成分占绝对优势:温带分布科、属分别占总数的29.03%和77.92%,表明本区系具有明显温带性质。(4)科属特有现象不明显,没有中国特有科分布,仅有1个中国特有属分布,说明佩枯错植物区系的特有化程度极低,表现出寒旱化与高山、高原特化综合而成的高寒植物区系的年轻性。  相似文献   

6.
色季拉山区高山寒带种子植物区系研究   总被引:4,自引:0,他引:4  
通过对西藏色季拉山高山寒带进行实地野外调查,鉴定统计得到种子植物285种,分属于33科103属,其中双子叶植物有26科、77属、236种,裸子植物有1科、1属、4种,中国特有植物125种。对该区域种子植物区系从科、属、种三级水平统计分析,初步探讨了其植物区系的性质和基本特点。地理成分简单,但特有现象明显,在种类上缺乏古老、原始的类型;从科、属和种的分布类型统计分析,基本上都是温带成分,反映出典型的温带区系特征和区系的年青性,因而具有高寒区系的显著特色。在区系成分中存在较多中国-喜马拉雅成分,表明了该区系具有明显的高原及高山植物区系的特色。  相似文献   

7.
滇川干暖河谷种子植物区系成分研究   总被引:4,自引:1,他引:3  
金振洲   《广西植物》1998,18(4):313-321
本文论及滇川干暖河谷种子植物区系成分由科级到种级的研究结果。所统计分析的植物共692个种,分属于336个属,111个科。科级区系成分中,明显以亚热带科为主,暖温带科次之,热带科很少。属级区系成分中,热带属多于温带属,有14个特有属。热带科属偏多说明本河谷历史上有过以热带区系为主体时期和近代区系发源于热带。种级区系成分中,有中国特有种421种,占61.90%,其次是温带种多于热带种。干暖河谷的植物区系标志种有158种,分三个等级,一级为本河谷特有种,有18种,二级103种,三级37种。干暖河谷的特有区系成分和各级植物区系标志种均较好地反映本河谷区系演化的近代趋势及其独特性。  相似文献   

8.
中国红原泥炭沼泽植物区系研究   总被引:3,自引:0,他引:3  
沼泽植物是形成泥炭物质来源的重要资源植物。我国省西北部高原的红原县是我国沼泽最发达的地区之一,沼泽植物约有155种,隶属于39科,87属,包括世界分布属20属,泛热带分布属51属,旧世界温带分带属7属,温带亚洲分布属2属,地中海,西亚至中亚分布属1属和东亚分布属5属,在泥炭沼泽植物中,莎草科是种数最多的科,其次是菊科、毛茛科、玄参数、禾本科和龙胆科,它们的种数约占全部泥炭沼泽植物种数的53.54%  相似文献   

9.
山西朔县种子植物区系及其生态经济意义   总被引:10,自引:0,他引:10  
朔县(现朔州市朔城区)植物种属相对丰富,具有维管束植物938种,隶属于420属,105科。其植物区系主要起源于古北大陆;种子植物属的地理成分复杂多样,以温带成分占绝对优势,具有典型的温带草原性质;与相邻地区植物区系的比较分析表明,联系最为密切的是蒙古草原植物区系,其次是黄土高原植物区系。该县植物资源利用应采取的对策是:既要合理开发利用,又要加强物种的保护。  相似文献   

10.
为探讨尧山国家级自然保护区种子植物区系性质、特征,对尧山国家级自然保护区种子植物区系进行了调查分析。结果表明,尧山共有种子植物132科698属1 978种,包括裸子植物5科8属10种,被子植物127科690属1 968种。科的地理成分以热带分布略占优势,为53.57%,温带成分占44.05%,而属以温带成分占明显优势,占比69.76%,热带性属仅占25.76%,表明热带成分在尧山已不占优势,尧山区系呈现出明显的热带性向温带性过度特征。尧山共分布中国特有属28属,其中木本属有11属,如银杏属(Ginkgo)、杜仲属(Eucommia)、青钱柳属(Cyclocarya)等,仅分布1种及少数种的属占比高达87.25%,包含单型属45属,体现出尧山植物区系的古老、残遗性质。尧山与邻近地区(宝天曼、鸡公山、天目山)的区系组成均呈现出温带性,并以尧山温带成分占比最高。总体上,尧山区系呈现出明显的温带性,在区系来源上主要为华东成分,并受到华北、华中成分的渗透。本研究为尧山地区植物资源的可持续利用、珍稀濒危植物的评估和保护管理等提供科学依据。  相似文献   

11.
黑龙江省木本植物区系分析   总被引:6,自引:1,他引:5  
曲秀春  刘祥君  于爽 《植物研究》2006,26(2):250-256
黑龙江省有木本植物392种,隶属于42科90属。其中裸子植物4科8属34种,双子叶植物37科81属357种,单子叶植物1科1属1种。本省为大兴安岭植物区、东北植物区和蒙古草原植物区三区汇集之地,木本植物地理成分复杂,具有非常明显的温带性质:温带分布科虽然与热带分布科数目相同,但所含种数多,优势明显;温带分布属占75.86%,以北温带分布比例最高;温带分布种占80.43%,以东北分布居首位,其次是中国—日本分布。该区系木本植物起源古老,有珍稀濒危植物9种,特有植物14种及红松、黄檗等孑遗植物,为第三纪植物区系系统。  相似文献   

12.
四川被子植物区系特征的初步研究   总被引:25,自引:0,他引:25  
四川地区被子植物区系188科1493属8711种及1252变种,全球50%以上的科都有代表,与毗邻地区及世界植物区系有着广泛而密切的联系。区系古老而原始,珍稀孑遗类群丰富;单型或少种的科属众多,含100种以上的大科和大属也十分繁荣;含5种以下的属占76.89%,但占总属数约22.64%的多种属和大属是区系的主体,包含区系总种数的63.28%。科的分布类型有明显热带性质,属、种的分布类型反映出典型的亚热带属性。优势现象明显,特有类群和表征类群丰富。该地区被子植物区系对中国乃至东亚都有代表性。  相似文献   

13.
The valley in upper reaches of Yellow River is situated in the east of Qinghai, China, between latitude 35b20c~ 36b 25c N and longitude 100b55c~ 102b50c E. This area belongs to the transitional zone of Qingha-i Tibetan Plateau and Loess Plateau at an altitudinal range of 1 780m to 4 969 m. The total area is c113 480 km2. Its climate is continental or plateau- continental one. There are 1 027 species of wild seed plants which belong to 86 families and 404 genera in the area. They are 44195% of the total species, 95156% of the total families and 79153% of the total genera in Qinghai, respectively. The floristic characteristics in wild seed plants for the area are as follows: ( 1) Species and woody ones are richer. ( 2) Species endemic to China also richer, but those endemic to Qinghai are very poor. ( 3) On the level of genera, all the fifteen distribution types in China, especia-lly all the six tropical ones only occur in the area in Qinghai. ( 4) On the analysis of genera and species, the flora is temperate in nature which is dominated by North Temperate elements especially the typical elements from the warm and cold zone of Eurasia, and also with some elements of thewarm, cold warm and alpine types. ( 5) The area is of a marginal one in distribution for many species or genera and especially for many tropical ones, so the flora of the area is clear in maginal nature. ( 6) In floristic geography, it is a converged and transitional region for the Loess Plateau Flora, Hengduan Mountians Flora, Alpine Qingha-i Tibetan Plateau Flora, as well as Qaidam Alpine Desert Flora, so the flora of the area is also conspiarously a transitional one. Therefore, as a marginal region far from the center of Qingha-i Tibetan Plateau and with a transitional flora more or less keeping the floristic nature of plateau and alpine types, so the valley in upper reaches of Yellow River in Qinghai should be a flora still belonging to the Tangute one, although it is weaker in alpine nature but conspicuously much more related to North China one.  相似文献   

14.
欧芷阳  杨小波 《广西植物》2008,28(3):344-351
铜鼓岭位于海南省东北部,共有维管植物166科626属984种及变种。五指山位于海南岛中部山区,共有维管植物196科911属2146种及变种。前者共有单型科54科,单种属431属,分别占科和属总数的27.11%,68.74%;后者共有单型科35科,单种属496属,分别占科及属总数17.77%,54.5%。说明五指山物种组成比铜鼓岭的更丰富,但两个区系属内种系分化程度都较弱。区系分析表明:(1)铜鼓岭以泛热带分布占优势,热带亚洲分布次之,分别占该区非世界分布属总数的34.5%和17.8%;五指山以热带亚洲分布占优势,泛热带分布次之,分别占非世界分布属总数的37.5%和24.1%;两个区系热带性质强烈,但前者以泛热带分布为主,后者以热带亚洲成分为主。(2)铜鼓岭共有35种海南特有种,占海南536个海南特有种(变种)的6.53%;五指山共有284个海南特有种,五指山特有种16种,占海南特有种的52.99%,说明其在海南植物区系中比铜鼓岭更重要。  相似文献   

15.
色季拉山区高寒山地植物的生态特征   总被引:2,自引:0,他引:2  
通过野外调查和现有文献资料,分析了色季拉山高寒地带植物的构成特征,结果表明:该区有种子植物33科103属285种,其中双子叶植物有26科77属236种,裸子植物有1科1属4种,中国特有植物125种,占总种数的44.01%,西藏特有植物53种,占18.66%。在整个高山寒带中,草本有239种,占83.86%,其中多年生草本230种。植被区系组成、群落植物生活型和叶的性质等特征总体都反映了植被的温带性质。并阐述了该区高山植物对高山恶劣气候环境相适应的形态结构特征。  相似文献   

16.
The Rosaceae is one of the five largest families of Xizang flora, consisting of 30 genera with 242 species, the total number of species is slightly less than those of Compositae, Graminae, Leguminosae and Ericaceae in Xizang, amounting to 62.5% of the total number of genera and 28% of the total number of species of the rosaceous flora in China. The four subfamilies of Rosaceae including primitive, intermediate and advanced groups have been found in Xizang. These groups consist of 11 types of floristic elements, i.e. 4 genera belong to cosmopolitan, 9 genera belong to North Temperate, 3, E. Asian-N. American, 3 Sino-Himalayan, 3 Sino-Japanesa, 2 Old World Temperate, 1 Temperate Asian, 2 Mediterranean-W. and O. Asian, 1 C. Asian, I Tropical Asian and 1 endemic to China. It is obvious that Rosaceae in Xizang comprises holarctic, Ancient Mediterranean and paleotropical elements, among which the temperate components are the most dominant. The characteristics of the floristic composition of Rosaceae in Xizang may be summarized as follows: (1) Xizang abounds in both genera and species of the family which are diverse in forms, including the primitive, intermediate and advanced groups, (2) The geographical elements are rather complex, mostly belonging to the temperate, among which the Sino- Himalayan components and the elements endemic to China are dominant, (3) The proportion of plants endemic to China and distributed in Xizang is much higher than those endemic to Xizang itself, but there exist newly arisen species and infraspecific forms or varieties which show that the speciation is apparently still active in Xizang. The rosaceous flora of Xizang is a combination of old and new floristic elements, based on the old floristic components, affected by the upheaval of the Himalayas, the differentiation and speciation have been taking place in the long history. The geographical distribution of Rosaceae in Xizang may be divided into 5 regions, i.e. the northeastern, southeastern, southern, northwestern and northern. The rosaceous plants are most abundant in the southeastern area, next in southern area, fewer in the northeastern and very rare in the northwestern and northern regions. The general tendency of the distribution of Rosaceae in Xizang is that the number of species gradually decreases from the southeast to the northwest and the habit gradually changes from trees, shrubs and herbaceous plants in the southeast to cushion-like scrubs and dwarf perennial herbs in the northwest. These facts clearly show that the uplift of the Himalayas has deeply affected the phytogeographical distribution of Xizang Rosaceae. The rosaceous flora of Xizang has close relationships with those of the adjoring regions, i.e. Yunnan and Sichuan. Besides, it is connected with floras of Nepal, Sikkim, Bhutan nothern Buram and nothern India, but silghtly influenced by the Ancient Mediterranean flora.  相似文献   

17.
重庆武隆天生桥是国家4A级风景名胜区,处于云贵高原大娄山褶皱带与武陵山系的过渡地带。对该区植物从科、属和种的分布区类型进行了统计分析,另外将该区区系特征与其他几个地区进行了对比分析。结果表明:①该区内有种子植物115科、475属、1292种。②大、中属共有37属,仅占总属数的7.79%,但所含种数达389种,占总种数的30.11%。说明本植物区系中优势属较为明显。③从种子植物科属分布区类型所占比例来看,该地区区系性质以热带成分占优势,其中热带分布属214属,占总属数的50.71%,这一特点与当地的环境特点是密切相关的。④区系分析表明,温带分布类型也占相当优势,有温带分布属203属,占总属数的48.10%,说明该地区区系性质具有热带到温带过渡的性质。⑤中国特有种丰富,共有881种,占总种数的68.83%。⑨经对比分析和聚类分析表明:该区与相距较远地区属的相似性系数较低,表明区系上联系较为疏远;而与邻近的几个地区属的相似性系数较高,特别与西南地区植物区系联系紧密。  相似文献   

18.
在野外植被调查、标本采集和资料查询整理的基础上,汇总了察隅河流域种子植物名录,并对流域内植物物种的组成、优势科属、区系地理成分及性质进行分析。运用R语言在属水平上与其周边16个地区的植物区系进行聚类及主成分分析,探讨察隅河流域种子植物区系与其他区系之间的关系。结果表明:(1)察隅河流域共含种子植物138科、689属、2 771种(含变种),其中裸植子物4科12属56种,被子植物134科677属2 715种,被子植物中双子叶植物112科531属2 270种占绝对优势。(2)区内地理成分联系广泛,科的区系划分除世界分布类型外,热带分布型53科(55.21%),温带分布型43科(44.79%);属的区系划分中所有类型均有分布,温带分布型396属(62.07%),热带分布型230属(36.05%);属的分布型与科相比具有更明显的温带性质;植物种类丰富度高但特有成分低,无特有科,仅含12特有属。(3)流域内植被垂直地带性分布较为明显,保留了较多古老孑遗植物,如裸子植物的西藏红豆杉(Taxus wallichiana)、察隅冷杉(Abies chayuensis)和云南松(Pinus yunnanensis)等;由于青藏高原的上升运动,成为杜鹃花属(Rhododendron)、虎耳草属(Saxifraga)、龙胆属(Gentiana)和报春花属(Primula)等新生高山植物区系成分分化繁衍的摇篮。(4)察隅河植物区系属喜马拉雅山南侧热带成分向温带成分过渡的区系性质,与珠峰自然保护区植物区系更为相似。  相似文献   

19.
该研究在对德夯风景名胜区种子植物进行多次野外调查及查阅相关资料文献的基础上,从科、属、种层面、不同特殊生境类型,并与邻近地区进行比较,综合分析探讨德夯的植物区系特征,深入揭示该区植物区系的性质和地位,为该区自然资源的保护和管理以及持续利用提供科学依据。结果表明:(1)德夯种子植物类群丰富,该区共有野生种子植物154科710属1 626种,分别占武陵山地区种子植物科、属、种总数的94.48%、83.43%、54.00%,分别占湖南省种子植物科、属、种总数的73.33%、54.20%、33.46%。(2)该区种子植物区系地理成分复杂,科含12个分布区类型,属含14个,种含15个,科和属的地理成分均以泛热带分布型所占比例最高,种的地理成分以中国特有分布型所占比例最高;特有现象明显,该区含7个东亚特有科、2个中国特有科,27个中国特有属,588个中国特有种,其中含39个华中特有种,29个武陵山地区特有种和6个德夯特有种。(3)该区植物区系成分随生境不同出现分化,台地、悬崖、谷地3种代表性生境区系成分差异明显,和邻近的壶瓶山、小溪、乌龙山3个地区具有较高的相似性。总体上,德夯风景名胜区植物区系具有东亚植物区系特征,在武陵山地区植物区系中具有重要地位。  相似文献   

20.
新疆灌木植物共416种(包括20个变种),隶属于109属,35科.对新疆灌木区系科、属的组成和地理成分进行分析,结果表明:新疆灌木植物地理成分多样,区系性质以温带为主.在科级水平上,除去世界分布科,温带分布科占80%.在属级水平上,北温带分布、旧世界温带分布和温带亚洲分布共有54属,占新疆灌木植物非世界属的56.25%;植物区系的种类趋向于集中在有限的少数科内,单种属和寡种属居多,区系的优势现象比较明显;在属的水平上,北温带成分和地中海成分占优势,分别占总属数的37.5%和23.96%,无中国特有成分,表明新疆灌木植物区系与本地区所处的北温带和古地中海地理位置是一致的.  相似文献   

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