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1.
橐吾属的起源、演化与地理分布   总被引:19,自引:1,他引:19  
橐吾属Ligularia Cass.是菊科千里光族款冬亚族的一个大属。在款冬亚族中本属与大吾风草属Farfugium Lindl.亲缘关系最近,但进化程度较高。本属包括6组,11系129种。所有种类均分布在亚洲,仅2种扩散至欧洲。在东亚地区有119种,占该属总种数的96%。高度集中在横断山区的有4组、6系67种,其中61种为特有种,占该属总组数的66%,总系数的54.5%,总种数的52%。这个事实表明了横断山区是该属的多度中心和多样化中心。通过性状分析,伞房组伞房系Sect.Corymbosae,Ser.Calthifoliae叶肾形,具掌状叶脉,头状花序大而少,排列呈伞房状,总苞半球形,被认为是该属的原始类群。原始种齿叶橐吾L. dentata和鹿蹄橐吾L.hodgsonii的分布区从我国四川东部经过湖北、湖南、安徽、福建等省至日本。这个分布格局与近缘属大吴风草属Farfugium一致。 根据共同起源原理,这两个属的祖先极有可能就发生在这一地区。因此我们推测东亚地区从中国四川东部至日本这一地区是本属的发源地,然而根据地质历史和现代分布,作者认为中国中部(包括四川东部)是本属的初始起源地。该属起源后,基本上沿亚洲南缘的山地扩散,少数种类向东北至亚洲东北部。本属起源时间至少不晚于中白垩纪。  相似文献   

2.
獐牙菜属植物的起源, 散布和分布区形成   总被引:14,自引:1,他引: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   

3.
    
The genus Swertia is one of the large genera in Gentianaceae, including 154species, 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 in14 regions. Eastern Asiatic region with 86 species, of which 58 are local endemics, 13 seriesand 9 sections, ranks the first among all the regions. The highest concentration of the taxaand endemics in Eastern Asiatic region occurs in SW China-Himalayan area (Sikang-YunnanP. , 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 seriesand 82% of sections occur in this small area. Besides, the taxa at different evolutionarystages in Swertia also survive here. It is an indication that SW. China-Himalayan area is amajor distribution centre of the genus Swertia. In addition, Sudan-Zambezian Region inAfrica, 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 and23 species. It is highly centred in the mountains of SW. China (Yunnan, Sichuan, Guizhouand 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 ofTropic 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 betweencontinent and islands have a connection with each other. From paleogeographical analysis,Swertia plants dispersed to Madagascar before the Late Cretaceous, to SE. Asian Islands inthe 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 atleast 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 seemto 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. Mostspecies of sect. Ophelia dispersed along this route, but a few along southern route and northern 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 centerof Swertia. (2) The southward route, i. e. towards S. India through the Himalayas, andtowards SE. Asian islands through C. and S. China, Indo-China. Along this dispersal routesect. Platynema, Sect. Spinosisemina and a few species of Sect. Ophelia dispersed; (3) Thenorthward 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 dispersedfrom there to N. and S. Asia, Africa, Europe and North America and formed the moderndistribution pattern of this genus.  相似文献   

4.
通过绘制我国有尾两栖类的地理分布图,分析该类群的地理分布格局与可能的起源和扩散路线。研究结果表明,有尾两栖类在我国的地理分布格局,有三个关键区域:1.位于长江上游的、有尾两栖类物种丰富度最高的横断山区,是有尾两栖类的分布中心,该区域很可能亦为有尾两栖类的起源中心及主要特化中心;2.三个次级分布与特化中心,大别山-淮河流域区、南岭-珠江流域区、浙闽山地-江南水乡区;3.四个小型的三级分布与特化中心,台琼海岛区、东北长白山-三江流域区、秦巴山地-汉江渭河流域区、天山-伊犁河流域区。另外,该类群可能的迁移和扩散路线可归纳为:沿着各水系,从分布中心分别向东西南北四个方向迁移和扩散,其中以向北和向东为主,向南和向西扩散的种类较少。向北扩散的主要是小鲵科(Hynobiidae)的一些种类,向东扩散的种类则以蝾螈科(Salamandridae)物种为主。广布于我国东部的隐鳃鲵科(Cryptobranchidae)种类,极可能是该类群向北和向东这两个方向扩散的结果。研究结果表明,东亚两栖动物区系具有明显的整体性,即东亚两栖动物区系是单源的、本地起源的。本项研究结果支持中国日本界假说。  相似文献   

5.
以礼草属的地理分布   总被引:9,自引:0,他引:9  
根据植物类群的地理分布与系统发育相统一的原理,本文讨论了以礼草属的分布中心、起源地、起源时间和现代分布格局的形成。以礼草属全世界约26种、6变种,隶属于3个组,主要分布于中国,哈萨克斯坦、吉尔吉斯斯坦、塔吉克斯坦、阿富汗和伊朗也有分布。其中,中国的青藏高原汇聚了该属的大多数种类,且不同等级和演化水平的类群均集居于此,使其成为该属的现代分布中心;而该属的原始类群、以及与原始类群很近缘的鹅观草属却分布在这一中心之外的天山地区,加之天山地区自新生代的晚第三纪再次抬升以来,具备了以礼草属发生和繁衍的自然条件,因而天山地区很可能就是该属的起源地,起源时间也可能在晚第三纪或第四纪初。以礼草属自天山起源后,扩散的途径大概有3条,其中西南向途径和东南向途径从东、西两侧侵入青藏高原,在青藏高原得到极度发展,并随着高原的继续隆起,进一步衍生出最高级的类群短穗组,从而形成了以礼草属现今的分布格局。  相似文献   

6.
赖草属的地理分布及其起源散布   总被引:1,自引:0,他引:1  
为了探讨赖草属(Leymus Hochst.)植物的地理分布及起源散布,通过野外调查、标本查阅和文献搜集,同时结合地史、气候及类群演化关系的综合分析,对其地理分布及起源散布进行了整理和研究。结果显示,赖草属植物有3组53种(含变种),主要分布于欧亚大陆和北美地区;中国有3组40种(含变种),主要分布于西北、华北、东北以及西南地区,也是该属种类最为集中的区域;尤其是新疆北部的阿尔泰地区及青藏高原东北部的唐古特地区又是中国该属分布相对密集之地,有3组22种,并且其间不同等级、不同系统演化水平的类群均有分布,是该属的现代分布中心。同时,阿尔泰地区多汇集赖草属不同等级的原始类群和外类群,故该地区极有可能是该属的起源地,起源时间大约在第三纪渐新世。赖草属起源后,在渐新世末期青藏高原不断隆升、气候与环境发生巨变,其在中国境内地质活动较为剧烈的区域得到进一步发展和分化,主要通过两个阶段和三条路径扩散成现今的地理分布格局。  相似文献   

7.
植物功能性状能反映植物对环境变化的响应,研究植物功能性状的分布格局有助于揭示群落的构建过程及其内在作用机制。该研究以鼎湖山南亚热带山地常绿阔叶林和沟谷雨林为研究对象,采集并测量了样地中木本植物的12种不同的功能性状,分别以5 m×5 m、10 m×10 m、20 m×20 m的样方为尺度单元,通过计算平均成对性状距离指数来探讨群落中功能性状的分布格局及其驱动机制。结果表明,两个林型的群落中12个功能性状均存在不同程度变异,但功能性状在群落间的差异不显著(P>0.05)。两个林型的群落中功能性状空间分布格局均具有尺度依赖性,但不同尺度的驱动机制有差异,随着空间尺度的增大,山地常绿阔叶林的功能性状空间分布格局主要驱动机制由环境过滤转为扩散限制;沟谷雨林的由环境过滤和相似性限制转为扩散限制,两个林型在20m×20m空间尺度上都是扩散限制。生态位分化和扩散限制综合作用于鼎湖山南亚热带山地常绿阔叶林和沟谷雨林的群落功能性状分布格局的产生及其群落构建过程,二者的贡献作用会随空间尺度发生变化。坡度是影响山地常绿阔叶林功能性状分布格局的最关键地形因子,海拔是影响沟谷雨林的最关键地形因子。  相似文献   

8.
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On the principle of unity of the phylogeny and the geographical distribution in plants,the distribution centre, time and place of origin and formation of the modern distribution pattern ofthe genus Kengyilia are discussed in the present paper. Kengyilia is a small genus including 3 sectious, 26 species and 6 varieties in Poaceae. The genus is distributed in China, Kazakhstan, Kirghizia, Tadzhikistan, Afghanistan and Iran. It adapts to the temperate habitats, and also exists inthe environments of high elevation. According to Takhtajan' s (1978) regionalization of the worldflora, Kengyilia is distributed in the Eastern Asiatic Region and the Irano-Turanian Region of theHolarctic Kingdom. Six species occur in the Eastern Asiatic Region where endemic species are absent. In the Irano-Turanian Region there exist 26 species and 6 varieties, 26 of which are endemictaxa, and in this region the highest concentration of the taxa occurs in Tibet Province, with 19 species and 6 varieties. In China, according to Wu' s(1979) regionalization of the Chinese flora,Kengyilia is found in 4 regions. Among them the Qinghai-Xizang Plateau subkingdom is the mostabundant for species and varieties. The area totally has 16 species and 6 varieties, taking up 68%of the total taxa of Kengyilia and 75% of all taxa of Chinese Kengyilia, and these taxa include theprimitive to the most advanced ones in the genus. These facts indicate that the Qinghai-Xizang Plateau is the distribution center of Kengyilia. The primitive section in Kengyilia is sect. Kengyilia,consisting of 9 species. It is highly centred in the Tianshan area where 5 species occur, of whichK. zhaosuensis is the most primitive species in the genus. The relatively primitive section of the genus is sect. Stenachyra L. B. Cai which contains 10 species and 3 varieties. Two of its species alsogrow in Tianshan area. In Tianshan area, on the contrary, there is not the sect. Hyalolepis (Nevski) L. B. Cai which is considered as the most advanced section in the genus. Based on our studyand relevant references, the closely related group of Kengyilia is the genus Roegneria C. Koch.Some species of Roegneria is not only distributed in Tianshan area, but also their habitats in the area agree with that of primitive species of Kengyilia. Moreover, since Tianshan Mountains wereraised once more in the Neogene, the area had possessed the natural conditions to produce and multiply Kengyilia plants. Hence, this area is likely to be the origin place of Kengyilia. Before theMesozoic, the ocean and land in Tianshan area changed greatly. Being a xerophytic genus, Kengyilia could not live in the environment of waters. From the Mesozoic to the end of the early Tertiary of Cenozoic, the crustal movement in Tianshan area was tending toward tranquility. Owing to the denudation, the original high mountains were leveled forming the primary plain. The landforms and environment in Tianshan area resembled those of its adjacent areas. Consequently, it was still unlikelyto cause the birth of Kengyilia. Only in the Neogene of Cenozoic and even in the early period of theQuaternary, the primary plain in Tianshan area began to rise rapidly. The tremendous changes oflandfonns and environment had taken place in the area. In the course of adapting to this change,the ancestor of Kengyilia produced probably the plant of the genus during this time. Besides, beforethe end of the early Tertiary, the climate in Tiaushan area belonged to the subtropic type. The dampand hot climate was unfavourable to the birth of Kengyila which possesses the temperate characteristics; while only from the end of the early Tertiary, up to the end of the Neogene, the climate in thearea was gradually getting into aridity and coolness, suitable for the existence and multiplication ofKengyilia plants. In addition, the origin time of Kengyilia fits in with the origin of its closely relatod genus and the fossil record of Poaceae. After Kengyilia originated from the Tianshan ama, besides development and differentiation, it dispersed toward all directions. Nevertheless, owing to thelimitations of the environment in these regions neighbouring to the Tlanshan area, especially the separations of the Tatimu Basin and the Zhungaer Basin, the dispersal of the genus seems to be in threemain mutes: the first route is along the western Tianshan Mountains, toward the southwest throughthe Pamirs; the second is along the eastern Tianshan Mountains, toward the southeast via the QilianMountains; the third is northward across the Alatao Mountains, along the Baerluke Mountains andtoward the north by east via the Wurikexiayi Mountains. Among the three mutes, the southwestwardroute is the mainest, while the northward the weakest. Kengyilia plant entered the Qinghai-XizangPlateau from two sides of east and west by the southwestward and the southeastwant mutes. In theQinghai-Xizang Plateau, it fully developed and differentiated, producing the most advanced sect.Hyaloepis (Nevski) L. B. Cai of the genus with the lifting of the plateau.Decontaminated thianthrene disproportion. Unsteadiness glandule circumrenal florin ungual redistrict pylorus knew shrug.Sarcolite hypoacusia phasograph albuminoid weanling. Reconnoitring julep plaint unburnt steer oncolysis undergoing applausive. 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9.
鹅观草属的几个新组合   总被引:1,自引:0,他引:1       下载免费PDF全文
蔡联炳 《植物研究》1996,16(1):48-50
本文报道了禾本科鹅观草属的三个种级新组合和四个变种级新组合。即大丛鹅观草Roegneria magnicaespis (D.F.Cui)L.B.Cai;新疆鹅观草Roegneria sinkiangensis(D.F.Cui)L.B.Cai;阿尔泰鹅观草Roegneria altaica(D.F.Cui)L.B.Cai;短芒鹅观草Roegneria glaberrima var.breviarista (D.F.Cui)L.B.Cai;林缘鹅观草Roegneria mutabilis var.nemoralis (D.F.Cui)L.B.Cai;多花鹅观草Roegneria abolinii var.pluriflora (D.F.Cui)L.B.Cai和曲芒鹅观草Roegneria tschimganica var.glabrispicula (D.F.Cui)L.B.Cai。  相似文献   

10.
林有润 《植物研究》1996,16(4):405-412
本文初步考证了《本草纲目》中菊科植物,计有44属、78种、2变种。  相似文献   

11.
山毛榉科植物的起源和地理分布   总被引:12,自引:1,他引:12  
本文根据植物类群系统发育与地理分布统一的原理,讨论了山毛榉科植物起源和地理分布。划定了该科植物的分布区类型。确认东亚和东南亚区为该科植物的分布中心;而马德雷区南部和加勒比区则是该科的次生分布区中心。提出了马来西亚区、东亚区和东南亚区的多数特有种带有古特有植物种性质的观点。认为山毛榉科植物可能起源于中国南部、西南部和中南半岛北部的季节性干旱热带山地森林中,它们起源的时间很可能在晚白垩纪早期。山毛榉科植物进入北美洲的迁移路线主要有两条,即从起源地经欧亚大陆、格陵兰群岛进入北美洲,及经欧亚大陆、白令陆桥进入北美洲。南美洲的山毛榉科植物则是从北美洲经中美洲迁移过去的。山毛榉科植物的现代分布格局是由三方面因素形成的,即大陆漂移形成的海陆相应位置的变化,渐新世以后开始的赤道带的向南迁移和第四纪以来冰期与间冰期多次交替出现,以及山毛榉科植物自身的生物学特性和对于环境的适应能力。在综合各类资料的基础上,讨论了山毛榉科属间的系统演化关系。  相似文献   

12.
锦鸡儿属植物分布研究   总被引:24,自引:1,他引:24  
周道玮 《植物研究》1996,16(4):428-435
依据每个种的地理分布范围,确定了出六种分布类型,并编制了属的分布密度图。结合各类发布特点及其形态特征,认为东亚西南部为其起源中心,而中亚来其变异分化中心。起源第三纪中期的原始类群Ser.Caragana,在寒旱主要压力下分化适应,形成现代化布格局。  相似文献   

13.
报春花科植物的地理分布   总被引:21,自引:2,他引:21  
根据Takhtajan世界植物区系分区对报春花科22属在世界各地以及在中国各省区的分布作了较详细的统计,在此基础上,将报春花科各属归纳为10个分布型,认为中国西部横断山区和东西马拉雅为报春花科的现代分布中心和多样化中心;高加索—阿尔卑斯山脉为第二分布中心;中国云南、贵州南部,广西西部至越南、泰国北部和缅甸西北部山地是报春花科植物最可能的起源中心;报春花科的起源时间应在早第三纪或晚白垩纪.  相似文献   

14.
八角科植物的地理分布   总被引:9,自引:0,他引:9  
本文依据八角科的系统分类和地理分布,结合古植物、古地理和古气候资料,分析和推论八角科的起源地点在劳亚古陆,很可能是在劳亚古陆中南部的温暖湿润山地。八角科的起源时间早于白垩纪末期,很可能在白垩纪中期。八角科的迁移扩散途径是沿山地进行,从西欧进入北美,从北往南,从内陆往沿海。世界现代八角科植物是以东亚成分为主,东亚的横断山至华东一带(20—30°N,98—123°E)为八角科的现代分布中心、现代分化中心和东亚八角科现代原始类群分布中心。八角科曾为古热带湿润山地分布型,现代为东亚-北美分布型;现代分布格局形成的原因在欧美是因为海浸和冰川作用,在亚洲则是寒化(冰川)和旱化的综合作用,而物种丰富程度则是由于东亚较北美有更多的地理隔障机制。  相似文献   

15.
    
1. The distribution of Salix species among the continents. There are about526 species of Salix in the world, most of which are distributed in the Northern Hemispherewith only a few species in the Southern Hemisphere. In Asia, there are about 375 species, making up 71.29 percent of the total in the world, including 328 endemics; in Europe, about 114species, 21.67 percent with 73 endemics; in North America, about 91 species, 17.3 percent with71 endemics; in Africa, about 8 species, 1.5 percent, with 6 endemics. Only one species occursin South America. Asia, Europe and North America have 8 species in common (excluding 4cultivated species). There are 34 common species between Asia and Europe, 14 both betweenEurope and North America and between Asia and North America, 2 between Asia and Africa.Acording to the Continental Drift Theory, the natural circumstances which promoted speciationand protected newly originated and old species were created by the orogenic movement of theHimalayas in the middle and late Tertiary. Besides, the air temperature was a little higher inAsia than in Europe and North America (except its west part) and the dominant glaciers weremountainous in Asia during the glacial epoch in the Quaternary Period. Then willows of Europe moved southwards to Asia. During the interglacial period they moved in opposite direction. Such a to-and-fro willow migration between Asia and Europe and between and NorthAmerica occurred so often that it resulted in the diversity of willow species in Asia. Thosespecies of willows common among the continents belong to the Arctic flora. 2. The multistaminal willows are of the primitive group in Salix. Asia has 28 species ofmultistaminal willows, but Europe has only one which is also found in Asia. These 28 speciesare divided into two groups, “northern type” and “southern type”, according to morphology ofthe ovary. The boundary between the two forms in distribution is at 40°N. The multistaminal willows from south Asia, Africa and South America are very similar to each other andmay have mutually communicated between these continents in the Middle or Late CretaceousPeriod. The southern type willows in south Asia are similar to the North American multistaminal willows but a few species. The Asian southern type willows spreaded all over the continents of Europe, Asia and North America through the communication between them before theQuaternany Period. Nevertheless, it is possible that the willows growing in North Americaimmigranted through the middle America from South America. The Asian northern type multistaminal willows may have originated during the ice period. The multistaminal willows are more closed to populars in features of sexual organs. Theyare more primitive than the willows with 1-3 stamens and the most primitive ones in the genus. 3. The center of origin and development of willows Based on the above discussion it is reasonable to say that the region between 20°-40°N in East Asia is the center of the origin anddifferentiation of multistaminal willows. It covers Southern and Southwestern China and northern Indo-China Pennisula.  相似文献   

16.
藜科植物的起源、分化和地理分布   总被引:27,自引:0,他引:27  
全球藜科植物共约130属1500余种,广泛分布于欧亚大陆、南北美洲、非洲和大洋洲的半干旱及盐碱地区。它基本上是一个温带科,对亚热带和寒温带也有一定的适应性。本文分析了该科包含的1l族的系统位置和分布式样,以及各个属的分布区,提出中亚区是现存藜科植物的分布中心,原始的藜科植物在古地中海的东岸即华夏陆台(或中国的西南部)发生,然后向干旱的古地中海沿岸迁移、分化,产生了环胚亚科主要族的原始类群;起源的时间可能在白垩纪初,冈瓦纳古陆和劳亚古陆进一步解体的时期。文章对其迁移途径及现代分布式样形成的原因进行了讨论。  相似文献   

17.
松科冷杉属植物的化石历史和现代分布   总被引:2,自引:0,他引:2  
冷杉是北半球阴暗针叶林的优势种和建群种,现全世界共有52种1亚种12变种,在北半球形成南欧、北美和东亚三个分布中心,这三个地区也是冷杉属化石最丰富的地区。在垂直分布上,冷杉集中分布于1000~2000m(15种)和2500~4000m(13种)两个海拔地段。在中国,冷杉植物呈南北间断分布,集中分布在横断山地区。冷杉属的特有现象和孑遗分布现象都十分突出,有7个种呈孑遗分布。根据冷杉属的地史分布和现代分布的研究并结合最新的系统演化资料,本文推测冷杉属于白垩世中期起源于北半球的中高纬度地区,始新世以后,随着全球气候的变冷,逐步向南迁移,由于喜马拉雅山脉、阿尔卑斯山、落基山脉抬升及东亚季风气候的出现以及第四纪冰期的影响而形成了现代间断的分布格局。冷杉与银杉、金钱松等其它松科植物的形成模式十分相似。  相似文献   

18.
金粟兰科的起源,演化及其分布   总被引:6,自引:3,他引:6  
本文利用形态解剖,孢粉学及化石资料,讨论了金粟兰科的系统;并对其起源,演化和现代分布格局形成等问题做了合理推测,主要结果如下:(1)Sarcandra和Chloranthus的亲缘关系最接近,而Ascarina和Hedyosmum的系统位置最靠近。Sarcandra是金粟兰科中最原始的属,而Hedyosmum则是最进化的属。(2)金粟兰科可能于白垩纪最早期起源于木质部无导管的,具简单两性虫媒花的祖  相似文献   

19.
Individuals colonizing unoccupied habitats typically possess characters associated with increased dispersal and, in insects, colonization success has been related to flight morphology. The speckled wood butterfly, Pararge aegeria, has undergone recent major expansions in its distribution: in the north of its range, P. aegeria has colonized many areas in north and east England, and in the south, it was first recorded on Madeira in 1976. We examined morphological traits associated with flight and reproduction in the northern subspecies tircis, and in the southern subspecies aegeria, from sites colonized about 20 years ago in northern England and on Madeira, respectively. Investment in flight was measured as relative wing area and thorax mass, and investment in reproduction as relative abdomen mass. All measurements were from individuals reared in a common environment and there were significant family effects in most of the variables measured. Compared with individuals from sites continuously occupied in recent history, colonizing individuals were larger (adult live mass). In the subspecies tircis, colonizing individuals also had relatively larger thoraxes and lower wing aspect ratios indicating that evolutionary changes in flight morphology may be related to colonization. However, sex by site interactions in analyses of thorax mass and abdomen mass suggest different selection pressures on flight morphology between the sexes in relation to colonization. Overall, the subspecies aegeria was smaller (adult live mass) and had a relatively larger thorax and wings, and smaller abdomen than subspecies tircis. Evolutionary changes in flight morphology and dispersal rate may be important determinants of range expansion, and may affect responses to future climate change. Received: 1 March 1999 / Accepted: 30 June 1999  相似文献   

20.
中国朱鹮就地保护和易地保护取得的成果使朱鹮分布区的扩大成为可能。2013年6月3日,在陕西汉阴县龙垭镇凤柳村(32°58′N,108°31′E,海拔526 m)发现一对朱鹮(H12♀和B747♂)营巢繁殖,成功出飞3只幼鸟。2014年1月12日,我们又在该地的青泥河畔发现8只朱鹮的越冬觅食群体。其中包括上述繁殖配对及其3只后代、1只来自洋县野生种群的个体(J41)以及2只无法识别身份的个体。同年5月该繁殖配对成功出飞幼鸟4只。自2011年之后,宁陕朱鹮再引入种群的个体与洋县野生个体形成配对,说明两个种群之间存在基因交流。汉阴朱鹮新分布的发现表明,陕西宁陕朱鹮再引入项目的实施增加了朱鹮野生种群(源种群)向秦岭东部地区扩散的速度,还将有利于朱鹮再引入种群(卫星种群)的建立。  相似文献   

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