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1.
中国木蓼属的研究兼论木蓼族的系统   总被引:3,自引:0,他引:3  
我国木蓼属有11种,3变种,其中特有种3个。本文通过对它们的形态,花粉等性状的研究,探 讨了属的系统位置,提出了木蓼族的演化系统。在分析了木蓼属的性状后,认为木蓼组Sect Tragopyrum(Bieb.)Meisn.较为原始,应置于刺木蓼组Sect.Atraphaxis之前。本文还研究了该属的地理分布,初步探讨了它的起源及现代分布格局的形成。  相似文献   

2.
通过多年野外实地考察和资料统计分析,对蓼族植物在中国的地理分布进行了深入研究。结果表明,该类群在中国的分布具有一定规律。在水平分布上,物种数目由东北到西南呈逐渐增加的趋势,有6个高密度的分布区,集中沿横断山脉—秦巴山脉分布。除首乌属全国广泛分布外,其他各属或组均有其主要的分布区域。在垂直分布上,整个蓼族植物几乎都分布在海拔5 000 m以下。在海拔1 000~3 000 m,蓼族植物广泛分布,冰岛蓼属、拳参组、头状蓼组一年生型和神血宁组植物主要分布在海拔3 000 m以上,萹蓄组、春蓼组、刺蓼组、首乌属、虎杖属、金线草属和荞麦属主要分布在海拔1 000 m以下。  相似文献   

3.
中国蓼属头状蓼组植物叶表皮微形态及其分类学意义   总被引:2,自引:0,他引:2  
采用光学显微镜对中国蓼属头状蓼组17种7变种植物的叶片下表皮微形态进行了观察研究,结果表明,其叶片下表皮微形态特征分为4种类型:(1)气孔器类型为无规则型,表皮细胞不规则形,垂周壁波状或深波状;(2)非典型不等型,偶有无规则型,表皮细胞多边形或不规则形,垂周壁弓形、波状或深波状;(3)平列型,表皮细胞不规则形,垂周壁深波状;(4)平列型兼有非典型不等型,表皮细胞不规则形,垂周壁波状。根据其叶片下表皮气孔器类型,结合该组植物形态、习性等特征,将中国蓼属头状蓼组植物划分为4个系,即掌裂叶系、多年生系、蓼子草系以及一年生直立系。  相似文献   

4.
中国蓼属叉分蓼组植物花粉形态的研究   总被引:7,自引:0,他引:7  
采用光学显微镜和扫描电镜对中国蓼属叉分蓼组20种3变种的花粉形态进行了观察和研究。结果表明其花粉形态大多数为近球形至近长球形,少数为扁球形或长球形;花粉大小为20.4~44.0µm×17.0~34.0µm:从萌发孔看,有3沟、3 孔沟、多沟、散沟;外壁纹饰为微刺—穴状、刺状、粗网状、皱块状。据此,该组花粉可划分为5种类型,即叉分蓼型(Aconogonon-type)、钟花蓼型(Campanulatum-type)、大连线冰岛蓼型(Forrestii-type)、西伯利亚蓼(Sibiricum-type)及多穗蓼型(Polystachyum-type),编制了这些花粉类型检索表。叉分蓼型花粉的主要特征是具3沟,外壁纹饰为微刺-穴状,此种类型的植物有14种2变种。钟花蓼型花粉的主要特征是具6散沟,外壁纹饰为微刺-穴状,此种类型的植物有钟花蓼和绒毛钟花蓼。西伯利亚蓼型花粉的主要特征是具3孔沟,外壁纹饰为皱块状,此种类型的植物有西伯利亚蓼。多穗蓼型花粉的主要特征是具6(~8)多沟,外壁纹饰为粗网状,此种类型的植物有松林蓼及多穗蓼。大连线冰岛蓼型花粉的主要特征是具散沟,外壁纹饰为显著的长刺状,此种类型的植物有大铜钱叶蓼及铜钱叶蓼,结果表明叉分蓼组的花粉形态具有重要的分类学意义,研究结果支持将叉分蓼组上升为属的等级,也支持Knorringia的属的地位,大铜钱叶蓼和铜钱叶蓼应移入Koenigia属中,而松林蓼和多穗蓼仍保留在蓼属中。  相似文献   

5.
云南铁线莲属植物地理分布及区系特征   总被引:2,自引:0,他引:2  
依照王文采和李良千最新系统,云南有铁线莲属(Clematis)植物59种24变种,分属于3亚属6组,是中国该属种类分布最多的省份。横断山区可能是该属的起源、分化和特有中心,而滇西、滇西南以及滇东南地区也与该属的分化有一定联系。云南铁线莲属植物特有现象较为突出:含中国特有的56种(含变种),占云南总种数的67·2%;云南特有16种(含变种),占云南分布的中国特有种的35·0%。云南铁线莲属植物与国内邻近的四川关系最为密切,西藏的关系最弱;与国外邻近的缅甸具有一定的联系。  相似文献   

6.
潘洁 《植物研究》2000,20(1):27-35
贡嘎山地区位于青藏高原的东南缘,横断山系的东北段,现有杜鹃属植物73种4变种2亚种。在贡嘎山地区东坡的不同垂直高度上分布有43种(包括变、亚种)杜鹃,西坡则分布有63种(包括变、亚种)。贡嘎山地区杜鹃属植物的区系组成属于泛北极植物区,大致分为:1、中国-日本森林植物亚区,只有1种杜鹃。2、中国-喜马拉雅森林植物亚区,有78种(包括4变种, 2亚种),其中(1)1种分布于西藏、云南,并经云南入缅甸分布;(2)44种为四川特产;(3)5种为贡嘎山地区特有种。另外,贡嘎山地区杜鹃属植物区系还有其特点:1、贡嘎山地区是杜鹃属植物分布中心之一;2、贡嘎山地区是杜鹃属植物分化中心之一;3、贡嘎山地区杜鹃属植物有垂直替代现象。  相似文献   

7.
通过对翼蓼Pteroxygonum giraldii Damm. &; Diels及相关属(蓼属Polygonum、何首乌属Fallopia、虎杖属Reynoutria、荞麦属Fagopyrum和金线草属Antenoron)的形态观察、果实解剖学观察、花被片脉序观察、花粉形态、核型分析, 以及ITS序列的分析确定了翼蓼和荞麦F. esculentum Moench较远的亲缘关系。其中我们发现翼蓼果实基部有三个角状物明显不同于其他属果实的形态特征。翼蓼外果皮明显加厚, 并有零星散布的波状内腔, 而荞麦的外果皮很薄, 细胞不等径, 中果皮极厚。以上证据证明了翼蓼与荞麦属亲缘关系较远。在观察荞麦属和翼蓼的花被片脉络时发现了两种不同的脉序类型, 符合将荞麦属分为两个组的划分。翼蓼花被片脉序为三出状, 支持将翼蓼归为Persicarieae族。对翼蓼及荞麦属植物的花粉进行比较后, 发现荞麦属植物的花粉网孔有明显的内凹穿孔而翼蓼却没有, 结果表明二者亲缘关系较远。通过对nrDNA ITS区域序列分析得出翼蓼及相关属为一个单系类群, 含有两个稳定的分支: 第一个分支由蓼属(萹蓄组sect. Avicularia)、何首乌属、虎杖属的植物组成, 第二个分支由蓼属(刺蓼组sect. Echinocaulon、蓼组sect. Polygonum、分叉蓼组sect. Aconogonon、拳参组sect. Bistorta、翼蓼和荞麦属植物组成。同时第二个分支又分成了两个亚分支, 蓼属(刺蓼组、蓼组、分叉蓼组、拳参组)和翼蓼属Pteroxygonum植物属于第一个亚支而荞麦属植物属于第二个亚支。结果支持翼蓼不属于荞麦属的范畴。实验结果显示翼蓼是个单型属, 属于Persicarieae族。  相似文献   

8.
中国蓼族植物系统分类研究综述   总被引:10,自引:0,他引:10  
关于蓼族属级及属下分类问题,分类学家持有不同的意见。介绍了自蓼属建立以来,蓼族植物分类的研究现状,认为蓼族在系统分类上尚需进一步的研究。  相似文献   

9.
蓼科是一个极常见的科,有40属、800多种。中国有12属、200多种蓼科植物,大凡平原、丘陵、高山乃至青藏高原,都能见到。 极面熟的酸模叶蓼 酸模叶蓼(Polygonum lapathifolium)恐怕是平原地区最常见的蓼属植物了,分布遍及南北各省区。大凡水沟边、潮湿地都能见到,而且一见即是一片,很少只有单株的。原因是它一年生,靠种子繁殖,年年结的果实小而多,撒下  相似文献   

10.
以蓼科Polygonaceae酸模亚科Rumicoideae酸模族Rumiceae大黄属Rheum L.作外类群, 对蓼亚科Polygonideae蓼族Polygoneae 4属19种1变种的trnL-F序列以及16种1变种的matK序列进行了测定(部分序列取自GenBank)和聚类分析, 探讨了虎杖属Reynoutria Houtt.和西伯利亚蓼Polygonum sibiricum Laxm.的系统学位置, 结果表明: (1)虎杖属在两个严格一致树中都聚到了何首乌属Fallopia Adans.的内部, trnL-F序列的支持率为99%, matK序列的支持率为100%, 说明虎杖属应归入何首乌属中, 所以虎杖属的R. japonica Houtt.与R. sachalinense (F. Schmidt ex Maxim.) Nakai应分别命名为Fallopia japonica (Houtt.) Ronse Decraene和F. sachalinense (F. Schmidt ex Maxim.) Ronse Decraene; (2)两个严格一致树都表明, 西伯利亚蓼远离蓼属Polygonum L., 聚到了何首乌属的附近, 两个序列支持率都为99%, 应将该种从蓼属中移出来, 提升为属级, 即西伯利亚蓼属Knorringia Tzvel., 西伯利亚蓼应命名为Knorringia sibirica (Laxm.) Tzvel.。另外, 本文对何首乌属与西伯利亚蓼属作了界定。  相似文献   

11.
云南南部和西南部是中国竹类资源最为丰富的地区 ,与其邻近地区一起构成了世界木本竹类的多样性中心。德宏正处于这个中心位置 ,竹子种类丰富 ,有 16属 5 6种及变种 ,其中中国特有种 2 1种 (云南特有 15种 ) ,占其竹亚科全部区系成分 (45种 )的 4 6 6 7%。热带亚洲分布类型占绝对优势 ,本地区的竹亚科区系与热带亚洲特别是缅甸 (有 18种共有种 )及云南南部和东南部有非常密切的联系  相似文献   

12.
The Xizang (Tibetan) flora with numerous endemics is of importance in Chinese flora. According to recent statistics there are in Xizang 27 genera of spermatophytes endemic to China, being only 2.25% percent of the total number of genera in the Xizang flora. Four of them are regarded as palaeoendemics (14.81%) and the others as neoendemics (85.19%). These endemic genera, of 30 species and 3 varieties, belong to 17 families, of which, Umbelliferae contains 6 genera, 7 species and 3 varieties; Compositae has 6 genera and 7 species, and Gentianaceae 1 genus and 2 species. All the other families each comprises one genus with a single species. The cosmopolitan families together comprising 14 genera with 15 species have the highest perecentage (52.92%) and the tropical ones (5 families, 5 genera with 5 species) come to the next (29.42%), followed by the temperate ones (3 families, 10 genera with 10 species) (17.66%). It shows that these endemic genera are obviously related to the tropical flora and temperate one in essence. According to the number of species, the genera endemic to China and occurring in Xizang flora may be grouped as fallows. Monotypic endemic ones 14 (51.85%) Ditypic endemic ones 6 (22.22%) Oligotypic endemic ones 4 (14.81%) Small endemic ones 3 (11.11%) The formation of the endemic genera is correlated with the topography, climate and environmental conditions, and they may have resulted from the diversification in geography and climatic influence for a long time. The southeastern part of Xizang Plateau is of very diverse ecological conditions, with the adequate precipitation, which may explain the concentration of these endemic genera in this region. The largest similarity coefficient (38.30%) of the genera endemic to China and occurring in Xizang is with those in Qinghai Plateau, next, with those in Yunnan and in Sichuan provinces (both 27.60%), which shows that these endemic genera are related to the floras of the regions mentioned above. The difference in the horizontal distribution of these endemic genera is obviously between the southern and northern parts of Xizang Plateau. The vertical distribution of the genera is also rather obvious, from 800 m to 5200 m above sea level, but concentrated in the zone of 3000 m to 4500 mm. Therefore their occurrence in Xizang is not only affected by the historical environmental conditions but also controlled by the horizontal and vertical distribution. The origin and evolution of some endemic genera, such as Psammosilene, Parateropyrum, Sphaerotylos, Salweenia, Ajaniopsis, Xizangia, Sinoleontopodium, are discussed in this paper. Parateropyrum, a monotypic palaeotropic endemic, belongs to the tribe Atraphaxideae including Atraphaxis, Calligonum and Pteropyrum. It may be a comparatively advanced group in the tribe, and is closely related to the genus Pteropyrum which is distributed in western Asia. The genus Parapteropyrum has possibly survived as a palaetropic-tertiary relic in this region. Sphaerotylos, a member of the subtribe Sphaerotylinae, the tribe Boehmerieae in the family Urticaceae, is a comparatively primitive genus in the tribe Boehmerieae so far known. As the other subtribes, such as Boehmerinae, Sarconchlamydinae, Orecnidinae and Maoutinae, are distributed in the tropics, rarely in the subtropics, the genus is no doubt a palaetropic -tertiary relic. Sinoleontopodium, belonging to the tribe lnuleae in Compositae, is also related to the genus Leontopodium. It is probable that the genus Sinoleontopodium arised later than the other. We come to the conclusion that the southern part of Xizang Plateau is also one of thecentres of the origin and differentiation of genera endemic to China.  相似文献   

13.
横断山区唇形科植物的地理分布   总被引:8,自引:0,他引:8  
李锡文 《植物研究》1989,9(2):103-122
横断山区唇形科植物相当丰富,有46属240种,在国内仅次于云南和四川,但明显多于其它省区。通过对其属、种的分布区类型分析,其地理分布表现如下一些特征;1)从属的分布区类型来说,横断山区唇形科植物主要是温带性质,温带分布区类型的属数占总属数(世界分布的不计算在内,下同)85.3%,其中东亚分布类型为数最多,占总属数34.1%,其次是旧世界分布类型和北温带分布类型,分别占总属数29.2%和12.2%,而东亚分布类型中占绝对优势的是中国喜马拉雅分布亚型。2)从种的分布类型来说,我国特有分布的种占绝大多数,占总种数75%,而温带分布类型和热带分布类型分别占总种数20%和5%。在我国特有分布的种中横断山区特有的占72.8%。在横断山区特有分布的种中滇西北一地特有的占横断山区特有总种数32.1%,川西南一地特有的占横断山区特有总种数9.9%,滇西北和川西南两地共同特有的占横断山区特有总种数25.2%,要是把滇西北川西南看成一整体无疑是横断山区特有种分布中心,占横断山区特有总种数67.2%。3)滇西北川西南特有种分布中心,从其特有种组成分析,其成因有历史的也有生态的,但生态成因多于历史成因,因此该中心的植物区系较为年青,这是由于新构造运动强烈、垂直气候带变化明显,冰川多次进退,导致气候上下位移频繁以横断山脉的纵向深切,促进植物在发展过程中强烈分化的结果。  相似文献   

14.
The subfam. Spiraeoideae, consisting of 22 genera and more than 260 species in the world,is the most primitive subfamily of Rosaceae. It has developed into two groups,i.e. evergreen and deciduous ones, of which eight genera and 100 species in China are totally deciduous. In the present paper, the origin,evolution and distribution of the Chinese genera is discussed mainly, and the distribution of the whole subfamily in the floristic regions of the world is also mentioned. Based on evolutionary trends of morphological characters, Spiraea L. is considered as the most primitive genus in the deciduous group of subfam. Spiraeoideae, from which some genera are been derived, the systematic position and evolutionary relationships between different genera are elucidated in this paper. Through the analysis on the geographical distribution of the genera in China, the areal types may be divided as follows: (1) North Temperate Type: Spiraea, Physocarpus, Aruncus. (2) East Asian and North American Disjunct Type: Sorbaria. (3) Mediterranean, West Asian (or Central Asia) and East Asian Type: Sibiraea. (4) Temperate Asian Type: Exochorda.(5) East Asian Type: (a) Sino Himalayan Distribution: Neillia; (b) Sino Japan Distribution: Stephanandra. After analysis of the distribution of subfam. Spiraeoideae in the world, it is shown that the Eastern Asiatic Region, being the richest in genera, species and endemic species of the world,is not only the center of distribution and differentiation,but also an important region for occurrence and development of some deciduous genera of this subfamily, while in North America, the Madrean Region and Rocky Mountain Region, genera, species and endemic species are abundant, which indicates that the western part of North America is also the distribution center of this subfamily at the present, but it may be the secondary center of distribution. It can be seen that the relatively primitive and evergreen g enera, i.e. Quillaja and Kageneckia, are now confined to South America. The fact implies that the South America may be the region for early differentiation and development of the evergreen genera in Subfam. Spiraeoideae. The analysis of Chinese plants has shown that China has the most members of the subfamily in Eastern Asiatic Region, with eight genera, 82 species and 62 endemic species and that the maximum concentration is in western Sichuan, northwestern Yunnan and their adjacent areas. It is very obvious that the center of distribution and diversity of Subfam. Spiraeoideae in China lies in the Hengduan Mountain Region of Sino Himalayan Forest Subkingdom and the western part of Sino Japan Forest Subkingdom, where may be the birthplace of some genera in China. It may be considered that the deciduous genera of Subfam. Spiraeoideae might have originated in Laurasia.According to the fossil records, the time of origin of Subfam.Spiraeoideae dates back to the Lower Cretaceous.  相似文献   

15.
绣线菊亚科是蔷薇科最原始的亚科,共有22属260余种, 包括常绿和落叶两大类群,前者是 原始类型。我国有8属100种,全都为落叶性。本文着重讨论中国各属的起源、演化和分布等 ,同时也概述全亚科植物在世界各植物区的分布等问题。绣线菊属Spiraea是该亚科落叶类群中最原始的属,它在早期发生趋异进化,衍生出形态各异而亲缘关系密切 的不同属,本文阐明了中国各属的系统位置和属间的亲缘关系。通过对我国各属地理分布的 分析对比,属的分布区可归纳为5个类型。对全球绣线菊亚科植物在世界各植物区中的属、种数统计表明,东亚区有8属105种,其中有96个特有种,是该亚科植物分布最多而又最集中 地区,具有在系统发育上处于各主要演化阶段的落叶类型,因此,东亚区是全球绣线菊亚科植 物的现代分布和分化中心,也是落叶类群发生和发展的关键地区。在北美洲,从马德雷区至落基山区一带分布着11属46种,均为特有种,显然北美洲西部也是该亚科植物的现代分布中心,但可能是第二分布中心。南美洲至今保存2个较古老的常绿属,即Quillaja和K ageneckia,基于此,南美洲可能是绣线菊亚科某些常绿属早期分化和发展的关键地区 。中国绣线菊亚科植物在东亚区占绝对优势,有8属82种,其中有62个特有种,分别占该区属 、种和 特有种数的100%、82%、和65%, 这些类群分布最密集地区是在中国喜马拉雅森林植物亚区 中的横断山脉地区和中国日本森林植物亚区的西部,这一带是中国绣线菊亚科的现代分布和多样性中心,很可能是某些属的发源地。由此看来,绣线菊亚科的落叶属可能起源于劳亚古陆。据化石记载,该亚科植物的起源时间可以追溯到白垩纪早白垩世。  相似文献   

16.
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   

17.
梧桐科植物的地理分布   总被引:5,自引:0,他引:5  
梧桐科植物全世界有60属约1546种,主要分布在热带和亚热带地区,只有少数种类可分布至温带地区,由于梧桐科是多型的科,科的范围较大,对有些属是否应隶属于该科,国内外学者的意见很不一致。本文基本上按照J.Hutchinson系统和参考有关文献对一些属的分类位置作了调整,把梧桐科分为12族,根据A.Takhtajan的世界植物区系区划的原则,将梧桐植物在世界上的分布区,划分为6区8亚区23地区,并指出各属在中国各省区的地理分布,现在中国梧桐科植物连引种栽培的在内共有25属99种7变种,其中野生的有18属85种7变种,引种栽培的有8属14种,对梧桐科植物的起源和发展作了一些探讨。  相似文献   

18.
The Hengduan Mountain Region on the south-eastern fringe of the Qinghai- Xizang (Tibet) Plateau is located in W. Sichuan, N. W. Yunnan and E. Xizang, with a wide area of juxtaposition from the east to the west, the mountains extending and the rivers flowing from the north to the south. In this paper it covers an area from Daojie, Wayao, Yingping, Yangbi, Dali of Yunnan and Dukou of Sichuan in the south, to Banbar, Dengqeu, Shenda of Tibet and Serxu, Dainkog, Shuajingsi and Nanping (Jiuzhaigou) of Sichuan in the north, and from Lharong, Baxoi and Zayü of Tibet in the west, to Maowen, Wenchuan, Mt. Erlang, Mt. Emei and Xichang of Sichuan in the east (Fig. 1.). The Gongga Mountain is the highest in the region, its summit being at an altitude of 7556m, whereas the Dadu River Valley in the eastern part of the area is only 1150 m above sea level. Therefore, the relative height is about 6400 m in the region. The Hengduan Mountain Region is well-known for its various topography, complex natural conditions and rich flora. The floristic composition and features of orchids in Hengduan Mountain Region. 1. The species of orchids are abundant in the region. As we know so far, orchids in the Hengduan Mountain Region comprise 91 genera and 363 species with 9 varieties, and thus it is one of concentration centres of orchids in China, making up 56.17% of the total number of orchids genera in China, only less than in Yunnan and Taiwan, and 34.87% of the total number of orchids species in China, only less than in Yunnan and Sichuan. 2. The orchids genera in the Hengduan Mountain Region are complex in geographical components as indicated below: (1) Four geneva are endemic to China and one of them is endemic to the region. (2) Fourteen genera are of the north temperate distribution pattern, 2 of the Old World temperate one, 18 of the East-Asian one (including Sino-Himalayan and Sino-Japanese) and 3 of the East-Asian-North American one. (3) Twenty one genera belong to the tropical Asian distribution pattern, 3 to the tropical Asian-tropical African one, 13 to the tropical Asian-tropical Australian one, 1 to the tropical Asian-tropical South American one, 8 to the Old World tropical one and 2 to the pantropical one. (4) Two genera are cosmopolitan. The analysis of genera: Fourty eight genera (containing 151 species with 4 varieties) of the tropical distribution occur in the region, among which Calanthe and Cymbidium distributed in the temperate region, and Bulbophyllum and Peristylus in the subtropical part of China are comparatively abundant (with over 10 species), but the other 25 genera are monospecific and 11 genera each contain only 2-3 species. Some epiphytic genera mainly distributed in tropical Asia and belonging to tropical florestic elements, such as Vanda, Luisia, Schoenorchis, Flickingeria, Monomeria, Kingidium, Acampe, Phalaenopsis, Thrixspermum, Eria, Taeniophyllum, and terrestrial genera, such as Aphyllorchis, Collabium, Mischobulbum, Paphiopedilum, Thunia, Brachycarythis, Satyrium, Corybas, Geodorum, Zeuxine, Tropidia, have the Hengduan Mountain Region as the northern limit of distribution. Of 151 species with 4 varieties, 41 species with 4 varieties are endemic to China, and 14 species with 3 varieties of them are endemic to the area, making up 3.86% of the total in the region under discussion. There are 41 genera (containing 189 species with 5 varieties) of the temperate distribution, which occur in the region. Among them Platanthera (22 species with 1 variety), Cypripedium (17 species), Herminium (16 species), Amitostigma (15 species with 1 variety), Orchis (12 species), Hemipilia (8 species with 1 variety), Neottianthe (4 species), Gymnadenia (4 species), Diphylax (3 species), Bletilla (3 species), have the Hengduan Mountain Region as the distribution centre and differentiation centre. Among the 189 species with 5 varieties, 111 species with 5 varieties are endemic to China, and 54 species with 5 varieties are endemic to the area, making up 14.88% of the total of orchids in the Hengduan Mountain Region. Although the number of temperate distribution genera is smaller than that of tropical distribution ones, several points may be mentioned: (1) The Hengduan Mountain Region is distribution centre and differentiation centre of a number of temperate genera in China, and is the northern limit of many genera mainly distributed in the tropics. (2) The number in the former category is obviously larger than that in the latter. (3) Endemic species in the former category in the area are over three times as many as those in the latter. The differentiation of species of the temperate distribution genera is obviously stronger than the tropical ones, which characterizes the orchid flora in the area as the temperate one. The life forms of genera. The orchid flora in the Hengduan Mountain Region so far known comprises 91 genera, among which 51 are terrestrial, 32 epiphytic and 8 saprophytic, thus with the terrestrial one dominant. The analysis of species: The orchid flora in the Hengduan Mountain Region so far known comprises 363 species with 9 varieties. Their distribution patterns and floristic components, to which they belong, are indicated as follows: (1) Fifty four species, belonging to 33 genera, are widespread, covering the whole East Asian Region, but 6 of them are endemic to China. (2) Forty four species, belonging to 27 genera, are the elements of the Sino-Japanese Subregion, but 22 species of them are endemic to China. (3) One hundred and ninety five species with nine varieties, belonging to 53 genera, are the elements of the Sino-Himalayan Subregion under discussion: (A) Four species (i.e. Aphyllorchis alpine, Listera divaricata, L. pinetorum and Oreorchis micrantha) are distributed in the Himalayan Region and S. E. Xizang (Tibet), western part of this region. (B) Twenty five species, belonging to 17 genera, are distributed in N. W. Yunnan and the Himalayan Region (Appendix, 1.). (C) Sixteen species, belonging to 11 genera, are distributed in the Himalayan region and W. Sichuan. Among them 6 species occur only with Mt. Emei as the easternmost limit and 10 species occur in the region west of Mt. Emei. (D) Ten species, belonging to 9 genera, are distributed in the Himalayan region, this region and S. Shaanxi, S. Gansu or S. E. Qinghai. (E) Eight species, belonging to 6 genera, are distributed in the Himalayan region and this region. Among them 6 species have their range extending eastwards to Guizhou and 2 species eastwards to Guangxi. (F) Five species, belonging to 5 genera, having their range extending from this region southwards to N. Burma. (G) One handred and twenty seven species with nine varieties are endemic to China behind discussion. (4) (A) Three species (i.e. Anoectochilus moulmeinensis, Bulbophyllum forrestii and Liparis chapaensis) are distributed in Indo-China, Burma and the region. (B) Nine species, belonging to 7 genera, are distributed in Indo-China, N. E. India and this region. (C) Forty six species, belonging to 21 genera, are distributed in Indo-China, the Himalayan Region and this region (Appendix, 2.). (D) Twelve species, belonging to 11 genera, are distributed in Indo-China and this region (Appendix, 3.) 3. The vicarism is obvious in the orchid flora of the Hengduan Mountain Region. There are 10 species-pairs (in genera Calanthe, Tropidia, Anoectochilus, Mischobulbum, Bulbophyllum, Gymnadenia, Pogonia, Tipularia, Tulotis, Orchis, etc.) of the horizontal vicarism and 7 species-pairs (in genera Epigeneium, Epipogium, Platanthera, Pogonia, etc.) of the vertical vicarism in the region. 4. The endemic species are prolific in the region. In the orchid flora of the Hengduan Mountain Region there are 155 species and 9 varieties endemic to China: (1) Six species are widespread in the whole East-Asian Region. (2) Twenty two species are the elements of the Sino-Japanese Subregion. (3) One hundred and twenty seven species with nine varieties are the elements of the Sino-Himalayan Subregion. Among them 69 species with 5 varieties are endemic to the region (Appendix, 4.), making up 19% of the total in the region; other 58 species with 4 varieties are distributed in the region and neighbouring regions or provinces of it (Appendix, 5.). 5. Remarkable differentiation of the orchid flora in the Hengduan Mountain Region is shown by evident vicarism and abundance of endemic elements, exampled by Amitostigma, Herminium, Orchis, Cypripedium, Platanthera, etc. and one group of Platanthera, which is confined to the south fringe of the Xizang (Tibet) Plateau-Hengduan Mountain Region. The group consists of 12 species, of which one (P. edgeworthii) is distributed in the Western Himalayas from Hazara in Pakistan to Kumaun in India, and all the other 11 species (i.e.P. stenantha, P. bakeriana, P. roseotincta, P. deflexilabella, P. longiglandula, P. exilliana, P. chiloglossa, P. leptocaulon, P. platantheroides, P. clavigera and P. latilabris) occur in China, with 3 of them (i.e.P. deflexilabella, P. longiglandula and P. chiloglossa) endemic to China. According to their structure of gynostemum and form of labellum they belong to Platanthera without question, although they are different from the other members of Platanthera in stigma convex (not concave) and sepals mammillary-ciliate, stigma exhibits a series of evolutionary trends in part of species, from stigma single, convex, elliptic and located near rear of spur mouth (in P. stenantha) to stigma single, suddle, and located near front of spur mouth (in P. bakeriana) and to stigma double, separate and located at front of spur mouth in the other ten species. The group in Platanthera is only confined to the area from the south fringe of the Xizang (Tibet) Plateau to the Hengduan Mountain Region. It seems that the genus has been affected by intense lift of the area, causing variation and differentiation and giving rise to the group due to the long-term natural selection. Mt. Emei in Sichuan Province is the eastern limit of distribution of the group, where there are three spcies, among which two (P. deflexilabella and P. longiglandula) are endemic to the mountains. In addition, among Risleya (1 species), Diphylax (3 species) and Diplomeris (2 species), three genera typical of distribution in the Sino-Himalayan Subregion, Risleya and Diphylax have Mt. Emei as their eastern limit. Eleven species, belonging to elements of the SinoJapanese Subregion, occur only from Japan to Western Sichuan with Mt. Emei as the western limit. Among nine species, belonging to elements of the Sino-Himalayan Subregion, six occur from the Himalayas to W. Sichuan and three of them are endemic to the Hengduan Mountain Region, with Mt. Emei as their eastern limit of distribution. There are eight endemic species and one variety of orchids in Mt. Emei, making up about 11.59% of the total endemic species in the Hengduan Mountain Region. Orchid floristic elements in Mt. Emei are obviously different from those in Mt. Jinfo, the former being mainly of the Sino-Himalayan Subregion, while the latter being mainly of the Sino-Japanese Subregion. From the distribution patterns of the orchid floristic elements in the Hengduan Mountain Region and Eastern China, the Emei Mountain is considered important for drawing a boundary line between the Sino-Japanese Subregion and the Sino-Himalayan Subregion. The discussion may be summarized as follows: the floristic features of the orchid flora in the Hengduan Mountain Region are: (1) rich in species, complex in geographical components, eminent vicarism and differentiation, and prolific in endemic species; (2) terrestrial life form is dominant one; (3) mainly consisting of temperate and subtropical East-Asian elements, es pecially, elements of Sino-Himalayan Subregion, though with some tropical elements and elem-ents of other regions.  相似文献   

19.
对湖北鳞毛蕨后植物的地理分布和区系特点进行了研究。鳞毛蕨后植物广布于世界各地,该后的分布和多样性中心位于中国西南部和东喜马拉雅山区;另一中心则位于日本,中国东南部和南部。鳞毛蕨后是一个自然的北温带分布属。中国有鳞毛蕨后植物134种(包括7变种),西南地区(云南、四川、贵州等)是国产鳞毛蕨属植物分布最集中的地区。区系分析表明:湖北鳞毛蕨后植物种类比较丰富,有36种,主要分布于鄂西北和鄂西南山区,是构成湖北森林植物区系林下草本植物的主要成分之一;地理成分比较复杂,种的分析显示出以中国一日本分布和中国持有分布为主的特点;与相邻省鳞毛蕨属植物区系的关系比较密切;区系过渡性明显。  相似文献   

20.
依据云南大学植物标本馆蕨类植物标本室(PYU)和国内主要标本馆保存的莲座蕨科植物标本,以及多年来积累的研究资料,建立该科植物在云南的产地GIS数据库。以此为基础,分析云南莲座蕨科植物空间分布的多样性和特有性,及其在云贵高原及横断山区的地理分布特征。研究结果如下:① 云南莲座蕨科植物种类丰富,分布海拔范围为100~2400m;② 滇东南是莲座蕨科植物分布的多样性和特有性中心,其多样性由滇东南向西、北方向递减;③ 云南有莲座蕨科2个属分布,即莲座蕨属(Angiopteris)和原始莲座蕨属(Archangiopteris),其中原始莲座蕨属的物种多样性较低而特有性较高。初步分析了该科植物中5个广布种和1个高山峡谷种分布格局的成因,以及5个特有种的发生史,推断广布种的分布格局形成于第四纪冰期之前,高山峡谷种的分布格局形成于第三纪之后,而特有种的主要成因可能是自然杂交和边缘效应。  相似文献   

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