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1.
兰科在横断山地区是维管束植物中的大科之一,共有91属,363种及9变种。 4属为我国特有属,其中1属为本地区所特有;155种及9变种为我国特有种。  其中69种及5变种为本地区所 特有。本文对属、种进行了分析,并对全部种的分布格局作了详细的介绍,概述了本地区兰科植物的区系组成及特点。本文从兰科植物属、种的分布提出了四川峨眉山是东亚植物区中划分中国-喜马拉雅植物亚区和中国-日本植物亚区的分界线上的一个重要的点的看法。  相似文献   

2.
The Gongga Mountain Region, located on the eastern fringe of Qinghai- Xizang Plateau and at the north-eastern end of Hengduan Mountains, is one of the well-known large mountain areas in Sichuan Province.  There are forty five high peaks with the elavation of 6000 m or over in the area, among which the Gongga Mountain is the highest one, with its summit being at the altitude of 7556 m, whereas the Dadu River Valley in the eastern part of the area is only 1150 m above sea level;  The rela- tive height in the region is thus about 6400 m.      As we know so far the orchids in Gongga Mountain Region comprise 34 genera and 75 species with 1 variety, of which 12 species are epiphytes, 59 species with 1 variety terrestrials and 4 species saprophytes (Table 1.).      I.  The geographical distribution in the Gongga Mountain Region.      The vertical distribution of the orchids in the area.      Eastern flank:  There are 39 species with  I  variety  of orchids  at  1150-2300 (-2400) m alt. in the subtropical evergreen broadleaf forest zone, of which 12 species, such as Bulbophyllum andersonii, Dendrobium hancockii, Otochilus porrecta, etc., are epiphytic (including a semiepiphyte, Pleione bulbocodioides), 25 species with 1 variety, such as Bletilla formosana, Calanthe davidii, Cypripedium henryi, etc., are terrestrial, and 2 species are saprophytic (i.e. Gastrodia elata and Neottia listeroides), the upper limit of the real epiphytic orchids is 1800 m alt.  At the altitude 2300(-2400)-3600 (-3800) m, in the coniferous forest zone, found are 23 species, including 20 terrestrial species with 1 variety, such as Amitostigma gonggashanicum, Calanthe fimbriata, Coe- loglossum viride, etc., 2 saprophytic species (Neottia acuminata and Risleya atropurpu- rea) and one semiepiphytic species.  There are only 2 terrestrial species (i.e. Cypripe- dium tibeticum and Orchis chusua) at 3600(-3800)-4000m alt., in alpine shrub zone, the upper limit of the terrestrial orchids being 4000 m alt.  At 4000-4400 m alt., in alpine meadow zone no orchids have so far been found.      Western flank:  There are 14 species of orchids, such as Habenaria limprichtii, Hemipilia flabellata, Satyrium ciliatum, etc., at 2300-2800 m alt., in the river valley shrub zone, and they all belong to the terrestrial orchids.  At the altitude of 2800- 3800m, in the coniferous forest zone found are 19 species of orchids, among which 18 species are terrestrial (such as Amitostigma monanthum, Cephalanthera longifolia, Pe- ristylus coeloceras, etc.) and one is saprophytic.  There are only 4 species of terrestrial orchids (i.e. Cypripedium tibeticum, Gymnadenia orchidis, Orchis chusua and O. dian- tha) at 3800-4800 m alt., in the alpine shrub-meadow zone, the upper limit of vertical distribution of terrestrial orchids being 4400 m alt.  Twelve species here are common to the eastern flank.       II.  The floristic composition of orchids in Gongga Mountain Region.       1.  Twenty three species, belonging to 13 genera, are widespread in Whole East- Asian Region.       2.  Eight species, belonging to 8 genera, are the elements of the Sino-Japanese Subregion.      3.  Forty one species with 1 variety, belonging to 24 genera, are the elements of the Sino-Himalayan Subregion, more than five times the elements of the Sino-Japanese Subregion.      4.  The floristic features of the orchids in the area.       (1)  The floristic elements are mainly temperate and subtropical ones.       (2)  The life form is mostly terrestrial.       (3)  The species endemic to China are prolific (35 species with 1 variety, belong- ing to 18 genera, are endemic to China, and 26 species with 1 variety are distributed in south-western China and its adjacent region; Amitostigma gonggashanicum is endemic to the area).      The floristic composition of orchids in the area is characterized by the dominance of terrestrial species and temperate and subtropical East-Asian elements, though with a few Indo-African tropical elements (such as genus Satyrium (1 species) ).      In conclusion, it may be considered that the species of orchids are abundant and floristic elements are comparatively complex in the Gongga Mountain Region.  相似文献   

3.
为探讨山地植物区系构成特征及其垂直梯度的生态意义,根据对三峡大老岭地区植被垂直样带 调查获得的植物区系资料,分析了该地区植物区系成分构成的基本特征及其随海拔梯度的变化趋势,寻找了区系平衡点的位置;并利用聚类方法分析了山地气候垂直分异对区系成分构成的影响。结果表明:①大老岭植物区系具有温带性质,但仍反映了与热带区系的历史联系,有强烈的区域性;②属的分布区类型可归为热带分布、温带分布、地中海—中亚中心和东亚中心4组,各组区系成分的垂直梯度特征不同;热带、亚热带成分与温带成分的平衡点大致位于海拔650m;③区系成分构成和属的物种数量构成的聚类分析结果一致显示了植物区系构成与山地气候和植被垂直带相对应的格局。  相似文献   

4.
 本文从兰科植物中一些属于中国-喜马拉雅植物亚区和中国-日本植物亚区典型分布属(或亚属的地理分布格局的研究,提出此两个植物亚区在我国四川省境内是以峨眉山和岷江为其分界,及这条线的走向是从南坪(九寨沟),松潘(黄龙寺)、茂汶、灌县(光光山)、宝兴、二郎山(天全以西)、峨眉山、石棉、西昌、德昌、米易至攀枝花市。  相似文献   

5.
通过半个世纪以来对金佛山近2000号藓类植物标本的鉴定,现确定金佛山藓类植物有40科,133   属和245种(包括4亚种、9变种和1变型)。其区系成分以东亚成分为主(33.77%),其次为温带成分   (28.57%)及热带、亚热带成分(24.68%)。文内还全面分析了金佛山藓类植物区系及我国南北8个山区藓   类植物区系之间的关系,用排序方法统计它们之间的相似性与非相似性系数,并着重就金佛山藓类植物区  系的过渡性特点作了探讨,提出在该山区与其邻近地区,存在一个苔藓植物东亚特有属的分布中心。  相似文献   

6.
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 ele- ments,  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 Me- diterranean 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 geographi- cal 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 differen- tiation 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 ten- dency 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 Hi- malayas 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 Medi- terranean flora.  相似文献   

7.
我国荒漠植物区系形成的探讨   总被引:2,自引:0,他引:2  
    1.  Based upon the analyses in the floristic elements of the three genera (Suaeda, Salsola and Zygophyllum) in different regions we can see that the genesis of our desert floras in these regions is very much diversified.  The flora of Songaria is similar to that of the Middle Asia, while the Hosi Corridor seems to be a transitional area very close to Alashan and also related to the Tarim Basin in floristic elements. Thus, we may classify the desert floras into three parts: the flora of Songaria, of Alashan including the Hosi Corridor and of the Tarim Basin including the Tsaidam Basin. The ages and approa- ches in their formation are different.      2. There are plenty species but no or rare endemics in Songaria. In spring there are a number of ephemeral plants. The variation of aspect is evident.  The vegetation cover is abundant. The floristic elements are developed from the flora of Middle Asia and it was formed in Quaternary period.      3. The floristic elements of the Tarim Basin are poor, but there are not few en- demics and the distribution of the endemics is much limited.  They are of the charac- teristics of relic species.  Therefore it was formed in the Tertiary period and developed in Quaternary period.  The elements are related to the Mediterranean flora.      4.  There are a large number of endemics and many endemic monotypie genera in Alashan.  They represent the flora formed in Tertiary period. Although it is of a special style, it relates both to the Middle-Asian and the Mediterranean flora.      5. The historic causes for the formation of the different floras lie chiefly on: (1) The rise of the Tibetan plateau and mountains strongly changed the climatic and edaphic conditions and in the long course of evolution some species survived or even developed, while the others deteriorated or even died out from the flora. (2) Because the circum- stances of transgression or regression of the Tethys were different in these regions. (3) The mountain-making movement, the transgression and regression and the fluence of glaciation, all the mutation of these associated factors modified the climatic zonation and then the plant species changes followed, new species formed and migration of floristie elements occurred. (4) Songaria is the nearest region to the then Sibirian glacier, so the frozen injury to the flora might be the greatest. (5) In the Glacial period the descension of snow line in Songaria was greater than that of the Tarim Basin, so the frozen injurymight be greater.  相似文献   

8.
湘西北壶瓶山自然保护区植物区系   总被引:1,自引:0,他引:1  
壶瓶山自然保护区具有丰富的植物区系成分,现知维管束植物有205科(蕨类和拟蕨类 植物40科,裸子植物7科,被子植物158科),839属,约1961种(包括154变种)。其中,古  和原始的科、属不乏其代表。从种子植物属的分布区类型的比较分析,该区具有我国15个种子植物属的分布区类型中的14个,表明了与世界各地区植物区系的联系程度。另一方面,该 地区的植物区系虽含有丰富的热带成分,但根据各类温带属占该区总属数的百分比以及分布于该地区的中国特有属中的木本属几乎所有都是落叶的乔木或灌木,该区的植物区系性质明显偏重于温带性质。而且,这种温带性质可能与该区的山体海拔高度有着重要的联系。  相似文献   

9.
The present paper deals with a collection of plant fossils from the Wu- yun Group of Heilongjiang Province.  These fossils belong to 28 families, 39 genera and 53 species.  The flora is composed of 7 species of pteridophytes, 8 of conifers and 37 of angiosperms.  All have been fully described, of which ten are new species.      Most elements of this flora are subtropic or warm-temperate, with only a few of them are temperate ones.  The flora consists of conifers and broad-leaved trees adapted to humid warm-temperate or subtropic climate.        With the physiognomy of leaves, 40 per cent of them are of entire margin, and most are medium-sized, with some megaphyllous. The nervation is mostly palmate.  These characters indicate that the climate was warm-temperate or subtropic.      Among 35 genera known from the Late Cretaceous of East Asia, 27 are also found in North America, which indicates that the floristic relationship between East Asia and North Americal was closer  at that time than it is now. Therefore the number of genera in common has been decreasing through the age, because these two regions have been detached from each other since the late Eocene, as a result of continental drift. Only some relic forms left on both sides, and only 4.1% of genera are common to both continents.  After the early Tertiary the floras of East Asia and North America have been developing independently.       The Chinese flora of the Late Cretaceous may be divided into three Zones from the north to the south: (1) warm temperate-subtropic zone, rich in Metasequoia, Ginkgo, Trochodendroides, Platanus, Trochodendron, Protophyllum, Ampelopsis Pterospermites and Menispermites; (2) subtropic or dry subtropic transitional zone; and (3) subtropic- tropic zone, rich in Brachyphyllum, Cinnamomum, Nectandra and Palms.       The Wuyun flora is considered closely related to the Chajiayang Group and Sikhote- Alin flora of USSR, with 15 genera in common and also related to the Kuji flora of Japan (Cenonian), with 11 genera in common.  It is interesting to note that 11 genera are also found in North America (Canada and Alaska) of the Late Cretaceous.  The pa- lynological assemblage of the Wuyun flora is closely related to Minshui flora of the So- uliao Basin, 15 genera being common to the both.  Seventy per cent of megafossils of the Wuyun flora have become extinct, which seems to show that the age of the flora is older than Paleocene and is assigned to the Latest Late Crataceous (Maestrichtian-Dani-an).  相似文献   

10.
本文根据对舟山群岛种子植物348个种(及种以下分类单位)在18个地理单位的分布状况进行 计算机聚类分析和主成分分析(PCA),表明了该群岛与我国大陆的浙江和江苏植物区系有着密切的亲 缘关系和相似性;与日本和我国台湾植物区系的联系则不如一般所认为的那样接近,当然,仍有不少十 分有意义的连锁植物存在于三者之间。     舟山群岛在植物区系区划上应为中亚热带北部亚地带,区系特点之一是岛屿植物较发达,而山地森 林区系则与我国南方植物区系相接近。  相似文献   

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