| Abstract: | The Gongga Mountain Region, located on the eastern fringe of QinghaiXizang Plateau and at the north-eastern end of Hengduan Mountains, is one of thewell-known large mountain areas in Sichuan Province. There are forty five high peakswith the elavation of 6000 m or over in the area, among which the Gongga Mountainis the highest one, with its summit being at the altitude of 7556 m, whereas the DaduRiver Valley in the eastern part of the area is only 1150 m above sea level; The relative height in the region is thus about 6400 m. As we know so far the orchids in Gongga Mountain Region comprise 34 genera and75 species with 1 variety, of which 12 species are epiphytes, 59 species with 1 varietyterrestrials 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., areepiphytic (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 upperlimit 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 terrestrialspecies with 1 variety, such as Amitostigma gonggashanicum, Calanthe fimbriata, Coeloglossum viride, etc., 2 saprophytic species (Neottia acuminata and Risleya atropurpurea) and one semiepiphytic species. There are only 2 terrestrial species (i.e. Cypripedium 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., inalpine 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 valleyshrub zone, and they all belong to the terrestrial orchids. At the altitude of 28003800m, in the coniferous forest zone found are 19 species of orchids, among which 18species are terrestrial (such as Amitostigma monanthum, Cephalanthera longifolia, Peristylus coeloceras, etc.) and one is saprophytic. There are only 4 species of terrestrialorchids (i.e. Cypripedium tibeticum, Gymnadenia orchidis, Orchis chusua and O. diantha) at 3800-4800 m alt., in the alpine shrub-meadow zone, the upper limit of verticaldistribution of terrestrial orchids being 4400 m alt. Twelve species here are commonto 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 EastAsian Region. 2. Eight species, belonging to 8 genera, are the elements of the Sino-JapaneseSubregion. 3. Forty one species with 1 variety, belonging to 24 genera, are the elements ofthe Sino-Himalayan Subregion, more than five times the elements of the Sino-JapaneseSubregion. 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, belonging to 18 genera, are endemic to China, and 26 species with 1 variety are distributedin south-western China and its adjacent region; Amitostigma gonggashanicum is endemicto the area). The floristic composition of orchids in the area is characterized by the dominanceof terrestrial species and temperate and subtropical East-Asian elements, though witha few Indo-African tropical elements (such as genus Satyrium (1 species) ). In conclusion, it may be considered that the species of orchids are abundant andfloristic elements are comparatively complex in the Gongga Mountain Region. |
