Abstract

China has rich terrestrial orchid resources, with the number of terrestrial orchid species equal nearly to that of epiphytic orchids. From a conservation perspective, the Chinese terrestrial orchids deserve considerable attention. Considering the huge areas of the temperate zone and alpine mountains of China, where most terrestrial orchids are distributed, and the different abundance of terrestrial orchids in different areas and different habitats, it is important to identify “hotspots” for the conservation of the Chinese terrestrial orchids. Huanglong Valley, at an elevation of 3100-3569 m and only 3.5 km long, is the main landscape feature of Huanglong Nature Reserve, Sichuan, China. It is also the largest travertine region in the world. In this narrow valley rich terrestrial orchid diversity was found: a total of 30 orchid species in 19 genera were found in the valley, all of which were terrestrial orchids, including 4 saprophytic orchids. These orchids grew in two different habitats: one was open shrub and forest margin with travertine stream flows, where 20 orchid species occurred; another was relatively dense mixed coniferous broad-leaved forest without water flows, where 10 orchid species were found. Cypripedium flavum, C. tibeticum, C. bardolphianu, Orchis chusua, O. diantha and Calanthe delavayi were the main orchid species found in Huanglong Valley with abundant indi-viduals. The florescence times of these terrestrial orchids overlapped because of the short growing season of the alpine mountains. However, there were rich intraspecific variations in floral morphology in some orchid species. Huanglong Valley could be considered one of the terrestrial orchid “hotspots” in China, and even in the world. We believe our study results could supply basic data for generating specific management strate-gies, long-term monitoring and study of terrestrial orchids in Huanglong Valley.