The Research Of The Diversity Of Wild Orchids In Southern Hunan

The areas have been studied include Yongzhou city,Chenzhou city and Yanling county which are located in Southern Hunan.The geographical coordinates are between 24°39'N to 26°51'N and 111°06'E to 114°14'E,boasting a total land of 43,900 square kilometers.Based on the investigation and analysis of wild orchids in these areas,some conclusions can be drawn as follows:The species of orchids in these areas are very rich.According to the field investigation,there are 144 species of orchid plants,belonging to 61 genera,including terrestrial orchids,epiphytic orchids and saprophytic orchids.Terrestrial orchids are the most,there are 88 species,belonging to 37 genera,accounting for 60.66%of the total genera and 61.11%of the total species.The second one is the epiphytic orchids.Its 43 species,belonging to 19 genera,accounts for 31.48%and 29.86%of the total number of genera and species respectively.Saprophytic orchids are the least,with 13 species,belonging to 9 genera,accounting for 14.75%and 9.03%respectively.Some new materials of Orchid plants in Hunan Province were found in this field investigation.Six genera,viz.,Crepidium,Epipogium,Erythrodes.,Hancockia,Hemipilia,and Myrmechis are newly recorded in Hunan province.Twenty-two orchid plants,viz.,Anoectochilus zhejiangensis,Cephalanthera nanlingensis,Crepidium acuminatum,C.purpureum,Dendrobium henanense,Epipogium roseum,Erythrodes blumei,Gastrochilus nanus Gastrodia huapingensis,Hancockia uniflora,Hemipilia galeata,Lecanorchis nigricans,Liparis brunnea,L.tsii,Myrmechis urceolata,Odontochilus nanlingensis,O.saprophyticus,Platanthera fujianense,P.nanlingensis,Pleione chunii,Tainia acuminata,and Yoania prainii,are newly recorded in Hunan province.In addition,three species were doubtful,viz.,Bulbophyllum sp.,Calanthe sp.,and Liparis sp..The floristic composition of Orchid plants in Southern Hunan is complex,which can be divided into 12 distribution types and 5 forms.The orchid flora in this region is relatively tropical,with 40 genera,accounting for 65.57%of the total number,and there are only two China's endemic genera,which shows that the specificity is not strong.The main components of Orchidaceae flora in southern Hunan are Calanthe,Dendrobium,Liparis,Bulbophyllum,Goodyera,Habenaria,Platanthera and Cymbidium.Orchids are widely distributed in Southern Hunan,and they are distributed in every administrative regions.The species of orchids in mountainous areas are more than those in hilly areas,roughly featuring a decreasing trend from south to north and a trend of more-less-more from east to west.The orchid diversity presented a hump-shaped pattern along the elevational gradient with a peak at mid-elevations.In the small areas,suitable for orchids to survive and reproduce,the phenomenon of cluster distribution often appears.The phased work of orchid protection in Southern Hunan has been finished well,and the commercial poaching has been basically eliminated.At present,the main threats faced by orchids are habitat loss and sporadic individual excavation.The protection of orchids should keep pace with the times,from surface to point,and make the work meticulous and professional.