Systematic And Taxonomic Study On Odontochilus And Allies (Orchidaceae) In China

Odontochilus s.s.and allies belong to Subtrib.Goodyerinae,Trib.Cranichideae,Subfam.Orchidoideae,Orchidaceae.The identification of this group is difficult because of similar habitat and flower structures,accompany with indefinite intergeneric boundaries and frequent subordinated species changes,taxonomic problems are badly needed to be solved.In this study,the relationship of genera and related species had been clarified through morphological and phylogenetic studies.We coded 42 morphological characters to summarize and build ML tree,at the same time,nr DNA ITS,cp DNA trn L-F and mat K were selected as markers for building phylogenetic trees by using the MP,ML and BI methods.Sixty two molecular samples belong to seven genera and 28 species of Odontochilus s.s.and allies,248 DNA sequences in total with other groups related(24 are from Gen Bank).Results were as follows:1.Both morphological and molecular studies indicated that Chamaegastrodia is monophyletic,C.nanlingensis and C.poilanei,which were merged into Odontochilus,should be reinstated as valid names.There are five species of Chamaegastrodia in China.2.It is appropriate to merge Odontochilus s.s.,Kuhlhasseltia,Myrmechis and Pristiglottis to Odontochilus s.l.to get the monophyletic status.Meanwhile,the results indicated that it is unsuitable to have further division within it.There are 17 species of Odontochilus s.l.in China.3.Phylogenetic results indicated that combined gene fragments got higher resolution than single nr DNA or cp DNA results.All data sets displayed that Odontochilus and allies are closer to Dossinia,Anoectochilus,Rhomboda and Cystorchis than to Cheirostylis,Hetaeria and Zeuxine.4.Cheirostylis franchetiana King & Pantl.should be independent and merged into Odontochilus,while Chamaegastrodia asraoa(J.Joseph & Abbar.)Seidenf.& A.N.Rao and Anoectochilus tetrapterus J.D.Hook.should recover former status respectively.Odontochilus napoensis H.Tang & Y.F.Huang was recorded in Baihe village,Pingbian County,Yunnan province,which should be a new record to Yunnan province.5.Keys to genera and species of Chamaegastrodia and Odontochilus s.l.are provided here,with detailed descriptions,interrelated pictures and distribution maps.