Molecular Phylogeny Of Orchideae(Orchidaceae)

The tribe Orchideae,one of the largest tribes of family Orchidaceae,comprises around 68 genera and more than 2000 species.The tribe represents predominantly in northern temperate and tropical areas of both the Old and New Worlds,and Orchidinae is one of the highest subtribes in diversity of Orchidaceae in China.There are still many debates on the delimitations and systematics of its insiders in progress.In this study,utilizing seven DNA markers(cpDNA rbcL,trnS-trnG,matK,trnL-F,psbA-trnH and nrDNA Xdh,ITS)and extensive sampling 61 genera and 393 species,the generic delimitation and phylogenetic relationships within the Orchideae were reassessed.The main results are shown as follows:1.The phylogenetic results show that Pachites is sister to other groups except Brownleeinae;Huttonaea is sister to other groups except Brownleeinae and Pachites.These results support the Pachites and Huttonaea must be removed from Coryciinae.A new subtribe,Pachitinae G.Z.Chen&S.P.Chen should be established,and Huttonaeinae Schltr.should be recovered.Orchideae should be divided into 6 subtribes,and the relationship is(Brownleeinae(Pachiteinae(Huttonaeinae(Orchidinae(Coryciinae,Disinae))))).2.Orchidinae is the highest in diversity and the most controversial subtribes in Orchideae.The result shows Orchidinae is monophyletic and should be divided into eight groups:Satyrium,Habenaria alliance,Schizochilus,Brachycorythis,Amitostigma alliance,Chamorchis,Orchis alliance and Platanthera alliance.3.Habenaria and Herminium are polyphyly in Habenaria alliance.The Amitostigma alliance is divided into seven sections:sect.Pinguiculae,sect.Lepidum(newly establish),sect.Hemipilia,sect.Tetralobae,sect.Alpestres,sect.Ponerorchis and sect.Neottianthe.Platanthera is polyphyly in Platanthera alliance.