兰科石仙桃属隶属贝母兰亚族，主要分布于亚洲热带和亚热带地区。该属不少种类为我国传统的药用植物。由于标本较少、缺少野外调查及系统深入的研究，目前该属在分类学方面尚存在较多问题，尤其与耳唇兰属、曲唇兰属、贝母兰属等近缘类群(包括约80种)的属间关系不清，物种划分比较混乱。分子系统学研究表明，根据形态性状建立的该属及其近缘属均非单系，其主要形态分类学性状存在趋同进化的现象。本项目拟对石仙桃属及其近缘类群广泛采样，在深入的文献、标本研究和野外调查基础上，重建其系统发育关系，结合形态学、孢粉学和分子系统学等证据，在系统发育框架下，全面评估各性状的系统学价值，厘清石仙桃属与近缘属的属间界限，建立该属合理、自然的属下分类系统。本研究亦可为该属的保护和开发利用提供可靠的理论依据。

Pholidota Lindl. ex Hook. is a genus of the subtribe Coelogyninae (Orchidaceae) mainly distributed in tropical and subtropical Asia. Many species of Pholidota are usually used in traditional Chinese medicine. Due to a scarcity of field surveys and specimens, limited number of phylogenetically informative morphological characters, the present infrageneric classification of the Pholidota species and their phylogenetic inter-relationships with related Otochilus Lindl., Panisea (Lindl.) Lindl. and Coelogyne Lindl. (including about 80 species in total) remain controversial. Molecular results indicate that most of these currently recognised genera are not monophyletic groups and some similarities in their morphological characteristics with taxonomic significance can be attributed to convergent evolution. On the basis of literature survey, specimen and field observation, as well as the extensive taxon sampling of the genus Pholidota and its allies, the present project intends to reveal their phylogenetic relationships with the results of the comprehensive evaluation of the taxonomical significance from molecular systematics and palynology, to clarify the generic delimitation, and to establish a reasonable taxonomic system for the species of Pholidota. The results of this study will also provide a reliable reference for the protection and development of this medicinal plant resources.