尾鳞苔属是皱萼苔亚科中唯一产生芽胞的泛热带分布的属，该属主要分布在非洲，特有种比例非常高，少数种类呈跨洲际分布，是一个独特的洲际间断分布类群。随着全球气候的变化尤其是人类活动的影响，全球热带雨林面积日益缩减，而主要生长在热带雨林地区以叶片作为主要生境的尾鳞苔属受到影响最大，物种容易濒危。因此，开展对全球尾鳞苔属植物的形态及分子系统学研究对于生物地理学研究及物种保护都具有重要的意义。由于一些新的性状的增加，使得本来很清晰的属的界限又变得模糊，属下分类系统过时，种间关系混乱。本项目拟采用形态分类、实验分类与分子分类相结合的综合研究方法研究该属全球标本，重建该属系统发育关系，明确属的界线，建立合理的属下分类系统，为探讨该属的洲际间断分布格局成因奠定基础。

The genus of Caudalejeunea (Steph.) Schiffn., with the capacity of the species to reproduce asexually by means of discoid gemmae, is the only frequently epiphyllous genus and abundant in humid tropical regions in Ptychanthoideae.The center of diversity of the genus is tropical Africa with highest endemics, and some species exhibit intercontinental disjunctions between tropical regions of Africa, America, Asia and Oceania. It is an optimal genus to study the reasons of intercontinental disjunctions. To conserve the endemic or endangered taxa and solve the biogeographic problems, the taxonomic and molecular systematic study of Caudalejeunea, mainly distributed in tropical rainforests, is urgent for reduction of diversity caused by loss of global tropical rainforests as the consequence of increasing human being activities and deterioration of the environment. At present, the definition and circumscription of Caudalejeunea is obscure and intraspecies classificaiton is in dispute since more interesting species were added into the genus.Therefore, this project using morphological classification based on global specimens, integrating molecular techniques for investigation of its phylogeny, and experimental classification studying the process of gemmae, aims to construct a comprehensive phylogeny of Caudalejeunea, more naturally scheme of its intraspecies and interspecies classification, and povide basis data for studying the reason of intercontinental disjunctions of the genus.