细鳞苔属是细鳞苔科中种类最多、分类最为困难的属之一，主要分布于温带和泛热带地区，我国和喜马拉雅地区被认为是该属物种多样性最丰富的地区。最近的形态学研究和分子系统学研究已经解决了该属最富争议的属的界定问题，因此，展开细鳞苔属的分类修订，调查物种多样性是当前一项迫切的任务。中国已经报道的细鳞苔属植物共有42种，是亚洲物种最丰富的国家，但存在不少存疑种以及大量亟待解决的分类学问题，至今还缺乏全国性的专门区系调查和现代的分类修订。本项目以我国以及邻近国家的细鳞苔属植物为重点，拟运用形态分类和分子系统学相结合的方法，通过关键种类的野外采集和新鲜材料关键特征的观察以及核和叶绿体相关基因序列的分析， 对我国细鳞苔属植物进行全面、系统的修订，揭示我国细鳞苔属的物种多样性和地理分布。

Lejeunea Lib. is one of the genera in the family Lejeuneaceae with richest species and most difficult identifications. It is distributed mainly in temperate to pantropical regions. China and Himalayas are the region with richest species diversity. Recent taxonomic and phylogenetic studies have clarified the delimitation of the genus which was long subject to controversy. Hence, the taxonimic revision and investigation of species diversity will be a urgent task. There are 42 Lejeunea species reported in China, which has the richest species diversity of Lejeunea in Asia. However, many doubtful species and taxonomic problems still exist. In addition, there is no mordern taxonomic revision of this genus in China. By using the method of combined taxonomy and molecular phylogeny the present study will emphasize the Lejeunea species in China and adjacent regions, make a detailed taxonomic revision, and reveal the species diversity and geographical distribution of Lejeunea in China by detailed morphological observation on key characters and sequences of several nuclear and chloroplast genes.