随着全球气候变暖、环境污染和原始森林的减少，许多物种还没有被发现和利用就已经灭绝了。片叶苔属是苔类植物门的一个大属，目前已接受有277种，主要分布于潮湿的自然森林中，是对环境极为敏感的简单叶状体苔类。由于形态结构简单，可靠的分类特征有限，形态可塑性又大且缺少分子系统发育的研究，片叶苔属的分类一直备受挑战，至今我国苔藓志还没出版这一重要的类群。本项目拟首次通过世界范围的取样，利用核基因ITS片段, 叶绿体基因trnK-psbA, rps4-trnL, trnD-T, trnL-F片段，结合形态分类学和分子系统学的方法，建立该属新的分类系统，修订我国片叶苔属的分类，探讨形态特征和生态位分化与多样化速率在时空上转化的相关性，揭示其物种多样性形成和分化的机制。本项目的实施，不仅将揭示我国片叶苔属的物种多样性和分布，也为全球气候持续变化下简单叶状体苔类物种多样性维持和保护提供理论依据。

With global warming, environmental pollution and deforestation, many species have been extinct before nomenclature and utilization. Riccardia, comprising 277 species mainly distributed in moist natural forests, is a large genus in liverworts and sensitive to the quality of habitats. Owning to simple thalloid structures, the lack of constant diagnosis characters, great morphological plasticity and limited phylogenetic research, the classification of this genus is greatly challenged. Until now, the group of Riccardia have not been included in the published Bryophyte Flora of China. In the present project, we will conduct a first phylogeny focusing on the deep phylogenetic framework of Riccardia based on nuclear ribosomal DNA and four plastid regions (trnK-psbA, rps4-trnL, trnD-T, trnL-F) with the worldwide samples in order to shed new light on the classification of this genus and reveal the diversity and distribution of Chinese Riccardia. Moreover, the spatial-temporal evolution history and mechanisms of diversification within this genus will be examined. The results will provide new insights on the maintenance, use and conservation of plant resources in the simple thalloid liverworts.