凤尾蕨科书带蕨亚科包含两个形态、生境特征和分子演化速率迥异的姐妹分支——铁线蕨属和书带蕨类，是研究物种多样化机制的理想类群。前人研究所采用的分子片段或物种取样有限，时间估算策略不完善，致使该亚科系统发育关系尚不明确，其起源和分化时间估算结果争议较大。本项目拟对书带蕨亚科全部12个属约120种的代表类群进行取样，在此基础上利用基因组浅层测序方法获取质体全基因组、部分线粒体基因以及核nrDNA序列。综合三套基因组数据解析书带蕨亚科属间和属下主要分支的系统发育关系；对质体基因组分子替代速率和外源序列插入进行分析，为蕨类植物质体基因组演化提供线索；结合化石记录并利用多种分析策略进行分化时间估算和多样化速率分析，以及进行祖先性状和祖先分布区重建，探究该亚科现今分布格局成因和物种多样化历史。该项目的实施有望揭示书带蕨亚科的物种多样化模式和机制，并为其它植物类群的物种多样化研究提供新思路。

The Vittarioideae (Pteridaceae) are composed of two lineages with radically different morphology, habitat, and molecular substitution rate, the maidenhair ferns (Adiantum) and the vittarioid ferns. Therefore, Vittarioideae are an ideal group to study the mechanism of species diversification. Hindered by limited molecular sequences or species sampling, or imperfect dating strategies used in previous studies, the phylogenetic relationships among some genera of vittarioid ferns and main lineage of Adiantum are unclear, the estimated divergence times of Vittarioideae are still controversial. In this project, we plan to sample representatives from all 12 genera (ca. 120 species) of Vittarioideae, and obtain the whole plastid genomes, some mitochondrial genes, and nuclear nrDNA sequences using genome skimming methods. We will (1) Reconstruct the phylogenetic relationships among genera and main lineage of Vittarioideae by integrating these three part of genome data. (2) Analyze the molecular evolutionary rate and the insertion of exogenous sequences within plastid genomes of Vittarioideae, which is expected to provide a clue for the plastid genome evolution of ferns. (3) Estimate the diversification times and rates of Vittarioideae based on fossil records and different dating schemes, and reconstruct the ancestral morphologies and geological distribution areas of Vittarioideae. (4) Explore the chrono-geological patterns and mechanism of species diversification within Vittarioideae by integrating all the results revealed in this study, and is expected to shedding new light on the species diversification studies of other plant lineages.