肘杆藻(Ulnaria)属于淡水无壳缝羽纹类硅藻，是重要的环境指示生物。由于该属的确立经历了复杂的历史过程，加上其模式种至今尚未得到详细的研究，亟需对该属进行系统的分类研究。武陵山片区硅藻资源十分丰富，特别是其中的肘杆藻属种类多且丰富度高，这为开展肘杆藻分类研究提供了宝贵的材料。本项目针对肘杆藻属急需解决的该属边界界定和属下如何分组的问题，拟以武陵山片区19个国家级自然保护区内及其毗邻水域为研究区域，采用形态和分子证据相结合的方法来加以探索。首先从形态学特征确定每个肘杆藻种类的身份，获得研究区域内肘杆藻属的种类名录，并进行属下分组；然后获得所研究肘杆藻种类的rbcL基因序列，加上GenBank已有的rbcL序列一起来构建分子系统树。本项目的完成可以确立肘杆藻属种类较全面的分类系统，可以探讨如何分析和协调形态资料与分子资料之间的关系，最终获得到对肘杆藻属全面和系统的科学认识。

Ulnaria is an araphid, pennate freshwater diatom genus. Some of its species are important environmental indicators. A systematic study of the classification of Ulnaria is in urgent need because both the establishment of this genus has gone through a convoluted and historic process, and its type species has not been studied in detail yet. Diatom diversity is relatively abundant in the Wuling Mountains Area. In particular, the genus Ulnaria has high species diversity with many individuals that provide precious material for the study of its classification. Since there is an urgent need to resolve the problems concerning the genus Ulnaria: how to circumscribe this genus and how to sub-group the taxa in this genus, the current project is to perform a comprehensive study of species in this genus using both morphological and molecular characters from the sample sites locating in the areas in or near the 19 national nature reserves within the Wuling Mountains Area. First, each species of Ulnaria will be identified using morphological characters, a species list will be acquired, and sub-groups, if possible, will be made. Following this, rbcL sequences from all studied taxa will be gained and a phylogenetic tree constructed from them, together with existing rbcL sequences in GenBank. Completion of this project will establish a comprehensive classification for the species in the genus Ulnaria, will explore how morphological and molecular data can be analyzed and finally acquire a comprehensive and systematic knowledge of the genus Ulnaria.