巨孢衣科是子囊菌门的重要类群，是基于表型特征和分子数据综合分析而建立的，包括5属约280种，在世界干旱半干旱地区广泛分布。除巨孢衣属外，其余4属仅据表型特征不易进行属级鉴定，需辅助于nuITS rDNA序列。巨孢衣科地衣有许多繁殖结构缺失或表型特征界线模糊的类群，亦有表型特征各异而nuITS rDNA序列极为相似的物种，这些物种的界定均需联合表型特征和分子数据进行。前人零散报道的60种中国巨孢衣科地衣是依据旧分类系统和传统研究手段而界定的，亟需新的分类系统和方法对其订正研究。申请者已积累了相关标本2100余份，并800份标本进行了系统分类学研究，发现3个新种。本项目将在全国范围内补采巨孢衣科地衣标本，结合形态解剖学特征、地衣化学成分及地理分布，并测定所有中国巨孢衣科地衣物种的nuITS rDNA序列（每种3-5条），对该类群地衣的物种进行科学界定，澄清中国巨孢衣科地衣的属、种组成与分布。

Megasporaceae (Pertusariales, Ascomycota) is one of the largest families of lichenised fungi and contains 5 genera and about 280 species, which is an important ascomycous group and widely distributed in arid and semi-arid regions of the world. The establishment of the family was based on the comprehensive analysis of phenotypic characteristics and molecular data. Except Megaspora (including only 2 species worldwide), the other four genera of the family are not easily to be identified without nuITS rDNA sequences. In the family Megasporaceae, so many populations or species, which have no ascocarp, or incomplete phenotypic characteristics, or different Phenotype but with almost the same nuITS rDNA sequences, could only be identified by the combination with phenotype and genotype method. Studies of the group in China were mainly focused on the genus Aspicilia before 1998 and incomplete, about 60 species had been reported in scattered papers and herbarium materials of these species needed to be reexamined with the new taxonomic system and modern methods of lichen taxonomy by combining morphological and molecular data methods. We have collected about 2100 specimens of the family, 800 specimens of them have been identified and 3 new species have been described. On the basis of the previous researches, the field investigation will be taken to collect more new materials in this project. The genera and species composition of the family will be found out, and 3-5 nuITS rDNA sequences of every species will also be determined. The result of this research will promote fungal taxonomy and systematics, and will be useful to the reasonable exploitaion of the resource.