毛冠菊属舌片的微形态特征与系统学意义.pdf

植物分类学报 43(1): 12–21(2005)Acta Phytotaxonomica Sinica ———————————2004-07-15收稿, 2004-10-19收修改稿。基金项目: 中国科学院知识创新工程项目(KSCX2-1-06B)(Supported by the Knowledge Innovation Project of the Chinese Academy of Sciences (Grant No. KSCX2-1-06B))。毛冠菊属舌片的微形态特征及其系统学意义高天刚陈艺林(中国科学院植物研究所北京 100093)Microcharacters in the ligules of positae) and their systematic significance GAO Tian-Gang CHEN Yi-Lin (Institute of Botany, the Chinese Academy of Sciences, Beijing 100093, China) Abstract The systematic position of the taxonomically controversial Nannoglottis is investigated based on SEM observation on microcharacters of the ligules in eight species of the genus. All the species are characterized by having an adaxial epidermis of the ligules consisting of oblong, tabular cells, with the radical and tangential walls being straight; the outer wall with a characteristic thickening along the median plane of the cell; the median plane of the cuticle of outer wall with a pattern of longitudinal rugose stripes; and no systematic connection between the patterns of adjacent cells. This supports a close affinity between the genus Nannoglottis and Astereae, and also indicates the unique systematic position of this genus in the tribe. These results agree with those of the study of the phylogeny of Astereae using ITS sequences. The evolutionary trends of some microcharacters and the utility of microcharacters in t