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 the taxonomy of some species of Nannoglottis are also discussed.

Key words: Nannoglottis, microcharacter, scanning electron microsco