Scanning electron microscope studies of the indumentum of Cissus adnata Roxb., C. assamica (Laws.) Craib and C. aristata Blume, show that the structure of the trichomes varies between taxa but is consistent within each taxon. These three species are distinct and easily recognised by the nature and distribution of these trichomes although they have been frequently confused in the literature with respect to their circumscription and synonymy. Cissus adnata, which extends from India to Australia, has both multicellular, uniseriate and unicellular 2-armed trichomes on the abaxial leaf surface, glabrous stipules and pubescent ovary; C. assamica found from India to New Guinea has unicellular, 2-armed hairs sparsely distributed, glabrous stipules and ovary; C. aristata extending from Burma to Papua New Guinea has scattered unicellular, 2-armed hairs, pubescent stipules and glabrous ovary. There are 4 text-figures.