Ctenium Panzer presents about 6 species in Brazil, and its southern limit of distribution is about 24ºC. Among these species, C. chapadense (Trin.) Doell and C. polystachyum Balansa, as well as C. brachystachyum (Nees) Kunth and C. brevispicatum J.G. Smith have been mistaken, and frequently appear misidentified in the herbaria. As a contribution to clarify the circumscription of these species, the useful characters to differentiate them and their geographical distribution are discussed, as well as illustrations are provided
Ctenium; Gramineae; species circumscription; Brazil