Abstract
This work is a study of the genus Riedeliella Harms (Trib. Acosmieae Yakovl.), that has three species, only known of South American. The authors describe, illustrate, elaborate a dichotomic key, discuss these species and ellucidate the taxonomic position of the genus. The genus Itaobimia was sinonimized and a new combination is presented: R. magalhaesii (Rizz.) Lima et Vaz.