Monographs Details: Orthaea
Authority: Maguire, Bassett. 1978. The botany of the Guayana Highland--part X. Mem. New York Bot. Gard. 29: 1-288.
Discussion:Orthaea is distributed from Colombia to northern Bohvia, and eastward to Guyana and Trinidad. Twenty-two species are currently recognized (including the 6 new species herein described). Nine species are found within the area of the Guayana Highland, which is the center of distribution for the genus.
A. C. Smith (1932) placed Orthaea near Cavendishia and its allies primarily because of the presence (in two species) of large, cavendishioid floral bracts. As was mentioned earher, pollen morphology also indicates a possible relationship between Orthaea, Notopora, and Satyria.