Svenson (1943) in the Flora of Panama reported this species to have black or brown achenes, but I have found them to be white or more rarely light brown at maturity. Achenes are exposed along the rachis as the bracts become deciduous, beginning at the base. Standley 40831, reported by Svenson as Dichromena pubera Vahl, should probably be included here despite the fact that the scales are scabrid on the keel and margins; its achenes are like those of R. nervosa, and it does not differ in any other way. In Central America, flowers open between 9:00 and 11:00 A.M. and are visited by the bees Trigona sp., Fombus mexicanus, and Apis mellifera (Leppik,1955). Throughout most tropical areas of the Western Hemisphere. In Panama, known principally from tropical moist forest in the Canal Zone, Bocas del Toro, Colón, Chiriqui, Veraguas, Panama, and Darién; known also from tropical dry forest in Los Santos, Herrera' Coclé, and Panama, from premontane dry forest in Los Santos, from premontane moist forest in the Canal Zone and Panama, from premontane wet forest in Chiriqui and Panama, and from tropical wet forest in Chiriqui.