Monographs Details: Chaetocarpus williamsii Steyerm.
Authority: Maguire, Bassett. 1967. The botany of the Guayana Highland--Part VII. Mem. New York Bot. Gard. 17: 1-439.
Family:Euphorbiaceae
Description:Distribution and Ecology - Known only from its type.

Discussion:

Type. “Cerca de la margen arboreada en la Isla al frente de Marao, Rio Guainia, Territorio Federal Amazonas, Venezuela, alt 127 m, 12 Feb 1942, Llewelyn Williams 14312 (isotype in NY).

Chaetocarpus williamsii is very similar to C schomburgkianus from which it differs by the longitudinally costate tubercules of the fruit. Flowers both female and male are unknown