This species was based on a collection from Sao Gabriel, Rio Negro, Amazonas, Brazil, and has subsequently been found in Dept. Loreto, Peru. It is distinguished from P. basijugum Ducke, also a species of Guayana, mainly by its setaceous (not rounded) leaflet apices, and from the Amazonian P. umbriflorim Ducke by its smaller, more numerous leaflets, and larger flowers. Critical comparison ol two Suriname collections (Hall 15; Lanjouw & Lindeman 2270) and one from Guayana (Maguire, Wurdack, & Maguire 41958) with type materials and descriptions of the three mentioned species raises questions about their distinctness and, at this point, tends to suggest their being treated as a single varying species. The Guayana collection very closely approximates Ducke (RB) 20174, the type of P. basijugum. The Suriname collections, while mutually similar, seem quite distinct from all three taxa. However, owing to the sterile and fragmentary condition of both these specimens, there is an inadequate basis for more detailed study.