Memoirs of The New York Botanical Garden
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of Vascular Plants of Northeastern United States and adjacent Canada
Details: Psychotria blakei Standl. & Steyerm.
Maguire, Bassett. 1972. The botany of the Guayana Highland--part IX. Mem. New York Bot. Gard. 23: 1-832.
Psychotria blakei Standl. & Steyerm.
The caudate appendage of the bracts of the inflorescence is much more conspicuous (1.5-2 mm long) than in P. lupulina and subspecies, the marginal nerve more conspicuously thickened, and the stem is much stouter than in that species.