Monographs Details: Psychotria altsonii (Sandwith) Steyerm.
Authority: Maguire, Bassett. 1972. The botany of the Guayana Highland--part IX. Mem. New York Bot. Gard. 23: 1-832.

Cephaelis altsoni Sandw., Kew Bull. 1931: 475. 1931.

Within the four showy outermost involucral bracts, decussately arranged in two pairs, are 13-15 small, fleshy, narrowly triangular-lanceolate, subfalcate bracts. On either side at the base of these small bracts are smaller bracts with an elongate, subulate, fleshy gland or with three such glands at the base on each side. Subtending the base of the individual flowers or at the base of two flowers appears a small triangular bracteole 3-4 × 1 mm, which is present only on one side of a flower or may subtend two flowers. The flowers are supported by fleshy pedicels, in the earlier stages appearing subsessile, but elongating from 1-3.5 mm, the outermost flowers maturing earlier and showing more elongated pedicels.