Monographs Details: Psychotria lupulina subsp. rhodoleuca var. maypurensis f. pubens Steyerm.
Authority: Maguire, Bassett. 1972. The botany of the Guayana Highland--part IX. Mem. New York Bot. Gard. 23: 1-832.
Family:Rubiaceae
Description:Latin Diagnosis - A subsp rhodoleuca var maypurensis petiolis hypanthioque pubescentibus recedit; foliorum laminis subtus costa media pubescenti; bracteis sparse puberulis atque ciliolatis; calycis margine dense ciliato.

Discussion:

The leaf blades are sessile and obtuse or rounded at the base, at least on the upper ones, as in var maypurensis, but sparsely puberulous on the midrib beneath, and densely puberulent on the petiole. The densely pubescent hypanthium and densely ciliate calyx margin further distinguish this as a pubescent form of var maypurensis.

Although the subspecies lupulina and rhodoleuca can generally be distinguished from one another by the shape and width of their involucral bracts, intermediate specimens are found which suggest that the taxa are best treated as subspecies. In Holt & Gehriger 250, Vareschi & Magdefrau 6800, Breteler 4863, and Maguire & Politi 27379, all from Amazonas, Venezuela, intergrading forms are manifest between the narrow bracts of subsp rhodoleuca and the broader ones of subsp lupulina. In general, the involucral bracts of subsp lupulina are broadest at the middle and IV2-3% times longer than broad, but in Linder 32 they are 4% times longer than broad, approaching those of subsp rhodoleuca. The involucral bracts of subsp lupulina are usually 2.5-5 mm wide or up to 8-10 mm wide in Irwin, Pires & Westra 48401, but in Breteler 4863 are narrowed to 1.8 mm, thus overlapping into the width of subsp rhodoleuca, in which the bracts vary from 1-2 mm wide. In subsp rhodoleuca the bracts are usually of about the same width throughout or slightly wider above the middle and usually range from 6 1/2-13 times longer than broad. However, they may be only 5 1/2 times longer than broad, as in Holt & Gehriger 250 or as much as 15 times or more longer than broad, as in Steyermark 86862.

So far as Psychotria leucophaea Poepp. & Endl, is concerned, it represents the broader-bracted extreme of P. lupulina subsp lupulina. Müller-Argoviensis states (Mart. Fl. Bras. 6(5): 317. 1881) for P. leucophaea that the bracts have the following measurements: “bracteae exteriores 16-18 mm longae et 6-8 mm latae.” These dimensions fall within the limits of variation shown by the bracts of P. lupulina subsp lupulina. However, an examination of an isotype (Poeppig 2545) shows the outer bracts attaining smaller dimensions of 12-13 mm long by only 5 mm wide.