Monographs Details: Platycarpum orinocense var. grandiflorum Steyerm.
Authority: Rogers, George K. 1984. Gleasonia, Henriquezia, and Platycarpum (Rubiaceae). Fl. Neotrop. Monogr. 39: 1-135. (Published by NYBG Press)
Description:Variety Description - Young stem densely cinereous- to ferrugineous-hispid or pilose, the hairs to 1(-2.2) mm long, sometimes with shorter, hispidulous layer. Leaves bearing adaxially on lamina stiff, antrorse or variously bent hairs to 1 mm long, abaxially densely tawny- to ferrugineous-villous or pilose, the hairs 0.5-2.5(-3) mm long; petiole bearing abaxially near base a U-shaped gland 5-10 mm long. Inflorescence axes usually ferrugineous-hispid(-ulous) to pilose, the hairs to l(-2) mm long, sometimes with shorter puberulent layer. Calyx lobes 9-12 x 3-5 mm, rounded to acuminate at apex; corolla 1.9-2.2 cm long, the lobes 0.7-1.0 x 0.6-1.0 cm, rounded to acuminate at apex; filaments inserted unequally 4-7 mm from base of tube, 5-9 mm long. Capsule 2.6-4.5 x 2.8-5.5 cm.

Discussion:This variety is only weakly distinguishable. Since Steyermark (1963) described it, specimens unseen by him have diminished the differences he described. For every character in his key, at least one collection of Platycarpum orinocense var. orinocense shows the condition ascribed to var. grandiflorum. Steyermark noticed that the most intermediate collection, Maguire et al. 36063, bridges the two varieties for floral characters as well as for pubescence on the lamina. Several collections, especially some of mine (Rogers 43, 44, 54, 55, 67), render impossible a clear distinction using the pubescence characters. The best characters appear to be the sizes of the perianth parts. Because the vegetative characters are somewhat inadequate, assignment of Jangoux 10109 (lacking flowers) to var. grandiflorum is only tentative.
Distribution:Venezuela South America| Amazonas Venezuela South America| BolĂ­var Venezuela South America|