In his treatment of this taxon, Dr. In-Cho Chung [Phytologia 15(4): 277-279. 1967] recognized two variations: var calycosa with the leaves glabrous except for the ciliate margins (or somewhat pubescent beneath on the veins) and calyx lobes glabrous within and without or sometimes with a few hispid hairs without, and var scaberrima (Wernh.) Chung with the upper side of the leaves frequently scabrous and the calyx lobes and leaf blades densely hispid abaxially. The Venezuelan and Colombian specimens are placed under var calycosa together with the West Indian specimens.
A study of the West Indian material leads me to regard it as distinct varietally from the Venezuelan and Colombian specimens, apart from the var scaberrima, and would indicate that var karsteniana Schum. merits recognition. In var calycosa of the West Indies the peduncles and pedicels are nearly glabrous except for the sparsely hispidulous ciliate angles, the hypanthium is nearly glabrous or has only a few hairs, the calyx lobes are glabrous dorsally and only shortly ciliate on the margins, the leaves are glabrous on both sides, and the stems are glabrous except for sparse ciliation on the angles. In var karsteniana, on the other hand, while some variation occurs in the abundance of pubescence on the lower midrib of the leaf, stem, and other parts, in general the pedicels, peduncles, and hypanthia are moderately to more densely pubescent, and the calyx lobes are more strongly ciliate with often a line of pubescence occurring on the lower dorsal half. The three variations may be distinguished as follows: