M. pachypoda Gleason, Fieldiana Bot. 28: 435. 1952. Certainly two morphologically distinct species are involved in the M. pachypoda-M. superba-M. acutifolia Ule complex, the ends of the line being altitudinally separated (as quite clearly seen by m e on the Chimanta Massif). In the ecotone, however, there apparently has been hybridization, and unfortunately Ule 8695 represents an intermediate. In overall features (flower and leaf size), the Ule collection falls slightly nearer M. pachypoda. The intermediates here placed under M. acutifolia show varying development of gland-tipped hairs up to 1.5 mm long on the steins, petioles, and inflorescence, but have the leaf and flower size of the eglandular Ule 8694. In the cumbres, M. acutifolia shows a leaf size reduction over the subcumbre elements and, like typical M. acutifolia, lacks glandular hairs.
In addition to the above complications, I believe there has been some hybridization between M. acutifolia and the widespread species M . guianensis (Aubl.) Cogn. and M . dodecandra (Desr.) Cogn, both of which are found in the eastern tepui slope forests. Maguire 33416, from Ilu-tepui, apparently is M . acutifolia with strong introgression (broad leaves, rather smaller stellate hairs) from M. guianensis. Cardona 244 (Auyan-tepui), Steyermark & Wurdack 1003 (Chimanta Massif), and Steyermark 59718 (Ptari-tepui) have rather narrow rigid leaves suggestive of M . acutifolia, but with the strongly stellate-pubescent hypanthia of M . dodecandra.