In two isotypes (K, U S ) examined, the ovary is 4-celled and the dorsal calcar on the large stamen connectives is acute, while the hypanthium is 6-7 mm long. Three recent Venezuelan collections—from the Chimanta Massif (Steyermark & Wurdack 1283), Cerro Paru (Cowan & Wurdack 31444), and Cerro Guanay (Maguire, Phelps, Hitchcock, & Budowski 31766)—seem referable to E. cataractae, although generally having slightly smaller (3-4.5 mm) hypanthia and usually blunt dorsal connective calcars. The Amazonas collections resemble the British Guiana material in foliage, but the Chimanta collection has more definitely 5-nerved (and occasionally sub-7-nerved) leaf blades. The scanty material thus far collected does not suggest subspecific distinction.
E. pidlei Gleason seems separable from E. cataractae most easily, apart from the 3-celled ovary, by the more definitely developed panicle and the setose (rather than merely acute) ends of the ventral connective lobes. E. minor Gleason has prostrate stems and a 3-celled (in two fruits examined) ovary. E. rubra Pulle has a definitely developed panicle, short calyx lobes, and setose ventral connective prolongations in the large stamens (but a 4-celled ovary). Further blurring Cogniaux' sectional distinctions in Ernestia is the predominantly 3-locular fruit of numerous recent Venezuelan and Colombian collections of E . tenella (Bonpl.) DC. var. sprucei Cogn.; the available material did not permit establishment of the dominant carpel number of E. tenella var. tenella, but of 9 fruits clearly seen, 5 were 3-celled and 4 were 4-celled. The puberulent ovary of E. tenella distinguishes it from all Guiana species. E. lata Gleason (Bull. Torrey Club 52: 328. 1925) is synonymous with E. tenella var. sprucei; the holotype of E. lata shows slightly abortive anthers and leaf blades caducously glandular-setulose on both sides, while the other differential characters cited in the original description have been negated by recent collections.