Tree 20-25 m; nodes densely minutely rufous-tomentellous. Leaves opposite or verticillate in whorls of 4; petiole slender, 2-4 cm long, sparsely rufous-puberulous or glabrous; blade membranaceous, elliptical, sometimes oblong-elliptical or ovate, 7.5-18 x 4-8 cm, apex acute, acuminate or obtuse, base often unequal and subrotund to acute, upper surface dark brown when dry, subopaque, glabrous, midvein prominent, lower surface dark brown, glabrous or sparsely minutely puberulous near base; lateral veins ca. 10, smaller veins laxly reticulate. Inflorescence terminal, cymose-paniculate or corymbose, 4-6 x 5-12 cm, with 2-4 ascending or divaricate branches, few- to many- flowered; peduncle to 11.5 cm long, sparsely rufous-puberulent or glabrous; branches densely minutely rufous- or brownish-puberulous; cymules short, few-flowered; bracteoles 4-5, 0.5-1 mm long, densely rufous-tomentellous. Male perianth infundibuliform, 5 x 3 mm, densely rufous-tomentellous, shortly 5-toothed, teeth obtuse; stamens exserted, anthers ca. 0.6 mm long. Female perianth narrowly tubular, 3-4 x 1.5 mm, densely rufous- or brownish-tomentellous, 5-toothed, teeth usually obtuse, flaring or sometimes erect, 0.5 mm long; style exserted to ca. 2 mm, black, stigma fimbriate. Anthocarp narrowly ovoid, ca. 10 x 3.5 mm, densely rufous-tomentellous.
forests of the Kanuku Mts. in Guyana endemic
Endemic to forests of the Kanuku Mts. in Guyana, alt. 150-400 m; 3 collections studied: the type specimen, see above; paratype, A.C. Smith 3486, (F, not seen; isoparatypes B!, K!, NY!, U, US!); Jansen-Jacobs et al. 408 (CAY, U).
The narrowly tubular, densely rufous-tomentellous female perianth is distinctive for the known Guianan species of this genus.
Guapira marcano-bertii Steyerm., Ann. Missouri Bot. Gard. 74: 618 (1987) and G. amacurensis Steyerm., op. cit. 615 (1987), both described from Delta Amacuro, Venezuela in the Guianan floristic province, may be speculated to possibly occur in Guyana; their relationship to known Guyanan taxa having reddish hairs is yet to be probed. Steyermark (op. cit. 618. 1987) noted that G. marcano-bertii has longer peduncles, longer fruits, and longer spreading pubescence throughout, than G. cuspidata.