Large vines; stems grooved, subterete, 5 mm. in diameter (near flowering node), pilose and puberulous, the long hairs mostly spread- ing, up to 7 mm, long, brown, the small hairs up to 0.2 mm. long, whitish, spreading; leaf blades ovate, up to 25 cm. long and 18 cm. wide, acuminate at tip, cordate at basc, rather thin, entire, ciliate, both surfaces pilose, the hairs ascending, mostly 3 to 6 mm. long, brownish, arising from stellate bases, these bases larger and more conspicuous on the upper surface than on the lower, the costa and lateral veins (4 pairs) rather prominent, the veinlets coarsely reticu- late; petioles up to 8 cm. long, 2.5 mm. in diameter, the pubescence that of the stems; flowers axillary, in threes, at least the lowermost; pedicels 4 cm. long, 1.25 mm. in diameter, the pubescence that of the stems; bracts elliptic, 3 cm. long, 11 to 17 mm. wide, obtuse or rounded at both ends, mucronate at tip, the mucro 5 to 8 mm. long, rigid, densely brown pilose, the hairs similar to those of the stems, the inner surface puberulous, the hairs up to 0.3 mm. long, mostly spreading; corollas not seen; drupe (mature ?) ellipsoidal, slightly flattened, 22 mm. long, 9 mm. broad, 6.25 mm. thick, puberulous, the hairs up to 0.5 mm. long.
Type in the Botanical Museum of the University of Copenhagen, collected at Tres Esquinas, on the Río Caquetá, Intendencia de Amazonas, Colombia, 200 meters altitude, August 1952 by M. Køie (No. 5043).
Mendoncia trichota is well marked by its large thinnish cordate leaves and its dense brownish pilosity. Its nearest relative is Men- doncia cordata Leonard, based on a specimen collected in the forest along the Río Anchicayá, Department of El Valle, Colombia, by J. Cuatrecasas (No. 15216). From this M. trichota differs in its predominantly longer hairs, the dense (under lens) understory of minute hairs on the stems, the larger leaf blades, and the smaller bracts. The leaf blades of M. cordata are up to 20 cm. long and 14 cm. wide and the hairs of the under surface are denser, giving it a velvety touch that is lacking in M. trichota, with its more scattered hairs. The bracts of M. cordata are as much as 3.5 cm. long and 2.5 em. wide, but in M. trichota do not exceed 3 cm. in length and 1.7 cm. in width.
The specific epithet is from the Greek word 7pxwrós, meaning provided with hairs.