Woody liana to 20 m, in the absence of support a shrub with decumbent long branches or a shrub to 4 m; ‘combretaceous hairs’ (often very scarce) and peltate scales present. Leaves opposite, coriaceous, narrowly oblong-ovate to broadly elliptic or almost orbicular, 4-20 x 2-12.5 cm, apex gradually or abruptly shortly to long acuminate, acute, obtuse or rounded, base cuneate to subcordate or sometimes cordate, hairless or almost so, moderately to rather densely lepidote below, sparsely or very sparsely so above, scales usually inconspicuous to naked eye, dark or whitish; venation usually eucamptodromous-brochidodromous, sometimes eucamptodromous or brochidodromous, midvein prominent on lower surface, secondary veins 7-17 pairs, close to distant, not to slightly or sometimes moderately prominent, lesser veins not prominent; petiole 0.3-1.4 cm long, glabrous to sparsely pubescent, inconspicuously lepidote. Inflorescence sparsely to extensively branched, slender, in opposite pairs in leaf-axils, 2-7 cm long, usually aggregated into terminal panicles up to 27 cm long, at lower nodes in axils of normal leaves (often fallen by fruiting), at upper nodes without subtending leaves, glabrous to densely pubescent or rarely tomentose, inconspicuously lepidote; flowers borne densely on rhachis. Flowers 4-merous, 2.6-3.5 mm long, moderately to densely but usually very inconspicuously lepidote on outside; lower hypanthium 1.1-1.3 mm long, without pedicel-like region, pubescent to very sparsely so,upper hypanthium deeply cupuliform, 1.5-2.9 x 1.5-3.4 mm, glabrous to sparsely pubescent outside, subglabrous to pubescent inside (degree not correlated to pubescence outside); calyx lobes erect, 0.2-0.3 mm long, apex subacute to obtuse; petals 4, patent at full anthesis, broadly spathulate with limb transversely oblong-elliptic, 0.7-1.5 x 1.1-1.6 mm, well exceeding calyx lobes, apex rounded or irregular, basal claw 0.1-0.3 mm long, glabrous; stamens 8, well exserted, filaments 3.5-4.8 mm long; disk glabrous to densely pubescent at margin, without or with narrow free margin up to 0.15 mm long; style 3.8-5.3 mm long, usually exserted about as far as stamens. Fruit variable, hairless or nearly so, moderately to densely but minutely lepidote especially on body, 1.5-4.5 x 0.7-1.7 cm, ovate or elliptic to narrowly so in side view, apex rounded to acute or acuminate and sometimes minutely apiculate, base rounded to narrowly cuneate, thick to narrow pseudostipe 0-0.6 cm long, body much thickened with spongy tissue, wings (or ridges) 4, stiff, 0-0.3 cm wide, sometimes spirally twisted undulateScales as in C. laxum.
Guianas present present, Southern America: Bolivia (Bolivia present); Peru (Peru present); Venezuela (Venezuela present), eastern Ecuador present, lowland Amazonas present
Typical of lowland Amazonas in Brazil, Venezuela and the Guianas, extending W to eastern Ecuador and Peru and S to almost 15° S in Bolivia.; about 42 specimens from the Guianas (GU: 23; SU: 10; FG: 9).
C. laxum by its much thicker coriaceous leaves. These vary in shape and the segregate C. laurifolium (apex acuminate) was based on the opposite end of the spectrum from C. pyramidatum (apex rounded). Combretum nitidum, the original material of which was wholly galled, has leaves intermediate between the two. There is much variation in fruit shape, but in this species only the ridged spongy fruits are present. Galls are common as in C. laxum. There must remain some doubt about the specific distinction of C. laxum and C. pyramidatum, but so far the differences are maintained.