Woody liana to 15 m, shrub to 7 m; ‘combretaceous hairs’ (often very sparse) and peltate scales present. Leaves opposite, chartaceous to subcoriaceous, ovate to elliptic or sometimes broadly or narrowly so, 4-17 x 2-11 cm, apex acute to acuminate, base cuneate to rounded or subcordate, usually hairless but sometimes sparsely pubescent on both surfaces, moderately to densely reddish- to golden-lepidote below, more or less scaleless to sparsely lepidote above; venation usually eucamptodromous-brochidodromous, sometimes eucamptodromous or brochidodromous, secondary veins (5-)6-9(-10) pairs; petiole 0.3-1 cm long, glabrous, contiguously reddish- to golden-lepidote. Inflorescence unbranched, stout, terminal or singly or in opposite pairs in leaf-axils, 3-18(-22) cm long, sometimes aggregated into terminal racemes up to 29 cm long, glabrous or rarely sparsely pubescent, densely to contiguously reddish-lepidote; flowers borne densely around rhachis but in nature all swept up to vertical position from ± horizontal rhachis, with long exserted stamens forming 'bottle-brush' syndrome. Flowers 4-merous, very variable in size and shape, 11-20.3 mm long, hairless on outside; lower hypanthium 3.3-4.3 mm long, 4-angled, pedicel-like region 0.6-1.5 mm long, contiguously reddish-lepidote,upper hypanthium variously shaped, infundibuliform to bucciniform, 6.3-16 x 3.5-7 mm, often swollen in region below disk and narrower above disk but flared near apex (below calyx lobes), 5.1-12 mm excluding calyx lobes, moderately to densely reddish-lepidote, sparsely to densely pubescent inside; calyx lobes erect, 1.2-4.3 mm long, apex acute to subacute, moderately to densely reddish-lepidote; petals 4, elliptic, 1.7-3.1 x 0.8-1.2 mm, usually falling well short of calyx lobes but sometimes reaching about to their apex, apex subacute to acute, base without claw, glabrous but sometimes sparsely lepidote outside; stamens 8, far exserted, filaments 18.5-29.5 mm long; disk densely pubescent at margin with straight hairs, distinct free margin 0.2-0.5 mm long; style 25.5-42 mm long, exserted about as far as stamens. Fruit moderately to densely reddish-lepidote especially on body, 2.2-3.9 x 1.3-2.8 cm, oblong to elliptic or broadly elliptic, apex rounded or truncate to deeply retuse and scarcely apiculate, base rounded or truncate to retuse, very distinct narrow pseudostipe 0.08-0.3 cm long, wings 4, 0.6-1.1 cm wide. Scales ca. 70-250(-275) µm diam., marginal cells ca. 35-70.
Guianas present, lower Amazon river-basin present
Centred on the Guianas and lower Amazon river-basin, extending more sparsely to W, N and S; about 117 specimens seen from the Guianas (GU: 49; SU: 35; FG: 33).
English (French Guiana): boso-oui, chigouma, pumalipe, pékéia; English (Guyana): firebrush, kuyari engayi, macaw comb, monkey comb, monkey toothbrush; English (Suriname): arimaka, baredaballi, bosowi, bosroe, jalimana, keskesbosro, keskeskankan, maribena, sekema, vreemoessoe-noto, yariman