Tree 3-60 m (? deciduous or evergreen), sometimes with large plank buttresses. Leaves chartaceous to subcoriaceous, obovate or obovate-oblong to oblanceolate, 9-22 x 4-10 cm, apex acuminate, base narrowly cuneate, pubescent when young then glabrous or nearly so when mature above, densely pubescent when young then subglabrous to sparsely pubescent when mature below; domatia absent; venation eucamptodromous or eucamptodromous-brochidodromous, midvein moderate, prominent, secondary veins 5-8(-10) pairs, distant, originating at moderately to widely acute angles, curved, prominent, intersecondary veins present; tertiary veins irregularly percurrent; higher order veins usually distinct; areolation large, well-developed to imperfect, slightly prominent; petiole 1.5-4.5 cm long, pubescent when young, becoming glabrous or ± so, usually biglandular. Inflorescence 7-14 cm long, simple, all flowers bisexual; peduncle 1.5-3 cm long, glabrous to sparsely pubescent; rhachis 5.5-11 cm long, glabrous to sparsely pubescent. Flowers 5-merous, 4-6 x 4-5.5 mm; lower hypanthium 2-3 mm long, very sparsely appressed-pubescent to tomentose with rufous hairs, upper hypanthium campanulate, 1.5-2 mm long, glabrous to sparsely pubescent; calyx lobes revolute, 1.5-2 mm long, glabrous to sparsely pubescent; stamens 4-6 mm long; disk villous; style 5-6 mm long, villous in basal half. Infructescence with usually few fruits, disposed along whole length or mostly near apex of rhachis; fruits glabrous, 2.5-4.5 x 2-4.5 cm, strongly flattened, suborbicular to very broadly elliptic or obtriangular in side view, apex rounded, emarginate or apiculate, base rounded to cuneate (not pseudostipitate), wings 2, stiff, equal, 7-15 mm wide, markedly thickened with spongy material adjacent to body and for most way to margin (thin part of wing only ca. 4-6 mm wide), rounded to strongly angled laterally (the angle nearer the fruit apex), body 0.6-1.2 cm wide but appearing much wider due to thickened base of wings, often 1-2-ridged on 1 face and slightly grooved on other.