Stems 30-140 cm, glabrous. Leaves: petiole angled, 20-50 cm, proximally deeply grooved adaxially, densely pubescent in groove, otherwise glabrous or sparsely pubescent. Leaf blade 1-2-ternately compound; leaflets 3-9(-17); terminal leaflet of central segments broadly obovate, deeply 3-5-lobed, 9-30 × 9-25 cm, with 5-9 prominent veins arising basally, base deeply cordate, margins coarsely and irregularly dentate, apex sharply acuminate, surfaces abaxially with long, appressed, delicate hairs, adaxially glabrous; other leaflets 8-24 × 6-22 cm. Inflorescences erect panicles of 2-6 racemelike branches, terminal raceme 15-30 cm, puberulent to short-pubescent; bracts 3, subtending pedicel, central bract larger, lanceolate, 2 mm, lateral bracts ovate-deltate; pedicel to 5 mm, short-pubescent, bracteoles absent. Flowers: sepals 5, white; petals absent; stamens 35-65; filaments 3-5 mm; pistils 1(-2), sessile, sparsely glandular; style short, straight or slightly recurved; stigma minute, 0.2-0.3 mm wide. Follicles 1(-2), sessile, oblong, strongly compressed laterally, 8-20 mm, thin walled. Seeds reddish brown, lenticular, covering of scales giving cylindric appearance, ca. 3 mm, covered with reddish brown, membranous scales. 2n = 16.
