Perennial herbs, clambering or erect, 3.5-12.0 dm tall from a short rhizome; stems leafy, often profusely branched, rarely unbranched, terete or sometimes quadrangular, becoming suberous or subligneous in age, 2-6 mm thick, scattered-hirtellous, the nodes more densely so, the young lateral branches hoary-puberulent, soon glabrate. Leaves cauline, petiolate, undivided, elliptic to ovate or suborbicu-lar, usually somewhat truncate at the base, acute to acuminate or subcaudate, 4-12 cm long, entire or slightly dentate, sparsely to densely pilosulous or subcanescent, especially beneath; blades abruptly expanding, 3.0-10.5 cm long, 1.4-4.8 cm wide; petioles rarely equaling the blades, 1.0-5.6 cm long, sparsely to densely pilosulous or subcanescent. Inflorescences aggregate or compound dichasia, more or less pyramidal, the terminal branches 2.6-20.0 cm long, 4.5-16.0 cm wide in anthesis, later diffuse, 8.5-53.0 cm long, 7.5-20 cm wide, the nodes and internodes glabrous or spreading-pilosulous; bracts 1.54.0 mm long, reduced above, glabrous or hirtel-lous. Flowers white, gynodioecious; calyx limb 10-12-fid; corolla infundibuliform, in the perfect flowers 2.0-5.5 mm long, in the pistillate flowers 0.9-3.0 mm long, white to pale lavender, glabrous or hirtellous towards the base of the tube without, the lobes half as long as the gibbous tube, the throat sparsely pilosulous within; stamens and style exserted. Achenes linear-oblong, somewhat falcate, 2.0-3.5 mm long, 0.9-1.2 mm wide, glabrous, smooth, tawny to rubiginose or purpurascent, abaxial ribs evident.
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