Vines. Stems annual, climbing, branching, to 2.5 m, herbaceous, glabrous; prickles absent. Leaves: petiole thin, 1-6 cm; tendrils numerous, long, functional; blade oblong-ovate, ovate, or round, 4.5-12 × 3-9 cm, glabrous abaxially, base cordate to truncate, margins entire, apex obtuse to acute; proximal cauline leaves narrower and smaller. Umbels many, axillary to leaves, 20-100+-flowered, globose; peduncle to 30 cm, progressively shorter distally. Flowers: perianth greenish, carrion-scented; tepals 3.5-4.5 mm; anthers much shorter than filaments; ovules (1-)2 per locule; pedicel 0.5-2 cm. Berries blue, subglobose, ca. 10 mm diam., glaucous. 2n = 26. Flowering May--Jun. Higher elevations in rich woods, alluvial thickets, and meadows, often in calcareous soils; 100--800 m; N.B., Ont., Que; Ala., Ga., Ky., Maine, Md., Mass., N.H., N.Y., N.C., Ohio, Pa., S.C., Tenn., Vt., Va., W.Va. The leaves and habit of Smilax herbacea are quite variable.