Rhizomatous perennial; stems sparsely hairy below to moderately or densely hairy above, straggling to ascending, branching at regular angles, not rooting at nodes. Lvs usually moderately hairy on petioles and undersurface of leaflets, glabrous on upper surface; petioles up to c. 80 mm long; leaflets usually elliptic, sometimes ovate or obovate, obtuse or acute, cuneate at base, ± entire, often with a faint whitish spot toward base, c. 15-40 mm long; lateral vein thin or slightly thickened and somewhat recurved toward leaflet margin; petioles c. 1 mm long, ± equal; stipules ovate or ovate-oblong, acuminate. Infls terminal, spicate, ovoid to globose, shortly pedunculate, particularly at fruiting, ± = or > lvs; fls numerous, sessile; bracts 0. Calyx glabrous or sparsely hairy on tube but teeth hairy, 10-veined, not inflated at fruiting; throat open, with a ring of hairs; calyx teeth unequal, much < corolla, linear, spreading at fruiting; upper teeth < or ± = tube; lowest tooth up to 11/2× as long as other 4, > tube; sinuses obtuse. Corolla reddish purple, tardily deciduous, 12-18 mm long. Pod glabrous, straight, < calyx, c. 2 mm long, 1-seeded; seeds c. 1.5-2 mm diam.