Annual; stems glabrous, procumbent, ascending or erect, not rooting at nodes. Lvs glabrous; petioles c. 5-30 mm long; leaflets obovate or obtriangular, acute, obtuse or slightly emarginate, mucronate, cuneate at base, finely serrate, c. 5-25 mm long; lateral veins slightly recurved or straight and slightly thickened toward leaflet margin; petiolules up to 1 mm long, ± equal; stipules ovate-oblong, acuminate. Infls axillary, racemose or umbellate, globose, pedunculate, ± = or somewhat > lvs; fls resupinate, numerous, rarely as few as 6 and umbellate, subsessile; bracts subtending fls much reduced, connate at infl. base. Calyx tomentose on upper side, moderately hairy when inflated, with c. 20 indistinct veins, greatly inflated on upper side at fruiting; throat open, ± glabrous; calyx teeth ± equal at flowering, erect at fruiting, < corolla; upper 2 teeth narrowly triangular, ± = tube, conspicuous on the inflated calyx; lower 3 teeth triangular; sinuses acute or obtuse. Corolla pink to reddish purple, persistent but ± enclosed by inflated calyx at fruiting, (4)-5-7 mm long. Pod glabrous, straight, < calyx, 2-3 mm long, 1-2-seeded; seeds c. 1-1.5 mm diam.