Annual, erect or diffussed herbs; stem much branched from below, smooth, hispid or scabrid, branches 4-angled; leaves subsessile, linear-lancelate, obtuse, entire or subserrete, base tapering; flowers sessile or nearly so, in terminal or axillary whorls up to 2-3 cm in diameter; bracts nearly as long as the calyx linear, filiform, acute, tipped in a bristle, margins ciliate; calyx tubular, tube curved, constricted above, lower portion usually glabrous, upper half ribbed, hispid or scabrid; mouth small, glabrous, oblique, upper lip the largest; corolla white, about 1 cm long, widened and hairy above, upper lip densely woolly, lower lip twice as long as the upper one, midlobe obovate, larger than acute, laterals; stamens 4, didynamous, included in the upper lip of corolla, filaments glabrous, anthers 2-celled, connivent; disc symmetrical; ovary 4-lobed, style subulate 2-fid; posterior branch very short or obsolete; nutlets oblong triquetrous, obtuse with subtruncate apex, smooth, brown.