Perennial herb, little branched; branches slender, glabrous or minutely hairy; leaves up to 8 cm long, broadly ovate, truncate or rounded at base, acuminate at apex, coarsely crenate, membranous, variously colored with yellow, red or purple; petioles up to 4 cm long; flowers small, in lax verticillasters in terminal racemes; calyx obliquely campanulate, upper tooth ovate, lateral teeth obtuse, lowest acute, throat glabrous within; corolla about 1 cm long, purplish blue or white, tube abruptly decurved, exserted, upper lip shorter; stamens-4, declinate, filaments connate below into a sheath around the style, glabrous, anther cells confluent; disc produced equaling or exceeding the ovary; 4-lobed ovary, style slender, stigma bifid; nutlets-4, orbicular, dry, ovoid or oblong, smooth, granulate or punctate.