Small annual or perennial herbs. Stems erect, creeping, decumbent or prostrate, obscurely to distinctly quardangular. Leaves opposite, simple, sessile to petiolate, peninerved. Flowers small, solitary and axillary, terminal raceme or terminal and axillary racemes. Calyx shallowly to deeply 5-lobed, angles not winged. Corolla tubular, bilabiate; upper lip either entire or emarginated to shallowly 2-lobed, lower lip usually widely spreading 3-lobed, upper lip usually shorter than lower lip. Stamens 4, didynamous, all fertiles (except in V. cambodgiana, V. hookeri and V. molluginoides); posterior stamens fertile and affixed to corolla tube, anterior stamens fertile or sterile, but not reduced to staminodes; usually anterior filaments each with distinct spur or geniculum arising at or near the base; anthers free or contiguous, thecae divaricate. Ovary superior, subglobose to ellipsoid, glabrous (Only, scarbid hairs at upper part in V. cambodgiana and V. hookeri), bicarpelate with 2 locules, axial placenta with numerous ovules; style slender, erect; stigma bilamellate, flat. Fruits septicidal 2-valved capsules, globose, subglobose, ellipsoid or cylindric. Seeds numerous, scrobiculate (bothrospermous), variously shaped.