Erect or decumbent herb; stem simple or branched, ascending from the base; rooting at nodes; leaves sessile, glabrous, linear lanceolate, rarely ovate, subacute at apex, rounded or subcordate at base, sheaths bearded or sparsely hairy, ciliate at mouth; panicle short, subterminal, subcorymbose, few flowered cymes at the ends of the branches; sepals-3, free, oblong, obtuse, membranous; petals-3, free, equal, obovate, blue or purple; stamens 3-fertile, alternating with 3 staminodes, anthers oblong, usually 1-lobe smaller than other, filaments of fertile or all bearded, staminodes hastate or lobed at apex; ovary sessile, 3-locular, 1-2 ovules in each, style short, slender; capsule with purple streaks, oblong, acute at both ends, 6-seeded; seeds trigonous, rugose, pitted.