Erect, annual herb, prostrate or spreading; stem terete, glabrous, rarely scaberulous, rooting at lower nodes; leaves subsessile, small, linear or linear-lanceolate, acute; stipules small, membranous, acute or bristly; flowers small, white or pink in axillary, pedunculate, corymbose or umbellate 3-8 flowered cymes; calyx pubescent, teeth 4, subulate rather shorter then tube; corolla salver shaped, tube slender, lobes-4, ovate oblong, valvate; stamens 4, epipetalous;, inserted on the throat of corolla; ovary 2 locular, ovules many, placenta attached to septum, style filiform, stigma 2-fid, linear; capsules globose or obvoid, didynamous, crown not raising above the base of calyx teeth opening at the apex; seeds pale-brown, angular.