Glabrous annual, 30-75 cm. Stems erect, usually branching from base. Branches rigid, strict. Leaves up to 10 x 0.2-0.6 cm., linear, scabrous, narrowly scarious-margined, the upper narrower. Inflorescences many-flowered, branched, sometimes corym¬bose. Pedicels shorter to longer than calyx. Flowers terminal. Epicalyx composed of 4 ovate, white-margined scales tapering into awns, about of same length or longer than calyx. Calyx 1.2-1.5 cm.; tube nerveless, densely and finely tuberculate; teeth shorter than tube, lanceolate, striate, scarious at apex. Petals about 1.5-1.8 cm., cuneate-oblong; limb pink, 4-6-dentate, glabrous or slightly hairy at base. Capsule shorter than calyx. Seeds black, finely tuberculate. Fl. April-July.