Erect, glabrous, perennial, 10-13 cm. Stem simple, 4-angled. Leaves 15-3 x 1-2 mm; lanceolate-linear, glabrous, sessile, acute. Inflorescence lax, of few. flowered dichasial cymes. Bracts c. 3 mm, scarious. Pedicel long, slender. Sepals 4-5 mm, lanceolate, acute, with serious margins. Petals white, 1½-2 times length of the sepals, deeply bilobed into linear-oblong lobes. Capsule ¾th as long as the calyx. Seeds obscurely tuberculate.