It is a perennial herb, 20-35 cm tall, with entire plant hairless, gray-green, rough along the stem edges, leaf margins, and midrib on the back, all with small milk protuberances. It has slender roots. The stems are tufted, erect, lower branches with four edges. The leaves are linear-lanceolate to linear, 2-4.5 cm long, 2-4 mm wide, pointed at the apex, slightly narrowed at the base, with short margin hairs, stalkless, pale green, hairless on both sides, and with a prominent midrib.
6-7月
It has dichasial cymes, with a peduncle 7-10 cm long; bracts lanceolate to narrowly ovate-lanceolate, (3-) 5-6 (-7) mm long, white on the edge, membranous; sepals ovate-lanceolate, (4-) 5-7 mm long, gradually pointed at the apex, membranous on the edge, with 3 obvious veins below; petals white, 4-7 mm long, deeply 2-lobed nearly to the base, equal to or slightly longer than sepals, lobes nearly linear, slightly narrowed at the base, blunt-pointed at the apex; stamens 10, slightly shorter than sepals; ovary ovate, with numerous ovules; styles 3, thread-like, 3 mm long.
It has an ovoid to oblong-ovoid capsule, slightly longer or nearly equal to persistent sepals, with numerous seeds; seeds are small, nearly round, slightly flattened, dark brown or blackish-brown, with distinct wrinkled convexities on the surface.