Plants annual or biennial. Stems erect, simple or branched, 4-88 cm, often pubescent. Leaves: sheath 1-4 mm, 1-2 times as long as stem diam.; blade linear to narrowly oblanceolate, 2-10.5 cm, green, margins basally ciliate. Inflorescences usually open 3-6-flowered cymes or flowers some-times solitary; bracts linear, equaling or longer than calyx, herbaceous, apex acute; bracteoles 4, green, linear to lanceolate, 4-1 times as long as calyx, herbaceous, apex acute. Pedicels 0.1-3 mm. Flowers subsessile; calyx 20-25-veined, 11-20 mm, pubescent, lobes acuminate, 2-7 mm; petals reddish with white dots (rarely all white), bearded, 3-8(-10) mm, apex dentate. Capsules 10-16 mm, slightly shorter than calyx. Seeds 1.1-1.4 mm. 2n = 30 (Europe).