Annual herb. Stem usually branching from below middle, with 2–4 internodes below branches, 5–25 cm high. Basal leaves absent at flowering. Stem leaves sessile, ovate to lanceolate, becoming longer upwards, 5–15 mm long, 2–10 mm wide, acute. Inflorescence a rather open, regularly-branched, dichasium; branches erecto-patent, divergent from axis at up to 45°; pedicels 1–5 (–10) mm long. Flowers (4-or) 5-merous, c. 5–8 mm diam. Calyx lobes to 7 mm long. Corolla bright rose pink, rarely white; tube c. 6–10 mm long, not narrowly constricted; lobes c. 3–4.5 mm long. Stamens (4 or) 5; anthers c. 1–1.2 mm long, rarely more. Ovary c. 7 mm long; style c. 1–2 mm long; stigmas ±capitate. Capsule c. 8–10 mm long. Seeds 0.15–0.25 mm diam., reticulate, light to dark reddish brown, sub-translucent.
Annual, much branched, often from the base, to 2 dm, without a rosette; principal lvs sessile, lanceolate or lance-ovate, 1–2 cm; infl many-fld, comparatively dense, with short internodes; pedicels mostly 3–5 mm; cal ca 9 mm; cor-tube slightly exceeding the cal, its lobes pink, 4 mm; anthers oval, under 1 mm, not coiled; 2n=36. Native of Eur., locally intr. in fields and waste places in our range. June–Sept.
A herb.