Corolla 5–8(10) mm. long, blue to white or yellow, deeply split into linear–lanceolate lobes, puberulous inside near the base, glabrous or shortly pubescent outside; tube 1–3·2 mm. long.
Leaves 3–20(35) x 0·3–2·5 mm., alternate, sessile, ± spreading, linear to linear–lanceolate, acute to subacute, glabrous or pubescent; margin ± incrassate, usually markedly denticulate.
Stems 0·1–1 m. long, usually many, ± decumbent and ascending, rarely erect, ± hirsute, puberulous or glab–rescent; hairs mostly retrorse; old sterns with persistent leaf–bases.
Ovary subinferior to semi–superior, 3–locular; style usually slightly longer than the corolla, thickened in the upper part, eglandular, hairy below; lobes 3, c. 0·6–1 mm. long.
Inflorescence lax or variously contracted; pedicels up to 20 mm. long, glabrous or shortly pubescent, or rarely flowers subsessile.
Seeds 0·4–0·6 mm. long, elliptic in outline, ± compressed or bluntly trigonous, usually very narrowly winged; testa almost smooth.
Calyx–lobes 1–5–5 mm. long, ± recurved and denticulate, glabrous or pubescent.
Stamens with filament–bases ± rhombic, ciliate; anthers 1·5–2·8 mm. long.
Hypanthium often broadly obconical, 10–nerved, glabrous or pubescent.
Perennial, rarely annual, often shrubby herb.
Capsule 3–locular, 10–nerved.