Leaves up to 15–60(80) x 1·5–10(15) mm., alternate, sessile, linear or narrowly lanceolate to lanceolate or elliptic, acute with truncate to cuneate base, ± hirsute especially on veins beneath, or glabrous; margin incrassate, dentate, often ± undulate; midvein prominent beneath, lateral veins less so, but usually clearly visible.
Inflorescence leafy, capitate, sometimes only a terminal head present, but usually also a number of smaller lateral sessile or pedunculate ones; flowers subsessile or rarely some flowers on pedicels up to 1·5 mm. long.
Ovary 3–locular, semi–inferior; style c. as long as or somewhat longer than the corolla, eglandular, slightly thickened in the upper part, glabrous below; lobes 3, 0·5–0·8 mm. long.
Corolla 5–6·5 mm. long, blue, white or mauve, split almost to the base into linear lobes, ± hirsute outside on the midvein or glabrous.
Stamens with filament–bases broadly dilated, sometimes almost cross–shaped, ciliate–pubescent; anthers 1·2–2·4 mm. long.
Annual or usually perennial (although probably often short–lived) ± erect herb, up to 1 m. tall, from a taproot.
Stem with long branches from near the base or unbranched, ± ribbed, hirsute at least below.
Seeds 0·5–0·8 mm. long, elliptic–oblong in outline, compressed; testa almost smooth.
Calyx–lobes 2·4–4 mm. long, ciliate–pubescent, rarely glabrous; margins incrassate.
Hypanthium obconical, ± 10–nerved, ± hirsute or rarely glabrous.
Capsule 3–locular, ± 10–nerved; valves 3, 1·5–2·5 mm. long.