Gard. Dict. ed. 8, Linum no. 8. 1768.
Herbs, biennial or short-lived perennial (flowering 1st year), 6–60 cm, glabrous. Stems erect, usually branched from near base and in inflorescence. Leaves: blade linear to linear-lanceolate, 5–25 × 1–1.5 mm. Inflorescences open panicles. Pedicels 10–25 mm. Flowers homostylous; sepals ovate, 4–5.5 mm, margins of inner sepals minutely ciliate, outer glabrous, apex acute to acuminate; petals blue, obovate, 6–10 mm; stamens 4–5 mm; anthers 1–2.5 mm; staminodia present or absent; styles distinct, 2 mm; stigmas linear or clavate. Capsules broadly ovate to subglobose, 4–6 × 4–6 mm, apex very sharp-pointed, segments ± persistent on plant, margins ciliate. Seeds 2.5–3 × 1.5–2 mm. 2n = 30.
Phenology: Flowering Mar–Aug.
Habitat: Grasslands, woodlands, disturbed places.
Elevation: 0–1900 m.
Introduced; B.C., Calif., Oreg., Pa., Europe, n Africa, introduced also in South America (Argentina, Chile), Pacific Islands (New Zealand).
Linum bienne is thought to be the progenitor of L. usitatissimum (D. J. Ockendon 1971).