Herbs, annual, biennial, or perennial. Stems usually terete (ridged in L. grandiflorum). Leaves alternate; stipular glands absent; blade margins entire, not glandular-toothed. Flowers homostylous or heterostylous; sepals persistent, margins scarious, entire, not glandular-toothed; petals usually blue or red to maroon, rarely white; staminodia present or absent; styles distinct, connate basally or to midlength; stigmas capitate, clavate, or linear. Capsules dehiscing into 10, 1-seeded segments; false septa incomplete. Pollen tricolpate.

Distribution

North America, Mexico, Eurasia, n Africa, Pacific Islands (New Zealand), Australia, introduced in s South America.

Discussion

Species ca. 50 (6 in the flora).

Selected References

Mosquin, T. 1971. Biosystematic studies in the North American species of Linum, section Adenolinum (Linaceae). Canad. J. Bot. 49: 1379–1388.

Lower Taxa

Linum bienne, Linum grandiflorum, Linum lewisii, Linum perenne, Linum pratense, Linum usitatissimum

Key

1	Petals bright red to maroon, fading to purple.	Linum grandiflorum
1	Petals usually blue, rarely white.	> 2
2	Stigmas linear or clavate; margins of inner sepals minutely ciliate.	> 3
3	Annuals; petals 10–15 mm; capsules 6–10 mm, apices rounded; seeds 4–6 mm.	Linum usitatissimum
3	Biennials or short-lived perennials; petals 6–10 mm; capsules 4–6 mm, apices very sharp-pointed; seeds 2.5–3 mm.	Linum bienne
2	Stigmas capitate or ellipsoid-capitate, margins of inner sepals glabrous.	> 4
4	Flowers heterostylous.	Linum perenne
4	Flowers homostylous.	> 5
5	Perennials; styles 2–12 mm, capsule apices acute.	Linum lewisii
5	Annuals; styles 1–3 mm; capsule apices obtuse.	Linum pratense