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
Lower Taxa
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 |