Description: Erect herbs, glabrous or almost so.
Leaves alternate, entire, sessile; stipules absent.
Inflorescence terminal, cymes, usually forming corymbs. Sepals 5, free, persistent in fruit. Petals 5, not persistent in fruit. Stamens 5, alternating with 5 staminodes; filaments united at base. Ovary usually 5-locular; 2 ovules in each loculus; styles 5, free or united.
Capsule ± globose to ovoid, dehiscing by 10 valves; topped by persistent styles; seeds 10.
Distribution and occurrence: World: 230 species, subtropical & temperate regions, especially Mediterranean region. Australia: 6 species (2 species native), all States except N.T.
This genus is economically important as the source of flax, linseed oil and oil-cake from L. usitatissimum L.
Text by C. L. Gardner Taxon concept:
| Key to the species | |
1 | Petals blue or white, more than 7 mm long; pedicels more than 10 mm long; capsules more than 3 mm diam | 2 |
| Petals yellow, less than 7 mm long; pedicels less than 10 mm long; capsules less than 3 mm diam | Linum trigynum |
2 | Perennial; leaves usually less than 20 mm long, rarely to 30 mm, less than 3 mm wide; styles united above middle; capsules 4–6 mm diam | Linum marginale |
| Annual; leaves mostly more than 20 mm long, ± 3 mm wide; styles free; capsules 6–9 mm diam Back to 1 | Linum usitatissimum |
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