Linum usitatissimum
Common flax
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Family: Linaceae · Type: Herb · Not Native
Linum usitatissimum (Common flax) is a non-native California herb in the Linaceae family, recognized by tall stature and large sepals distinguish from other blue-flowered species.
Common flax is a naturalized annual herb found in northwestern California, Sierra Nevada foothills, Central Valley, central and southern coastal areas, and southern deserts in disturbed areas and abandoned agricultural sites at elevations below 1,000 meters. Flowering from April to May, this plant produces distinctive blue (occasionally white) flowers with petals 10 to 15 millimeters long. Growing 20 to 100 centimeters tall with smooth, upright stems, it develops an elegant, slender form. Its leaves are narrow and linear to lance-shaped, alternately arranged along the stem and measuring 10 to 40 millimeters in length. The fruit is a capsule approximately 5 to 10 millimeters wide, containing brown seeds 4 to 6 millimeters long.
Identification and appearance
Key characters: 5 sympatric species; tall stature and large sepals distinguish from other blue-flowered species
Habitat and range
Habitat: Disturbed areas, abandoned cultivated sites
Elevation: < 1000 m
Outside California: Sporadic worldwide, native to Eurasia
Bloom period
Linum usitatissimum blooms Apr-May.
How to tell it apart
vs Nemophila: Linum has 5 separate styles; Nemophila has 1-2 styles.; vs Leptosiphon: Linum has 5 styles and no petal tube; Leptosiphon has 3 styles and fused petals forming a tube.; vs Pelargonium: Linum has 5 equal styles and radial flowers; Pelargonium has fused styles and bilateral flowers.; vs Papaver: Linum has 5 distinct styles; Papaver has a disc-like stigma with no separate styles.; vs Gilia: Linum has 5 separate styles; Gilia has 3 styles and tubular fused petals.
Frequently asked questions
Is Linum usitatissimum native to California?
No. Linum usitatissimum is not native to California (recorded as not native).
When does Linum usitatissimum bloom?
Linum usitatissimum blooms Apr-May.
What plant family does Linum usitatissimum belong to?
Linum usitatissimum is in the Linaceae family, genus Linum.
What habitat does Linum usitatissimum grow in?
Linum usitatissimum grows in Disturbed areas, abandoned cultivated sites.
Related species
Other California species in the same genus, family, or bioregion.
- Linum bienne — Narrow leaved flax
- Linum grandiflorum — Flowering flax
- Linum lewisii var. lewisii — Lewis' flax
- Linum puberulum — Plains flax
- Linum sp. — Flax
- Linum trigynum — French flax
- Sclerolinon digynum — Digynum flax
- Sclerolinon sp.
- Hesperolinon adenophyllum — Glandular western flax
- Hesperolinon bicarpellatum — Two-carpellate western flax
Sources: Jepson eFlora · CalPhotos
Last updated 2026-10-07
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.