Linum usitatissimum
Linum trigynum
common flax, cultivated flax, flax-seed, lin cultivé, lin-seed
French flax
erect, unbranched or few-branched at base (all flowering).
erect or spreading, few-branched.
divergent;
blade linear to linear-lanceolate, 10–40 × 1.5–5 mm.
alternate, spreading to ascending;
stipular glands absent;
blade linear-lanceolate to narrowly elliptic, 5–10 × 1–1.5 mm, margins entire, not ciliate, apex acuminate.
open panicles.
panicles.
erect in fruit, to 20–25 mm.
1–5 mm.
homostylous;
sepals ovate, 6–9 mm, margins of inner sepals minutely ciliate, outer ciliate, apex acuminate;
petals usually blue, rarely white, obovate, 10–15 mm;
stamens 5–7 mm;
anthers 1–1.5 mm;
staminodia present;
styles distinct or connate at base, 3–6 mm;
stigmas linear or clavate.
sepals persistent, lanceolate to ovate, 3–4 mm, margins of inner sepals broadly scarious, densely glandular-ciliate, glandular-toothed, apex acuminate to setaceous;
petals lemon yellow, oblong to obovate, 4–6 mm;
stamens 1.5 mm;
anthers 0.3 mm;
staminodia present or absent;
styles distinct, 1 mm;
stigmas linear.
ovoid to subglobose, 6–10 × 5–10 mm, apex rounded, dehiscing incompletely, segments falling freely, margins ciliate or not.
subglobose, 2 mm diam., apex sharp-pointed (easily crushed), readily dehiscing into 5, 2-seeded segments, segments persistent on plant, false septa incomplete, margins of true septa ciliate.
4–6 × 2.5–3 mm.
1.1 × 0.9–1 mm.
= 30.
= 20.
Linum usitatissimum
Linum trigynum
Linum usitatissimum has been cultivated since antiquity, and it is this cultivated form that has naturalized in the wild. Flax fibers twisted to make rope or dyed for fabric dated 32,000–26,000 years before present were found in a cave in Dzudzuana, Georgia (E. Kvavadze et al. 2009). Stem fibers of L. usitatissimum are used to make linen; the seeds are pressed to produce linseed oil; the rest of the seeds are compacted into cakes and used as fodder. Linum usitatissimum is the only species in the flora area except L. bienne that has linear stigmas and minutely ciliate inner sepals. It can be distinguished from L. bienne by its larger, apically rounded capsules.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Linum trigynum is one of three species in sect. Linopsis subsect. Halolinum (Planchon) C. M. Rogers. This section is characterized as having separate styles, linear stigmas, and incomplete false septa. Linum trigynum is homostylous; the other two species, L. maritimum Linnaeus and L. tenue Desfontaines, are heterostylous. Two populations of L. trigynum have been reported in Sonoma County on the Jenner and Fort Ross State Historic Park headlands, both with hundreds of individuals and apparently persisting. Where native, the species sometimes occurs on serpentine soils, and it is reported as a weed in western Australia.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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