Linum trigynum

Herbs, annual, 10–50 cm, glabrous. Stems erect or spreading, few-branched. Leaves 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. Inflorescences panicles. Pedicels 1–5 mm. Flowers: 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. Capsules 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. Seeds 1.1 × 0.9–1 mm. 2n = 20.

Phenology: Flowering May–Jul.
Habitat: Grasslands.
Elevation: 100–200 m.

Introduced; Calif., s Europe, w Asia, n Africa, introduced also in Pacific Islands (Hawaii, New Zealand), Australia.

Discussion

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.

Selected References

None.

Lower Taxa