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blue flax, Lewis blue flax, Lewis' flax, Lewis' or wild blue flax, prairie flax, western blue flax, wild blue flax

French flax

Habit Herbs, perennial, 5–80 cm, glabrous or glabrate throughout, ± glaucous. Herbs, annual, 10–50 cm, glabrous.
Stems

erect to spreading or ascending, branched from near base and in inflorescence.

erect or spreading, few-branched.

Leaves

blade linear to linear-lanceolate or linear-oblanceolate, 5–30 × 0.5–3(–4.5) 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.

Inflorescences

open panicles or racemes.

panicles.

Pedicels

5–20 mm.

1–5 mm.

Flowers

homostylous;

sepals elliptic or elliptic-ovate, 3.5–6 mm, margins glabrous, apex acute;

petals usually blue, sometimes white, base whitish or yellowish, cuneate-obovate, 6–23 mm;

stamens 3–10 mm;

anthers 1–2.2 mm;

staminodia present;

styles distinct, 2–12 mm;

stigmas thickened ellipsoid-capitate.

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

ovoid globose, 4–8 × 5–6 mm, apex acute, segments ± persistent on plant, margins arachnoid-ciliate.

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

2.5–5 × 1.5–3 mm.

1.1 × 0.9–1 mm.

2n

= 18.

= 20.

Linum lewisii

Linum trigynum

Phenology Flowering May–Jul.
Habitat Grasslands.
Elevation 100–200 m. (300–700 ft.)
Distribution
from FNA
AK; AR; AZ; CA; CO; ID; KS; LA; MN; MO; MT; ND; NE; NM; NV; OK; OR; SD; TX; UT; WA; WV; WY; AB; BC; MB; NT; NU; ON; QC; SK; YT; n Mexico
[WildflowerSearch map]
[BONAP county map]
from FNA
CA; s Europe; w Asia; n Africa [Introduced in North America; introduced also in Pacific Islands (Hawaii, New Zealand), Australia]
[BONAP county map]
Discussion

Varieties 3 (3 in the flora).

Linum lewisii grows in many habitats in western North America from northern Mexico to Alaska east to the Great Plains in the United States and to the west side of Hudson and James bays in Canada; it appears to be less common in the Great Basin. A component of wildflower seed mixes, the species may be expanding its range. Some authors have considered it conspecific with L. perenne, and many collections in herbaria are identified as L. perenne without an indication of variety; they are most likely L. lewisii var. lewisii (D. J. Ockendon 1971; C. M. Rogers 1984). Because of the prevalence of L. bienne, L. perenne, and L. usitatissimum in bird seed and wildflower mixes, it may be that these three non-natives are becoming more common than in the past. Capitate stigmas distinguish L. lewisii from L. bienne and L. usitatissimum, which have linear or clavate stigmas. Distinguishing L. lewisii from L. perenne is more difficult: the size of flower parts in the homostyled L. lewisii varies along elevational and latitudinal gradients, with smaller flowers and flower parts in higher elevations and higher latitudes; except in var. lepagei, the styles are always longer than the stamens. In the heterostyled L. perenne, populations usually include plants in which flowers have stamens much longer than the very short styles (short-styled form) and plants in which flowers have stamens much shorter than the very long styles, up to twice as long as the stamens (long-styled form).

C. A. Kearns and D. W. Inouye (1994) reported that Linum lewisii is facultatively autogamous but tends not to set seed in the absence of pollinators; small bees and flies are the most common pollinators. A. Cronquist et al. (1997b) reported unusual populations of L. lewisii on sandy soil in Nye County, Nevada, in the 40-Mile-Canyon drainage, that had persistent, ascending, pale blue petals with darker veins.

(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.)

Key
1. Petals mostly white; Hudson and James Bay regions.
var. lepagei
1. Petals usually blue; w North America.
→ 2
2. Petals (8–)12–23 mm; styles 6–12 mm.
var. lewisii
2. Petals 6–13 mm; styles 2–6 mm.
var. alpicola
Source FNA vol. 12, p. 375. FNA vol. 12, p. 394.
Parent taxa Linaceae > Linum > sect. Linum Linaceae > Linum > sect. Linopsis
Sibling taxa
L. alatum, L. allredii, L. arenicola, L. aristatum, L. australe, L. berlandieri, L. bienne, L. carteri, L. catharticum, L. compactum, L. elongatum, L. floridanum, L. grandiflorum, L. harperi, L. hudsonioides, L. imbricatum, L. intercursum, L. kingii, L. lundellii, L. macrocarpum, L. medium, L. neomexicanum, L. perenne, L. pratense, L. puberulum, L. rigidum, L. rupestre, L. schiedeanum, L. striatum, L. subteres, L. sulcatum, L. trigynum, L. usitatissimum, L. vernale, L. virginianum, L. westii
L. alatum, L. allredii, L. arenicola, L. aristatum, L. australe, L. berlandieri, L. bienne, L. carteri, L. catharticum, L. compactum, L. elongatum, L. floridanum, L. grandiflorum, L. harperi, L. hudsonioides, L. imbricatum, L. intercursum, L. kingii, L. lewisii, L. lundellii, L. macrocarpum, L. medium, L. neomexicanum, L. perenne, L. pratense, L. puberulum, L. rigidum, L. rupestre, L. schiedeanum, L. striatum, L. subteres, L. sulcatum, L. usitatissimum, L. vernale, L. virginianum, L. westii
Subordinate taxa
L. lewisii var. alpicola, L. lewisii var. lepagei, L. lewisii var. lewisii
Synonyms L. perenne subsp. lewisii, L. perenne var. lewisii L. gallicum
Name authority Pursh: Fl. Amer. Sept. 1: 210. (1813) Linnaeus: Sp. Pl. 1: 279. (1753)
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