Linum rupestre |
Linum rigidum |
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rock flax |
stiffstem flax |
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Habit | Herbs, perennial, 20–75 cm, glabrous or rarely sparsely hairy proximally. | Herbs, annual, 15–50 cm, glabrous throughout or puberulent near base of stem. | ||||
Stems | erect, branched at base and in inflorescence. |
erect, branches few, fastigiate or spreading-ascending. |
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Leaves | opposite near base or alternate throughout, appressed-ascending; stipular glands present; blade linear to linear-lanceolate, 8–20 × 0.5–2.1 mm, margins entire or with scattered minute marginal glands, not ciliate, apex acute; 1-nerved. |
alternate, erect; stipular glands present or absent; blade linear, 11–30 × 0.7–1.6 mm, margins entire or distally sparsely toothed, not ciliate, apex acute. |
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Inflorescences | panicles, with ascending to spreading branches. |
panicles or cymes. |
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Pedicels | 0–3 mm. |
4.5–9 mm. |
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Flowers | sepals persistent, lanceolate to ovate, 2.5–5 mm, margins of inner sepals narrowly scarious, conspicuously glandular-toothed, apex acute or acuminate; petals lemon yellow, oblanceolate or narrowly obcordate, 7–11 mm; stamens 2–8 mm; anthers 0.5–1 mm; staminodia present; styles distinct, 3–6.5 mm; stigmas capitate. |
sepals deciduous, lanceolate to broadly lanceolate, 5.5–9.5 mm, margins of inner sepals conspicuously scarious, all conspicuously glandular-toothed, apex sharply acute to acuminate; petals coppery yellow or orange, red-lined or with short pale to deep brown-red zone at base, obovate with short claw, 6–18 mm; stamens 6–8 mm; anthers 1–1.8(–2.3) mm; staminodia absent; styles connate nearly to apex, 3–11 mm; stigmas pale, capitate. |
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Capsules | ovoid, 2–3 × 2–2.5 mm, apex sharp-pointed, dehiscing readily into 10, 1-seeded segments, segments falling freely, false septa incomplete, false and true septa margins ciliate. |
ellipsoid, 3.5–4.5 × 2.6–3.4 mm, apex obtuse, dehiscing into 5, 2-seeded segments, segments blunt or subacute, persistent on plant, false septa complete, proximal part membranaceous, not terminating in loose fringe, distal part cartilaginous, margins not ciliate. |
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Seeds | 1.2–1.9 × 0.7–1.1 mm. |
2.6–3.6 × 0.9–1.2 mm. |
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2n | = 36. |
= 30. |
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Linum rupestre |
Linum rigidum |
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Phenology | Flowering Apr–Aug. | |||||
Habitat | Sandy soils, rocky slopes and ledges, often on limestone. | |||||
Elevation | 150–1500 m. (500–4900 ft.) | |||||
Distribution |
NM; TX; Mexico (Chihuahua, Coahuila, Durango, Nuevo León); Central America (Guatemala)
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AR; CO; IA; IL; KS; MN; MO; MT; ND; NE; NM; OK; SD; TX; WI; WY; AB; MB; SK; n Mexico
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Discussion | Linum rupestre has narrowly funnelform corollas and yellow stamens and styles. The anthers and stigmas are held closely adjacent at the mouth of the corolla tube, below the broad, spreading limbs. The species occurs from southeastern New Mexico and central Texas to Guatemala. It often grows with L. schiedeanum in Texas and Mexico. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Varieties 2 (2 in the flora). The corollas of Linum rigidum are funnelform at the base, opening out into a broader bowl. The styles and stamens are yellow, although the distinct portion of the style may be slightly maroon; the stigmas are grayish or light green. The stems of L. rigidum are angled. Its capsule walls are so thin that the dark seeds can be seen through them. C. M. Rogers (1984) noted that L. australe, L. berlandieri, L. compactum, and both varieties of L. rigidum are closely related, and that there is some overlap in character expressions, not easily resolved in a dichotomous key. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 12, p. 381. | FNA vol. 12, p. 391. | ||||
Parent taxa | Linaceae > Linum > sect. Linopsis | Linaceae > Linum > sect. Linopsis | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Name authority | Engelmann ex A. Gray: Boston J. Nat. Hist. 6: 232. (1850) | Pursh: Fl. Amer. Sept. 1: 210. (1813) | ||||
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