Linum australe |
Linum sulcatum |
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southern flax |
grooved flax, grooved yellow flax, lin à rameaux sillonnés |
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Habit | Herbs, annual, 10–50 cm, puberulent near base, otherwise glabrous. | Herbs, annual, 25–85 cm, glabrous. | ||||
Stems | stiffly ascending-spreading, few to many-branched. |
erect to ascending, unbranched proximally, few to many branches above middle, conspicuously sulcate. |
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Leaves | alternate, appressed; stipular glands present at basal nodes or throughout; blade linear, 7–20 × 0.5–l.9 mm, margins entire, not ciliate, apex aristate. |
proximal 0–13 pairs opposite (often fallen at anthesis), distal alternate, appressed-ascending; stipular glands usually present, very rarely absent; blade linear to narrowly lanceolate, 7–30 × 1–3 mm, margins entire, distal leaves not ciliate, apex acute to subulate; midrib prominent, marginal nerves less conspicuous. |
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Inflorescences | racemes. |
open panicles; bracts glandular-toothed, not ciliate. |
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Pedicels | 3–15 mm. |
1.3–4.7 mm. |
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Flowers | sepals deciduous, lanceolate to narrowly ovate, 4–7 mm, margins scarious, delicately glandular-toothed, apex aristate; petals yellow to yellow-orange throughout, oblanceolate to narrowly obovate, 5–10 mm; stamens (3–)4–7 mm; anthers 0.4–1 mm; staminodia present or absent; styles connate nearly to apex, 2–5.7 mm; stigmas green, capitate. |
sepals persistent, lanceolate, (3.1–)3.6–5(–7.3) mm, inner sepals more delicate than outer, shorter, margins not scarious, all very conspicuously glandular-toothed, apex acuminate, central and marginal veins conspicuous; petals pale yellow, obovate, 5–10 mm; stamens 3.3–5.7 mm; anthers 0.3–0.7 mm; staminodia absent; styles connate 0.2–1.8 mm at base, 2–4.5 mm; stigmas capitate. |
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Capsules | ovoid, 3.2–4.5 × 2.5–3.4 mm, relatively thick-walled and with characteristic thickened areas at apex in region of true septa, apex obtuse, dehiscing into 5, 2-seeded segments, segments persistent on plant, false septa complete, proximal part membranaceous, not terminating in loose fringe, distal part cartilaginous, margins ciliate. |
globose, 2.5–3.3 × 2.1–3 mm, apex rounded to acute, dehiscing freely into 10, sharp-pointed, 1-seeded segments; segments persistent on plant, false septa incomplete, margins prominently ciliate. |
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Seeds | 2–3 × 0.8–1.3 mm. |
1.6–2.1 × 0.8–1.1 mm. |
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2n | = 30. |
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Linum australe |
Linum sulcatum |
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Phenology | Flowering May–Sep. | |||||
Habitat | Sandy, gravelly fields, calcareous ledges and barrens, diabase barrens, cedar glades, prairies, alvars, sometimes in open woods, interdunal flats. | |||||
Elevation | 0–800 m. (0–2600 ft.) | |||||
Distribution |
AZ; CO; MT; NM; NV; TX; UT; WY; AB; Mexico
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AL; AR; CT; FL; GA; IA; IL; IN; KS; KY; LA; MA; MD; MI; MN; MO; MS; NC; ND; NE; NH; NJ; NY; OH; OK; PA; RI; SD; TN; TX; VA; VT; WI; WV; MB; ON; QC
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Discussion | Varieties 2 (2 in the flora). The stems of Linum australe are strongly ridged-sulcate to ribbed, especially distally. The corollas are broadly funnelform; petals are yellow to yellow-orange; stamens and styles are yellow; stigmas are bright to olive green. Staminodia in L. australe are short, deltoid, usually two between each pair of stamens, sometimes one or absent. Linum australe is the only species in its range that is glabrous beyond the base and has connate styles. It differs from L. aristatum, which it overlaps in the southern part of the range, in being much more highly branched and having more slender capsules. C. M. Rogers (1984) noted a compact form found in sunny areas from Wyoming northward that warrants more study. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Linum sulcatum and L. harperi are the only species of the genus in eastern North America with styles united from the base to the middle and all five sepals persistent and with glandular-toothed margins. In L. sulcatum, all parts of the flower are yellow and the corolla is funnelform. Dried plants of L. sulcatum are pale green. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 12, p. 390. | FNA vol. 12, p. 386. | ||||
Parent taxa | Linaceae > Linum > sect. Linopsis | Linaceae > Linum > sect. Linopsis | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | Cathartolinum sulcatum | |||||
Name authority | A. Heller: Bull. Torrey Bot. Club 25: 627. (1898) | Riddell: W. J. Med. Phys. Sci., 10. (1836) | ||||
Web links |