Mentzelia decapetala |
Mentzelia argillosa |
|
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10-petal western star, evening starflower, gumbo-lily, tenpetal blazingstar |
Arapien blazingstar |
|
Habit | Plants biennial or perennial, bushlike, perennials with ground-level caudices. | Plants perennial, bushlike, with subterranean caudices. |
Stems | solitary, erect, straight; branches distal or along entire stem, proximal or distal longest, antrorse, straight to upcurved; hairy. |
multiple, erect, zigzag or straight; branches distal or along entire stem, distal longest or all ± equal, antrorse, straight; hairy. |
Leaves | blade 72–295 × 14–45 mm, widest intersinus distance 10.1–23.3 mm; proximal oblanceolate or elliptic, margins serrate to pinnate, teeth or lobes 16–26, slightly antrorse, 1–16.5 mm; distal elliptic to lanceolate, base clasping or not, margins serrate to pinnate, teeth or lobes 9–20, slightly antrorse, 5.3–13.7 mm; surfaces with needlelike trichomes. |
blade 15.4–40(–86) × 4–12.2 mm, always some more than 10 mm wide, widest intersinus distance 4–12.2 mm; proximal oblanceolate to spatulate, margins usually entire, rarely dentate, teeth 0(–4), perpendicular to leaf axis, 0.1–1 mm; distal oblanceolate, spatulate, or elliptic, base not clasping, margins usually entire, rarely dentate, teeth 0(–4), perpendicular to leaf axis, 0.3–1.4 mm; abaxial surface with simple grappling-hook, complex grappling-hook, and needlelike trichomes, adaxial surface with simple grappling-hook and needlelike trichomes. |
Bracts | margins pinnate. |
margins entire. |
Flowers | petals white, 47–75 × 13–22.7 mm, apex acute to attenuate, glabrous abaxially; stamens white to yellow, 5 outermost petaloid, filaments spatulate, strongly clawed, 48–75 × 12–23 mm, without anthers, second whorl with anthers; anthers straight after dehiscence, epidermis smooth; styles 36–53 mm. |
petals golden yellow, 8.2–12.2(–15.2) × 2.4–5 mm, apex acute, glabrous abaxially; stamens golden yellow, 5 outermost petaloid, filaments narrowly spatulate, slightly clawed, 5.6–11(–13.5) × 1.4–3 mm, with anthers, second whorl with anthers; anthers usually twisted after dehiscence, epidermis papillate; styles 5.5–9.4 mm. |
Capsules | cylindric, 30–43 × 12–17 mm, base tapering, not longitudinally ridged. |
cup-shaped, 5–8.4 × 3.1–6 mm, base tapering to rounded, not longitudinally ridged. |
Seeds | 2.3–4 mm; coat anticlinal cell walls straight, papillae 4–10 per cell. |
coat anticlinal cell walls straight, papillae 3–5 per cell. |
2n | = 22. |
= 22. |
Mentzelia decapetala |
Mentzelia argillosa |
|
Phenology | Flowering Jun–Aug(–Oct). | Flowering Jun–Aug. |
Habitat | Rock outcrops, slopes, dry short-grass prairies, riverbanks, roadsides, loam, limestone, sandy, silty, clayey, and gravelly soils. | Sparsely vegetated steep cliffs or slopes composed of gypsum-rich clayey and gravelly soils. |
Elevation | 300–2400 m. (1000–7900 ft.) | 1600–1900 m. (5200–6200 ft.) |
Distribution |
CO; IA; IL; KS; MN; MT; NE; NM; OK; SD; TX; UT; WY; AB; MB; SK
|
UT |
Discussion | Mentzelia decapetala is introduced in Grundy County, Illinois. It appears to be native throughout the rest of its distribution. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Mentzelia argillosa is endemic to the Arapien Shale formation in Sevier and Sanpete counties. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 504. | FNA vol. 12, p. 507. |
Parent taxa | Loasaceae > Mentzelia > sect. Bartonia | Loasaceae > Mentzelia > sect. Bartonia |
Sibling taxa | ||
Synonyms | Bartonia decapetala | Nuttallia argillosa |
Name authority | (Pursh) Urban: Ber. Deutsch. Bot. Ges. 10: 263. (1892) | J. Darlington: Ann. Missouri Bot. Gard. 21: 153. (1934) |
Web links |