Mentzelia decapetala |
Mentzelia tridentata |
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10-petal western star, evening starflower, gumbo-lily, tenpetal blazingstar |
creamy blazing star, dentate blazing star, threetooth blazingstar |
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Habit | Plants biennial or perennial, bushlike, perennials with ground-level caudices. | Plants 5–25 cm. |
Stems | solitary, erect, straight; branches distal or along entire stem, proximal or distal longest, antrorse, straight to upcurved; hairy. |
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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. |
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Basal leaves | petioles present; blade lanceolate, to 9 cm; margins shallowly lobed, lobes rounded. |
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Cauline leaves | petioles present, rarely absent, present in distalmost leaves; blade broadly ovate to lanceolate, to 9 cm, base not cordate-clasping, margins dentate to serrate. |
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Bracts | margins pinnate. |
green, inconspicuous, not concealing pedicel, ovary, or capsule. |
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 white to pale yellow, obovate, 10–40 mm, apex mucronate; stamens 6–15 mm, less than 1/2 petal length, all fertile, none petaloid (flowers appearing to have 5 petals); filaments ± monomorphic, linear, most or all distally 2-lobed, lobes 0.1–0.7 mm; anther stalk longer than or equal to filament lobes; style 9–13 mm. |
Capsules | cylindric, 30–43 × 12–17 mm, base tapering, not longitudinally ridged. |
cylindric to ovoid, 9–18 × 5–8 mm, basal nodding, distal erect. |
Seeds | 2.3–4 mm; coat anticlinal cell walls straight, papillae 4–10 per cell. |
widest at middle, not grooved; seed coat anticlinal cell walls straight or wavy. |
2n | = 22. |
= 20. |
Mentzelia decapetala |
Mentzelia tridentata |
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Phenology | Flowering Jun–Aug(–Oct). | Flowering Apr–May. |
Habitat | Rock outcrops, slopes, dry short-grass prairies, riverbanks, roadsides, loam, limestone, sandy, silty, clayey, and gravelly soils. | Sandy or gravelly slopes, washes, desert scrub. |
Elevation | 300–2400 m. (1000–7900 ft.) | 600–1300 m. (2000–4300 ft.) |
Distribution |
CO; IA; IL; KS; MN; MT; NE; NM; OK; SD; TX; UT; WY; AB; MB; SK
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CA |
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 tridentata is known from the central and western Mojave Desert in Inyo, Kern, and San Bernardino counties. See 55. M. tricuspis for comparison with M. tridentata. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 504. | FNA vol. 12, p. 526. |
Parent taxa | Loasaceae > Mentzelia > sect. Bartonia | Loasaceae > Mentzelia > sect. Bicuspidaria |
Sibling taxa | ||
Synonyms | Bartonia decapetala | Acrolasia tridentata, M. tricuspis var. brevicornuta |
Name authority | (Pursh) Urban: Ber. Deutsch. Bot. Ges. 10: 263. (1892) | (Davidson) H. J. Thompson & J. E. Roberts: Phytologia 21: 287. (1971) |
Web links |