Mentzelia decapetala |
Mentzelia montana |
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10-petal western star, evening starflower, gumbo-lily, tenpetal blazingstar |
mountain blazing-star, variegated-bract blazingstar |
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Habit | Plants biennial or perennial, bushlike, perennials with ground-level caudices. | Plants wandlike or candelabra-form, (5–)20–40(–50) 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 | persisting; petiole present or absent; blade lanceolate to linear, margins usually deeply to shallowly lobed, rarely entire. |
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Cauline leaves | petiole present or absent (proximal leaves), absent (distal leaves); blade lanceolate to linear (proximal leaves), ovate-lanceolate to linear (distal leaves), to 13 cm, margins deeply to shallowly lobed or entire. |
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Bracts | margins pinnate. |
usually green with prominent white base conspicuously extending outwards from midvein, rarely green, usually obovate, rarely lanceolate, 5.9–9.2 × 1.7–5 mm, width 1/5–2/3 length, not concealing capsule, margins usually 3–7-lobed, lateral lobes usually prominent, rarely 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. |
sepals 1–4; petals orange proximally, yellow distally, 2–6(–8) mm, apex retuse or rounded; stamens 20–40, 2–7 mm, filaments monomorphic, filiform, unlobed; styles 1.5–3.5(–6) mm. |
Capsules | cylindric, 30–43 × 12–17 mm, base tapering, not longitudinally ridged. |
cylindric or clavate, 6–17(–20) × 2–3 mm, axillary curved to 45° at maturity, usually inconspicuously longitudinally ribbed. |
Seeds | 2.3–4 mm; coat anticlinal cell walls straight, papillae 4–10 per cell. |
15–35, in 2+ rows distal to mid fruit, tan, moderately to densely dark-mottled, usually irregularly polygonal, occasionally triangular prisms proximal to mid fruit, surface tuberculate under 10x magnification; recurved flap over hilum absent; seed coat cell outer periclinal wall domed, domes on seed edges more than 1/2 as tall as wide at maturity. |
2n | = 22. |
= 36. |
Mentzelia decapetala |
Mentzelia montana |
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Phenology | Flowering Jun–Aug(–Oct). | Flowering Apr–Aug. |
Habitat | Rock outcrops, slopes, dry short-grass prairies, riverbanks, roadsides, loam, limestone, sandy, silty, clayey, and gravelly soils. | Open, disturbed slopes or flats, grasslands, sagebrush scrub, coniferous forests. |
Elevation | 300–2400 m. (1000–7900 ft.) | 600–3400 m. (2000–11200 ft.) |
Distribution |
CO; IA; IL; KS; MN; MT; NE; NM; OK; SD; TX; UT; WY; AB; MB; SK
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AZ; CA; CO; ID; NM; NV; OR; TX; UT; WA; WY; Mexico (Baja California)
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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 montana is widely distributed and, in portions of its range, difficult to distinguish from M. albicaulis. Mentzelia montana is morphologically intermediate to M. albicaulis and M. congesta, but ecologically more similar to M. congesta (J. M. Brokaw 2009). Mentzelia montana generally occurs at higher elevations than M. albicaulis and is best distinguished morphologically from M. albicaulis by capsule and bract characteristics. Capsules of M. montana are usually not longer than 17 millimeters or curved more than 45°, whereas those of M. albicaulis are often longer and more curved. Both species may have bracts with some lobes and whitish base, but only M. montana has populations in which these features are prominent. Sepal and petal lengths, which have sometimes been used to distinguish these species, overlap completely. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 504. | FNA vol. 12, p. 539. |
Parent taxa | Loasaceae > Mentzelia > sect. Bartonia | Loasaceae > Mentzelia > sect. Trachyphytum |
Sibling taxa | ||
Synonyms | Bartonia decapetala | Acrolasia montana |
Name authority | (Pursh) Urban: Ber. Deutsch. Bot. Ges. 10: 263. (1892) | (Davidson) Davidson: in A. Davidson and G. L. Moxley, Fl. S. Calif., 240. (1923) |
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