Mentzelia nitens |
Mentzelia uintahensis |
|
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shining blazing star, Venus blazingstar |
Uintah blazingstar |
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Habit | Plants candelabra-form, 5–20(–35) cm. | Plants perennial, bushlike, with subterranean caudices or rhizomes. |
Stems | multiple, erect, zigzag or straight; branches distal or along entire stem, distal longest or all ± equal, antrorse, upcurved; hairy. |
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Leaves | blade 17–56 × 5.8–28 mm, widest intersinus distance 1–4.9(–6) mm; proximal oblanceolate to elliptic, margins pinnate to pinnatisect, lobes 4–12, antrorse, 1.9–7.7 mm; distal elliptic to lanceolate, base not clasping, margins pinnate to pinnatisect, lobes 4–12, antrorse, 2.6–13.3 mm; abaxial surface with simple grappling-hook and occasionally complex grappling-hook and needlelike trichomes, adaxial surface with simple grappling-hook and 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 absent; blade ovate-lanceolate to linear, to 15 cm, margins deeply to shallowly lobed or entire. |
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Bracts | green, lanceolate, 4.5–8.3 × 1.2–3.6 mm, width 1/5–1/2 length, not concealing capsule, margins entire. |
margins entire. |
Flowers | sepals 3–8 mm; petals yellow to orange proximally, yellow distally, (7–)8–18 mm, apex rounded or acute apex; stamens 20+, 3–8 mm, filaments monomorphic, filiform, unlobed; styles 4–8 mm. |
petals golden yellow, 8.5–15.2 × 3.8–7.9 mm, apex acute to rounded, glabrous abaxially; stamens golden yellow, 5 outermost petaloid, filaments broadly spatulate, strongly clawed, 5–10.4 × 2.8–6 mm, with anthers, second whorl with anthers; anthers usually twisted after dehiscence, epidermis smooth; styles 5.8–8.5 mm. |
Capsules | clavate, 13–26 × 2–3.5 mm, axillary curved to 180° at maturity, usually inconspicuously longitudinally ribbed. |
cup-shaped, 4.2–8.8 × 3.6–5.8 mm, base tapering to rounded, not longitudinally ridged. |
Seeds | 15–40, in 2+ rows distal to mid fruit, tan, usually dark-mottled, usually irregularly polygonal, occasionally triangular prisms proximal to mid fruit, surface colliculate under 10x magnification; recurved flap over hilum usually present; seed coat cell outer periclinal wall domed, domes on seed edges less than 1/2 as tall as wide at maturity. |
coat anticlinal cell walls straight, papillae 4–7 per cell. |
2n | = 18. |
= 22. |
Mentzelia nitens |
Mentzelia uintahensis |
|
Phenology | Flowering Apr–Jun. | Flowering May–Sep. |
Habitat | Sandy washes, rocky slopes, desert scrub. | Sparsely vegetated steep talus slopes and roadcuts. |
Elevation | 400–2000 m. (1300–6600 ft.) | 1500–2800 m. (4900–9200 ft.) |
Distribution |
CA; NV
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CO; UT |
Discussion | Mentzelia nitens is similar to both M. eremophila and M. jonesii but exhibits little distributional overlap with either species. See 71. M. eremophila and 73. M. jonesii for discussion of similarities. Reports of M. nitens from Arizona are based on specimens treated here as M. jonesii. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Mentzelia uintahensis is known from northwestern Colorado (Rio Blanco, Mesa, and Moffat counties) and northeastern Utah (Carbon, Duchesne, and Uintah counties). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 540. | FNA vol. 12, p. 510. |
Parent taxa | Loasaceae > Mentzelia > sect. Trachyphytum | Loasaceae > Mentzelia > sect. Bartonia |
Sibling taxa | ||
Synonyms | M. multicaulis var. uintahensis | |
Name authority | Greene: Fl. Francisc., 234. (1891) | (N. H. Holmgren & P. K. Holmgren) J. J. Schenk & L. Hufford: Novon 19: 120. (2009) |
Web links |