Mentzelia albescens |
Mentzelia laevicaulis |
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wavy-leaf blazingstar |
blazing-star mentzelia, common blazing-star, giant blazing-star, smooth-stem blazingstar |
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Habit | Plants biennial, candelabra-form. | Plants biennial or perennial (in rosette stage), bushlike. | ||||
Stems | solitary, erect, straight; branches distal, distal longest, antrorse, straight; hairy. |
solitary, erect, straight; branches distal or along entire stem, proximal or distal longest, antrorse, upcurved; hairy or glabrescent. |
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Leaves | blade 31–92(–157) × 10.5–27.6(–41) mm, widest intersinus distance 5.2–23.3(–29) mm; proximal lanceolate or elliptic, margins serrate to pinnate, teeth or lobes 8–22, slightly antrorse, 1.8–6 mm; distal lanceolate, base clasping, margins usually serrate to pinnate, occasionally entire, teeth or lobes (0–)10–20, slightly antrorse, 1.4–7.6 mm; abaxial surface with simple grappling-hook, complex grappling-hook, and needlelike trichomes, adaxial surface with simple grappling-hook and needlelike trichomes. |
blade 17.4–196 × 6.7–40.4 mm, widest intersinus distance 2.4–24.6 mm; proximal oblanceolate, lanceolate, or elliptic, margins pinnate, lobes 14–44, slightly antrorse, 2.5–8.9 mm; distal lanceolate, base clasping or not, margins pinnate, lobes 6–42, slightly antrorse, 2.1–13.8 mm; abaxial surface with simple grappling-hook, complex grappling-hook, and needlelike trichomes, adaxial surface with needlelike trichomes. |
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Bracts | margins entire. |
margins entire or pinnate. |
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Flowers | petals golden yellow, 5.7–9.2 × 1.3–3 mm, apex usually acute, occasionally rounded, glabrous abaxially; stamens golden yellow, 5 outermost petaloid, filaments narrowly spatulate, slightly clawed, 4.7–8.4 × 1–2.4 mm, without anthers, second whorl with anthers; anthers straight after dehiscence, epidermis smooth; styles 3.5–5.4 mm. |
petals golden yellow, 23.5–70 × 3–17.3 mm, apex acute, glabrous abaxially; stamens golden yellow, 5 outermost not petaloid, filaments linear to narrowly elliptic, not clawed, 17.7–55 × 0.5–2(–2.5) mm, with anthers, second whorl with anthers; anthers straight after dehiscence, epidermis smooth; styles 20.4–57 mm. |
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Capsules | cylindric, 13.6–23.5 × 5.1–7.8 mm, base tapering, not or slightly longitudinally ridged. |
cup-shaped to cylindric, 10.6–43 × 6.3–11.1 mm, base tapering or rounded, not longitudinally ridged. |
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Seeds | coat anticlinal cell walls straight, papillae 4–17 per cell. |
coat anticlinal cell walls straight, papillae 4–11 per cell. |
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2n | = 22. |
= 22. |
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Mentzelia albescens |
Mentzelia laevicaulis |
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Phenology | Flowering May–Nov. | |||||
Habitat | Dry grasslands, xeric habitats of arroyos, roadsides, roadcuts, washes, chat piles, slopes. | |||||
Elevation | 200–1600 m. (700–5200 ft.) | |||||
Distribution |
KS; MO; OK; TX; South America (Argentina, Chile) |
AZ; CA; ID; MT; NV; OR; UT; WA; WY; BC
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Discussion | Phylogenetic analyses (J. J. Schenk and L. Hufford 2011) recovered representative populations of Mentzelia albescens from Texas and South America in a monophyletic group. Phylogenetic placement of these populations among lineages in sect. Bartonia, as well as a lack of morphological differentiation among North American and South American populations, suggests a recent dispersal to South America. In the flora area, this species is native to central and western Texas, and introduced in Kansas, Missouri, and Oklahoma. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Varieties 2 (2 in the flora). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 12, p. 518. | FNA vol. 12, p. 514. | ||||
Parent taxa | Loasaceae > Mentzelia > sect. Bartonia | Loasaceae > Mentzelia > sect. Bartonia | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | Bartonia albescens, B. wrightii | Bartonia laevicaulis | ||||
Name authority | (Gillies ex Arnott) Bentham & Hooker f. ex Grisebach: Abh. Königl. Ges. Wiss. Göttingen 19: 150. (1874) | (Douglas) Torrey & A. Gray: Fl. N. Amer. 1: 535. (1840) | ||||
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