Mentzelia decapetala |
Mentzelia mollis |
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10-petal western star, evening starflower, gumbo-lily, tenpetal blazingstar |
smooth blazingstar, smooth stick-leaf, soft blazingstar |
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Habit | Plants biennial or perennial, bushlike, perennials with ground-level caudices. | Plants candelabra-form, 3–15(–20) 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 | not persisting. |
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Cauline leaves | petiole present (proximal leaves), absent (distal leaves); blade lanceolate to linear (proximal leaves), ovate to lanceolate (distal leaves), to 6 cm, margins dentate or entire (proximal leaves), entire (distal leaves). |
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Bracts | margins pinnate. |
green, ovate to elliptic, 5–8.5 × 2–5 mm, width 2/5–3/5 length, not concealing capsule, 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. |
sepals 3–5.5 mm; petals yellow to orange proximally, yellow distally, 8–12 mm, apex rounded; stamens 20+, 3–8 mm, filaments monomorphic, filiform, unlobed; styles 7–9 mm. |
Capsules | cylindric, 30–43 × 12–17 mm, base tapering, not longitudinally ridged. |
cylindric or clavate, 5–22 × 2–4 mm, axillary curved to 45° at maturity, often prominently longitudinally ribbed. |
Seeds | 2.3–4 mm; coat anticlinal cell walls straight, papillae 4–10 per cell. |
15–25, in 2+ rows distal to mid fruit, tan, dark-mottled, irregularly polygonal, surface smooth to minutely tessellate under 10x magnification; recurved flap over hilum absent; seed coat cell outer periclinal wall flat to slightly convex. |
2n | = 22. |
= 36. |
Mentzelia decapetala |
Mentzelia mollis |
|
Phenology | Flowering Jun–Aug(–Oct). | Flowering Apr–Jul. |
Habitat | Rock outcrops, slopes, dry short-grass prairies, riverbanks, roadsides, loam, limestone, sandy, silty, clayey, and gravelly soils. | Barren, sodic or calcic clay slopes and bluffs derived from volcanic ash. |
Elevation | 300–2400 m. (1000–7900 ft.) | 800–1500 m. (2600–4900 ft.) |
Distribution |
CO; IA; IL; KS; MN; MT; NE; NM; OK; SD; TX; UT; WY; AB; MB; SK
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ID; NV; OR
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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 mollis is narrowly distributed in eastern Malheur County, Oregon, and western Owyhee County, Idaho, and disjunctly in the Black Rock Range of Humboldt County, Nevada. Recent phylogenetic studies support treatment of these disjunct populations as a single species (J. M. Brokaw and L. Hufford 2010b). In both ranges, M. mollis is predominantly limited to barren soils with high salinity. Mentzelia mollis is listed as endangered by the Oregon Department of Agriculture and is in the Center for Plant Conservation’s National Collection of Endangered Plants. (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 | |
Name authority | (Pursh) Urban: Ber. Deutsch. Bot. Ges. 10: 263. (1892) | M. Peck: Leafl. W. Bot. 4: 183. (1945) |
Web links |