Mentzelia decapetala |
Mentzelia gracilenta |
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10-petal western star, evening starflower, gumbo-lily, tenpetal blazingstar |
blazing star, grass blazingstar, slender blazingstar |
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Habit | Plants biennial or perennial, bushlike, perennials with ground-level caudices. | Plants wandlike or candelabra-form, (3–)20–60(–70) 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 linear-lanceolate to linear, margins deeply to shallowly lobed. |
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Cauline leaves | petiole absent; blade ovate-lanceolate to linear, to 13 cm, margins deeply to shallowly lobed or entire. |
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Bracts | margins pinnate. |
usually green with white base, occasionally green, obovate to ovate, 7.1–11.3 × 3–6.2 mm, width 2/5–3/5 length, not concealing capsule, margins 3–12-lobed. |
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 3–8 mm; petals usually orange, rarely yellow, proximally, yellow distally, (7–)8–18 mm, apex retuse; stamens 20+, 5–11 mm, filaments monomorphic, filiform, unlobed; styles 5–11 mm. |
Capsules | cylindric, 30–43 × 12–17 mm, base tapering, not longitudinally ridged. |
cylindric or clavate, 9–15(–23) × 3–5 mm, axillary curved to 20° at maturity, usually inconspicuously 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 or not, 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 1/2 as tall as wide at maturity. |
2n | = 22. |
= 36. |
Mentzelia decapetala |
Mentzelia gracilenta |
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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. | Serpentine talus, gray-white calcium-rich soils, grasslands, pine-oak woodlands. |
Elevation | 300–2400 m. (1000–7900 ft.) | 200–1700 m. (700–5600 ft.) |
Distribution |
CO; IA; IL; KS; MN; MT; NE; NM; OK; SD; TX; UT; WY; AB; MB; SK
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CA
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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 gracilenta occurs in the southern Coast Ranges and western Transverse Ranges (Fresno, Monterey, and San Benito counties below 1400 meters, and southern San Luis Obispo, Santa Barbara, and Ventura counties above 1500 meters). Populations in the northern portion of its range are commonly associated with serpentine or other stressful substrates. Mentzelia gracilenta is very similar morphologically to M. ravenii, but it does not occur in desert communities, as does M. ravenii. Furthermore, these taxa appear to be phylogenetically distinct (J. M. Brokaw and L. Hufford 2010b). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 504. | FNA vol. 12, p. 537. |
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) | Torrey & A. Gray: Fl. N. Amer. 1: 534. (1840) |
Web links |