Mentzelia pectinata |
Mentzelia rhizomata |
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San Joaquin blazing star |
Roan Cliffs blazingstar |
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Habit | Plants candelabra-form, (8–)20–50(–60) cm. | Plants perennial, bushlike, with rhizomes. |
Stems | multiple, erect or decumbent, zigzag; branches along entire stem, distal longest, antrorse, upcurved; hairy. |
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Leaves | blade 8.1–29 × 4.1–12.7 mm, widest intersinus distance 4.1–7.4 mm; proximal oblanceolate, margins entire; distal elliptic, base not clasping, margins entire or dentate, teeth 0–8, perpendicular to leaf axis, 0.6–2.7 mm; abaxial surface with simple grappling-hook and needlelike trichomes, adaxial surface with needlelike trichomes. |
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Basal leaves | persisting; petiole present or absent; blade lanceolate to linear, margins deeply to shallowly lobed. |
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Cauline leaves | petiole absent; blade ovate to linear, to 12 cm, margins deeply lobed to dentate. |
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Bracts | green, ovate to lanceolate, 6.6–12.8 × 1.9–6.8 mm, width 1/5–2/3 length, not concealing capsule, margins 3–7-lobed. |
margins entire. |
Flowers | sepals 3–13 mm; petals red to orange proximally, orange to yellow distally, 8–22 mm, apex mucronate, rounded, or retuse; stamens 20+, 4–11 mm, filaments monomorphic, filiform, unlobed; styles 5–13 mm. |
petals golden yellow, 12.5–17.2 × 6.1–11.2 mm, apex rounded to obtuse, glabrous abaxially; stamens golden yellow, 5 outermost petaloid, filaments narrowly spatulate, strongly clawed, 7–9.5 × 2.7–6 mm, with anthers, second whorl with anthers; anthers straight after dehiscence, epidermis smooth; styles 7–10 mm. |
Capsules | clavate, 12–35 × 2–4 mm, axillary curved to 90° at maturity, usually inconspicuously longitudinally ribbed. |
cup-shaped, 7–10 × 6.5–8 mm, base rounded, not longitudinally ridged. |
Seeds | 20–40, 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 more than 1/2 as tall as wide at maturity. |
coat anticlinal cell walls straight, papillae 9–13 per cell. |
2n | = 18. |
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Mentzelia pectinata |
Mentzelia rhizomata |
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Phenology | Flowering Mar–May. | Flowering Jul–Aug. |
Habitat | Slopes of sandy or gray-white silty soils, grasslands, oak savannas, uncommonly juniper woodlands. | Sparsely vegetated, steep talus slopes with loose gravelly soils. |
Elevation | 200–1400 m. (700–4600 ft.) | 1700–2100 m. (5600–6900 ft.) |
Distribution |
CA
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CO |
Discussion | Mentzelia pectinata occurs in Kern, San Luis Obispo, Santa Barbara, and Tulare counties, around the southern rim of the San Joaquin Valley, extending into the Inner Coast Ranges and the southern foothills of the Sierra Nevada. Petal color varies from orange to yellow, and fully fertile artificial hybrids have been obtained between populations representing the extreme phenotypes (J. E. Zavortink 1966). Phylogenetic studies suggest that M. pectinata and M. congesta have hybridized to form several allopolyploid species (J. M. Brokaw and L. Hufford 2010b) despite their current allopatric distributions. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Mentzelia rhizomata is known only from Garfield County. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 541. | FNA vol. 12, p. 513. |
Parent taxa | Loasaceae > Mentzelia > sect. Trachyphytum | Loasaceae > Mentzelia > sect. Bartonia |
Sibling taxa | ||
Synonyms | Nuttallia rhizomata | |
Name authority | Kellogg: Proc. Calif. Acad. Sci. 3: 40, fig. 9. (1863) | Reveal: Syst. Bot. 27: 763, figs. 1, 2. (2002) |
Web links |