Mentzelia pectinata |
Mentzelia marginata |
|
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San Joaquin blazing star |
Colorado blazingstar |
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Habit | Plants candelabra-form, (8–)20–50(–60) cm. | Plants winter annual or biennial, candelabra-form. |
Stems | solitary, erect, straight; branches mostly distal, proximal longer than distal, all usually extending to near the distal end of plant, antrorse, straight; hairy. |
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Leaves | blade 22–115 × 2.8–10.9(–17.2) mm, widest intersinus distance 2.2–7(–9) mm; proximal oblanceolate, elliptic, or lanceolate, margins dentate, teeth 10–24(–38), perpendicular to leaf axis, 0.5–4 mm; distal elliptic to lanceolate, base not clasping, margins dentate, teeth 8–20, perpendicular to leaf axis, 0.3–5.6 mm; abaxial surface with simple grappling-hook, complex grappling-hook, and usually with 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 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, 8–14.4 × 2.1–3.9 mm, apex acute, hairy abaxially; stamens golden yellow, 5 outermost petaloid, filaments narrowly spatulate, slightly clawed, 5.5–11.1 × 1.2–2.9 mm, with anthers, second whorl with anthers; anthers straight after dehiscence, epidermis papillate; styles 5.3–10 mm. |
Capsules | clavate, 12–35 × 2–4 mm, axillary curved to 90° at maturity, usually inconspicuously longitudinally ribbed. |
cylindric, 7–14.6 × 3.5–6.7 mm, base tapering, 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 to slightly wavy, papillae 4–10 per cell. |
2n | = 18. |
= 20. |
Mentzelia pectinata |
Mentzelia marginata |
|
Phenology | Flowering Mar–May. | Flowering May–Aug. |
Habitat | Slopes of sandy or gray-white silty soils, grasslands, oak savannas, uncommonly juniper woodlands. | Steep roadside banks, steep cliffs. |
Elevation | 200–1400 m. (700–4600 ft.) | 1500–2000 m. (4900–6600 ft.) |
Distribution |
CA
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CO
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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 marginata occurs on the western edge of Colorado in Delta, Garfield, Mesa, and Montrose counties. Reports of this species from Utah are based on specimens treated here as M. cronquistii. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 541. | FNA vol. 12, p. 506. |
Parent taxa | Loasaceae > Mentzelia > sect. Trachyphytum | Loasaceae > Mentzelia > sect. Bartonia |
Sibling taxa | ||
Synonyms | Nuttallia marginata | |
Name authority | Kellogg: Proc. Calif. Acad. Sci. 3: 40, fig. 9. (1863) | (Osterhout) H. J. Thompson & Prigge: Great Basin Naturalist, 46: 549. (1986) |
Web links |