Mentzelia pectinata |
Mentzelia sivinskii |
|
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San Joaquin blazing star |
Sivinski's blazingstar |
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Habit | Plants candelabra-form, (8–)20–50(–60) cm. | Plants biennial, bushlike or candelabra-form. |
Stems | solitary, erect, straight; branches distal or along entire stem, distal or proximal longest, antrorse, straight; hairy. |
|
Leaves | blade 32.8–112.2 × 2.9–11.4 mm, widest intersinus distance 1–2.9 mm; proximal oblanceolate to elliptic, margins pinnate, lobes 18–24, perpendicular to leaf axis, 0.8–4 mm; distal elliptic to lanceolate, base not clasping, margins pinnate, lobes 6–16, perpendicular to leaf axis, 1–5.1 mm; abaxial surface with simple grappling-hook, complex grappling-hook, and needlelike trichomes, adaxial surface with needlelike and occasionally simple grappling-hook trichomes. |
|
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 light to golden yellow, 9–14.7 × 3.1–6.4 mm, apex rounded, glabrous abaxially; stamens light to golden yellow, 5 outermost petaloid, filaments narrowly spatulate, slightly clawed, 6.3–11.5 × 2.4–4.9 mm, with anthers, second whorl with anthers; anthers straight after dehiscence, epidermis smooth; styles 4.6–9.9 mm. |
Capsules | clavate, 12–35 × 2–4 mm, axillary curved to 90° at maturity, usually inconspicuously longitudinally ribbed. |
cup-shaped, 8.2–12.7 × 5.1–7.7 mm, base tapering to 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 sinuous, papillae 12–21 per cell. |
2n | = 18. |
= 18. |
Mentzelia pectinata |
Mentzelia sivinskii |
|
Phenology | Flowering Mar–May. | Flowering Jun–Aug. |
Habitat | Slopes of sandy or gray-white silty soils, grasslands, oak savannas, uncommonly juniper woodlands. | Knolls, slopes, and grassland roadsides, gypsum or brown clayey soils. |
Elevation | 200–1400 m. (700–4600 ft.) | 1500–1900 m. (4900–6200 ft.) |
Distribution |
CA
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CO; NM |
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 sivinskii is known from La Plata County, Colorado, and Rio Arriba and San Juan counties, New Mexico. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 541. | FNA vol. 12, p. 522. |
Parent taxa | Loasaceae > Mentzelia > sect. Trachyphytum | Loasaceae > Mentzelia > sect. Bartonia |
Sibling taxa | ||
Synonyms | M. linearifolia | |
Name authority | Kellogg: Proc. Calif. Acad. Sci. 3: 40, fig. 9. (1863) | J. J. Schenk & L. Hufford: Madroño 57: 253, fig. 4A. (2010) |
Web links |