Mentzelia pectinata |
Mentzelia desertorum |
|
---|---|---|
San Joaquin blazing star |
desert blazing star |
|
Habit | Plants candelabra-form, (8–)20–50(–60) cm. | Plants candelabra-form, 5–40 cm. |
Basal leaves | persisting; petiole present or absent; blade lanceolate to linear, margins deeply to shallowly lobed. |
persisting; petiole present or absent; blade linear, margins usually shallowly lobed, lobes rounded. |
Cauline leaves | petiole absent; blade ovate to linear, to 12 cm, margins deeply lobed to dentate. |
petiole absent; blade ovate-lanceolate to linear, to 12 cm, margins shallowly lobed or entire. |
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. |
green, ovate to ovate-lanceolate, 3.6–4.7 × 1.6–2.3 mm, width 1/3–1/2 length, not concealing capsule, 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. |
sepals 2–4 mm; petals yellow to orange proximally, yellow distally, 2–6 mm, apex acute or rounded; stamens 10–30, 2–4 mm, filaments monomorphic, filiform, unlobed; styles 2–4 mm. |
Capsules | clavate, 12–35 × 2–4 mm, axillary curved to 90° at maturity, usually inconspicuously longitudinally ribbed. |
clavate, 12–27 × 1–2.5 mm, axillary curved to 180° at maturity, usually inconspicuously longitudinally ribbed. |
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. |
10–50, in 2+ rows distal to mid fruit, tan, usually not, occasionally sparsely, dark-mottled, usually irregularly polygonal, occasionally triangular prisms proximal to mid fruit, surface tessellate under 10x magnification; recurved flap over hilum absent; seed coat cell outer periclinal wall flat to slightly convex. |
2n | = 18. |
= 18. |
Mentzelia pectinata |
Mentzelia desertorum |
|
Phenology | Flowering Mar–May. | Flowering Feb–Mar. |
Habitat | Slopes of sandy or gray-white silty soils, grasslands, oak savannas, uncommonly juniper woodlands. | Sandy flats, washes, creosote-bush scrub. |
Elevation | 200–1400 m. (700–4600 ft.) | 30–1000 m. (100–3300 ft.) |
Distribution |
CA
|
AZ; CA; Mexico (Baja California, Sonora) |
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 desertorum, a diploid, is most similar morphologically to the tetraploid M. obscura, and the two species may be difficult to distinguish prior to seed maturation. However, many populations of M. desertorum have narrow basal leaves with short, widely spaced lobes that are unique among species within sect. Trachyphytum. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 541. | FNA vol. 12, p. 536. |
Parent taxa | Loasaceae > Mentzelia > sect. Trachyphytum | Loasaceae > Mentzelia > sect. Trachyphytum |
Sibling taxa | ||
Synonyms | Acrolasia desertorum | |
Name authority | Kellogg: Proc. Calif. Acad. Sci. 3: 40, fig. 9. (1863) | (Davidson) H. J. Thompson & J. E. Roberts: Phytologia 21: 280. (1971) |
Web links |