Mentzelia desertorum |
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desert blazing star |
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Habit | Plants candelabra-form, 5–40 cm. |
Basal leaves | persisting; petiole present or absent; blade linear, margins usually shallowly lobed, lobes rounded. |
Cauline leaves | petiole absent; blade ovate-lanceolate to linear, to 12 cm, margins shallowly lobed or entire. |
Bracts | 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 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, 12–27 × 1–2.5 mm, axillary curved to 180° at maturity, usually inconspicuously longitudinally ribbed. |
Seeds | 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. |
Mentzelia desertorum |
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Phenology | Flowering Feb–Mar. |
Habitat | Sandy flats, washes, creosote-bush scrub. |
Elevation | 30–1000 m. (100–3300 ft.) |
Distribution |
AZ; CA; Mexico (Baja California, Sonora) |
Discussion | 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. 536. |
Parent taxa | |
Sibling taxa | |
Synonyms | Acrolasia desertorum |
Name authority | (Davidson) H. J. Thompson & J. E. Roberts: Phytologia 21: 280. (1971) |
Web links |