Mentzelia obscura |
Mentzelia crocea |
|
---|---|---|
Pacific blazing star |
saffron blazing star, Sierra blazingstar |
|
Habit | Plants candelabra-form, 8–45 cm. | Plants candelabra-form, 30–70(–100) cm. |
Basal leaves | persisting; petiole present or absent; blade linear-lanceolate to linear, margins usually irregularly deeply lobed, lobes pointed. |
persisting; petiole present or absent; blade lanceolate to linear, margins usually shallowly, rarely deeply, lobed. |
Cauline leaves | petiole absent; blade ovate-lanceolate to linear, to 15(–22) cm, margins few-lobed or entire. |
petiole absent; blade ovate to lanceolate, to 40 cm, margins deeply to shallowly lobed. |
Bracts | green, ovate to ovate-lanceolate, 2.9–8.2 × 1.1–1.9 mm, width 1/8–1/2 length, not concealing capsule, margins entire. |
green, broadly ovate to lanceolate, 6–12.7 × 3.5–7.7 mm, width 1/2–4/5 length, not concealing capsule, margins 3–10-lobed. |
Flowers | sepals 2–6 mm; petals yellow to orange proximally, yellow distally, 3–8 mm, apex rounded or acute apex; stamens 20–40, 2–7 mm, filaments monomorphic, filiform, unlobed; styles 2–6 mm. |
sepals 7–20 mm; petals usually orange, rarely yellow, proximally, yellow distally, usually elliptic to ovate, rarely obovate, 21–42 × 8–17(–21) mm, apex acute; stamens 20+, 11–40 mm, filaments heteromorphic, 5 outermost linear, inner filiform, unlobed; styles 20–35 mm. |
Capsules | clavate, 11–31 × 1.5–3 mm, axillary curved to 250° at maturity, usually inconspicuously longitudinally ribbed. |
clavate, 20–35 × 3–5 mm, axillary curved to 45° at maturity, usually inconspicuously longitudinally ribbed. |
Seeds | 15–50, 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 colliculate under 10x magnification; recurved flap over hilum absent; seed coat cell outer periclinal wall domed, domes on seed edges less than 1/2 as tall as wide at maturity. |
30–40, in 2+ rows distal to mid fruit, tan, dark-mottled, irregularly polygonal, surface minutely tessellate under 10x magnification; recurved flap over hilum absent; seed coat cell outer periclinal wall domed, domes on seed edges less than 1/2 as tall as wide at maturity. |
2n | = 36. |
= 36. |
Mentzelia obscura |
Mentzelia crocea |
|
Phenology | Flowering Feb–May. | Flowering May–Jun. |
Habitat | Sandy to rocky washes or slopes, desert scrub, Joshua-tree woodlands, roadsides. | Rocky slopes, roadsides, grasslands, oak-pine woodlands. |
Elevation | 200–1700 m. (700–5600 ft.) | 150–1700 m. (500–5600 ft.) |
Distribution |
AZ; CA; NV; UT; Mexico (Baja California, Sonora)
|
CA |
Discussion | Mentzelia obscura is morphologically intermediate to M. desertorum and M. albicaulis and is known to occur in mixed populations with both species. Reliable discrimination among these species usually requires mature seeds. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Mentzelia crocea and M. lindleyi are very similar morphologically and are most reliably distinguished geographically, with M. crocea occurring on the west slope of the Sierra Nevada and M. lindleyi occurring in the Coast Ranges. Low fertility of interspecific crosses supports recognition as separate species (H. J. Thompson 1960), which has been substantiated by genetic differences and non-sister relationships of the two species (J. M. Brokaw and L. Hufford 2010b). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 540. | FNA vol. 12, p. 536. |
Parent taxa | Loasaceae > Mentzelia > sect. Trachyphytum | Loasaceae > Mentzelia > sect. Trachyphytum |
Sibling taxa | ||
Synonyms | M. lindleyi subsp. crocea | |
Name authority | H. J. Thompson & J. E. Roberts: Phytologia 21: 284. (1971) | Kellogg: Proc. Calif. Acad. Sci. 7: 110. (1877) |
Web links |