Mentzelia obscura |
Mentzelia conspicua |
|
---|---|---|
Pacific blazing star |
remarkable blazingstar, rio chama blazingstar |
|
Habit | Plants candelabra-form, 8–45 cm. | Plants biennial, candelabra-form. |
Stems | solitary, erect, straight; branches distal, distal longest, antrorse, straight; hairy. |
|
Leaves | blade 69–195 × 11.6–55.7 mm, widest intersinus distance 1.3–2.5(–3.5) mm; proximal oblanceolate or elliptic, margins pinnatisect, lobes 16–26, slightly antrorse or perpendicular to leaf axis, 5.1–15.1 mm; distal elliptic, base not clasping, margins pinnatisect, lobes 10–20, slightly antrorse or perpendicular to leaf axis, 6.2–12.3(–22.5) mm; abaxial surface with needlelike and occasionally simple grappling-hook trichomes, adaxial surface with needlelike trichomes. |
|
Basal leaves | persisting; petiole present or absent; blade linear-lanceolate to linear, margins usually irregularly deeply lobed, lobes pointed. |
|
Cauline leaves | petiole absent; blade ovate-lanceolate to linear, to 15(–22) cm, margins few-lobed or entire. |
|
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. |
margins entire. |
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. |
petals golden yellow, 30–42.2 × 5.7–10.8 mm, apex acute, glabrous abaxially; stamens golden yellow, 5 outermost petaloid, filaments narrowly spatulate, slightly clawed, 27–37.4 × 4.8–9.7 mm, without anthers, second whorl with anthers; anthers straight after dehiscence, epidermis smooth; styles 24–32.4 mm. |
Capsules | clavate, 11–31 × 1.5–3 mm, axillary curved to 250° at maturity, usually inconspicuously longitudinally ribbed. |
cylindric, 15–26 × 5–7.2 mm, base tapering to rounded, not longitudinally ridged. |
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. |
coat anticlinal cell walls sinuous, papillae 8–12 per cell. |
2n | = 36. |
= 20. |
Mentzelia obscura |
Mentzelia conspicua |
|
Phenology | Flowering Feb–May. | Flowering Jun–Sep. |
Habitat | Sandy to rocky washes or slopes, desert scrub, Joshua-tree woodlands, roadsides. | Slopes, pinyon pine and juniper woodlands, grasslands, sparsely vegetated soils composed of red and brown loam. |
Elevation | 200–1700 m. (700–5600 ft.) | 1800–2400 m. (5900–7900 ft.) |
Distribution |
AZ; CA; NV; UT; Mexico (Baja California, Sonora)
|
NM |
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 conspicua is known from Rio Arriba, Sandoval, and Torrance counties. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 540. | FNA vol. 12, p. 515. |
Parent taxa | Loasaceae > Mentzelia > sect. Trachyphytum | Loasaceae > Mentzelia > sect. Bartonia |
Sibling taxa | ||
Name authority | H. J. Thompson & J. E. Roberts: Phytologia 21: 284. (1971) | Todsen: Sida 18: 819, fig. 1. (1999) |
Web links |