Mentzelia obscura
Mentzelia affinis
Pacific blazing star
yellow comet
persisting;
petiole present or absent;
blade linear-lanceolate to linear, margins usually irregularly deeply lobed, lobes pointed.
persisting;
petiole present or absent;
blade linear-lanceolate to linear, margins usually deeply to moderately lobed, sinuses extending 1/4+ to midvein, rarely entire.
petiole absent;
blade ovate-lanceolate to linear, to 15(–22) cm, margins few-lobed or entire.
petiole absent;
blade ovate-lanceolate to lanceolate, to 17 cm, margins usually dentate or entire, rarely deeply lobed.
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, ovate to lanceolate, 2.7–6.6 × 0.9–2.1 mm, width 1/5–1/3 length, not concealing capsule, margins 3-lobed or entire.
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 1–7 mm;
petals yellow to orange proximally, yellow distally, 4–12 mm, apex acute;
stamens 20+, 3–6.5 mm, filaments monomorphic, filiform, unlobed;
styles 3–6.5 mm.
clavate, 11–31 × 1.5–3 mm, axillary curved to 250° at maturity, usually inconspicuously longitudinally ribbed.
narrowly cylindric, 7–32 × 1–3 mm, axillary curved to 90° at maturity, often prominently longitudinally ribbed.
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.
10–20, in 1 row distal to mid fruit, tan, dark-mottled or not, triangular prisms, surface ±smooth under 10x magnification; recurved flap over hilum absent;
seed coat cell outer periclinal wall flat.
= 36.
= 18.
Mentzelia obscura
Mentzelia affinis
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.)
Herbarium specimens of Mentzelia affinis are often difficult to distinguish from those of M. dispersa despite distinct evolutionary histories (J. M. Brokaw and L. Hufford 2010). Several characters, including flower size, leaf margins, and capsule surfaces, differ substantially between these species, but habitat is the most dependable diagnostic character. Verified populations of M. affinis have not been found above 1200 meters in desert habitats, and grassland populations are usually restricted to much lower elevations. Sympatric populations of M. affinis and M. dispersa have not been found, and, in areas of range overlap in southern California, M. dispersa has not been found below 1200 meters or in desert vegetation.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
CA
WildflowerSearch
iNaturalist
USDA Plants Database
