Mentzelia obscura
Mentzelia monoensis
Pacific blazing star
Mono craters blazing star
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 moderately to shallowly lobed, rarely entire.
petiole absent;
blade ovate-lanceolate to linear, to 15(–22) cm, margins few-lobed or entire.
petiole present or absent (proximal leaves), absent (distal leaves);
blade linear-lanceolate to linear (proximal leaves), ovate to linear (distal leaves), to 13 cm, margins usually moderately to shallowly lobed, rarely entire.
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, sometimes with white base, ovate, 3–4.1 × 1.1–1.7 mm, width 1/4–1/2 length, not concealing capsule, margins 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 2–3 mm;
petals orange proximally, yellow distally, 2–4 mm, apex retuse or rounded;
stamens 10–30, 2–3 mm, filaments monomorphic, filiform, unlobed;
styles 2–3 mm.
clavate, 11–31 × 1.5–3 mm, axillary curved to 250° at maturity, usually inconspicuously longitudinally ribbed.
cylindric or clavate, 6–15 × 2–3 mm, axillary curved to 20° at maturity, usually inconspicuously 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.
15–30, in 2+ rows distal to mid fruit, tan, not 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.
= 36.
= 54.
Mentzelia obscura
Mentzelia monoensis
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 monoensis is narrowly distributed predominantly south of Mono Lake and north of Lake Crowley in Mono County, California, and is most commonly found in soils derived from the eruptions of the Mono Craters (J. M. Brokaw et al. 2015). Phylogenetic studies suggest that this hexaploid is the only allopolyploid derived from representatives of both the “Affines” and “Trachyphyta” clades (Brokaw and L. Hufford 2010b). Mentzelia monoensis is morphologically similar to sympatric populations of M. montana. However, the bracts of M. monoensis are more often unlobed and green throughout. Furthermore, seeds of M. monoensis have tan, unmottled coats that are always composed of cells that are rounded, appearing as shallow domes. In contrast, seeds of M. montana have mottled coats with cells that stand out as rough, pointed knobs along the seed edges.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
CA
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iNaturalist
USDA Plants Database
