Threetooth blazingstar Threetooth blazingstar

Acrolasia tridentata Davidson, Bull. S. Calif. Acad. Sci. 9: 71. 1910; Mentzelia tricuspis A. Gray var. brevicornuta I. M. Johnston

Plants 5–25 cm. Basal leaves: petioles present; blade lanceolate, to 9 cm; margins shallowly lobed, lobes rounded. Cauline leaves: petioles present, rarely absent, present in distalmost leaves; blade broadly ovate to lanceolate, to 9 cm, base not cordate-clasping, margins dentate to serrate. Bracts green, inconspicuous, not concealing pedicel, ovary, or capsule. Flowers: petals white to pale yellow, obovate, 10–40 mm, apex mucronate; stamens 6–15 mm, less than 1/2 petal length, all fertile, none petaloid (flowers appearing to have 5 petals); filaments ± monomorphic, linear, most or all distally 2-lobed, lobes 0.1–0.7 mm; anther stalk longer than or equal to filament lobes; style 9–13 mm. Capsules cylindric to ovoid, 9–18 × 5–8 mm, basal nodding, distal erect. Seeds widest at middle, not grooved; seed coat anticlinal cell walls straight or wavy. 2n = 20.

Flowering Apr–May. Sandy or gravelly slopes, washes, desert scrub; of conservation concern; 600–1300 m; Calif.

Mentzelia tridentata is known from the central and western Mojave Desert in Inyo, Kern, and San Bernardino counties. See 55. M. tricuspis for comparison with M. tridentata.