Mentzelia desertorum (A. Davids.) H.J. Thompson & Roberts (redirected from: Acrolasia desertorum)
Family: Loasaceae
[Acrolasia desertorum A. Davids.]
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Plant: annual herb; to 40 cm tall

Leaves: to 12 cm long, sessile, nearly linear to narrowly elliptic or lanceolate; margin mostly toothed to lobed. BRACTS (lanceolate) ovate, green, mostly not on ovary; margins usually entire

INFLORESCENCE: cymose

Flowers: sessile; petals yellow, broadly to narrowly obovate, 2.5-4 mm long, 1.5-2.5 mm wide; staminodia 0; stamens ca. 15-30, all with linear filaments; style 2-4 mm long

Fruit: capsules, very narrowly clavate, long-tapering to base; base not woody; body 12-30 mm long, arching to 180 degrees. SEEDS pendulous, not winged, those in upper half of capsule grain-like, several-faceted; irregular in cross-section, the angles rounded; testa cells with straight adjoining walls, the surface walls flat

Misc: on sand; 50-500 m (200-1700 ft); Mar-May

REFERENCES: Christy, Charlotte M. 1998. Loasaceae. J. Ariz. - Nev. Acad. Sci. 30(2): 96.

Brokaw et al 2014

Duration: Annual

Nativity: Native

Lifeform: Forb/Herb

General: Habit: Annual 5--41 cm. Stem: erect, glabrous to hairy.

Leaves: Leaf: 1--12 cm, lower toothed to lobed, upper entire to lobed. Inflorescence: bracts lanceolate to ovate, generally entire, green.

Flowers: Inflorescence: bracts lanceolate to ovate, generally entire, green. Flower: sepals 2--4 mm; petals 2.5--6 mm, ovate to obovate, yellow, base yellow to orange; stamens = style; style 2--4 mm.

Fruits: Generally curved < 180-, 12--27 mm, 1--2.5 mm wide, obconic. Seed: +- 1 mm, irregular-rounded to -angular above mid-fruit, -section occasionally triangular with grooves along longitudinal edges below mid-fruit, tan, not or sparsely dark-mottled; seed coa

Ecology: Sandy flats in creosote-bush scrub; Elevation: < 950 m; flowers Feb-Mar.

Distribution: s CA, w AZ; Baja Calif, MEX

Notes: Hybridizes with Mentzelia obscura. Mentzelias are tricky; please note that mature fruits and seeds are nearly always necessary for ID.

Synonyms: Acrolasia desertorum

Editor: pasted from Jepson