Plant: Annual herb; 20-75 cm tall Leaves: 8-18 cm long, 4-8 cm wide; petiole 1.5-6.5 cm long; blade ovate, often broadly so, with two large teeth near base; uppermost leaves sublanceolate INFLORESCENCE: cymose Flowers: sessile; calyx usually deciduous; petals orange, 6-10 mm long, 5 mm wide, with trichomes at apex only; staminodia 0; outer stamens with slightly broadened filaments; style ca. 3 mm long Fruit: capsules, clavate, long-tapering to base, erect; body 2.4-3 cm long. SEEDS 5-6, pendulous, not winged, blocky in outline except for the protruding hilum end; testa cells elongate, the surface striate Misc: Rocky slopes; 1050-1850 m (3500-6000 ft); Aug-Sep REFERENCES: Christy, Charlotte M. 1998. Loasaceae. J. Ariz. - Nev. Acad. Sci. 30(2): 96.
Duration: Annual Nativity: Native Lifeform: Forb/Herb General: Annual herb with spreading, ascending, longitudinally striate stems 10-40 cm long, puberulent with straight or slightly curved, spinelike hairs, retrorsely barbed. Leaves: Lanceolate to ovate-lanceolate, to broadly ovate 10-15 cm long to 8 cm broad, acute to acuminate at apex, more or less cuneate to subcordate at base, serrate or deeply incised or sometimes hollowly 3-lobed, dark green on upper surface, paler and more densely scabrous beneath. Flowers: Calyx tube 6-11 mm long, attenuate at base, lobes lanceolate 3-4 mm long, 1-1.5 mm wide, acuminate; 5 petals, obovate to obovate-orbicular, 4-8 mm long. Fruits: Subcylindrical capsule, 1.5-2.5 cam long, 3-5 mm in diameter, terete, obtuse at base, papery, sessile. Ecology: Found on sandy or rocky soil below 4,000 ft (1219 m); flowers July-October. Notes: Diagnostic for this plant is the striate stems. Ethnobotany: Unknown, but others of this genera had wide use as food, medicine, and for ceremony. Etymology: Mentzelia named for Christian Mentzel (1622-1701), a 17th century German botanist, botanical author and physician, while aspera means rough. Synonyms: None Editor: SBuckley, 2010