Plant: annual herb; 2.5-35 cm tall Leaves: 2.5-16 cm long, 0.4-5 cm wide, sessile, lanceolate to elliptic; margins dentate or lobed to pinnatifid; upper leaves with a broad to markedly clasping base. BRACTS 2-several, ovate to elliptic, scarious with green margins, obscuring ovary INFLORESCENCE: cymose Flowers: pedicellate; petals light yellow to cream, each with a horizontal orange band at base, 1-4.5 cm long, 0.5-2 cm wide; staminodia 0; stamens ca. 100, the outer filaments broadened and 3-toothed at apex; styles 10-20 mm long; papillae of stigmas not conspicuous Fruit: capsules cylindric, 1-3 cm long, erect. SEEDS horizontal, not winged, subrectangular, flattened, tapered at hilum end but not constricted; testa cells with straight adjoining walls, the surface walls mostly smooth Misc: Roadsides, rocky slopes, washes; 250-900 m (700-2900 ft); Feb-May References: C. Christy - Loasaceae - JANAS 30:96-111.ASU Specimens.
Christy 1998, Jepson 2012, Kearney and Peebles 1969
Duration: Annual Nativity: Native Lifeform: Forb/Herb General: Herbaceous annuals, to 35cm tall, stems pale pink or white, branched or not, herbage with minutely barbed hairs. Leaves: Alternate, lanceolate to ovate, 2-18 cm long, with irregularly toothed margins, basal leaves petiolate, usually in rosettes, cauline sessile and becoming reduced distally. Flowers: Conspicuous and showy, white to pale yellow with orange veins, petals obovate, 13-62 mm long, sepals lanceolate to deltate, persistent, 7-23mm long, stamens 4-26 mm, filaments broadened, distally 2-lobed; style 8-30 mm, ovaries cylindric, styles thread-like, stigmas 3-furrowed or lobed, infloresences with 4-5 ovate to obovate subtending bracts per flower, bracts with 6-20-toothed, scarious white or green margins, flowers solitary or few in cymose infloresences. Fruits: Erect, cylindric capsules, 14-25 mm long and 5-10 mm wide, borne erect. Seeds 1-many, 2-3 mm long and 2-2.5 mm wide, compressed, middle transverse-ridged, beaked, ashy-white. Ecology: Found in dry, sandy soils, in washes, alluvial fans, steep slopes, and creosote-bush scrub communities, to 3,000 ft (914 m); flowering January-May. Distribution: Arizona, California; Mexico. Notes: This Mentzelia has peach or cream-colored flowers with translucent petals, the petals have conspicuous orange veins, especially near the throat, thick leaves with irregularly toothed margins, the whole plant is covered with long, stiff hairs, and may stick to clothing. Mentzelias are tricky; please note that mature fruits and seeds are nearly always necessary for ID. Ethnobotany: Parched seeds ground into flour and used to make mush and leaves thrown by children at one another because they stick and were hard to remove. Etymology: Mentzelia is named for Christian Mentzel or Christianus Mentzelius (1622-1701), a 17th century German botanist, philologist, botanical author, personal physician to the Elector of Brandenburg, and father of the first King of Prussia, and involucrata means provided with an involucre, a ring of bracts surrounding or enclosing a head of several flowers. Synonyms: Bicuspidaria involucrata, Nuttallia involucrata Editor: LCrumbacher2012