Argemone platyceras Link & Otto var. rosea J. M. Coulter

Plants annual to short-lived perennial. Stems 4-8(-12) dm, sparingly prickly. Leaf blades: abaxial surface moderately prickly on veins, adaxial surface unarmed to sparingly prickly on main veins; basal and proximal lobed to 4/5 distance to midrib. Inflorescences: buds broadly ellipsoid-oblong, body 12-20 × 10-15 mm, somewhat prickly; sepal horns often angular in cross section, 5-10 mm, slightly prickly basally. Flowers 6-9 cm broad, usually closely subtended by 1-2 foliaceous bracts; petals white or lavender; stamens 150 or more; filaments lemon yellow to red; pistil 3-6-carpellate. Capsules narrowly to broadly ellipsoid, 25-40(-50) × 8-15(-18) mm (including stigma and excluding prickles), prickly, surface clearly visible; prickles unequal, longest 5-7(-10) mm. Seeds ca. 1.5 mm. 2 n = 28, 56.

Flowering early spring-summer; fruiting spring-summer. Coastal plains and westward; 10-1500 m; Tex.; Mexico (Coahuila, Durango, and Nuevo León).