Stems 5-16 dm, with 0-10 prickles per cm² on main stem below capsule. Leaf blades: abaxial surface sparingly prickly on main veins. Capsules scattered-prickly, surface not obscured, prickles nearly equal, longest 6-8 mm. 2 n = 28.

Flowering spring-summer; fruiting summer-fall. Dry, rocky soil, full sun; of conservation concern; 1500-1700 m; Calif.

Argemone munita subsp. robusta is endemic to the Santa Ana Mountains.