Bull. Calif. Acad. Sci. 2: 59. 1886.
Plants perennial. Stems 2-8 dm, scattered-prickly. Leaf blades: surfaces shallowly to deeply lobed, thick, leathery, surfaces unarmed to sparingly prickly, especially abaxial surface on veins; distal clasping. Inflorescences: buds subglobose to ellipsoid-ovoid, body 10-18 × 8-14 mm, sparingly prickly; sepal horns terete or flattened in cross section, 5-7 mm. Flowers 4-9 cm broad; petals white; stamens 100-120; filaments pale yellow; pistil 3-5-carpellate. Capsules ovoid to lanceoloid, 25-35 × 10-16 mm (including stigma and excluding prickles), prickly, surface clearly visible, prickles simple, well spaced, subequal, longest 5-7 mm. Seeds 1.5-2 mm.
Ariz., Calif., Utah
Subspecies 2 (2 in the flora).