Distribution: Montana east to North Dakota, south to Texas; occasional introduction in Washington.

Habitat: Prairies, foothills and mesas.

Flowers: May - July

Conservation Status: Not of concern

Pollination: Bees, flies

Glaucous annual or biennial herbs, the stems 4-8 dm. tall, branching, sparingly prickly.

Leaves alternate, sessile, the blades with prickles on mid-vein on the lower surface, the upper surface unarmed; lower leaves deeply lobed; upper leaves clasping; leaf margins dentate, each tooth terminating in a prickle.

Inflorescence a terminal, bracteate cyme; sepals 2 or 3, each with an erect, sub-terminal, hollow horn 6-10 mm. long tipped with a prickle; flowers 7-10 cm. broad, each subtended by 1-2 leaf-like bracts; petals white, in 2 whorls of 3 each; stamens numerous, the filaments lemon yellow; style short.

Capsules ellipsoid, 35-50 mm. long and 10-17 mm. wide, the surface covered with widely-spaced prickles.