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U.S. Forest Service

Plant of the Week

Map of the United States showing states. States are colored green where the Southwestern prickly poppy may be found. Range map of the Southwestern prickly poppy. States are colored green where the Southwestern prickly poppy may be found.

southwestern prickly poppy, Pediocactus simpsonii. The endangered Sacramento prickly poppy on the Lincoln National Forest, New Mexico. Photo © Bob Sivinski, New Mexico Energy, Minerals and Natural Resources Department; from, used with permission.

Southwestern prickly poppy (Argemone pleiacantha)

By Charlie McDonald

Oh those prickles! The southwestern prickly poppy protects itself with sharp little spines that cover its leaves, stems, and fruits. And if that fails to deter predators, its broken leaves and stems exude a poisonous sticky alkaloid sap. But, what glorious flowers; these are 3-5 inches across, white with yellow centers of clustered stamens, and delicate wrinkled petals that look like crepe paper.

These showy plants are easy to find in southwestern New Mexico and southeastern Arizona where they flourish along roadsides, in old fields, and other waste places. Interestingly, one subspecies of southwestern prickly poppy, the Sacramento prickly poppy (Argemone pleiacantha ssp. pinnatisecta) is found only in a small part of New Mexico’s Sacramento Mountains and is federally endangered.

The United States has 15 species of prickly poppy, with at least one species in every region of the country except the Pacific Northwest. Mexican prickly poppy (Argemone mexicana) is found along the east coast from New England to Texas and less frequently inland. Crested prickly poppy (Argemone polyanthemos) is found in the Great Plains from the Dakotas to Texas. Most of the other species occur in the Southwest from California to Texas and northward to Nevada, Utah, and Colorado.

Prickly poppies have a solid history of herbal use and cultivation in the Americas, Europe, Africa, and Asia. They have been studied in research laboratories for several of their potential pharmaceutical effects.

For More Information

PLANTS Profile - Argemone pleiacantha, Southwestern prickly poppy