prickly poppy

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. Any of various plants of the genus Argemone, chiefly of tropical America, having large yellow, lavender, or white flowers and prickly leaves, stems, and pods.

GNU Webster's 1913

1. n. (Bot.) Argemone Mexicana, a yellow-flowered plant of the Poppy family, but as prickly as a thistle.

WordNet 3.0

1. n. any plant of the genus Argemone having large white or yellow flowers and prickly leaves and stems and pods; chiefly of tropical America
2. n. annual Old World poppy with orange-red flowers and bristly fruit