white thistle

(noun) any plant of the genus Argemone having large white or yellow flowers and prickly leaves and stems and pods; chiefly of tropical America. Synonyms: prickly poppy, argemone, white thistle, devil's fig.

(noun) spiny shrub with silvery-scurfy foliage of alkaline plains of southwestern United States and Mexico. Synonyms: quail bush, quail brush, white thistle, Atriplex lentiformis.