Argemone albiflora (Wikipedia)
Argemone albiflora, the white prickly poppy, also known as the bluestem prickly poppy or the Texas prickly poppy, is a small erect plant with a decorative white flower with a yellow latex. It is deeply rooted with yellow or red stamens. The plant is known for the sharp prickles on its stem and leaves. The sepals fall off as the flower of this plant grows bigger. It grows in the arid regions of the southern Midwest along roadsides and disturbed pieces of land. Native Americans have long revered this plant for its medicinal and other uses.