The precise identification of Argemone species is problematic and a revision of the genus is in process by Andrea Schwarzbach. Argemone polyanthemos is sometimes identified as A. albiflora but the latter is apparently a species of the southeast United States.

"Argemone" is a herb referred to by the Greeks thousands of years ago.  Linnaeus named this genus in 1753.

Semi-desert. Desert valleys in sand. Spring.
Above and left: Valley of the Gods, Utah, April 19, 2017.

Argemone corymbosa grows 8-24" tall and often as wide. Leaves are leathery, glaucous, prickly (usually only on the veins of the underside of the leaf). Almost all surfaces of the plant have spines and trying to examine the plant closely is an ouching affair. Flowers can be a bit over 3" in diameter and are crinkled and white.

The second photograph above gives you a view of the typical habitat of Argemone corymbosa. A stroll across this high desert turned up dozens of plants. Where there is one plant, there are often a number more scattered nearby. See the last photograph.

This species is rare over its very limited range in southern Utah and northern Arizona. Its presence in the one Colorado county shown below in the map is questionable.

Edward Greene named and described this species in 1886 from a collection made by Katherine Curran (later Katherine Brandegee) in the Mohave Desert in 1884. That taxon is now considered Argemone corymbosa var. corymbosa.

"Corymbosa" refers to the arrangement of the flowers or fruit and "arenicola" is Latin for "sand dweller" and you can see that habitat (and our new 4Runner) in the photograph immediately above.

Argemone corymbosa var. arenicola. (Mojave Prickly Poppy)
Papaveraceae (Poppy Family)

Semi-desert. Desert valleys in sand. Spring.
Valley of the Gods, Utah, April 19, 2017.

Soft and delicate appearing flowers are a strong contrast to the myriad of prickles on the sepals, which are tipped with especially formidable horns.

Argemone corymbosa var. arenicola. (Mojave Prickly Poppy)
Papaveraceae (Poppy Family)

Semi-desert. Desert valleys in sand. Spring.
Valley of the Gods, Utah, April 19, 2017.

Argemone corymbosa var. arenicola leaves are leathery, glaucous, and have prickles along the vein on the underside. The upper leaf surface is usually smooth. Other Argemone species have different arrangements of prickles on leaf surfaces.

The yellow stem is also formidably guarded by prickles. (I had to use the stick to hold the leaf down because the prickles were far too sharp for me.)

Argemone corymbosa var. arenicola. (Mojave Prickly Poppy)
Papaveraceae (Poppy Family)

Semi-desert. Desert valleys in sand. Spring.
Valley of the Gods, Utah, April 19, 2017.

Last year conditions were good for the seeds that fell in this area to germinate. Next year and the following years (A. corymbosa is a perennial) there will probably be a thicket of Argemone on this spot.