A conspicuous herbaceous perennial prickly poppy with gray-green foliage, stems lying on the ground but erect at or near the apex of the branches, and attractive, large, white flowers growing in disturbed soils in open, sunny, bare areas in the Supai Sandstone formation. Leaves, stems, and buds very prickly.

A perennial herb, 5-8 dm tall. Stems diffusely branched, often decumbent, very prickly, about 60-80 perpendicular prickles per square cm of surface, the largest prickles 7-10 mm long; leaves prickly on the veins beneath, remotely prickly on the midrib above, glabrous between the veins; lower and middle cauline leaves lobed five-sixth to nine-tenths to the midrib, the lobes often five or more times as long as wide, the margin angular at the apex, the sinuses to five times the width of the main lobes; uppermost leaves similar but smaller; flower buds elliptic-oblong; calyx with 80-120 perpendicular prickles per sepal, the sepal horn 12-15 mm long with 7-15 prickles near its base, the apical prickle terete at its base; petals white, stamens 150 or more; capsules fusiform, with 40-60 simple prickles per square cm of surface, the largest prickles 8-10 mm long.

Large, white, six-petaled flowers. The stigma is dark red purple, seeds white with a coarsely reticulate seed surface structure (Schwarzbach and Kadereit 1999). The chemical characters (alkaloids) for the species are unknown (Schwarzbach and Kadereit 1999). The leaves are divided, with divisions almost to the mid-rib. The prickles are long, slender uneven in size. The herbage is blue-green in color. The stems are diffusely branched and often spreading. Prior to blooming, the terminal sepal horn or spine is unusually long and round, not flat in cross-section. Specimens of A. peiacantha have been incorrectly identified as A. arizonica in the past (Rutman 1992).