With 1 1/2–4-foot tall, branching, often purplish stems, the plant is prickly throughout with large, showy white flowers and numerous yellow stamens. Note the leaf surfaces are not prickly but the veins are, and the sap is yellow.

FLOWERS: Spring–fall. White, 3–5 inches (8–12 cm) diameter, 6 tissue-like petals; 150+ orange-yellow stamens clustered in center. Buds prickly and spherical to oval; sepal horns are evenly narrow (not tapering), protruding, slightly flattened. Seed capsules oval to elliptic, 1–1 3/4-inches (25–45 mm) long, sparsely to densely covered with prickles 3/16–3/8-inch (4–10 mm) long, unbranched.

LEAVES: Alternate, upper leaves not clasping. Blades gray-green, to 8 inches (20 cm) long, lobed about 3/4 to the mid-rib, lobes pointed and tipped with thorny prickles, surfaces smooth or only with minute prickles, veins prickly, especially on bottom surface.

HABITAT: Sandy, gravelly, clay-loam soils, roadsides, washes, foothills; desert grasslands and scrub, pinion-juniper, pine-oak woodlands.

ELEVATION: 4,000–8,500 feet.

RANGE: AZ, NM; Mexico.

SIMILAR SPECIES: 4 widespread species in NM. The look-alike Crested Pricklypoppy, A. polyanthemos (lumbed with A. albiflora in recent floras), has white flowers (rarely red or lavender on Otero Mesa), gradually narrowing, round sepal horns, seed capsule elliptic with widely spaced prickles, upper leaves clasping, and yellow sap; Rough Pricklypoppy, A. hispida, has prickly leaf surfaces, and stems and seed capsules densely covered with unbranched  prickles; Hedgehog Pricklypoppy, A. squarrosa, has deeply lobed, bluish leaves densely prickly to smooth between veins, capsules with the longest prickles branched, 3/8–5/8-inch (8–15 mm) long, and yellow sap.

NM COUNTIES: Southern half of NM in low- to mid-elevation, dry habitats: Bernalillo, Catron, Chaves, Grant, Hidalgo, Lea, Lincoln, Luna, Otero, Sierra, Socorro.