The stem and leaf hairs are the best diagnostic feature of
euphorbia arizonica, both their presence, as many similar species are glabrous, and also their characteristics, being shiny, glistening and translucent, and also club-shaped, with a narrow stem and wider tip. Stems grow upright or at an angle rather than along the ground. Leaves are broadly ovate, and asymmetric towards the base; one side is lower than the other. Leaves are hairiest along the margins, and they have a faint midvein.
Flowers have an urn-shaped involucre, relatively long and thin, also sparsely hairy, above which are four dark red glands, oblong or kidney-shaped, each linked to a white, petal-like appendage, usually notched or toothed along the upper edge. At the center are several stamens or pistils. Involucres are attached by short stalks, up to 0.15 inches.