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.