Monographs Details: Acacia greggii var. arizonica Isely
Authority: Isley, Duane. 1973. Leguminosae of the United States: I. Subfamily. Mimosoideae. Mem. New York Bot. Gard. 25 (1): 1-152.
Discussion:Range as key, n into s Utah. Lower deserts to upper Sonoran: desert slopes, canyons, road cuts; rocky sandy to clay soil; with Prosopis, Carnegiea, Celtis, Cercidium, Larrea; occasional to codominant. 300-5500 ft. April-June.
Var. arizonica, the xeric wing of this species, varies from moderately to conspicuously cinereous. Many of the Californian forms have the loose inflorescence characteristic of A. wrightii. Perhaps the demarcation between vars. greggii and arizonica is not as clear cut as indicated on map (no. 7). Some Trans-Pecos Texas material is moderately pubescent, but examination of holdings of several herbaria had been completed before decision to characterize var. arizonica was reached. The subsequent decision to designate all Texas material as A. greggii may be moot.