Comments: Treated as Echinocereus coccineus var. arizonicus by Kartesz (1994 checklist, 1999 Synthesis), following N.P. Taylor's [revised] work on Echinocereus (pers. comm. J. Kartesz to L. Morse, 25Nov99). USFWS tracks as E. triglochidiatus var. arizonicus (Benson 1982; Taylor 1985). Treated by Flora of North America Editorial Committee (2003) as the distinct species Echinocereus arizonicus.