Subspecies, varieties, forms and cultivars of plants belonging to the Echinocereus engelmannii group

• Echinocereus engelmannii (Parry ex Engelm.) Lem.: ( var. engelmannii) ha 4 to 6 central spines whitish, golden-yellow, reddish brown to nearly black. It is a highly variable species. Distribution: Southwestern USA (California, Nevada, and Arizona) and northwestern Mexico (Baja California and Sonora).
• Echinocereus engelmannii var. acicularis L.D.Benson in L.D.Benson: has only 2-4 central spines and more robust habit. Distribution: California, Arizona, Baja California and Sonora.
• Echinocereus engelmannii var. armatus L.D.Benson: is the most formidably spiny extreme of the species, central spines up to 13 cm long. Distribution: California and Nevada.
• Echinocereus engelmannii var. chrysocentrus (Engelm. & J.M.Bigelow) Rümpler in C.F.Först.: has 5-6 very stout yellowish to brown central spines, up to 7 cm long (or more), but it is very variable. Distribution: California, Nevada, Arizona, and Utah.
• Echinocereus engelmannii var. howei L.D.Benson: Distribution: California and Nevada.
• Echinocereus engelmannii var. munzii (Parish) W.Pierce & Fosberg: is a mountain form with white spines twisting up up from small bodies, with 4 central spines (except in an occasional areole) instead of 1 and magenta flowers. Distribution: California and Baja California.
• Echinocereus engelmannii var. purpureus L.D.Benson: is a dark-colored, short-spined morphological form that occurs interspersed throughout populations of Echinocereus engelmannii var. chrysocentrus. Distribution: Utah.
• Echinocereus engelmannii var. variegatus (Engelm. & J.M.Bigelow) Rümpler in C.F.Först.: has multicoloured dark-colored spines, typically the central spines are long red or black and contrasts nicely with the white radial spines. Distribution: Arizona and Utah.