Cereus greggii Engelmann var. transmontanus Engelmann, Proc. Amer. Acad. Arts 3: 287. 1856; C. greggii var. roseiflorus Kunze

Areoles nearly circular, 2 × 2 mm; spines radially spreading. Flowers 22-25 × 7-8 cm.

Flowering spring-summer; fruiting summer-early fall. Sonoran Desert, sandy or gravelly loams, creosote bush-bursage flats, edges of washes and on slopes of small hills; 300-1100 m; Ariz.; Mexico (Sonora).

Peniocereus greggii var. transmontanus is in the Center for Plant Conservation’s National Collection of Endangered Plants.