Body extremely large, columnar, tree-like, to 15 m or so tall in nature, branching from the main trunk. Ribs numerous. Areoles close-set and more woolly in the flowering region. Flowers more or less nocturnal, arising near the body apex, variously shaped. Pericarpel and flower tube with numerous scales, at least the low-ermost ones areolate and with bristles in their axils, perianth reddish to white. Fruit green to red, tuberculate, areolate and bristled.
This concept of Carnegiea Britton & Rose includes the genus Neobuxbaumia Backeb. and the species C. polylopha (DC.) D.R. Hunt (Neobuxbaumia polylopha (DC.) Backeb.) from C Mexico.
The 2 most commonly cultivated species are keyed out below: they are the familiar cacti associated with western movies and the Arizona Desert.
Large, tree-like, cylindrical, branching desert cactus, familiar from cowboy movies.
8 species of Mexico (Sonora Desert), Arizona and California.
Source: (1997). Cactaceae. In: . Horticultural Flora of South-eastern Australia. Volume 2. Flowering plants. Dicotyledons. Part 1. The identification of garden and cultivated plants. University of New South Wales Press.