There is only one species in the genus, which is named in honour of Carnegie, the well-known Americanphilanthropist. These wonderful giantare indeed the silent sentinels of the desert. They are often referred to as “Sahuaro”.
Carnegiea gigantea. Arizona and SE. California. The columnar, with 12 to 24 obtuse ribs, branches at 10 to 15 feet, and eventually grows to 30 to 50 feet. One of the largest of the family, it attains a great age, often 250 years or more. It bears numerous awl-shaped spines, brown or greyish, with darker tips, thick and stiff; the radials are spreading, with 3 to 6 centrals which are thicker and longer. The , produced near the top of mature plants, are greenish outside, white inside, and have numerous stamens with yellow anthers. Growth is very slow, so that specimens of a foot high are already of considerable age. Grows readily from .