Cholla cactus represent more than 20 species of the Opuntia genus (Family Cactacea) in the North American deserts. Cholla is a term applied to various shrubby cacti of this genus with cylindrical stems composed of segmented joints. These stems are actually modified branches that serve several functions -- water storage, photosynthesis and flower production.

Like most cactus, chollas have tubercles -- small, wart-like projections on the stems -- from which sharp spines -- actually modified leaves -- grow. But chollas are the only cactus with papery sheaths covering their spines. These sheaths are often bright and colorful, providing the cactus with its distinctive appearance.

Prickly pears are also members of the Opuntia genus, but their branches are manifested as pads rather than cylindrical joints. Opuntia are unique because of their clusters of fine, tiny, barbed spines called glochids. Found just above the cluster of regular spines, glochids are yellow or red in color and detach easily from the pads or stems. Glochids are often difficult to see and more difficult to remove, once lodged in the skin.

Range & Habitat

Cholla cactus are found in all of the hot deserts of the American Southwest, with different species having adapted to different locale and elevation ranges. Most require coarse, well-drained soil in dry, rocky flats or slopes. Some have adapted to mountain forests, while others require steep, rocky slopes in mountain foothills.

Most cholla cactus have orange or greenish-yellow flowers with a variety of colors, even among the same species. Most species bloom April through June, depending on local conditions. Stems and joints vary in width, length, shape, and color, as well as in the profusion of spines and glochids. Chollas may appear as ground creepers, shrubs or trees, varying in height from less than a foot (Club or Devil Cholla) to as much as 15 feet (Chain-Fruit Cholla).