The genus includes about 20 species. They are natives of the West Indies and S. America, and are distinguished when adult by a singular woolly or bristly body termed the cephalium or head, which is formed on the crown of the globose plant. This cephalium is a form of terminal flowering branch with a woody centre, and grows to a considerable height. Theare invariably small and pink.
Cactus intortus. West Indies. The body of this plant is at first spherical but subsequently becomes cylindrical. The cephalium is round, flat at first, and completely covered with white wool and soft brown bristles. Ribs number 14 to 20; spines 10 to 15. Flowers, pink.
Discocactus and Cactus genera are not, for they require more heat than the majority of other .