There are about 30 species of barrel cactus included in the genus Ferocactus. They are found in southwestern USA and northwestern Mexico. The young specimen are columnar, as they grow older, the ribs get formed and they start taking the typical barrel shape.Most of the species are solitary, but others like Ferocactus robustus and F. glaucescens are clumping.
The flowers are pink, yellow, red or purple depending on the species. The petals often have a midstripe of a darker color