Ferocactus viridescens

About

Ferocactus viridescens is a species of flowering plant in the cactus family Cactaceae. This barrel cactus is known by several common names, including coast barrel cactus, keg cactus and San Diego barrel cactus. Most of its native range in the United States is in San Diego County, California, where it is threatened by development, agriculture, and other alterations in its habitat. It is also found in northern Baja California, Mexico.

Summary from Wikipedia