Ferocactus viridescens

Ferocactus viridescens is a species of flowering plant in the cactus family Cactaceae. This rare barrel cactus is known by several common names, including coast barrel cactus, keg cactus and San Diego barrel cactus. Most of its native range 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.
It is spherical, oblate, or nearly cylindrical, usually wider than tall, and less than in height. The flesh is bright green and arranged into several ribs covered in arrays of long spines. The spines, which stick straight out and may curve slightly, are red when new, dulling to gray or tan. The cactus bears yellow to greenish flowers with red or pink scales. The fruit is yellow or red.
The Latin specific epithet "viridescens" means "turning green".
This plant, which is hardy down to , must be grown under glass in temperate regions, though it may be placed outside in a sheltered spot in the warm summer months. It has gained the Royal Horticultural Society's Award of Garden Merit. 