Ferocactus cylindraceus

Ferocactus cylindraceus is a species of barrel cactus which is known by several common names, including California barrel cactus, Desert barrel cactus, compass barrel cactus, and miner's compass. It was first described by George Engelmann in 1853.

Description
Ferocactus cylindraceus is usually cylindrical or spherical, usually found in clusters with some older specimens forming columns grow up to 50 cm in diameter and 3 m in height. The stem has 18 to 27 distinct ribs and is covered in long, plentiful spines, which are straight and red when new and become curved and gray as they age. Each areola typically contains four to seven central spines that are 5 to 15 cm long, as well as 15 to 25 radial spines resembling strong hairs.

The cactus bears funnel-shaped flowers that are maroon outside, and bright yellow inside, with red tints and yellow centers on the side that faces the sun, measuring 3 to 6 cm in length and 4 to 6 cm in diameter. The fleshy, hollow fruits are spherical, yellow, and about 3 cm long.

Subspecies
Accepted Subspecies:

Distribution and habitat
This cactus is native to the eastern Mojave Desert and western Sonoran Desert Ecoregions in: Southern California, Nevada, Arizona, and Utah in the Southwestern United States; and Baja California, and Sonora state in Northwestern Mexico.

It is found in gravelly, rocky, or sandy soils, in Creosote Bush Scrub and Joshua Tree Woodland habitats, from 60 - 1500 m in elevation.

Taxonomy
In 1852, George Engelmann first described Ferocactus cylindraceus as Echinocactus viridescens var. cylindraceus. The name "cylindraceus" is derived from Latin, meaning "cylindrical," which describes the shape of the plant's shoots. In 1926, Charles Russell Orcutt moved this variety to the Ferocactus genus.

Conservation
Having a sculptural form and picturesque qualities, this already uncommon cactus is threatened by plant collectors. It is also losing habitat to clearing for new wind farms and solar power plants in the Mojave Desert and Colorado Desert.


 * Protected areas with notable populations include:
 * Anza-Borrego Desert State Park
 * Joshua Tree National Park
 * Mojave National Preserve
 * Santa Rosa and San Jacinto Mountains National Monument