Barrel Cacti in Arizona

To identify Arizona's three common barrel cacti, look at the spines in a single areole (cluster of spines).
Each cluster has a single long stout projecting spine surrounded by smaller flat-lying spines.
Ferocactus wislizenii:   Hooked red central spine surrounded by thread-like white flexible spines.
Ferocactus covillei (F. emoryi):  Hooked or curved red central spine surrounded by equally stout straight red or white spines.
Ferocactus cylindraceus:  Curved yellow central spine surrounded by thin straight yellow or white spines.
Arizona Rare Cactus Photos

Ferocactus wislizenii  Arizona Barrel, Fishook Barrel, Compass Barrel
The most common and familiar barrel cactus in southern Arizona.  Called "Compass Barrel" because plants tend to lean toward the south.
Prefers gentle bajada slopes or flat gravelly areas in desert upland and desert-grassland transition.
Grows at higher elevations than other barrels.  Flowers bloom in August and are larger and more variable in color than the other two species.
Typically dark orange but may also be red or yellow.  Large fleshy yellow fruits are filled with black seeds.  Fruits eaten by ground squirrels.

Ferocactus emoryi (F. covillei)  Coville's Barrel
Rocky or gravelly desert slopes and ridges.  Small red flowers in June.
Habitat similar to F. wislizenii but more common further north and at lower elevations.

Ferocactus cylindraceous  Fire Barrel, California Barrel
Among rocks on steep desert hillsides.  Small yellow flowers in June.
Narrower and more cylindrical than the other barrels, and often grow closer together.
Tolerates lower elevations and hotter, dryer habitat than other barrels.

F. cylindraceous:  Unusual multi-headed plant.