Stems straight, erect or nearly so (or leaning), cylindric, (20-)45-150(-300) × (20-)25-40(-50) cm; ribs (18-)21-31, shallowly notched immediately above each areole. Spines 12-32 per areole, central spines and larger radial spines whitish, yellow, pink, dull red, or brown; smallest spines per areole slender, sometimes bristlelike, less than 1 mm diam. (rarely absent); central spines 4 per areole, major rigid central spines surrounded by weaker subcentral spines; principal central spine moderately curved, sometimes twisted, usually not strongly hooked except on relatively young plants, annulate, adaxial surface usually flat or even concave, 36-140[-170] × 2-4.5 mm. Flowers maroon outside, yellow inside, 3-6 × 4-6 cm; inner tepals commonly yellow, (rarely with reddish midstripes, very rarely orange to red with a darker red midstripes); stigma lobes yellow (to red). Fruits ± readily dehiscent through basal pore, bright yellow (very rarely reddish), 30-40(-50) × 15-20 mm, leathery or fleshy, locule dry, hollow except for seeds. Seeds (1.5-)2-3 mm, pitted. 2n = 22. Flowering early spring-early summer (late summer-early fall). Interior chaparral, Mojave desert scrub, Sonoran desert scrub, usually on rocky slopes, igneous and limestone substrates; 0-1500 m; Ariz., Calif., Nev., Utah; Mexico (Baja California, Sonora). The name Ferocactus acanthodes has been widely applied to this species but was based on a small plant of unknown origin (and the original specimen lost), and is therefore ambiguous (N. P. Taylor 1979). The vernacular name 'compass barrel' is sometimes misapplied to Ferocactus cylindraceus , which grows straight up in its old age, instead of leaning as would F. wislizeni.

The varieties recognized by L. D. Benson (1982) are not consistently distinguishable.

FNA 2003

Common Name: California barrel cactus Duration: Perennial Protected Status: No status in Arizona. General: Stems cylindric, straight and erect or nearly so (rarely leaning) 45-150 cm tall by 25-40 cm wide, with 21-31 ribs that are shallowly notched immediately above each areole, the plant is generally taller than wide. Spines: Spines 12-32 per areole with the central spines and larger radial spines whitish, yellowish, pink, dull red or brown, the smallest spines per areole are slender and sometimes bristlelike but less than 1 mm in diameter, there are 4 central spines per areole with a curved principal central spine with an upper surface that is flat to concave and 36-40 mm long by 2-4.5 mm wide, the central spine of each areole curved or twisted but not strongly hooked. Flowers: Maroon outside and yellow inside, they are 3-6 cm long and 6 cm wide, sessile and radial, the inner tepals are yellow but rarely with reddish midstripes while the stigma lobes are yellow to red. Fruits: Fleshy or leathery to scaly and bright yellow, 30-40 mm tall by 15-20 mm wide, they are readily dehiscent through basal pore. Ecology: Found on gravelly or rocky slopes and sandy areas from sea level to 5,000 ft (1524 m), flowers early spring to summer. Notes: This is similar in appearance to the F. wislizeni, but is different in that it grows (generally) straight up, rather than leaning. Another note in FNA suggests that the earlier recognized varieties are not consistent. Ethnobotany: The plant was used as a reliable source of water, the buds were sun dried for food, eaten fresh, parboiled, or baked in a pit. Etymology: Ferocactus from Latin ferus, fierce and cactus referring to spines, while cylindraceus means long, round, and cylindrical. Synonyms: Ferocactus acanthodes Editor: SBuckley, 2010