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Compass Barrel
California Barrel Cactus

Ferocactus cylindraceus
(F. acanthoides)

Photo © by Michael Plagens

Photographed near Shaw Butte, Phoenix, Maricopa Co., Arizona. June 18, 2002. The tough cortex and sharp spines have been breached by the feeding activity of Audubon's Cottontail and/or White-throated Woodrat.

Photo © by Michael Plagens

Photographed near Mesquite Wash, e. Maricopa Co., Arizona, USA, Sept. 2002.

SPINES: Also known as yellow- or even red-spined barrel cactus because the spine clusters contain yellow, as well as reddish, pink and gray spines. There are four central stiff, spines, another series of 4 to 10 stiff spines, then a series of fine wispy spines. The central spine may be strongly curved, but is not hooked. The clusters of spines may be so long and dense that they nearly obscure the stem.

FLOWERS: Yellow or yellowish flowers open mostly in May or June.

STEM: Pleated, columnar, and up to 2 m or more tall.

FRUIT: Flowers and yellow fruits are arranged at the top, the growing tip, of the cactus.

RANGE: Generally distributed throughout the Arizona Sonoran Desert but more common near Phoenix than near Tucson.

Once the flower buds appear and until they open, large numbers of ants, especially Forelius and Myrmecocystus, are drawn to feed on a sticky exudate from the bud surfaces. Both of these ant species are able to spray noxious chemicals that would deter herbivorous animals from nipping at the buds. In a sense the cactus hires them as guards!

Despite Barrel Cactus' dense armor of spines, Desert Bighorn Sheep are able to penetrate the defenses and feed on the flesh. (Harquahalla Mountains, Warrick et al. (1989) report.)

Cactaceae -- Cactus Family

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Ferocactus cylindraceus photo © by Michael Plagens

This example in the Wickenburg Moutains of Yavapai Co., Arizona, has exceptionally colorful spines. One could imagine the spines to be bloody from a hiker that got too close!

More Information:

Sonoran Desert Field Guide
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Sonoran Desert Naturalist Home Page


Copyright Michael J. Plagens, page created 11 Dec. 2006,
updated 11 June 2012