(Photograph: Ferocactus echidne rhodanthus, Amante Darmanin)
Introduction
Ferocactus means fierce spiny plant (Latin ferox; Greek kaktos). And these barrel cacti do constitute a genus of heavily spined plants. These are large plants; some can be over 9-ft tall, and some can be 1-m wide.
The Details
Many barrel cacti that were formerly in Echinocactus are now considered to be Ferocactus spp. The two differ in various ways, but only Echinocactus has densely woolly growing tips. Additionally, Echinocactus species are mostly semi-globular, whereas many Ferocactus species form barrels.
Anderson (2001) recognizes about 30 Ferocactus species. Almost all of them are found in Mexico only. Five species occur in the United States: F. cylindraceus, F. eastwoodiae, F. emoryi, F. hamatacanthus, and F. wislizeni. Only F. eastwoodiae is a USA-only species. Thus, essentially all the Ferocactus species are found in Mexico, and the large majority are found only in Mexico.
Some species grow at high elevations; F. haematacanthus has been reported from an altitude of 7,200 ft in Puebla state, Mexico. F. cylindraceus is the most northern-growing species and is found in Utah.
Additional Reading: Pollination of Two Species of Ferocactus
