The taxonomy of Ferocactus pilosus is still muddled. Over time there have been 3 names applied to apparently 1 species. Sometime in 1845, Frederic Staines, who was an official with a mining company in San Luis Potosi, sent a large specimen to Kew Gardens, and although the plant was referred to as Ferocactus stainesii, the name was not validated until well after Ferocactus pilosus. In 1850, Ferocactus pilosus was given a full description by Salm-Dyck based on a plant supplied by Galeotti from somewhere in Mexico. At this point F. stainesii is relegated to synonymy under F. pilosus. The third name, Ferocactus pringlei was based on material collected by Pringle in Coahuila.