Emory's barrel cactus

Ferocactus emoryi is spherical or cylindrical solitary barrel cactus, light green to glaucous, reaching a diameter of 60–100 centimetres (24–39 in) and a height of 2–2.5 metres (6 ft 7 in – 8 ft 2 in). It has 15 to 30 ribs with tubercles, especially in the juvenile stage. The spines are white to reddish. The central spine is very strong, 4–10 cm long, while the seven to twelve radial spines reach lengths of up to 6 cm. The large and funnel-shaped flowers are usually red or yellow, reach lengths of up to 7.5 centimeters and have a diameter of 5 to 7 centimeters. The fruit is ovoidal, about 5 cm long. The subspecies F. e. subsp. rectispinus has been found with center spines as much as 25 cm (9.8 in) long, to even 32 cm (13 in). These are the longest spines of any cactus.

This species is found in nature in Mexico in the states of Sonora, Sinaloa and Baja California Sur and in the United States in Arizona in Yuma, Pima and Maricopa counties. Ferocactus emoryi grows in the desert scrubs, hillsides, rocky slopes and gravely rocky or sandy soils, at an elevation from 0–1,200 metres (0–3,937 ft).