Ferocactus hamatacanthus var. hamatacanthus
Stems ovoid or ovoid-cylindric, 10–63 × 7.5–30 cm; ribs 13–17, undulate or crenate. Spines 12–16 (–28) per areole; central spines 4 (–8) per areole, principal central spine terete or angled, 60–165 × (0.5–) 1–1.5 (–2.5) mm, hard. Flowers 5.5–8 (–10) × 6.5–9.5 cm; stigma lobes 11–14. Fruits green to greenish brown or dull brownish purple, 30–50 × 25–30 mm. Seeds 1.4–1.6 mm. 2n = 22.
Phenology: Flowering summer.
Habitat: Chihuahuan desert scrub, prairies, semidesert grasslands, oak-juniper savannas, pine-oak woodlands, stony hills, bluffs, and flats, igneous and calcareous substrates
Elevation: 500-2300 m
N.Mex., Tex., Mexico (Chihuahua), Mexico (Coahuila), Mexico (Durango), Mexico (San Luis Potosí), Mexico (Zacatecas)
In Mexico, plants of Ferocactus hamatacanthus var. hamatacanthus grow much larger; our measurements pertain only to northern specimens.