The tomentose areoles on new shoots are 1 to 1.5 cm (0.39 to 0.59 in) apart and about 3 mm (0.12 in) in diameter.

Buds emerge from a woolly white pad with reddish-brown bristles.

[2] Echinocereus acifer is found in the Mexican states of Guanajuato, Zacatecas, San Luis Potosí, and Durango, typically growing in rocky forest areas, moss, or rock crevices.

First described as Cereus acifer in 1850 by Joseph zu Salm-Reifferscheidt-Dyck, Georg Albano von Jacobi reclassified it into the genus Echinocereus in 1856.

[3] The specific epithet acifer comes from the Latin words "acus" (needle) and "-fer" (bearing), referring to the plant's thorniness.