Echinocereus acifer is a species of Echinocereus found in Mexico[1]
The plant sprouts from the base, forming small cushions of 5 to 8 stems. The dark green, cylindrical plant body grows to a height of and a diameter of . It has 9 to 12 heavily warty, tuberous ribs. The tomentose areoles on new shoots are apart and about in diameter. The thorns are yellow to reddish-brown, later turning gray, with up to 5 central spines surrounded by 10 to 15 radiating marginal spines.
Buds emerge from a woolly white pad with reddish-brown bristles. The funnel-shaped flowers are red on the outside and yellow on the inside, rarely crooked, and measure long with a diameter of up to . Unlike the monoecious flowers of Echinocereus polyacanthus, the flowers of Echinocereus acifer are hermaphroditic and self-pollinating. The stamens are yellow, and the stigma is green to light green. The oval fruits remain greenish, measuring in diameter and in length.[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.[4]