Tuna Colorada

The prickly pear cacti often are hard to identify to species level, especially because they hybridze. However, Opuntia stenopetala presents the following combination of features which make it one of the more distinctive specis:

Its growth form can vary from bushy to having elongated, segmented branches creep and rest on the ground. Stem segments -- variously called "pads", "joints," "cladodes" or phylloclades -- are up to 20 cm (7+7⁄8 in) long, round to widest above the middle, grayish green to sometimes purplish, and often very spiny. Images on this page show young pads bearing small, cone-shaped, bright red objects, which are vestigial leaves, the remains of the regular leaves of early cactus ancestors; these fall off as the pads enlarge and mature. Clusters of 2-4 spines arise from each areole, which may position themselves up to 3 cm (1+1⁄8 in) apart. Often lower areoles develop no spines, but produce white, woolly hairs when young. Spines may reach up to 5 cm (2 in) long, the larger ones being somewhat flattened. Usually they are reddish brown to black, but with age become pale, even white. …

Opuntia stenopetala is endemic just to Mexico. It occurs in the northern and central states of Aguascalientes, Coahuila, Durango, Guanajuato, Hidalgo, Nuevo León, Querétaro, San Luis Potosí, Tamaulipas, Veracruz and Zacatecas.

Opuntia stenopetala is pollinated by hummingbirds. In dry environments of the central Mexican state of Querétaro, among plants considered most important for bee populations, Opuntia stenopetala was considered to be of second-most value. A bee associated with the species is Augochlorella pomoniella. A study of the desert scrub of Cerro de San Pedro in the Mexican state of San Luis Potosí found that Opuntia stenopetala was important as a forage for animals during period of drought.

The origin of the genus name Opuntia is uncertain, though possibly it was based on the name of a Greek town where a cactus-like plant grew. The species name stenopetala is derived from the Greek stenos, meaning "narrow, straight", and petalon, meaning petal. Thus "narrow petal," describing the narrow tepals of Opuntia stenopetala.