Photo unattributed.
Introduction
Opuntia atrispina is an early-flowering, attractive prickly pear from southwestern Texas and adjacent Coahuila. In limestone brushlands and on rocky flats, plants stay low and densely branched. A key field mark is the two-tone armament: spines are dark red-brown to nearly black at the base, and abruptly pale tan to yellow toward the tips.
The Details
Form and pads: Plants are usually 30–50 cm tall (occasionally to ~90 cm) and can spread to about a meter. Cladodes are green, typically 10–15 cm wide and 10–20 cm long, and round to ovate or obovate; joints are firm, not easily shed. Areoles bear scattered glochids and several round, robust spines.
Flowers and fruit: From spring into early summer, buds open pale yellow to cream, then shift through salmon or pink to rose as the day progresses. Filaments are yellowish distally and greenish near the base; the style is white; stigmas are yellow to greenish-yellow or cream. Fruits are reddish-purple when mature.
Range and habitat: In southwestern Texas, plants occur from roughly the Uvalde–Del Rio–Langtry corridor onto nearby limestone hills and grasslands, with outposts just across the Rio Grande. In exposed sites, stands often occupy warm, rocky slopes and ledges.
Look-alikes: In bright sun, other local prickly pears can show dark spines, but O. atrispina’s crisp, two-tone spines plus the pale-to-rose flower shift are a useful combination. In cultivation, stress colors can blur these cues, so pad shape and spine tone should be considered together.
O. atrispina is diploid.
Additional reading: Opuntia atrispina at JSTOR
