Anthony, American Midland Naturalist 55: 246. 1956
Opuntia spinosibacca is prickly pear cactus found only in the Big Bend region of Texas and in adjacent Mexico. It is often found on hot limestone substrates. It is a large cactus, to 4-ft tall and 5-ft wide, some times with a very short trunk (5 to 8 cm tall) that may be 10-15 cm in diameter. The cladodes are generally obovate and 10 to 18 cm long and 8 to 15 cm wide. There are 2 to 5 spines in almost all areoles. Mature spines are reddish-orange or even chestnut red; the longest spines are 5 to 10 cm long. Spines age to gray.
Powell and Weedin (2004) reported that “The plants of O. spinosibacca are upright, compact shrubs to 1- to 1.5-m tall…The pads are light green to yellowish-green [but sometimes appearing bluish] with spines in areoles across most of the pad except near the base.” A purple blotch near each areole is often present. Sometimes, a low spreading variant of O. spinosibacca may be confused with a tall plant of O. camanchica.
The taxon is proposed to be an Opuntia species created through the natural hybridization of O. aureispina (a diploid species) and O. phaeacantha (a hexaploid species). Hybridization attributed to O. phaeacantha-like parents might mean O. dulcis, O. camanchica, or some other not-too-large Opuntia. Irrespective of its ancient origins, the taxon is self-reproducing and is considered a discrete species of prickly pear by these authors. See the original description. O. spinosibacca is probably tetraploid.
This Opuntia species is a superb plant in larger gardens because of its unique coloration and its stout tree- shrub-like look. It is not for small gardens.