Griffiths, Bulletin of the Torrey Botanical Club 43(2): 90, 1916
What is Opuntia pyrocarpa?
Opuntia pyrocarpa is a commonly encountered prickly pear cactus in central and north-central Texas where it often grows in deep, limestone-derived soils. It is found into Mexico and perhaps Oklahoma.
O. pyrocarpa is an ascending spreading plant to 1 m tall. Often the main branches of this prickly pear cactus are prostrate but ascend at the ends. The cladodes are large, approximately 25(30) to 15(20) cm, or they may be smaller in some plants. The cladodes are often constricted at the base to form a short neck. The spines are porrect in new cladodes, but often slope down with age. Spines are present on the upper 50% to 60% of the areoles and are yellow darkening to a brown base. Spines are 2 to 3 cm long.
The flowers are yellow with light-red centers or pure yellow. This Opuntia has a white style tipped with a light-green stigma. The petals are irregularly cleft or even nearly bifurcated. The fruit is long, pyriform, and various shades of carmine, often with a purplish tinge outside and inside.
O. pyrocarpa may form large plants that create piles of cladodes spread over 6-8 feet, making up for lack of height by achieving breadth. Or prostrate ascending branches by reach upwards. Several large plants growing together can create a formidable thicket. The species occurs with others found in Texas such as O. lindheimeri, O. macrorhiza, and O. orbiculata, etc. The type location is Marble Falls, TX. See the original description.