About Opuntia polyacantha var. erinacea (Engelm. & J.M.Bigelow) B.D.Parfitt
Opuntia polyacantha grows 10 to 30 centimeters (4 to 12 inches) tall, forming low, wide mats of pads that can reach 2 to 3 meters (6 1/2 to 9 7/8 feet) across. Its succulent green pads are oval or circular, growing up to 27 centimeters long and 18 centimeters wide. Areoles on the pads are tipped with woolly brown fibers and glochids, and most areoles bear spines that vary greatly: spines range from 0.4 to 18.5 centimeters (1/8 to 7 1/4 inches) in length, can be stout or thin, straight or curling, and come in a variety of colors. Flowers grow from semi-flattened pear-shaped spine-covered stem segments. The flowers themselves are 2.5 to 4 centimeters (1 to 1 5/8 inches) long, and can be yellow, magenta, or red, usually fading to pink or orange as they age. The fruit is cylindrical, brownish, dry, and covered in spines. This cactus reproduces via seed, layering, and re-sprouting from detached stem segments. Across its natural range, it tolerates an extremely wide range of temperatures, surviving lows of −46 °C (−50 °F) in Yukon Territory, Canada, and highs well above 38 °C (100 °F) in locations such as Chihuahua, Mexico. This variety is native to North America, where it is widespread across Western Canada, the Great Plains, the central and western United States, and Chihuahua in northern Mexico. In 2018, a disconnected isolated population was discovered in the Thousand Islands region of Ontario, Canada. It grows in a wide variety of habitat types, including sagebrush, Ponderosa pine forest, prairie, savanna, shrublands, shrubsteppe, chaparral, pinyon-juniper woodland, and scrub. Individual plants generally grow best in sandy soil, and new plants can develop from a displaced stem segment. Native Americans used this plant as a medicinal plant, with different plant parts used to treat a range of symptoms. This prickly pear provides food for many types of animals. In one area, it makes up over half of the black-tailed prairie dog’s winter food. Pronghorn antelope feed on this cactus, especially after wildfires burn off its spines. When little other forage is available, ranchers intentionally burn stands of this cactus to make it edible for livestock. It can also grow in waste areas where higher-quality forage will not grow; an abundance of this cactus indicates that the land is poor quality. Several insect species attack this cactus: the cactus moth Melitara dentata, the blue cactus borer Olycella subumbrella, and the cactus bug Chelinidea vittiger. This cactus was both admired and often complained about by members of the Lewis and Clark Expedition. When the skin and seeds are removed, the fruit can be eaten raw or made into candy.
