Stop 3: Western Prickly Pear (Opuntia macrorhiza)

Common Name: Western Prickly Pear 

Scientific Name: Opuntia macrorhiza 

Family Name: Cactaceae 

Duration: Perennial 

Size: Up to about 1 foot tall, often shorter 

Leaf Arrangement: Other/Complex 

Blooming Months: Spring, Summer 

Distribution: AR, AZ, CO, IA, ID, IL, KS, LA, MN, MO, MT, NE, NM, OH, OK, SD, TX, UT, WI, WY 

General Description 

The Western prickly pear cactus, Opuntia macrorhiza, is part of the cactus family and produces long, sharp spines that are actually modified leaves, which harden as they age. The red fruit it produces in the late summer months also have spines and are known as pears or tunas. The fruits are named for their pear-like appearance in English, while the Spanish name “tuna” is derived from the Caribbean word “tun,” meaning fruit or seed. The jointed stem segments are referred to as “nopals,” deriving from the Nàhautl tribe’s name for the Opuntia “Nopalli” and the Spanish “nopalito.” The flowers of this cactus sport very bright and showy colors, ranging from yellows to reds. Each nopal of prickly pear cacti is capable of producing roots for several weeks after detachment, making vegetative spread common, especially after storms. 

Park Wildlife Ecology/Connections 

Like other cacti, the prickly pear cactus is capable of storing large quantities of water within its nopals and fruit, making it an important source of nourishment for the animals that can overcome its spiky defenses. Jackrabbits, javelinas, rodents, bats, and coyotes have been known to feed on this vegetation. In cattle, Opuntia has been cited as being the difference between life and death during periods of drought due to the extensive amounts of water found within the nopals, although the spines may become lodged in the cattle. Further harmful effects may include bloating and diarrhea in young cattle if they are not accustomed to the cactus as a food source, but these consequences are greatly preferred over death by malnutrition and dehydration. 

North American Ethnobotany 

Just as wildlife has found great value in the prickly pear cactus, humans have long benefited from their interactions with the plant. The Navajo people in particular found great use with this particular species of prickly pear, using the plant for its fruit by either eating them raw, drying and boiling them, or harvesting them for later winter use. They also used the spines in dermatological efforts and the stems for assistance in childbirth. In the mid-19th century, Confederate states described the process of using the leaves of the prickly pear to aid in the making of hard tallow candles. In another historical context, the prickly pear cactus is indirectly responsible for the red dye that colored the British “red coats.” The cochineal scale insect that eats the cactus is crushed to produce the red cochineal dye. Over 20,000 pounds of cochineal, the result of approximately 1.4 million insects, was found aboard the 1554 shipwrecks here at Padre Island. After gold and silver, cochineal was the third most prolific Spanish export from the New World.