Trails List - Prickly Pear

Prickly Pear

Definitions Tubercles are small, wart-like projections on the stems from which sharp spines (modified leaves) grow.

Glochids are hair-like spines or short prickles, generally barbed, found on the areoles of cacti. Cactus glochids easily detach from the plant and lodge in the skin, causing irritation upon contact.

Brown-spined Prickly Pear (Opuntia phaeacantha) is found at elevations of 2,000-8,000 feet and forms low, spreading clusters, 2 to 3 feet high. It has oval or nearly circular stems, bearing clusters of 8 or fewer white or brown central spines, between 1 and 3 inches in length and quite thick. Areoles towards the base of the pad often have no spines; sometimes spines are found only at the areoles on the uppermost quarter of the pad. During dry periods the blue-green pads (typically 4-6 inches long) may take on a purplish tinge along the tips. Central spines point outwards or downwards, while the 1 to 3 lower spines always point downwards, and are much shorter, generally less than half an inch. Opuntia polyacantha is another similar species, but this generally has more spines per areole, and is less likely to have areoles with no spines. The flowers may be lemon yellow, orange or pink, usually with, but sometimes without, a reddish center. The fruits are reddish purple. This Brown-spined prickly pear was photographed on the ranger led hike to the ruins in Tonto National Monument.

Brown-spined Prickly Pear

Englemann's Prickly Pear

Englemann's Prickly Pear (Opuntia engelmannii) is perhaps the most widespread of all prickly pear cacti and is one of the largest growing at elevations between 1,500 and 6,200 feet. It has light green or bluish green pads up to 12 inches circular or oblong, forming sizeable clusters up to 5 feet tall. Mature clumps have no central trunk, instead spreading at ground level. Lateral pads take root readily enabling the plant to colonize an area of up to 30 feet across. The white (occasionally yellow) spines grow from widely spaced areoles in clusters of 2 to 6 and always point downwards. Glochids are quite prominent. Spines are shorter than all similar opuntia species, at most one inch long. The large yellow flowers which bloom in springtime are followed by purple-red fruits. New pads are bright lime green and the areoles bear small, thin leaves, which soon drop off as the spines start to develop.The photo to the bottom left was taken from the top of the cactus looking down so the glochids are quite prominent on the top of the pad. This Englemann's prickly pear was also photographed on the ranger led hike to the ruins in Tonto National Monument.

Pancake Prickly Pear

Pancake Prickly Pear (Opuntia chlorotica) is a widespread prickly pear that grows at elevations of 2,000 to 6,000 feet and forms large clusters. Old specimens reach heights of 8 feet or more and have hundreds of pads branching from a thick central trunk. The pads are usually covered in golden-yellow spines, between 1 and 2 inches long in clusters of up to 7, which continue to grow on old segments, so that the lower limbs of these large plants seem especially prickly. Spines may be largely or completely absent, but the large glochids are always present to a greater or lesser extent and are gold colored. Pads are grey green or blue green in color, between 5 and 8 inches long, circular or ovate. The pads of this prickly pear are typically almost perfectly round, giving rise to its common name. Flowers are yellow with red centers, fruit is fleshy and purple-gray.

Tuberous Prickly Pear

Tuberous Prickly Pear (Opuntia macrorhiza) is one of the most geographically widespread prickly pears in the US, forms large, low (6 inch) clumps many feet across, often partly covered by bushes or long grass. It grows at elevations of 2,000 to 9,000 feet. Pads are greenish blue, and medium sized, up to 6 inches long, bearing 1 to 6 spines per areole, white to red-brown, to 2.4 inches long and mostly pointing downwards. The attractive orange or yellow flowers appear May to July, followed by red fruits in late summer. In winter the pads may shrink and become wrinkled as the water content decreases, but soon return to normal during spring. The wide distribution is due to good frost tolerance, and the cactus is even found as far north as British Columbia, Canada.

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