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| Picture Notes: Though I have observed these cacti in a variety of locations during my many hikes, all three of the examples shown here (Figs. 1-3) were found along Wheeler Pass Road near the summit of the pass, at an elevation of over 7,000 feet. |
| Description: Prickly Pear Cactus (Opuntia engelmannii), a.k.a. Cow's Tongue Cactus, Cow Tongue Prickly Pear, Desert Prickly Pear, Discus Prickly Pear, Engelmann's Prickly Pear, and Texas Prickly Pear, has an overall form that is generally shrubby, with dense clumps that can grow from 12 inches to 11 feet high, usually with no apparent trunk. The pads are green (rarely blue-green), obovate to round, about 5-12 inches long and 4.5-8 inches wide. Its glochids (spines) are yellow initially, then brown with age. Spines are extremely variable, with anywhere from 1-8 per areole, and often absent from lower areoles; they are yellow to white, slightly flattened, and .5-3 inches long. The flowers are yellow, occasionally reddish, 2.5-4 inches in diameter and about as long. The flowering period is usually between April and May, with each bloom lasting only one day, opening at about 8AM and closing 8 hours later. Pollinators include solitary bees, such as the Antophoridae, and sap beetles. After flowering it produces a purple fleshy fruit about 1-3.5 inches long. This species of prickly pear is common across the south-central and Southwestern United States and northern Mexico. In the Sonoran Desert, terminal pads face predominantly east-west, so as to maximize the absorption of solar radiation during summer rains. Although found occasionally in the Mojave Desert, it tends to be replaced by Opuntia basilaris (the Beavertail Cactus), which does not need the summer rain. |
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