A low, spreading, succulent cactus. Flowers numerous, yellow, with many similar-looking sepals and petals, the innermost often with an orange splotch, to 3 inches across, with many stamens. Blooms May–July. The large, paddlelike green parts (pads) are technically the thickened, flattened stems. New pads have tiny, soft, conical protuberances that are the true leaves; these persist only briefly before drying and falling off. At the base of each leaf is a cluster of 1-6 spines plus many tiny, hairlike bristles that are very difficult to remove from the skin once they are embedded. Fruit is edible, purplish red, and pear-shaped, with tufts or bristles. The seeds are embedded in a pale, mucilaginous substance.
Similar species: Plains prickly pear (O. macrorhiza) is uncommon and found mostly in southwestern Missouri. It might actually be a spinier variety of eastern prickly pear. Starvation cactus (O. polyacantha) was once found in Jasper County but has probably been extirpated.
This cactus grows along the ground and sometimes forms low mounds.
Grows in sunny, dry places: rocky areas of upland prairies, sand prairies, glades, tops and exposed ledges of bluffs, and rocky stream terraces; also pastures, roadsides, railroads, and open, disturbed areas.
Prickly pears and nearly all other members of the cactus family are indigenous to the Americas. There are about 200 species in the genus Opuntia. Another large genus of cacti, Cylindropuntia, the chollas, which have a similar growth habit but have cylindical and not paddle-shaped stems, used to be considered members of the Opuntia genus.
The fruits and young pads of some species of prickly pears are eaten in regions where cacti are more common. Prickly pear candy is made in the desert southwest, and canned, sliced nopales (the pads) can be bought in the Hispanic section in grocery stores. Try them in Mexican-style scrambled eggs!
The spines of prickly pears serve the plant in at least two ways. First, they deter herbivores from eating them. Second, since the pads easily break off at the joints and can take root elsewhere, the spines can facilitate their distribution by hooking on to the feet of animals.
A very simple way of thinking about the green world is to divide the vascular plants into two groups: woody and nonwoody (or herbaceous). But this is an artificial division; many plant families include some species that are woody and some that are not. The diversity of nonwoody vascular plants is staggering! Think of all the ferns, grasses, sedges, lilies, peas, sunflowers, nightshades, milkweeds, mustards, mints, and mallows — weeds and wildflowers — and many more!