Prickly Pear Fruit - Tuna - with Glochids Glochids are often difficult to see and more difficult to remove, once lodged in the skin. Found just above the cluster of regular spines, glochids are yellow or red in color and detach easily from the pads. But members of the Opuntia genus are unique because of their clusters of fine, tiny, barbed spines called glochids. Like other cactus, most prickly pears and chollas have large spines - actually modified leaves - growing from tubercles - small, wart-like projections - on their stems. Chollas are also members of the Opuntia genus but have cylindrical, jointed stems rather than flat pads. The pads are actually modified branches or stems that serve several functions - water storage, photosynthesis and flower production. All have flat, fleshy pads that look like large leaves. Prickly pear cactus represent about a dozen species of the Opuntia genus ( Family Cactaceae) in the North American deserts. The beavertail, Santa Rita and blind pear are regarded as spineless, but all have glochids. Pads can vary in width, length, shape and color. They vary in height from less than a foot (plains, hedgehog, tuberous) to 6 or 7 feet (Texas, Santa Rita, pancake). Most prickly pear cactus have yellow, red or purple flowers, even among the same species.