Adaptation of Plants to a Desert Environment (continued)

OTHER COMMON CACTUSES

The barrel cactus, or bisnaga, is sometimes mistaken for a young saguaro. Stocky and unbranching, this cactus rarely attains a height of more than 5 or 6 feet. It bears clusters of sharp spines, called "areoles," with the stout central spine flattened and curved like a fishhook. In bloom this succulent plant produces yellow or orange flower clusters on its crown in late summer or early autumn. The widely circulated story that water may be obtained by tapping the barrel cactus has little basis in fact, although it is possible that the thick, bitter juice squeezed from the plant's moist tissues might, under extreme conditions, prevent death from thirst. Carefully avoiding the spines, desert rats, mice, and rabbits sometimes gnaw into the plant's tissues to obtain moisture.

The group of cactuses called opuntias have jointed stems and branches. They are common and widespread throughout the desert and are well represented in the monument. Members of this group with cylindrical joints are known as chollas, while those with flat or padlike joints are called prickly pears. Many of the chollas attain shrub or tree size and often grow in extensive stands or forests. The joints of some are brittle often breaking off when the bristling spines become entangled in the clothing of persons or in the hair of animals brushing against them. Flowers of many are large and colorful. The prickly pears, too, produce large blossoms in the late spring, plants on the monument being principally the yellow-flowered species. The red-brown to mahogany colored fruits, called tunas, attain the size of large strawberries, and are edible. When mature in the autumn, they are consumed by many desert animals.

Some of the smaller cactuses are so tiny as to be unnoticeable except when in bloom; examples are the hedgehogs, the fishhooks, and the pincushions. Blossoms of these ground-hugging species are large, in some cases larger than the plants themselves, and spectacular in form and color. All of them add to the monument's spring and early summer display of floral beauty.