Silver Cholla
Cholla cactus represent more than 20 species of the Opuntia genus (Family Cactacea) in the North American deserts. Cholla is a term applied to various shrubby cacti of this genus with cylindrical stems composed of segmented joints. These stems are actually modified branches that serve several functions -- water storage, photosynthesis and flower production.
Like most cactus, chollas have tubercles -- small, wart-like projections on the stems -- from which sharp spines -- actually modified leaves -- grow. But chollas are the only cactus with papery sheaths covering their spines. These sheaths are often bright and colorful, providing the cactus with its distinctive appearance.
Description
Most cholla cactus have orange or greenish-yellow flowers with a variety of colors, even among the same species. Most species bloom April through June, depending on local conditions. Stems and joints vary in width, length, shape, and color, as well as in the profusion of spines and glochids. Chollas may appear as ground creepers, shrubs or trees, varying in height from less than a foot (Club or Devil Cholla) to as much as 15 feet (Chain-Fruit Cholla).
Chollas, classified in the subgenus Cylindropuntia, are distinguished by having cylindrical, not flattened, stem segments, and with the large spines barbed. Some botanists treat Cylindropuntia as a distinct genus. The stem joints of several species, notably the Jumping Cholla (Opuntia fulgida), are very brittle on young stems, readily breaking off when the barbed spines stick into clothing or animal skin; this helps distribute the cholla as when the stem falls off the person or animal, it is able to take root and grow where it falls. The barbed spines often remain embedded in the skin, causing significant discomfort and sometimes injury.
Opuntia spinosior
Grows from desert floors to grasslands to lower mountain slopes, developing a thick trunk and with purple jointed joints.
Desert: Chihuahuan Desert of southern Arizona and southwestern New Mexico
Height: Up to 8 feet
Joints: Thick, tubercled, covered with gray spines
Flowers: From deep purple to yellow and white
Fruit: Flesh, spineless, yellow in winter
Elevation: 2,000-7,000 feet
Range and habitat
Its range is dry areas from Utah, New Mexico, and west Texas (rarely northeast to western Kansas) south to Durango, Zacatecas, and San Luis Potosí--one of the most northern and eastern ranges of all chollas. It occurs at altitudes from 1200 m to 2300 m (4000 to 7500 feet) and is hardy for a cactus. USDA Zone 5A
In parts of its range, often just below the pinyon-juniper belt, it can be abundant, surrounded by low grasses and forbs that are brown most of the year; in such places chollas are conspicuous as the only tall green plant. Plants may form thickets or be spaced at a few times their width in "gardens".
Cultivation
The plants are sometimes grown as ornamentals, despite their sharp thorns and tendency to spread. Dead stems decay to leave a hollow wooden tube with a regular pattern of lengthwise slits. These are sometimes used as canes or to make decorative curios. The Roman Catholic Penitentes of New Mexico formerly tied fresh stems to their bare backs in Holy Week processions.
