The chollas (pronounced choy'-ah) are members of the genus Opuntia, a large genus found from Canada to southern Argentina. Opuntia can range from dwarf size, only a few inches tall, to tree-like, up to 100 feet tall.

Two features make the Opuntia genus unique from most other cacti genera. The first distinctive characteristic, shared by only a few other genera, is the presence of glochids. These are small, easily detached, barbed spines borne on the areoles at the base of the spines. Glochids can be very irritating if they get into the skin, and in some species they can become airborne during handling.

The growth habit of Opuntia is the second distinctive characteristic. Most grow in joints or segments which can separate from the plant and be easily rooted to form new specimens. The genus is often separated into two classes based on this growth habit. The prickly pears, Platyopuntia, have flattened, round joints (or pads) and these pads and their fruits are often edible. The chollas, Cylindropuntia, form long, cylindrical joints that are usually too woody and tough to be eaten. However, the ornamental skeletons of dead chollas are often used to make fences, attractive crafts, and trinkets.

Buckhorn chollas are a much branched shrubby cholla with a wide distribution. They can be found in rocky, sandy slopes from 2,000-6,000 feet elevations in Arizona, Utah, Nevada, California, and Sonora Mexico. It is a variable, sturdy plant that can range from 1-5 feet tall depending on elevation. The branches become woody with age and alternate at a tight angle on the rather short trunk. The stems (or joints) are 6-12 inches long with distinct elongated tubercles. The spines are 3/4-11/4 inches long and are covered with a thin straw colored sheath. There are numerous yellow glochids at the base of the spines. The large 1-11/4 inch red to yellow flowers begin to open in April. The pear-shaped fruits are tan to brown with a shallow, wide umbilicus, a navel-like depression on the end of the fruit.

	O. clavata crest is an interesting genetic mutation (fasciation) of O. clavata

This is a small, low-growing cholla that forms spreading mats up to 6 feet in diameter. It is found in sandy soils on rocky hillsides or in grasslands at 4,500-8,500 feet elevations in central and portions of northwest New Mexico. While hiking you have to be careful not to step on their dangerous, dagger-like spines that can penetrate your shoes. The short club-shaped or egg-shaped stems branch from the base of the plant and form mats 2-3 inches tall and 3-6 feet across. The joints are nearly upright, about 1-2 1/2 inches long, and are covered with low, broad rather indistinct tubercles. The spines are white and rough when mature, pinkish when young. The 4-7 main inner spines are 1/2-1 1/4 inches long and are conspicuous for their thickness and flatness, tapering to a point like a dagger. There are two varieties of dagger cholla, major and minor, with O. clavata var. major having bigger,showier joints and spines. The glochids vary in number and are yellowish. The 1 1/4-2 inch yellow flowers open in June. The light yellow fruits are club-shaped with a deep umbilicus.

The pencil cholla is a shrubby plant that can grow to 7 feet tall and form vast impenetrable thickets in the desert. It can be found growing at 2,000-3,000 feet elevations on limestone hills, in flat areas, and washes in several counties of southern Arizona and northern Mexico. Some authorities give it a wider distribution into Texas, New Mexico, and Oklahoma. The long (4-12 inch), narrow (1/4-3/8 inch) stems give the pencil cholla its name. The areoles are filled with a white wool and yellow to brown glochids. The spines are 5/8-1 inch long and covered with a tan sheath. The flowers which appear in May are pale greenish-purple, lavender or pinkish, about 1-1 1/2 inches in diameter with a broad petal. The red-orange fruits are egg-shaped, 3/4-1 inch long.

The cane cholla is a tree-like cholla 6-7 feet tall with a short woody trunk, an open growth pattern and large branches. It can be found at elevations of 2,000-6,000 feet in valleys, grasslands, or on hillsides of the juniper belt from east-central Arizona, western New Mexico, and northern Mexico. The stems are 5/8-1 inch in diameter and 4-5 inches long at right angles to the branches. The greyish-green stems are often purplish in winter. The tubercles form almost continuous rows and contain the pink to gray to brown spines. The glochids are inconspicuous and yellowish-white. The flowers appear in May and are variable in color: commonly purple, also red, yellow or white. The 1-1 1/2 inch fruits are oblong and yellow when ripe.

This cholla is a short, shrubby plant 2-41/2 feet tall with many branches. In more favorable locations it can reach 6-7 feet tall. It is found growing in the high grasslands along with pinyon pine and juniper at elevations of 4,000-8,000 feet in western New Mexico, Colorado, Utah, Nevada and Arizona. It is often confused with O. spinosior and O. echinocarpa, but O. whipplei is much smaller, more northern, has fewer spines, and always has greenish-yellow flowers. The short, upright cylindrical stems are 2-5 inches long with many narrow tubercles. The spine color ranges from silvery-white to golden yellow and even tan. The areoles are prominent and filled with light brown wool. The glochids are white to pale yellow. The pale yellow to chartreuse flowers bloom in May and don't open widely. The fruits are yellow and fleshy when ripe with a deep cuplike apical cavity persistent through the winter.

In the demo garden there are several varieties of tree cholla that demonstrate the variability in plant size, flower color, and spine length, density, and color. O. imbricata is an upright, tree-like cholla, 4-8 feet tall found in New Mexico, Arizona, Utah, Colorado, Kansas, Oklahoma, and Texas. The tree cholla has a short woody trunk and older stems begin to look like they are bark-covered. The stems can be 5-12 inches long and are covered with prominent tubercles. The spines are 3/4-11/4 inches long with brownish sheaths. The flowers are variable ranging from pink, purple, orange and yellowish to pale green on the outside. The fruits are spherical or hemispherical with deeply pitted umbilici.

Opuntia grahamii

The dog chollas are very low growing, inconspicuous mat-forming chollas that grow on gravelly hillsides along the Rio Grande from Brownsville, Texas to Big Bend. The 1-3 inch long joints are usually club-shaped and covered by broad, elongated tubercles. There are 8-14 spines per areole with one main central spine that is 1-2 1/2 inches long and very flat with a rough surface often distinctly striated. The straw-colored to light brown spines turn gray when old. The flowers are yellow and about 2-2 1/2 inches across. The fruits are an elongated club-shape and very light yellow when ripe. These chollas are closely related to Opuntia clavata, another low-growing, mat-forming cholla. The dog chollas are some of the worst pest cacti because of their habit of forming impenetrable thickets.

The name ramosissima, means many branched, and clearly describes this cactus which grows up to 5 feet tall and has numerous gray-green branches that criss-cross each other. It grows in alluvial soil along watersheds of the Colorado River in southern Nevada, eastern California, and western Arizona. The joints are 2-4 inches long, thin (1/4 inch) in diameter and are solid and woody. The tubercules are flattened with diamond shaped plates, a characteristic not found in other chollas in the southwest. The spines are 1 1/2-2 inches long and can be yellow, red or gray. Flowers appear in May and are yellowish tinged with red. The brown fruit is covered with a thick cluster of long brown spines which make it the appear burr-like, a characteristic that helps identify this plant.

The Christmas cholla is a compact, bushy, narrow-stemmed cholla that grows 2-3 feet high, though in favorable conditions it can get as tall as 8 feet. It is found in mesas, valleys and plains at 200-3,000 feet elevations in Arizona, New Mexico, Oklahoma, Texas and northern Mexico. The smooth, dull green joints are 1-12 inches long and about as wide as a pencil. The spines are conspicuous, whitish in color tipped in yellow or bronze and can look very attractive when highlighted by the sun. Small (3/8-3/4 inch) greenish-yellow flowers appear in May at the terminal ends of the joints or along the sides of the stem. The globular, fleshy fruits are covered by itchy glochids, but this doesn't stop birds or rodents from enjoying the juicy fruits. This cholla gets its name because the ripe fruits turn red in December just in time for Christmas, and the plant appears to be covered with ornaments. In its native habitat, O. leptocaulis is one of the most hated cacti because it often hides among shrubs and stabs the unwary as they walk by.

The Chinle Cactus and Succulent Club