A spectrum of coloring is _Opuntia versicolor_, with green or dull purple joints, green-yellow, red, purple, or deep maroon blossoms, not so very showy but a maze of tints and hues. The countless flowers give the landscape a rich tone in April and May, and the plants in their armament of mottled spines, brown, gray, and purple, are a picturesque sight at any season. The stems grow six to twelve feet tall, with a trunk two or three feet high from which appear many fantastic arms intricately branched to form a broad rounded head, five to ten feet across. This dwarf tree is adequately protected from the hot sun and animal marauder by sharp sheathed thorns about a half-inch long, encasing its entire body in an impenetrable suit of armor far more effective than any coat of mail donned by warrior of old. The flowers cluster at the tips of the brightly colored joints, which are two to ten inches long; the small fruit remain green on the plant for about a year. _Versicolor_ is a good name for this bright Cholla since it means “variegated or diversified in color.” [Illustration: MANY COLORED TREE CHOLLA (Opuntia versicolor)] [Illustration: POPULAR CHOLLA (Opuntia tetracantha)] Popular Cholla (_Opuntia tetracantha_) _Southern Arizona_ This slender little Cholla is interesting because of its inch-long purple-brown and yellow flowers, unfolding once in the afternoon, then closing at night never to open again. Many of them seem to sulk on their heavy moisture-laden stems during the hot dry hours of the desert day, and then swiftly to unfold themselves and parade in evanescent beauty when the long shadows of a departing day begin to paint the mountain slopes, bidding the day to hurry and beckoning night to approach for the fashion show of the desert flowers. _Tetracantha_ is a very popular addition to a cactus garden, and many are the tourists who carry one or more of these smallest of the Cholla back to their homes to preserve as relics from the land of the burning sun. The bloom, yellow-green suffused with purple, reminds one of a small old-fashioned dahlia; May and June is blossoming time, and only a few minutes is required for a flower to open in full. A rare and attractive species is this matchless little beauty, spreading over the sandy desert mesas and in gravelly or rocky foothills in southern Arizona. The name _tetracantha_ alludes to the four reddish brown thorns enclosed in loose straw-colored sheaths. Prolific Tree Cholla (_Opuntia arbuscula_) _Southern Arizona_