Although a close relative of the Catalpa, the willow-like foliage of this small tree has given it the name Desertwillow. A small and inconspicuous part of the desert vegetation when not in flower, unnoticed among the heavier growth of trees and shrubs that crowd the banks of desert washes, the tree’s beautiful orchid-like flowers of white to lavender mottled with dots and splotches of brown and purple bring exclamations of delight from persons viewing them for the first time. Because of the beauty of the tree when in bloom, it is sometimes cultivated as an ornamental. Leaves are rarely browsed by livestock, and the durable, black-barked wood is used for fenceposts. In Mexico, a tea made by steeping the dried flowers is considered to be of medicinal value. By early autumn, the violet-scented flowers which appear after summer rains are replaced by the long, slender seed pods which remain dangling from the branches and serve to identify the tree long after the flowers are gone. Although Desertwillows are never found in pure stands, growing singly and rather infrequently among other trees and shrubs lining desert washes, the species is quite common below 4,000 feet across the entire desert from western Texas to southern Nevada, southern California and southward into Mexico. LAVENDER [Illustration: Lemaireocereus thurberi Lophocereus schotti] Common names: ORGANPIPE CACTUS, SINITA; (_PITAHAYA DULCE_) Arizona desert: (_Lemaireocereus thurberi_). Pink lavender. May-June. Arizona desert: (_Lophocereus schotti_). Pink. April-August. Cactus family. Size: In clumps, stems up to 15 feet. Two somewhat similar, columnar cacti occur in the United States only in Organ Pipe Cactus National Monument and in its immediate vicinity. Both are fairly common in northwestern Mexico. These two spectacular desert giants with their clumps of erect branches are sufficiently similar to be readily confused at first glance. However, the stems of the Organpipe (_L. thurberi_) are longer and contain more but much smaller ridges than do the stems of the Sinita or “Whisker cactus.” The name “Sinita” (meaning old age) refers to the long, gray, hair-like spines covering the upper ends of the Sinita stems. Both species are night-blooming, the flowers, which appear along the sides and at the tips of the stems, closing soon after sunrise the following morning. Fruits of the Organpipe are harvested by the Papago Indians. Although these two species of cactus are restricted to a very limited area, they are sufficiently spectacular and interesting to be considered worthy of inclusion in this booklet. It was to protect these species, threatened with extinction in the United States, and other rare and interesting forms of desert plants and animals, that Organ Pipe Cactus National Monument was established.