_Lower California, Sonora, and Southern Arizona_ An aristocrat of the Cactaceæ claims our attention next, _Cereus Thurberi_, called also the “Pipe Organ” cactus. It grows well in the arid mountain regions, on the lower mountains and flats of Lower California and from Sonora in Mexico to southern Arizona, usually in colonies, seeking the rocky, gravelly soil in foothills and along the mountain cañons. Notice how it branches near the base and grows from ten to twenty feet tall; very erect and stately, the plant makes quite an appearance in green armor with a thin waxy coat. Surrounded by smaller patches of cacti where it towers well over them all, _Thurberi_ presents a very striking picture in this setting of old Mexico or Lower California. We note that its great columns of yellow-green cuticle look much like the pipes of a giant organ silhouetted against the sky away out on the desert; hence the name Pipe Organ cactus or Pitahaya. We might even fancy that the rush of the wind through mountain and cañon, with its piercing shriek or duller roar, the song of the desert, is music emanating from the giant pipes of this great Organ cactus of Arizona and Lower California. The flowers, like those of many others of its kind, bloom in the night and are usually closed by nine o’clock in the morning; growing in the tops of clusters of slender spreading grayish spines, lining the fifteen or twenty ridges of the stems, and, it is to be noted, appearing only on the tips of the stems; beautiful blooms three inches long with white margins, the delicate petals light pink with green and white bands along their edges, the innermost petals satiny white with some pink above, gradually toning into the purple-red of the sepals. The fruit of “Pitahaya dulce” as the Indians call the plant, globose, olive-green, with a crimson sweet fleshy pulp when ripe, is a rare delicacy and is highly prized by Indians and Mexicans for the making of jellies and jams, conserves, syrups, and sweetmeats. From the syrup they also make wine. Serpent Cactus (_Cereus serpentinus_) _Mexico_