It is from Tucson, in the rocky foothills of southeastern Arizona, that we start on our long trip across the state and into old Mexico and California. The first of the lovely auroral coloring to attract our notice is the low spreading Prickly Pear called _Opuntia Blakeana_ in honor of Dr. William Blake, who was formerly Geologist and Director of the College of Mines and Engineering of the University of Arizona. Forming in loosely branched clumps on the desert, eight feet or more across and only a foot or so high, this growth is most strikingly characterized by its translucent brown fringe of spicules along the margins of the areolas and its needlelike purplish brown thorns suffused with gray toward the bases. The brilliant orange-red and yellow blossoms, nearly three inches long and as broad, like most of their sister species open and close in the daytime, the sepals greenish yellow toning off to an orange-red base. Blooming time is in April and May, the fruit comes on in July; the latter when ripe is used for food by the Pima and Papago Indians of Arizona, and while they eat it both raw and cooked it is not utilized as is that of some of the other and larger varieties. [Illustration: PAPAGO FRUIT CACTUS (Opuntia Blakeana)] Delicate Prickly Pear (_Opuntia delicata_) _Southern Arizona_ At altitudes of three to five thousand feet in the sandy and clay loams across southern Arizona one may see a prickly pear called _delicata_ on account of its small size and its slender joints and spines. This baby _Opuntia_ was only recently discovered and is considered a rare find, though little is known about its distribution. The tiny plants are sometimes but three inches high, growing to ten inches in different specimens, with one or several stems, long needlelike spines and large yellow flowers, as usual blooming in the morning and closing up their petals in the afternoon. New and interesting specimens of the cactus clan are discovered now and then, and it gives the botanist and the layman much pleasure to study and classify them, to look up their haunts and habits and place them where they belong, so that all may see and know them. [Illustration: DELICATE PRICKLY PEAR (Opuntia delicata)] Purple Prickly Pear (_Opuntia santa rita_) _Southern Arizona_ [Illustration: WHIPPLE’S CHOLLA (Opuntia Whipplei)] [Illustration: PURPLE PRICKLY PEAR (Opuntia santa rita)]