and saxifrages that recall snowy mountains; below these, yellow pine, nut pine, juniper, hop-hornbeam, ash, maple, holly-leaved berberis, cowania, spiraea, dwarf oak, and other small shrubs and trees.  In dry gulches and on taluses and sun-beaten crags are sparsely scattered yuccas, cactuses, agave, etc.  Where springs gush from the rocks there are willow thickets, grassy flats, and bright, flowery gardens, and in the hottest recesses the delicate abronia, mesquite, woody compositae, and arborescent cactuses.

The most striking and characteristic part of this widely varied vegetation are the cactaceae—­strange, leafless, old-fashioned plants with beautiful flowers and fruit, in every way able and admirable.  While grimly defending themselves with innumerable barbed spears, they offer both food and drink to man and beast.  Their juicy globes and disks and fluted cylindrical columns are almost the only desert wells that never go dry, and they always seem to rejoice the more and grow plumper and juicier the hotter the sunshine and sand.  Some are spherical, like rolled-up porcupines, crouching in rock-hollows beneath a mist of gray lances, unmoved by the wildest winds.  Others, standing as erect as bushes and trees or tall branchless pillars crowned with magnificent flowers, their prickly armor sparkling, look boldly abroad over the glaring desert, making the strangest forests ever seen or dreamed of.  Cereus giganteus, the grim chief of the desert tribe, is often thirty or forty feet high in southern Arizona.  Several species of tree yuccas in the same desert, laden in early spring with superb white lilies, form forests hardly less wonderful, though here they grow singly or in small lonely groves.  The low, almost stemless Yucca baccata, with beautiful lily flowers and sweet banana-like fruit, prized by the Indians, is common along the canyon rim, growing on lean, rocky soil beneath mountain mahogany, nut pines, and junipers, beside dense flowery mats of Spiraea caespitosa and the beautiful pinnate-leaved Spiraea millefolia.  The nut pine (Pinus edulis) scattered along the upper slopes and roofs of the canyon buildings, is the principal tree of the strange dwarf Coconino Forest.  It is a picturesque stub of a pine about twenty-five feet high, usually with dead, lichened limbs thrust through its rounded head, and grows on crags and fissured rock tables, braving heat and frost, snow and drought, and continuing patiently, faithfully fruitful for centuries.  Indians and insects and almost every desert bird and beast come to it to be fed.