By every mesa spring one may expect to find a single shrub of the buckthorn, called of old time Cascara sagrada--the sacred bark. Up in the canons, within the limit of the rains, it seeks rather a stony slope, but in the dry valleys is not found away from water borders.

In all the valleys and along the desert edges of the west are considerable areas of soil sickly with alkali-collecting pools, black and evil-smelling like old blood. Very little grows hereabout but thick-leaved pickle weed. Curiously enough, in this stiff mud, along roadways where there is frequently a little leakage from canals, grows the only western representative of the true heliotropes (Heliotropium curassavicum). It has flowers of faded white, foliage of faded green, resembling the "live-for-ever" of old gardens and graveyards, but even less attractive. After so much schooling in the virtues of water-seeking plants, one is not surprised to learn that its mucilaginous sap has healing powers.