THE MEAGER DESERT FLORA 



33 



mile; this is the paloblanco {Acacia wiUardiana), Associated with it 

 along rocky barrancas of permanent water supply is a fig tree (Ficus 

 pahneri), which has a habit of springing from the walls and crests of 

 cliffs, and sending white-bark roots down the cliff-faces to the water 

 50 or 100 feet below, and which yields a small, insipid, and woody fruit. 

 Interspersed among the larger trees, and spreading over the intervening 

 spaces, particularly in the drier and more saline spots, grow a number 

 of thorny shrubs, much alike in external appearance and habit, though 

 representing half a dozen distinct genera ( Cassia, Microrhainnus, Celtis, 

 Krameria, Acacia, Bandia, Stegnospherma, Franlcenia, etc), while con- 

 siderable tracts are sparsely occupied by straggling tufts of the Sonorau 



greasewood, or creosote bush (Larrea tridentata), whose minute but 

 bright green leafage relieves that prevailing gray of the landscape in 

 which the lighter greens of the paloverde and cactus stems are lost. 



Intermingling with the woody trees and shrubs in most stations, and 

 replacing them in some, are the conspicuous and characteristic cacti 

 in a score of forms. East of Desierto Enciuas, and sometimes west 

 of it, these are dominated by the saguaro (Cereus f/if/antens), though 

 throughout most of Seriland the related saguesa {Cereus pringleiif) 

 prevails. The saguaro is a fluted and thorn-decked column, 1 foot to 3 

 feet in diameter and 10 to GO feet in height, sometimes branching 

 into a candelabrum, while the still more monstrous saguesa (figure 4) 

 usually consists of from three to ten such columns springing from a 

 17 ETH 3 



