30 ANIMAL LIFE OF CARLSBAD CAVERN 



branches, it is generally eaten down to stumps by- 

 goats, cattle, and horses, and perfect plants are found 

 only in arid wastes or on inaccessible cliffs. 



The trifoliate barberry, or algireta of the Mexicans, 

 with its viciously spiny, three-pointed, and rigid ever- 

 green leaves, abundant large yellow and honey-scented 

 flowers, is one of the very successful shrubs of the 

 desert, resisting all enemies and bearing an abundance 

 of delicious berries, tart and refreshing when well 

 ripened. To the white people they suggest cranberries 

 and are used for jellies, but by the Indians they were 

 probably eaten either fresh or dried, as in camp we have 

 found them in either form very acceptable. 



The blue-thorn (Zi yphus lycioides) is a dense shrub as 

 high as one's head, growing singly or in clusters, with 

 small leaves on the branches and thorns and with 

 inconspicuous flowers and little blue berries. Almost 

 as spiny as the allthorn, it is one of the well armed 

 desert plants that can not be eaten or injured, and 

 offers its spiny protection to many less fortunate 

 plants as well as to birds and mammals. 



The sumacs of some three or four species are able to 

 exist without thorns or active poisons, for they exude 

 gums of rank odor and taste that evidently help to 

 keep browsing animals at a respectful distance. Still 

 in times of scarcity of other food they are sometimes 

 eaten, and the berries are the food of many birds and 

 small mammals. The small-leaved sumac grows to be 

 a large dense shrub, abundant in many places. The 

 evergreen sumac is recognized by its large green leaves, 

 and the skunk bush, with its trifoliate leaves, is a low 



