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THE AMERICAN BOTANIST 



grown in a moist atmosphere tend to lose their spines, and even 

 in some cases to put on leaves. 



The thousand or more species of cactus are all American, 

 though they are now to be found in many parts of the Old 

 World. The dry regions in other parts of the earth, however, 



The cactus is the response of vegetation to 

 desert conditions. . 



(Courtesy of Guide to Nature) 



have forms that are almost identical with those of the cacti, 

 but they belong to other plant families, among which the 

 spurge family is prominent. Many of these curious spurges 



