THE VOrCE OF THE DESERT 



64 



of a unique organ called the areole from which spines 

 are produced. Members of this family spread both north- 

 ward and southward and somewhere, possibly in what is 

 now one of the American deserts, they developed char- 

 acteristics which enabled them to survive a long annual 

 dry season. Then, when the slow Hfting of mountains 

 either in North or South America turned a seasonally 

 dry climate into a perpetually arid region they were 

 well on the way to their present ability to tolerate not 

 only seasonal but almost continuous drought. If all our 

 western mountains had always been where they are now, 

 there might be no cactus here because the country would 

 always have been too dry to permit the slow adaptation 

 of the family to arid conditions. If, on the other hand, 

 the mountains were not there now, then at least many of 

 the kinds of cactus now decorating the landscape would 

 not be there either, because the climate would be too 

 moist for them. 



What it all comes down to is this: the casual visitor 

 to the desert may not always be sure what is a cactus 

 and what is not. But he is quite right when he thinks of 

 cacti as the most characteristic plants of the region. Few 

 others have managed so successfully to make themselves 

 so completely at home there. No compromises, no. elud- 

 ings, no picking out of damp spots for the cactus. When 

 he came to the desert he took possession of it. Like the 

 road runner, he can say, as few other things can, "Veni, 

 vidi, vici/' 



