THE AMERICAN BOTANIST 



87 



most plants as too little, but the water lily and a few others 

 adapted to deep water have escaped the crowd of plants by 

 moving into the lakes and ponds in a manner similar to the 

 movement of the cactus into the desert. 



HI. 



Cactus are not without their arborescent forms. 

 (Courtesy of Guide to Nature) 



The spines of the cactus, instead of being reactions to the 

 attacks of animals, appear to be caused by desert conditions. 

 Wdierever the air is dry, the vegetation, no matter what family 

 of plants it belongs to, is likely to be armed. Moreover, cacti 



