DESERT PLANTS 



55 1 



the heavy fogs of the California coast are in this way a source of supply 

 for Cakile and other halophytes. In none of these cases, however, is the 

 existence of the plants concerned so dependent upon atmospheric absorp- 



Fig. 4. A Sahuaeo (Carnegiea gigantea) of which the Main Stem has been 

 Dead fok over a Yeah, with three living branches, one of which bore flowers. 



tion as has been found by Professor Peirce for the lichens which thrive 

 in the fog channels leading up the valleys and over the passes along the 

 Pacific shore. 



Any study of this subject leads in the end to a consideration of the 



