i 9 o 4 ] 



MAC DOUGAL— DELTA AND DESERT VEGETATION 



55 



The large number of species with laticiferous juices was especially 

 noticeable, but with the exception of the dozen Cacti no plants with 

 organs for the storage of water were seen, a fact possibly connected 

 with the extremely low precipitation and low water content of the 

 soil at all times. Seeds of a Cenchrus were very abundant and were 



w.- 



- 

 Sam*- *► 



Fig. 6. — Desert of Baja California, looking westward from beach north of San 

 Felipe Bay; Opuntia, Covillea, and Fouquiera. 



used by burrowing rodents as a means of fortification of the entrances 

 to their burrows, in the same manner that the joints of the "cholla" 

 are employed elsewhere. 



A mountain to the southwestward of San Felipe Bay was climbed 

 and a summit reached at an elevation of over iooo m . The granite 

 slopes supported a sparse vegetation of such types as Mammillaria, 

 Ephedra, Bur sera micro phylla, Aschpias albicans, Eriogonum infla- 



