114 NORTH AMERICA 



African and Asiatic deserts, the American desert is re- 

 markable for the extraordinary development of those 

 fleshy, thorny, leafless, or apparently leafless, plants 

 called succulents. Nowhere in the world is there such 

 a combination of w 7 eird, ungainly, menacing shapes: 

 giant candelabra cerei of most diverse varieties, ma- 

 millarias, opuntias, yuccas, agaves, dasilyrions, nolinas, 

 &c. Hardly less strange are the leafless brushes of the 

 creosote-bush (larrea) and the ocotillo (fouquiera) and 

 the formidable spines of several thorn-bushes belonging 

 to the acacia and mimosa type. A good many plants 

 wich strong underground stems only show themselves 

 after the occasional showers. This water-storing vege- 

 tation provides the rare native or traveller with a 

 beverage w 7 hich, such as it is, is often most necessary. 



Proceeding eastward, one has to cross a mountainous 

 tract which is the northern spur of the western Sierra 

 Madre : here the prickly chaparral resumes a prominent 

 position in the landscape, and pine forests crown the 

 summits and upper slopes. Not a few valleys collect 

 the underground waters and develop good pastures, while 

 some harbour delightful oases. 



Being destitute of large mammals, the American 

 desert does not even afford a good hunting-ground, and 

 the population is now dispersed in little communities 

 along the eastern margin and the few large rivers. Yet, 

 at one time, in more than one cafion, and on the out- 

 skirts of the plain, the Papagos Indians were able to 

 evolve a fairly advanced system of agriculture based on 

 extensive works of irrigation. These works reveal the 

 past existence of a highly organized agricultural com- 

 munity, of a centre of culture which has possibly 

 disappeared in the ever-present struggles between the 

 nomads and the house builders. 



