444 



THE AMERICAN NATURALIST 



[Vol. XLIV 



problems of desert vegetation and expressly points out the need 

 of continued investigation not merely of the area under con- 

 sideration (the so-called "Desert Laboratory domain"), but of 

 comparative studies of more areas widely distributed through 

 the desert. 



Having set itself the task of interpreting the ways of plants 

 in the desert, the management of the desert laboratory began 

 by investigating intensively a small area of typical desert country. 

 The laboratory site appears to have been selected with a view 

 to having at its door this ideal field of investigation, which is an 

 area of not over a mile in radius. 



Professor Spalding rightly supposes that no other small area 

 anywhere has had centered upon it the intensive study of so 

 many well-equipped investigators as has this typical bit of desert, 

 and he might have added that perhaps in no other case has there 

 been a more adequate equipment of apparatus and instruments 

 for work of a precise nature and, in the reviewer's opinion, 

 no other instance where more adequate methods have been de- 

 vised for pursuing the investigations. 



The work of collaborating specialists is largely presented as 

 distinct sections or chapters of the book. 



The geology of the vicinity of the Tumamoc Hills is presented 

 with particular reference to its relation to the distribution and 

 movements of plants by Professor C. F. Tolman, of the Univer- 

 sity of Arizona (pp. 67-82), in the chapter on Environmental 

 and Historical Factors. In this chapter also Dr. B. E. Living- 

 ston contributes a section (pp. 83-93) on the soils of the desert 

 laboratory domain. Reference is made here likewise to the evap- 

 oration studies conducted by Dr. Livingston. It is of course 

 beyond the range of the present reviewer's task to take up Dr. 

 Livingston's work in detail, but it seems an appropriate place 

 in which to point out a striking case in which endowed research 

 has yielded results of far- reaching application in behalf of eco- 

 nomic development, namely, in the relation of soils and evapora- 

 tion to plant production generally. 



Dr. W. A. Cannon, of the Desert Laboratory staff, contributes 

 a thoroughgoing study of the root system of the giant cactus 

 (Cereus giganteus), together with a comparison of the root sys- 

 tems of certain other marked desert species (pp. 59-66). Such 

 specific studies furnish the source of reliable data for conclu- 

 sions as to the relation which the habits and structure of plants 

 bear to their distribution. 



