DEPARTMENT OF BOTANICAL RESEARCH.* 



D. T. MacDougal, Director. 



The researches carried on by the members of the staff, collaborators, 

 and research associates have chiefly concerned problems upon which 

 some progress has been made previously. The greater part of the work 

 of the Department is carried on at the Desert Laboratory. But little 

 established knowledge of the surfaces of arid regions is available, and 

 the prevalent methods of meteorology do not obtain facts capable of 

 ready analysis in a manner suitable for correlation with physiological 

 experiments. It is therefore necessary to carry out extensive calibra- 

 tions of the physical features of both the substratum and the atmos- 

 phere, although such activities are only incidental to botanical science. 



The completion of the photo-chemical laboratory makes available 

 facilities for a study of light in its relations to organisms in a manner 

 and with a thoroughness not hitherto attempted. Similar small, inex- 

 pensive, but suitably designed buildings, with adequate equipment, will 

 best serve the needs of workers upon other groups of problems within 

 the scope of the Department, as illustrated by the account of the de- 

 tailed activities described below. 



EREMOGRAPHY OF CLOSED DRAINAGE SYSTEMS. 



The comprehensive study of the Salton Sea and the surrounding 

 region in the Cahuilla Basin, begun in 1906, was brought to an advanced 

 stage in 1913, and the result was described in Publication 193 of the 

 Carnegie Institution of Washington, issued in June 1914. 



Some of the problems taken up in this region include phenomena of 

 such general importance and wide occurrence that their study is being 

 continued, both in the region in question and in the desert basins to 

 the northward in California, Utah, and Nevada. 



It has become evident that a detailed study of the decaying drainage 

 system of the Mohave, tributary to the Death Valley basin in Cahfornia, 

 would yield some conclusions of the greatest value as to the clima- 

 tology, surface geology, and ecology of desert basins. Plans are now 

 taking shape for such a survey, and the Director, in company with 

 various collaborators, has traversed the Mohave Desert, Owens Valley, 

 Deep Springs Basin, some of the Amargosa drainage, the basin of 

 ancient Lahontan, and the Washoe Valley, in a reconnaissance pre- 

 liminary to the organization of this work. The results of this phase 

 of the activity of the Desert Laboratory are given below. 



''Situated at Tucson, Arizona. (For previous reports see Year Books Nos. 2-12.) 



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