38 THE PLANT WORLD. 



facts will allow, strategy to attain new view-points from 

 which to plan the contest. Toward this idea we owe much 

 to the original suggestions upon the matter formulated by 

 Mr. F. V. Coville, which led to the establishment of the 

 Desert Laboratory. 



The actual material equipment in all of the researches 

 of the nature which have been considered are centered at the 

 Desert Laboratory at Tucson, Arizona, at an altitude of 2700 

 feet in 32° N. This modest workshop, which has nearly 

 reached its full expansion as to buildings and major equip- 

 ment is the center of the activities of all the workers con- 

 cerned, and its facilities are planned to meet their needs alone. 



The unusual advantages presented by its environment 

 need not be enlarged upon at this time, being simple and 

 apparent. The amplitude of the range of conditions em- 

 braced in the adjunct experimental opportunities are worth a 

 moment's attention. The domain of the Laboratory itself 

 embraces over a square mile of desert mesa and volcanic 

 mountain range of nearly a thousand feet. Near it is an 

 irrigated experimental area in the alluvial bottoms of the 

 Santa Cruz river. The shoulder of the nearby Santa Cata- 

 lina mountains offers suitable conditions for the arid planta- 

 tion at 6000 feet, while in a higher moist valley the 

 mountain station lies at 8000 feet. About 40 species of 

 plants are now variously introduced, distributed and ex- 

 changed among these places, with the result that some exist 

 through a vertical mile and in a series of climates varying 

 from humid sub-alpine to arid sub-tropical, with what marked 

 somatic responses I must leave to a future communication 

 for description. In these plantations the experiments are 

 limited to a few species, are carefully restricted as to scope, 

 and are more or less under cultivation, careful measurement 

 of the environic features being possible and necessary. 



The seven surveyed areas around the Salton Sea will 

 be the scene of purely observational work with such measure- 

 ments of conditions as may be possible. All of these investi- 



