41 



The committee in [jerfurminy its work visited all the more im- 

 portant arid districts in the west, noting the character of the vege- 

 tation, and physical and soil conditions. This led them first into 

 the siliceous sand hills of Chihuahua, Mexico, and thence to the 

 drifting alkaline sand fields of the Tularosa Desert of New 

 Mexico, which cover an area of about lo by 40 square miles. 

 From the extensive arid country about Tucson, Arizona, with 

 its rich flora and varied conditions, they proceeded into the prov- 

 ince of Sonora, Mexico, giving an interesting account of the vege- 

 tation and the remarkable associations of forms occurring at 

 Torres and especially at Guaymas. Continuing westward, 

 detours were made at several points in the Colorado Desert, 

 revealing the extreme diverse topographical and soil conditions 

 which vary from mountains and hills to salt and alkali flats and 

 sand-swept plains. The exploration ended with a journey 

 through the Mohave Desert, concerning which Mr. Coville has 

 given a very comprehensive report in the Botan}' of the Death 

 Valley Expedition, and a trip to the Grand Canyon of the Colo- 

 rado. The selection, as a result of this survey of the field, of 

 Tucson, Arizona, as a site for the laboratory cannot be criticized. 

 It is situated on one of the great transcontinental lines, rendering 

 it easily accessible and the city of Tucson will furnish a con- 

 venient and satisfactory base of supplies. In addition to this the 

 large arid belt in this region presents a typical desert flora and 

 with such a diversity of conditions that it is exceptionally rich in 

 woody and annual species. It is to be hoped that the laboratory 

 may not only furnish facilities for the investigation of plant life in 

 the country adjacent to Tucson, but that it may have as one of 

 its functions the equipment of expeditions to the numerous 

 promising districts noted in the report. 



The value of the report has been greatly enhanced b}- the in- 

 troduction of thirty-nine illustrations of desert views. It is safe 

 to say that these are the most remarkable scenes of desert plant- 

 life that have ever been published. They bring very vividly before 

 us thecharacter of the vegetation and the atmosphere of the region. 



The Desert l-5otanical Laboratory of the Carnegie Institution 

 is to be congratulated on having so favorable an introduction to 

 the public. Carlton C. Curtis. 



