4 BOTANICAL FEATURES OF NORTH AMERICAN DESERTS. 
Godfrey Sykes, of Flagstaff, Arizona, participated, and an authentic 
map of the delta and contiguous regions was prepared, which was pub- 
lished in 1905, the principal features of which are reproduced in plate 34. 
Workers in several branches of science have visited Tucson for lim- 
ited periods and used the facilities of the Laboratory for securing desired 
information concerning their special researches. 
It was deemed desirable to correlate the work being carried on at the 
Desert Laboratory with the other botanical investigations of the Institu- 
tion, and by act of the Trustees on December 18, 1905, the Department 
of Botanical Research was created, with Dr. D. T. MacDougal as director. 
The staff of the station was constituted of Dr. W. A. Cannon, Dr. B. E. 
Livingston, Prof. V. M. Spalding, and Mr. Godfrey Sykes; and Prof. F. E. . 
Lloyd was appointed for one year to complete his work upon stomata. 
In accordance with the newly formed plans, the Desert Laboratory, 
at first established to carry on certain special investigations, was made 
the headquarters of the department and, so far as possible, the efforts of 
the members of the staff not resident at Tucson were brought into correla- 
tion with the activities of the Laboratory. 
The reorganized staff assembled early in 1906 and operations were 
begun at once by which the capacity of the Laboratory was doubled, a 
greenhouse was erected, a new pumping-plant and reservoir for well- 
water and rain-water constructed, and a wire fence was thrown around 
the principal tract of the domain of the Laboratory. By the acquisition 
of controlling titles, the tract of land originally given to the Institution 
for the use of the Laboratory in 1903 was increased to 860 acres, includ- 
ing nearly the whole of Tumamoc Hill and a large area of mesa-like 
slope to the westward. 
In addition to the individual researches undertaken by the various 
members of the staff, other questions arise in the activity of a laboratory 
of this kind which require the combined and organized effort of the entire 
staff for a term of years. Work of such character demands the utmost 
exactness and fullness of records, in which the observations and experi- 
mental results are interpreted in the broadest general manner. Fur- 
thermore, it is important that such work should be begun by adequate 
methods, and that it cover possible developments in advanced stages of 
the work, if the results obtained are to be commensurate with the total 
effort expended. ‘ 
A group of problems of this character was offered by the depressed 
basins which form a part of the delta of the Colorado River and which 
have an exceedingly arid climate. 
Much of the more pronounced desert of North America has been in 
submersion during comparatively recent geological periods, and conse- 
quently the origin and distribution of the highly specialized flora which 
inhabits such regions have resulted from forces which may now be studied 
