BOTANY 



Rainfall for the year ending June 30, 1916, was generally up to the 

 average or somewhat above, for the State as a whole. This was true 

 both as concerns the summer and the winter rainfall. As usual most of 

 the summer precipitation took place during July and August. October 

 and November were dry months and there was little growth on the 

 ranges after the middle of October. The long dry fall was unusually 

 favorable for the natural curing of the bunch grass growth, and also 

 enabled stock to consume the heavy crop of mesquite beans before this 

 could be damaged with moisture. 



The winter rains were abnormally heavy during December and 

 January and lighter than the average in February and March. As is well 

 known, rainfall on the ranges before January 20 is of less value than 

 that which comes later, and when heavy it may prove even detrimental. 

 The heavy rainfall of the earlier winter months caused considerable 

 erosion on the ranges and also serious floods in many of the river val- 

 leys and washes. Besides this, it damaged greatly the bunch grass feed 

 on the ranges through leaching. And, finally, it came at a time when 

 the temperatures were too low, even on the warmer desert ranges, for 

 active winter annual growth. When the temperatures were more favor- 

 able, in February and Anarch, the rainfall had dropped off greatly with 

 the result that the growth of the late winter and spring forage was not 

 as heavy as it would have been with a more timely distribution of the 

 rainfall. The rainfall on the small range reserve, near Wilmot, Ari- 

 zona, which is typical of southern Arizona fanges at the lower altitudes, 

 may be cited as an example of this. The total precipitation for this 

 area for the year ending June 30, 1916, was 13.95 inches, or about 2 

 inches above the average. Of this 5.65 inches fell during the summer 

 period, July to October inclusive, and 8.17 inches in the winter season, 

 December to April inclusive. Of the latter, 6.22 inches came during 

 December and January, which left but 2 inches of moisture to mature 

 the growth begun in the winter season. Naturally, this growth was 

 shorter than it would otherwise have been. 



ROOT-ROT DISEASE 



During the year, Mr. Uphof and the writer devoted some time to 

 the study of root-rot of alfalfa and fruit trees, both in the field and in 

 the laboratory. This work led to the isolation of several different or- 



