BOTANY 



J. J. TlIORXHnR 



The year ended June 30, 1919, was far from being favorable for 

 the grazing industry. The rainfall for this period was considerably 

 below the average throughout the State. This was particularly 

 true of the summer season, the precipitation of which was scant and 

 came mostly in light showers separated by dry, hot spells of from 

 one to three weeks' duration. The rainfall for this twelve-month 

 period at Tucson was 9.58 inches, which was proportionally greater 

 than in many other parts of the State. Of this amount 3.13 inches, 

 or 32.7 percent, came during the summer period, July to October 

 inclusive, and 5.31 inches, or 55.4 ]jercent, during the winter and 

 spring months, November tu .\pril. inclusive. The remaining 1.14 

 inches fell during May and June, 1919, and was not sufficient to 

 increase materially forage growth on the desert ranges. However, 

 on the prairies and in the foothills at altitudes of 3500 to 6000 feet 

 the rains in May were generally good and helped very much the 

 growth of the perennial grasses. 



The dry summer of 1918, unfortunately, was preceded by a 

 very dry winter and spring, with the result that conditions on the 

 stock ranges in the winter of 1918-19 were very bad and losses were 

 necessarily heavy. On many of the ranges there was practically no 

 feed during the winter season, and to prevent larger losses it was 

 necessary to ship stock out or feed them. This was noted in pan 

 in the Annual Report for the year ending June 30, 1918. 



With some exceptions, the winter and spring rainfall through- 

 out the State was nearly up to the average. Though never heavy 

 at any time, the winter rains, mostly in the form of showers, con- 

 tinued more or less regularly from November to May. inclusive. 

 January was the driest month, with but .26 of an inch rainfall : 

 while for the months of November, December, and April the rain- 

 fall averaged more than one inch. One-half the winter rainfall came 

 prior to February 1, during which season the temperatures are too 

 low for good winter annual growth, even at the lower altitudes 

 where the climate is mildest. The forage growth on the grazing 

 ranges during the spring months was slightly below the average, 

 but it was very timely. This, together with the favorable rains in 

 May, helped very much to carry stock on the ranges until July 1, 

 1919, when the summer rainy season set in heavily. 



