578 Thirty-second Annual Report 



browse (Cercocarpus) , and service berry (Amelanchier) , was 

 often abundant and diversified. At Grand View on the rim 

 of Grand Canyon in June, 1921, cattle were looking well and 

 were subsisting almost entirely on the leaves and twigs of post 

 oak, cliff rose or quinine bush, deer browse, and two species of 

 service berry. Generally, these shrubs were closely browsed to 

 a height of six feet or as high as the animals could reach. Dur- 

 ing June and even as late as the middle of July the growth of 

 grasses on these ranges had scarcely started, nevertheless the 

 stock were in fair to good condition. Browse plants and shrubs 

 are deeper and more permanently rooted and hence can endure 

 dry weather better and continue growth longer during a 

 drought than grasses or other herbs. As stated in an earlier 

 report, under favorable conditions the pure grass, ranges very 

 likely give larger yields than the mixed forage ranges, i. e., 

 those with a growth of browse and grass, but they do not give 

 as continuous a supply of feed throughout the year. 



In marked contrast with the condition of stock on the 

 browse-grass grazing ranges was the pitiable condition of stock 

 on the prairie grass lands having little or no growth of browse 

 plants and on areas where drought or frost had retarded the 

 growth of browse. Not alone was the percentage of losses 

 heavy, but the animals that survived came through the year 

 generally in very poor shape. Even with the return of favor- 

 able rains, such animals must continue to be a liability for 

 months to come. 



During the year a remarkably small number of instances 

 of losses of stock from poison plants have been reported. This 

 is not unusual during long droughty periods, since at such times 

 the poison plants make little or no growth. 



INSTRUCTIONAL DUTIES 



During the year just ended, as head of the Department of 

 Biology, the writer has found it necessary to give a larger pro- 

 portion of his time than heretofore to instruction in the de- 

 partment. This was due to the large increase in the number 

 of students in the department, to the writer's giving full time, 

 in the absence of an instructor, to instruction for one month 

 at the beginning of the regular school year at the University, 

 and one-half time during the remaining eight months. In ad- 

 dition to the above, the writer taught six weeks at the Uni- 

 versity Summer School, Flagstaff, Arizona. 



