24 



BULLETIN 1170, U. S. DEPARTMENT OF AGRICULTURE. 



to approximately 10 in number. Only those species that are the 

 most abundant or significant are recorded, but the same ones are 

 listed in all the quadrats. Out of the number that have been listed, 

 three species stand out as of primary significance. These are Ar- 

 temisia dracunculoides, A. gnaphalodes, and A. frigida. Of these 

 A. frigida is of greatest importance, because it is an indicator of 

 overgrazing 20 and because the cattle refuse to eat it until they are 

 forced to do so. During the past two years the cattle in the 30-acre 

 pasture have lost weight, while many of these plants were still stand- 

 ing in the pasture. Plate VI shows how many of these plants were 

 left in the 30-acre pasture at the close of the grazing seasons of 1917 

 and 1921. From Figure 1 of this plate it will be noted that prac- 

 tically all plants were eaten in 1917, while Figure 2 shows numerous 

 plants of A. frigida still standing at the close of the season in 1921. 

 The cattle do not seem to hesitate about eating the other two species 

 of Artemisia, though they do not take them as readily as most of 

 the grasses. They begin to eat A. frigida when other feed becomes 

 scarce in the small pasture. It is usual to see scattered over the 

 pasture the stalks of this plant that the cattle have pulled off and 

 spit out. This sage is bitter and distasteful to them and is therefore 

 avoided. Plate VII illustrates the condition of the 30-acre pasture 

 on July 15, 1919, and on the same date in 1921. The photographs 

 here reproduced were taken at the time the cattle usually begin to 

 eat A. frigida and afford a very clear idea of the effects of continuous 

 overgrazing in relation to this species of sage. The dark plants in 

 Figure 1 are A. dracunculoides. It will be noted that none of these 

 plants can be seen in Figure 2. 



Table 5. — Number of plants of Artemisia frigida per square meter in 16 quadrats 

 in the 100-acre and 30-acre pastures in 1915 and in the same square meters 

 in 1920. 1 



100-acre 



30-acre 



100-acre 



30-acre 



pasture. 



pasture. 



pasture. 



pasture. 



1915 



1920 



1915 



1920 



1915 



1920 



1915 



1920 



10 3 







4 







1 







5 



2 1 



1 











3 



8 



4 11 



1 











2 



4 



9 3 



2 4 



3 " 1 







5 



2 



8 



3 1 







6 



1 1 



3 



1 2 



3 10 



4 5 



2 







3 6 



10 1 6 

 2 1 



4 11 



7 







51 



35 



17 85 



1 These 16 square meters are not included in the 40 list quadrats previously discussed. 



A. frigida (pasture sage) has increased about five times per unit 

 area in the 30-acre pasture since the experiment started. There has 

 been an increase not only in number but also in the size of the in- 

 dividual plants. Plate VIII, Figure 1, illustrates clearly the size 

 a single plant may attain. The increase in number is best shown by 

 Tables 5 and 6. In both the 100-acre pasture and the 30-acre pasture 

 16 quadrats were permanently located in 1915. They formed areas 



20 Shantz, H. L. Natural vegetation as an indicator of the capabilities of land for crop 

 production in the Great Plains area. U. S. Dept. Agr., Bur. riant Indus. Bui. 201, 

 100 pp., 23 figs., 6 pis. 1911. 



