2 BULLETIN 545, U. S. DEPARTMENT OF AGRICULTURE. 



of tannic acid, which renders them unpalatable are of little or no 

 value for forage. 1 



In order to gain an intimate knowledge of the habits, requirements, 

 and life history of the more important species, a study was initiated 

 in 1907 by the Forest Service, in cooperation with the Bureau of 

 Plant Industry, upon the Wallowa National Forest in northeastern 

 Oregon. Data on the relative palatability of the different forage 

 plants were gathered by following bands of sheep and observing 

 their choice of feed as they grazed. Afterwards the relative value 

 of the individual range plants was determined by studying (1) their 

 abundance, distribution, time of flower-stalk production, aggressive- 

 ness, reproduction (both vegetatively and by seed), and seed habits; 

 and (2) their palatability and nutritiousness at various times during 

 the grazing season and their ability to withstand trampling. The 

 plan of study and the methods used are fully described at the end of 

 the bulletin. 



While the results of the study are largely based upon observations 

 in the high mountains in Oregon between elevations of 5,500 and 

 8,000 feet, they should nevertheless be helpful to stockmen through- 

 out the West in revegetating the range, since many of the species 

 described are widely distributed, and the genera represented are 

 among those of first importance on most of the natural range lands of 

 the West. 



A photograph of each important species in natural size accom- 

 panies its description, but where the general characters of two or 

 more species of the same genus are similar, a single photograph is 

 used. With the exception of Plate XXXVIII all specimens selected 

 for photographic purposes were either in flower or fruit, or both, 

 and care was taken to show the general character of the root sys- 

 tem, habit of growth, and external structure. Not only will these 

 photographs make possible, in practically every instance, the recog- 

 nition of the same species when met with in the field, but also other 

 species of the same genus will be recognized as congeneric, although 

 the specific name may not be known to the observer. 



CHARACTER OF THE RANGE AND FORAGE STUDIED. 



Between the lower and higher grazing lands of the mountains of 

 northeastern Oregon is a difference in elevation of about 7,000 feet. 

 Along with this wide altitudinal variation go widely different growth 

 conditions. Thus, according to the character of the vegetation, 

 the lands studied may be classified into four zones. 2 



1 The results of natural revegetation studies based upon observation of the plants described in this bulle- 

 tin are presented by Ihe writer in U. S. Dept . Apr. Bui. 31, " Range Improvement by Daferrcd and Rotation 

 Grazing," 1913, and in the Journal of Agricultural Research, Vol. Ill, No. 2, "Natural Revegetation of 

 Range Lands Based upon Growth Requirements and Life History of the Vegetation," 1914. 



- Iferriam, C. Bart, "Life Zones and Crop Zones of the United States," U. S. Dept. of Agriculture, 

 Biological Survey Bui. Xo. 10, 1898. 



