INTRODUCTION. 



The grasses whicli are known to grow on the Pacific slope of the [Tnitert States, 

 including Alaska, number not far from 20(» species. These are all specifically distinct 

 from the grasses growing east of the Mississippi Eiver, and also mainly distinct from 

 the grasses of the plains and of the desert, except in that part of California which 

 partakes of the desert flora. 



A considerable number of the grasses of the mountain regions of California, Ore- 

 gon, and Washington reappear in the mountains of Idaho, Montana, and the interior 

 Kockies. The interior of California is a dry region, verging in the extreme south into 

 the desert country, and is deficient in grasses, especially of those species which form 

 a continuous turf. In this part of the present Bulletin we have figured and described 

 mainly those grasses which are most conspicuous in size and apparent utility. Nearly 

 all are here illustrated for the first time. The work will be of great \'alue not only to 

 botanical students, but to all persons interested in agriculture and in the raising of 

 domestic animals. 



The descripticms of the species are almost wholly the. work of my assi.stant. Prof. 

 L. H. Dewey. 



Geo. Vasey. 



