218 



of ash, dog^voocl, alder, willow, and other low shrubs. On the 

 lighter gravelly soils, Querciis Garryana is the prevailing tree. 

 Many fine groves of the "Douglas fir" (Pseudotsnga taxifolia) 

 still exist in the level areas, and cover the steeper slopes of the 

 foothills. 



The climate is more oceanic than continental in character. 

 There are two sharply contrasted seasonal periods. During the 

 autumn, winter and spring months, the rainfall is heavy, some- 

 times as much as 14 inches in a single month, with a minimum 

 winter temperature of not below 20 degrees Fahrenheit. The 

 summer on the other hand is almost rainless, and temperatures 

 of 100 degrees are not unknown. During the long dry season 

 the porous soil becomes thoroughly desiccated, and all herbaceous 

 vegetation not under cultivation, with the exception of a few 

 drought-resisting plants and those along the streams, is dried up. 

 On the setting in of the fall rains, however, the vegetation 

 speedily revives, and continues green and luxuriant during the 

 mild winter, reaching its maximum development in 'Wax and 

 June. These conditions make it ven.' difficult for any of the 

 introduced pasture-grasses to survive the summer; and while a 

 few of the native species seem better adapted to the arid environ- 

 ment, little attention has hitherto been given them. 



Xo comprehensive attempt to catalogue the grasses of this 

 region seems to have been made. This will be evident from the 

 number of species included in the following list which have not 

 found mention in any of the published manuals dealing with the 

 flora of Western Oregon. These species are marked "X." 

 Introduced species are designated by an asterisk (*). The 

 nomenclature conforms to that used in A. S. Hitchcock's treat- 

 ment of the Gramineae in Jepson's Flora of California (i : 82-189. 

 1912). The writer is under obligation to Professor Hitchcock 

 and Mrs. Agnes Chase for their kindness in examining and verify- 

 ing practically all of his specimens. Professor C. \\ Piper has 

 kindly placed the results of his long and careful study of the 

 flora of the Xorthwest at my disposal; and Professor M. E. 

 Peck of Willamette University, who is probably more thoroughly 

 conversant with the flora of Oregon than an}' other Western 



