C CONTENTS. 



The Zonal distribution of Washington plants— Continued. Page. 



Origin of the Arid Transition flora . _ 51 



The Californian element 51 



The Rocky Mountain element ... . 53 



The Columbia Basin element - . 52 



Comparison of the Humid and Arid Transition floras. 53 



The Canadian zone 58 



The Hudsonian zone 60 



The Arctic zone . . 62 



Regions of peculiar botanical interest ... 65 



The Olympic Mountains ... 65 



The Columbia Gorge . 67 



Klickitat County .... 68 



Moiint Stuart and the Wenache Mountains 68 



The Blue Mountains ... 71 



Plants known to occur only in Washington 73 



Plants which i)robably will be found to occur in Washington 75 



Annotated catalogue of the species of vascular p'ants of Washington 76 



Addenda 613 



Bil)]iography 615 



Geographic index 619 



ILLUSTRATIONS 



PLATES 



Facing page. 



Plate I. Giant cedars ( Tli iija iiJicata ) Frontispiece 



II. Toi)ographic map of Washington 20 



III. Characteristic vegetation of the bluffs along Piiget Sound 21 



IV. Steamboat Rock, in the Grand oulee 25 



V. Rainfall map of Washington 28 



VI. Sagebrush plains in Yakima County . 36 



VII. Forest of red fir ( Pscudotsuga miicronata ) in Washington 41 



VIII. Characteristic view in a moist forest . 41 



IX. Pasture-like gravelly prairies of Pierce County 42 



X. Lnj^iniis rivularis on the gravelly prairies in Pierce County 43 



XI. Prairie of bunchgrass {Agv >pyron spicatnin) on the Horse 



Heaven Hills. Klickitat Coiinty 48 



XII. Range lands near Whita Stone Lake, Okanogan County 48 



XIII. View in a coulee near Lyons Ferry 49 



XIV. Forest of yellow pine {Pin us xtonderosa) 50 



XV. Forest of yellow pine {Finns p)onderosa) 50 



XVI. Forest of hemlock ( Tsuga heterophylla) ... . . 58 



XVII. Subalpine firs [Ahics lafiiocarpa) in Paradise Valley, Mount 



Rainier 60 



XVIII. Vegetation of the Gorge of the Columbia ! iver 67 



XIX. Bunchgrass {Agropyron spicatnin) growing on basalt outcrop- 

 pings 146 



XX. White hellebore ( Veratrum calif ornicum) 196 



XXI. Iris missouriensis . . 202 



XXII. Lupinus ornatus in low meadows near Wenas 355 



MAP. 



Map showing the floral areas of the State of Washington In pocket 



