8 CONTENTS. 



The Zonal distribution of Washington plants— Continued. Page. 



Origin of the Arid Transition flora 51 



The Calif omian 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 



Mount Stuart and the Wenache Mountains 68 



The Blue Mountains ... 71 



Plants known to occur only in Washington '. 73 



Plants which probably will be found to occur in Washington _ 75 



Annotated catalogue of the species of vascular plants of Washington 76 



Addenda :.. 613 



Bibliography 615 



Geographic index 619 



ILLUSTRATIONS. 



PLATES. 



Facing pago. 



Plate I. Giant cedars ( Thuja plicate) Frontispiece 



II. Topographic map of Washington 20 



III. Characteristic vegetation of the bluffs along Puget 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 ( Pseudotsuga mucronata) in Washington 41 



VIII. Characteristic view in a moist forest . 41 



IX. Pasture-like gravelly prairies of Pierce County 42 



X. Lupinus rivularis on the gravelly prairies in Pierce County 43 



XI. Prairie of bunchgrass {^Agr^pyron spicatum) on the Horse 



Heaven Hills, Klickitat County 48 



XII. Range lands near Whits Stone Lake, Olianogan County 48 



XIII. View in a coulee near Lyons Ferry 49 



XIV. Forest of yellow pine (Pinus ponder osa) 1 50 



XV. Forest of yellow pine (Pinus ponderosa) 50 



XVI. Forest of hemlock (Tsugaheterophylla) ... . 58 



XVII. Subalpine firs {Abies lasiocarpa) in Paradise Valley, Mount 



Rainier 60 



XVIII. Vegetation of the Gorge of the Columbia River 67 



XIX. Bunchgrass (Agropyron spicatum) 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 



