C X T 1: X 1^ S . 



Page. 



Introduction 9 



The b.itauical explore: s of Washington 10 



Menzies 11 



Lewis 11 



Douglas ---- 13 



Scouler 13 



Tolniie 14 



Gairdner -. 14 



Wyeth .__ 14 



Nuttall 14 



Pickering and Brackenridge 15 



Geyer 16 



Spalding .. 16 



Lyall 16 



Jeffrey _. 17 



Cooper ^ 17 



Collectors since 1860 _ - IT 



Phys'ography and geology . . _ _ 20 



The Pacific Coastal Plain 20 



Th3 Olym- ic Mou tains 21 



The Puget Sound Basin 21 



The Cascad > Mountains 22 



The Okanogan Hi-hlands _• 24 



The Columbia Plains 24 



The Blue Mount ains ~6 



Climate 26 



Precipitation 26 



Sunshine and cloudi ; e;- s 29 



T mperatiire -^0 



Western Wf, shington 30 



. Eastern Washington 31 



Winds ,.. 32 



The Zonal distribution of Washington plants 33 



Upper Siinoran life a: ea 36 



Origin of the Upptn- Sonoran flora 37 



Humid Ti ansition area 40 



Uplands 41 



Bottom lands . 42 



Gravelly prairie ; 42 



Seashores ; - - 45 



Sphaguura bogs . 46 



The Coastal strip 40 



Arid Transition area 47 



The Bunchgrass prairies . . . 48 



The Yellow Pine forests ^ 50 



