CONTENTS. 
Page 
Introduction. ..........-.-...--._-. -------------------------------------- 9 
The botanical explorers of Washington. __...-.-.--.---------------------- 10 
Menzies ....._..____. ____------ eee eee eee ee ee ee ee 11 
Lewis __...------- nnn eee 11 
Douglas -._..--.--.-------------------- -------------------- ---- ------ 12 
Scouler _______._-..-.-----.---.------------ -------------------------- 13 
Tolmie _..__.._____-__..--.----------- +--+ ------ -- +--+ +--+ ------ 14 
Gairdner _______--__--.-. ..-.---.-___-------------------------------- 14 
Wyeth ._._........--------------------------------------- + --- +--+ 14 
Nuttall__.______.......-.-------------------- (ee eee eee eee eee eee 14 
Pickering and Brackenridge ---.-...---.------------------------------ 15 
Geyer_--- | eee ee (ee ee ee eee ee eee 16 
Spalding = = __-. -- ee ee eee eee ee ee eee > 16 
Lyall... see eee eee ee ee ee ee ee ee eee ee 16 
Jeffrey _..4#__._-_---.-------- --- =. 22 2-2 = 2 22 2 - --- --- 17 
Cooper __.___.__-.--------------------- ----------- +--+ -- 2-25 52-2 17 
Collectors since 1860 ___.._ --------------- Oe ee ee eee eee ee 17 
Physiography and geology ----. -----.------------------------------------ 20 
The Pacific Coastal Plain _..........__..----------------------------- 20 
The Olympic Mountains --_.-_.--....-.-------------------------------- 21 
The Puget Sound Basin __._-_--.------------------------------------- 21 
The Cascade Mountains .__.......---.-------------------------------- 22 
The Okanogan Highlands __-.-------.-------------------- ------------ 24 
The Columbia Plains. _._...........---.-------------------- neces a 24 
The Blue Mountains _____...---.----------.-------------------------- 26 
Climate ________._...---.. 2 eee ee ee eee ee ee 26 
Precipitation ___.__.___-.-------------------------------. ------------ 26 
Sunshine and cloudiness ___.__. ..-.----.----------------------------- 29 
Temperature ___....._.-.-------------------------------------------- 30 
Western Washington --.--.- wee eee eee eee eee eee eee eee eee ee eee 30 
Eastern Washington. _._..__.------------------ ------------------ 31 
Winds ___..__________ eee eens we ee ee eee ee eee 32 
The Zonal distribution of Washington plants - --- --- ee eee eee eee eee eee 33 
Upper Sonoran life area...._....------------------------------- ee 36 
Origin of the Upper Sonoran flora ---...--.------------------------ 37 
Humid Transition area _..........----------------------------------- 40 
Uplands. .__.....------------------------------------ +--+ -------- 41 
Bottom lands __._.__-...-. ---------------------- woe eee eee eee eee 42 
Gravelly prairies __.__-.-------.------------------ eee ee eee eee 42 
Seashores._____._______-------------------- --- 2 ee ee ee ee 45 
Sphagnum bogs____------------------------------------- - loan eee 46 
The Coastal strip __.._.-.---------------------------------------- 46 
Arid Transition area ___.____.--..-------.---------------------------- 47 
The Bunchgrass prairies ____--.._.-------------------------------- 48 
The Yellow Pine forests. _...---- (oe eee ee ee eee ee ee eee eee eee 50 
