INTRODUCTION 



Winter, spring, summer, and fall, big-game biologists, forest rangers, 

 hunters, and recreationists are on the mountain trails of eastern 

 Oregon and eastern Washington. Regardless of season, shrubs are 

 always conspicuous to these travelers. And in the work of game 

 biologists and rangers, knowledge of browse plants at all seasons is 

 becoming increasingly important, Hence, a demand has arisen for 

 a shrub key based on'twig or leaf characters and prepared in laymen's 

 language. This key represents an attempt to meet that demand. 



Vegetative keys designed to distinguish shrubs without reference 

 to flowers or fruit require the definition of many characteristics for 

 each species. Therefore, some of the species descriptions are rather 

 lengthy; however, primary characteristics are in boldface type and 

 will commonly suffice to identify a shrub. 



Primary divisions of the key are based on whether or not a plant 

 is "evergreen" and the season of the year. Subsequent divisions 

 make use of such simple characteristics as arrangement of twigs 

 (alternate or opposite branching), subdivision of leaves, and the 

 presence or absence of thorns. Within the major divisions, each pair 

 of alternative characters is given the same number for the convenience 

 of the user. By choosing one character of a pair as applicable and 

 proceeding to the next pair, the user can move quickly through the 

 key to determine the name of the specimen he is interested in and can 

 compare the specimen with the illustrations provided. 



The alternate character of buds, leaves, and twigs for some species 

 is examined in more detail. For them the spiral arrangement serves 

 as a further characteristic for quick and reliable identification. Smooth 

 sumac is an excellent example (fig. 1). Starting with any given bud 

 and counting clockwise around the stem, the observer makes two 

 complete circles to reach the next bud directly above, and in the 

 process counts this bud as the fifth. This is called the % bud arrange- 

 ment, the one most commonly found; each bud is 144 degrees around 

 the stem from the preceding one. A % bud arrangement is found in 

 the wax currant (fig. 2). 



Scientific or Latin names are given for each species in addition 

 to common names, which follow the nomenclature in Standardized 

 Plant Names, by Harlan P. Kelsey and William A. Dayton (2d. ed., 

 1942). The index of accepted scientific and common names also 

 includes such synonyms as are needed for cross-reference to names 

 used in Oregon and Washington manuals or floras commonly con- 

 sulted. 



Botanists have not explored all of the Okanogan highlands, the 

 Blue Mountains, and the east slope of the Cascades; hence, some 

 shrubs may be found that are not among the 180 or so species and 

 varieties listed in the key. Some omissions were deliberate, as was 

 the case with certain willows. The 18 willows presented are the ones 

 most commonly encountered. In a work of this kind, more than errors 

 of omission are bound to occur in the first edition, but it is hoped none 

 of them will seriously handicap the field worker. 



The present work is the outcome of plant collections by the authors 

 and R. S. Rummell. During preparation of the key from collections 



