INTRODUCTION. 



When my Plant Materials pocket manual was issued, in 

 1917, an unusually full account was given of characters that 

 are not mentioned in the usual handbooks, but the keys were 

 based in large part on differences used by the old herbalists, 

 position and other peculiarities of the foliage. The key of 

 the present volume utilizes leaf-scar and bud differences in 

 the same manner. 



Because the keys of the first volume are as available for 

 coniferous evergreens in winter as in summer, this important 

 group of trees is not considered here at all ; but angiospermous 

 evergreens and the few deciduous conifers are treated now in 

 even greater fullness. To avoid .unnecessary repetition, fam- 

 ily descriptions are not repeated here, and the generic charac- 

 ters are confined to the direct purpose of the book. 



This purpose, naming our common trees and shrubs when 

 without foliage, involves a close accounting for small differ- 

 ences between small parts, so that illustrations are more in- 

 dispensable than for a Summer Manual leading to the same 

 end with the same plants. Such illustrations are inserted in 

 the text, where they may be used with convenience. Occa- 

 sionally a twig or leaf is pictured of natural size or reduced 

 to one-half (or in Magnolia one-fourth) its natural size. Ex- 

 cept for these and the self-evident cases of Ailanthus, Aralia 

 and Cedrela where details are seen easily without enlarge- 

 ment, the essential characters of leaf-scars, bud and pith are 

 shown with a uniform enlargement of three diameters, which 

 serves the purpose though details sometimes appear small as 

 a result. 



Even more necessary than in summer studies, is a good 

 pocket-lens of about 12-magnification; and it should bd an 

 invariable practice to examine carefully a number of buds 



vii 



