192 TREES IN WINTER 



ANALYTICAL KEY 



METHOD OF USE 



Despite the fact that the appearance of the bark and the method 

 of branching are almost exclusively depended upon by the experi- 

 enced woodsman in recognition of species, these characters are 

 difficult of precise description and not adapted to use in a key. 

 The twigs therefore with the scaly buds and leaf-scars are used, as a 

 basis of the following keys. The word "twig" in the sense here 

 used, it should be remembered, denotes the growth of the past 

 season only, and the word "bark" refers to the bark of the trunk 

 and older limbs and not of the twigs or branchlets. The student 

 should read the foregoing section and note the limitation of terms 

 and characters used in the following pages. 



Before attempting to identify an unknown tree it is necessary 

 to have good material to work with. Care should be taken that 

 the twigs selected are normal in appearance, being neither abnor- 

 mally stunted in growth nor unusually elongated as are twigs on 

 young sprouts. Frequently the species may be determined by an 

 inspection of the twigs alone but notes on the character of the 

 bark and the habit of growth as well as specimens of the fruit will 

 generally be found useful and sometimes necessary. 



In the key a choice is given between two paragraphs preceded 

 by the same number. This choice leads to a new number or to the 

 name of the species followed by the page where a detailed 

 description of the tree may be found. The White Ash may be 

 used to show the method of procedure. Starting with N'o. 1 we 

 have the choice between trees with "leaves persistent and green 

 throughout winter" and trees with "leaves 7iot persistent and green 

 throughout winter." We choose the latter and this takes us to No. 



11 where the decision must be made between "leaf-scars opposite 

 or in 3's" and "leaf-scars alternate." The leaf-scars on the Ash 

 are opposite and we take the first 11 and are led to No. 12. At 



12 we have the alternative between "leaf-scars, or some of them, 3 

 at a node" and "leaf-scars always 2 at a node." The first pair 

 of contrasting characters mentioned are always the most important. 

 The constant presence in the Ash of two leaf-scars at a node is 

 sufficient to cause us to choose the second 12, and our choice is 

 corroborated by the position of the bundle-scars and by the presence 

 of a terminal bud, so we pass to 13. The upper lateral buds of 



