The Trees of Vermont 



11 



VII. winter twig 



OF BLACK WALNUT 



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unaided eye can discern the tip-scars on some of the larger twigs, but 

 a hand lens will be found necessary when the smaller twigs are under 

 observation. 



The arrangement, size and shape of the 

 leaf-scars (c, fig. vii) are important fac- 

 tors in identification by winter characters. 

 Within the leaf-scars are one or more dots 

 (d, fig. vii), sometimes quite inconspicuous, 

 often very prominent. These are the scars 

 left by the fibro-vascular bundles which run 

 through the petiole into the blade of the 

 leaf, and are designated as bundle-scars. 

 There may be many as in the oaks, three 

 as in the poplars and cherries, or only one 

 as in tamarack and the spruces ; and they 

 may be arranged in a U- or V-shaped line, 

 or they may be without definite order. Often 

 stipule-scars (d, fig. vi) occur on either side 

 of the leaf-scar and are caused by the fall 

 of a pair of small leaflets called stipules, 

 located at the base of the leaves. Their 

 form varies according to the form of the 

 stipules which made them 



Bark. — The woodsman uses the bark 

 more than any other feature in identifying 

 trees, and often he is able in this manner 

 to distinguish trees with much accuracy at 

 great distances. However, the appearance 

 of bark differs so greatly with the age of 

 the tree and with its environment that it is 

 difficult to describe it accurately. Some char- 

 acters are distinctive, however, and serve as 

 a ready means of identification ; as for ex- 

 ample the peeling of the sycamore and paper 

 birch, the "shelling" of the shellbark hickory and the mucilaginous 

 inner bark of the slippery elm. 



Wood. — Under this heading are exhibited some of the general 

 characteristics of wood. While it is not expected that this information 

 will be of any particular value to the student of' tree botany in identify- 

 ing living trees, it happens often that such a one finds himself in the 



4: 



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Lateral bud. 

 Lateral bud. 

 Leaf-scar. 

 Bundle-scars. 

 Pith. 



