82 



AMERICAN 



MAPLE TWIGS 



Sugar, Silver, Norway and Box Elder. The graceful delicacy 

 of the slender twigs of the maple is marked. 



FORESTRY 



distinctions of shape than this. The scars of the white 

 and red ash are similar except that the top hne of the 

 white ash scar has a notch in the middle of it and the red 

 ash has no notch. The same difference occurs in the scars 

 of the walnut and the butternut. Sometimes the leaf 

 scars extend fully round the tree. They just meet in the 

 Norway maple, but there is a little spur formed at the 

 l)oint of meeting in the box elder (the ash-leaved maple.) 

 Every rib and vein in a summer leaf is in reality the 

 end of a sort of tube or channel which runs back through 

 the petiole of the leaf, down the stem, and communicates 



Sl(..\K. .NORW.W .WD .SILVER MAPLE TWIGS 

 This -.hows the great diversity of the buds in the same genus. 



BUR OAK TWIGS, SHOWING CORKY RIDGES 



The younger branchlets are often conspicuously corky-ridged, 

 but this is not an altogether dependable characteristic. 



with the root system. When the leaf fell in the autumn 

 each of these elements of the circulative system of the 

 tree left its individual mark. These bundle scars, as they 

 are called, vary greatly in number, shape, position and 

 distribution, but are uniform for a given species. There 

 may be one, three, seven, etc., arranged in a straight or 

 curved line, or variously grouped. Unless one uses a 

 hand glass for inspection the leaf scars of the elm and of 

 the mulberry look very much alike. One is oval, the 

 other, perhaps, a trifle more flattened. Both have sev- 

 eral bundle scars on a depressed center of the leaf scar. 

 Rut a closer examination with the glass reveals the fact 

 that the bundle scars of the white elm are still further 



