CHAPTER XV. 



LEAF-SCARS AND LENTICELS. 



Marks on winter twigs Buds and leaf-scars Sizes of terminal 

 buds Aborted buds and pseudo-terminal buds Sympodia and 

 false dichotomy Leaf-scars Their sizes, shapes, &c. Leaf- 

 trace bundles Scars of bud-scales "Spurs" or Dwarf-shoots 

 Thorns Buried buds Lenticels, or " Cork- warts." 



THE principal objects or marks to be commonly observed 

 on winter twigs are buds, leaf-scars, and lenticels. 



Buds we have already dealt with in detail, and it 

 suffices to remember that in their relations to twigs the 

 chief points are, the arrangement of the buds a matter in 

 intimate association with that of the leaves in the axil of 

 which they arise, and therefore of the leaf-scars which 

 mark the insertion of the latter; and the presence or 

 absence of a true terminal bud, and its relative size as 

 compared with the lateral buds. It is a common event to 

 find the terminal bud distinctly larger than the lateral 

 buds, and often of a somewhat different and more sym- 

 metrical shape, because it has not been subjected to the 

 lateral pressure of the leaf-base, and has been more uni- 

 formly exposed to light and other factors of the environ- 

 ment acting on it on all sides. 



Trees and shrubs with the terminal or pseudo-terminal 

 w. i. 8 



