THE STRUCTURE OF WOOD. 



35 



constitutes the characteristic "grain" of striped mahogany, Fig. 23. 

 It is rarely found in the inner part of the tree. 



Sometimes the grain of wood is "cross/' because it is "wavy" either 

 in a radial or a tangential section, as in maple, Fig. 25, and Fig. 26. 



"Curly grain" refers to the figure of circlets and islets and con- 

 tours, often of great beauty, caused by cutting a flat surface in 



.big. 47. Curi> Grained L,ong-ieai Pine 

 (full size). 



Fig- 28. Curly Yellow Poplar 

 (full size). 



crooked-grained wood. See Fig. 27, curly long-leaf pine, and Fig. 28, 

 yellow poplar. When such crookedness is fine and the fibers are con- 

 torted and, as it were, crowded out of place, as is common in and 

 near the roots of trees, the effect is called "burl," Fig. 29. The term 

 burl is also used to designate knots and knobs on tree trunks, Fig. 31, 

 Burl is used chiefly in veneers. 



