Bui. 75, Forest Service, U. S. Dept. of Agriculture. 



PLATE X. 



FIG. 1 .TRANSVERSE SECTION OF A S-YEAR-OLD TWIG OF TANBARK OAK, SHOWING THE 

 DISTRIBUTION OF TANNIN IN THE PITH AND PITH RAYS. MAGNIFIED 30 DIAMETERS. 



FIG. 2. LONGITUDINAL RADIAL SECTION OF A S-YEAR-OLD TWIG OF TANBARK 

 OAK, SHOWING THE TANNIN IN THE PITH AND PITH RAY CELLS. MAGNIFIED 30 

 DIAMETERS. 



