Plate XIII 



Fig. 1. Quercus imbricaria from Cedar Point, O. Twig (photographed 

 through a hand lens) showing the five bands made by the five pairs of broad medul- 

 lary rays and the enclosed wood; X 4. 



Fig. 2. Quercus velutina from Cedar Point, O. Twig showing numerous broad 

 medullary rays, five bands not distinct; X 4. 



Fi(i. 3. Quercus Leana from Cedar Point, O. Twig ahowing numerous broad 

 medullary rays; five bands somewhat distinct; X 4. 



Fig. 4. Quercus rubra from Denison Campus. Twig showing numerous 

 broad medullary rays; X 4. 



Fig. 5. Quercus vehilinn from Columbus, O. Twig showing numerous broad 

 rays; X 4. 



Fig. 6. Quercus Leana from Cincinnati, O. Twig from type tree, showing 

 broad medullary rays; two pairs and their bands are prominent; X 4. 



Fig. 7. Quercus coccinea from Denison Campus. Twig showing very numer- 

 ous, less distinct, broad medullary rays; X 4. 



Fig. 8. Quercus alba from Denison Campus. Twig showing wavy lines, no 

 broad medullary rays; X 4. 



Fig. 9. Quercus velutina. Tangential section showing protoplasmic connec- 

 tions between wood parenchyma cells; X 285. 



