DESCRIPTION OF PLATE III. 



FIG. 1. Quercus alba (white oak) : tangential section showing end of large ray 

 and numerous small uniseriate rays, separated by wood fibres, and occasional 

 wood-parenchyma strands. 



FIG. 2. Ulmus americana (American elm): cross section showing the largest 

 pores in a single row, the small pores in wavy tangential bands. 



FIG. 3. Robinia pseudacacia (black locust) : cross section showing arrange- 

 ment of pores and parenchyma, and very dense wood fibres in late wood; pores in 

 early plugged with tyloses and separated by abundant wood parenchyma and 

 tracheids. 



FIG. 4. Toxylon pomiferum (Osage orange) : radial section showing tyloses 

 in vessels; wood-parenchyma strands, tracheids and dense wood fibres; and hetero- 

 geneous ray. 



FIG. 5. Gymnocladus dioicus (Kentucky coffee tree) : cross section showing 

 comparatively large, thin-walled pores in late wood. 



FIG. 6. Gleditsia triacanthos (honey locust): cross section showing minute, 

 thick-walled pores in late wood. Growth ring limited by rather wide zone of wood 

 parenchyma. 



