KEY TO SPECIES 285 



II. POROUS WOODS: BROADLEAF WOODS: HARD- 

 WOODS 



A. Ring porous wood. 



1. Pores in radial lines branching more or less toward the 

 margin of the growth ring. 



a. Broad pith or medullary rays absent; rays uniform 



and inconspicuous. Wood rather light, mod- 

 erately stiff, but not strong. 

 al. Pores in spring wood very numerous and in a 



wide zone. Color brown, odor very mild. 



Astringent taste. 



CHESTNUT Castanea dentata 



b. Broad rays present. Wood heavy, hard, strong, 



characteristic odor. 



61. Pores in spring wood in few (1-3) rows, 

 usually not crowded, transition to smaller 

 pores of summer wood abrupt. Large 

 rays often very high on lengthwise sec- 

 tion; maximum 5 inches. Abundant 



WHITE OAK Quercus alba 



62. Pores in early wood mostly in several (3-5) 

 rows, crowded; transition to smaller 

 pores in summer wood gradual. Pores 

 in summer wood comparatively large, 

 circular outlines. Large rays, compara- 

 tively low, rarely 1 inch high on length- 

 wise section. Tyloses absent. 



RED OAK Quercus rubra 



2. Pores in spring wood in a single row or in a zone of 

 2-3 rows. Pores in summer wood arranged tan- 

 gentially in conspicuous festoons or concentric 

 bands, usually continuous, wavy, the pores 

 minute or small. 



a. Rays rather indistinct. Pores in spring wood 

 large, forming a continuous row. Wood rather 

 light, but hard to split. Texture coarse. 



WHITE ELM Ulmus americana 

 Tyloses are pith-like cells that sometimes fill the pores. 



