ECONOMIC WOODS OF THE UNITED STATES 101 



Wood parenchyma in tangential rows, occa- 

 sionally visible with lens. Pores crowded. 

 Wood dense; usually straight-grained; sp. gr. 

 .63-.80, average .69. Color reddish brown to 

 nearly white; uniform. Late wood rather 

 thick, of darker color than the spring wood. 

 Vessels without spirals; large perforations simple, small 

 ones often scalariform; pits into ray cells half-bordered 

 or simple. Rays heterogeneous. Wood fibres with 

 bordered pits. Beech, Fagus americana Sw., or 

 F. grandifolia Ehr. (C, N, S). 52 



b 4 No conspicuously broad rays present. 



a 5 Wood parenchyma in somewhat broken tan- 

 gential lines, faintly visible in part with lens 

 on moist cross section. Rays light red or 

 pink in color, very distinct. Color roseate 

 to reddish-brown, sometimes with greenish 

 hue. Wood very heavy, hard and tough. 

 Vessels without spirals; perforations scalariform with 

 many bars; bordered pits often scalariform; pits into 

 ray cells half-bordered. Rays heterogeneous. Wood 

 fibres with slit-like pits with distinct borders. 



a 6 Wood very dense, sp. gr. .76-.89, average 

 .82. Rays 1-7 cells wide, few to 80 cells high. 

 Flowering Dogwood, Cornus florida L. 



(N, C, S). 



b 6 Wood dense; sp. gr. .75. Rays 1-4 cells wide, 

 few to 40 cells high. (Western) Dogwood. 

 Cornus nuttallii Aud. (P.) 



b 5 Wood parenchyma not in tangential lines. 

 Vessels with spirals; perforations simple; pits not 

 scalariform; pits into ray cells half-bordered. 



a 6 Color rich reddish-brown or vinous. Rays 

 on radial surface appear considerably 

 lighter than background. Pores numerous, 

 solitary or in groups, often radial, of 2-6; 

 usually more abundant and larger in early 

 wood but with gradual transition. Vessels 



