ECONOMIC WOODS OF THE UNITED STATES 87 



usually spongy and difficult to cut smoothly 

 across the grain. Rays without tracheids.* White 

 7^-77jr ^ Cedar. C. thyoides B. S. P. (N, S)"; Arborvitse. 

 Thuya ocddentalis L. (N).^^ 



II. Heterogeneous or Porous Woods: Dicotyledons; 

 Broadleaf Woods; Hardwoods 



Vessels presen t. Wood composed of three to six kinds of ele- 

 ments not imiform in structure and rarely arranged in definite 

 radial rows. Growth rings often defined by zonate arrangement 

 of large pores in early wood as well as by the greater density of 

 the late wood. Resin cells and resin ducts absent. Rays variable 

 from very narow to very broad. 



A R ing-porous Wood s. Pores in early wood zonate, large, and 

 conspicuous, rarely small and inconspicuous; in late wood small 

 or few and scattered. Rays uniseriate or widely variable. ..Tex- 

 ture medium to very coarse. 



1 Pores in radial lines branching more or less toward the 

 periphery of the growth ring; pores small to very sm all. 

 Pores in early wood in one to several rows. Wood paren- 

 chyma in fine tangential lines. 



a Broad rays absent : rays uniform, uniseriate, incOTisgicjious, 

 5-15 cells high. Wood rather light, moderately soft, stiff 

 but not strong. 



a"^ Pores in early wood few, small, usually round or nearly 

 so, and rather widely separated in a single row. Wood 

 with roseate hue. Odorless and tasteless. 

 Western Chinquapin. Castanopsis chrysophylla deC. (P). 



b' Pores in early wood very numerous, usually oval or 

 elliptical and in a wide zone. Color brown. Odor very 

 mild. Astringent taste. Chestnut. Castanea dentata 

 Borkh. (C, N)^''; Chinquapin Chestnut. pumilaMill. (S). 



b .Broad rays present; intermediate rays mostly uniseriate, 

 invisible without lens (Plate III, Fig. 1). Wood heavy. 

 hard, strong. Odor_characteristi£j Oak.'"* 



* The occasional occurrence of ray tracheids in the low rays of C. thyoides 

 has been noted by Penhallow, North American Gymnosperms, p. 232. 



