ECONOMIC WOODS OF THE UNITED STATES 81 



brittle. Sp. gr. .3S-.52, mostly between .40 and 

 .45. Contrast between seasonal growths very 

 pronounced; transition abrupt. Color light 

 buff with reddish-brown tinge. No resin ducts 

 or aggregates of resinous tracheids. (Eastern) 

 Hemlock, Tsuga canadensis Carr. (N). 

 b 4 Odorless when dry; green wood slightly sour- 

 smelling. Wood of rather uniform texture, not 

 particularly harsh and splintery, straight- 

 grained and fairly easy to work. Sp. gr. .30-.57, 

 mostly between .40 and .50. Transition from 

 early wood to late wood rather gradual. Color 

 light, sometimes pinkish or reddish-brown. 

 Small black checks common. Aggregates of 

 resinous tracheids, somewhat resembling resin 

 ducts on cross section, fairly common; wound 

 ducts in peripheral rows occasionally present. 

 Western Hemlock, T. heterophylla Sarg. (P). 20 

 b 2 Resin cells numerous, visible under hand lens and 

 often collectively to unaided eye, particularly in sap- 

 wood; frequently zonate. Color of woods charac- 

 teristic. Distinct demarcation between heartwood 

 and sap wood. 



a 3 Color varying from light cherry-red to purplish. 

 Texture rather coarse. Woods without odor or 

 taste. Wound ducts sometimes present in periph- 

 eral rows. Resin masses in wood parenchyma 

 strands appear under lens on longitudinal surface 

 as rows of black or amber beads. Rays biseriate in 

 part; occasionally with marginal or isolated ray tracheids J 

 lateral pits in ray parenchyma cells large and, in early 

 wood, horizontally elongated; no terminal pits. Bordered 

 pits in tracheids of early wood commonly paired. 



Sequoias. 21 



a 4 Wood deeply colored, purplish or maroon. 

 Growth rings usually very narrow. Texture 

 uniform. Wood weak, brittle, and soft. Sp. 

 gr. .25-.33. Bigtree, Giant Sequoia, Sequoia 

 washingtoniana (Winsl.) Sudw., or S. gigantea 

 Dec. (P). 22 



