ECONOMIC WOODS OF THE UNITED STATES 91 



a^ Lines of pores in late wood short, narrow, 

 composed of few open pores and considerable 

 wood parenchyma; mostly near periphery of 

 growth ring; occasionally absent or very 

 indistinct in narrow rings. 

 White Ash. Fraxinus americana L. (C, N). 



b* Lines of pores in late wood long, narrow, 

 prominent, composed of abundant wood 

 parenchyma and inconspicuous pores; usu- 

 ally well distributed. Blue Ash. F. quad- 

 rangulata Michx. (C); Red Ash. pennsyl- 

 vanica Marsh. (N). 



b^ Pores in early wood in rather narrow zone; not 

 numerous. Lines of pores in late wood quite 

 long and conspicuous; well distributed. 

 Green Ash. F. lanceolata Borkh. (C, N, S). 



b' Pores in late wood rarely joined by wood paren- 

 chyma. Wood of medium hardness and strength. 



a^ Pores in early wood in very broad zone, com- 

 monly one-half the width of the growth ring. 

 Pores in late wood isolated, few, large. Color 

 dark brown. Wood comparatively soft and 

 weak. Ray cells small. Black Ash. F. nigra 

 Marsh. (C, N) (Plate V, Fig. 2). 



b^ Pores in early wood in zone of medium width, 

 commonly one-third the width of the growth 

 ring. Pores in late wood in radial groups of 2-5 

 and near periphery of growth ring somewhat 

 tangentially grouped. Color light brown; sap- 

 wood with reddish tinge. Wood harder and 

 stronger than preceding. Ray cells large. 

 Oregon Ash. F. oregona Nutt. (P). 



b^ Odoi: characteristic : somewhat resembling that of 

 kerosene. Tasteless. Wood very light and soft. 

 Pores m late wood in rather large groups and near 

 periphery or growth ring in broad, comparatively 

 short (sometimes continuous) tangential bands; in 

 very wide rings pores often indistinctly grouped. 

 Color light to medium dark brown, satiny; very 



