20 



ECONOMIC "WOODS OF THE UNITED STATES 



tapering, but sometimes they are flattened, or forked, or with a 

 saw edge (Fig. 2, C, C"), adding to the toughness of the wood. 

 Fibres usually run parallel to one another, but in some woods 

 they exhibit a decided interweaving which produces an irregularly 

 grained wood very difiicult to split. 



TABLE II 

 Length op Wood Fibres in Dicotyledonous Woods 



Botanical Name 



Average Maximum 

 mm. mm. 



Minimum 

 mm. 



Acer rubrum 



Betula nigra 



Castanea dentata 



Celtis occidentalis 



Fagus americana 



■^m^m-aiba. 



Ilex opaca 



Juglans nigra 



Liquidambar styraciflua 



-Liriodendron tulipif era x • • -v 



LMagnolia acuminata. \A<X(.i.v. UjUL} 



Nyssa sylvatica 



Platanus occidentalis 



Populus deltoides. 



^- r" grandidentata 



' "'" heterophyUa 



" trichocarpa 



Quercus alba 



— '-^ — coccinea 



" michauxii 



" rubra 



" virginiana 



■* SaUx nigra 



TiUa americana 



Ulmus americana 



.50 



1.50 



.80 



1.05 



.75 



.90 



1.15 



.65 



1.25 



1.40 



1.00 



1.05 



1.30 



.50 



.65 



1.00 



.50 



1.00 



1.00 



1.10 



.70 



.85 



.45 



.85 



1.15 



References 

 DeBakt, a.: Comparative Anatomy, pp. 481-483. 

 Solereder, H.: Anatomy of the Dicotyledons, Vol. II, pp. 1141-1143. 

 Greqort, E. L.: Pores of the Libriform Tissue, BuU Torrey Bot. Club, 



Vol. XIII, 1886, pp. 197-204; 233-244. 

 Anonymous: Length of Wood Fibers in Broadleaf Woods, Sc. American 



Sup., Sept. 30, 1911, p. 211. 

 Sanio, Carl: Bot. Zeitung, Vol. XXI, No. 13, 1863, pp. 89-111. 



