MACROSCOPIC STRUCTURE. 41 



woods. Even microscopic observation fails owing to similarity 

 in their structure. 



Species of Silver-fir (Abies) are characterized by the fact 

 that there is no colouring matter in either sapwood or heart- 

 wood ; in this they resemble sprucewood, but can readily be 

 distinguished from the latter by the absence of resin-ducts. 



itf. 2"). Typt of Silver-fir-wood 

 (Abirx) : of Hemlock- spruce (7X- //<///) ; 

 of Sftjiiohi. ('ri/i>ttiiiicriii. 7n.nit/i tun, 

 and ('<<! rnx. 



.Type of Cypress-wood (('lutnim'- 



riJlHiri*. ( Wyy/v-.v.s-//.v. Tlrui/d. L'lltuct'd nix. 

 ,J it in nc r n x. c{ i . ). 



Species of Hemlock-spruce (Tsuga) have a broad sapwood 

 and a grey or greyish-brown heartwood. 



In Sequoia the sapwood is narrow, the heartwood cherry - 

 red, eventually becoming greyish-brown. 



Taxodium has a broad sapwood and a greyish -brown heart- 

 wood ; Cryptomeria, a broad sapwood and a reddish -brown 

 heartwood. In cedarwood the sapwood is broad and the 



