CONIFEROUS WOOD. 



longitudinal and radial section (Fig. 15) it appears that the 

 tracheids are from ^V to T * ncn l n g> 50-100 times as long, that 



FIG. 13. Transverse section of Spruce (Picea exctUo.), magnified 100 times, 

 showing narrow rings, thin walls and three resin-ducts. From Hartig's 

 Timbers and how to know them, by permission of Dr. Somerville and Mr. David 

 Douglas. 



FIG. 14. Resin-duct in coniferous wood, in transverse section, highly 

 magnified, showing the epithelial cells surrounding the duct. 



is, as they are wide ; that they have their bordered pits in a 

 single row down their radial walls ; and that they are closed at 

 their ends by a tapering to one side like the cutting edge of a 



