5G ilfr, Arthur Deane 07i 



softwoods they consist of simple rows of cells, which afterwards 

 become filled with resin. Yew wood is entirely free from this 

 tissue. Wood cells always occur around the interior of resin 

 pores, so characteristic of many softwoods. 



Resin Pores appear as dark specks on the cross cut 

 surface, sparsely distributed, forming long tubular spaces without 

 true walls of their own, but lined by a circle of wood cells 

 (epitheliu7n), rich in protoplasm and large nuclei, which do not 

 store starch like ordinary wood cells, but exude resin into the 

 central passage. Resin pores extend to long distances through 

 the wood, generally singly, but sometimes in groups, and run not 

 only parallel to the axis of the tree, but also pass horizontally 

 along the rays when the latter, in surface or tangential section 

 of the wood, become lenticular or spindle-shaped. In Scots Pine 

 we find both the linear and lenticular types of ray. These two 

 kinds of resin pores communicate with one another, explaining 

 the outpour of resin daring the process of resin-tapping, and their 

 contents have importa'it effect on the technical properties of 

 wood, such, as dura.bility and elasticity. Resin pores have nothing 

 to do with the vessels or pores found only in hardwood trees, 

 which are provided \\'ith a wall of their own. The irregular 

 greyish outline of resin pores on the cross cut end and their 

 isolated distribution as they appear under a lens should help to 

 distinguish the two. On the longitudinal surfaces they appear as 

 fine yellowish or brownish streaks, and occur in Pines, Spruces, 

 Hemlocks, Douglas Fir, and Larch, but are absent in Silver Fir, 

 Yew and Cypresses. Their presence or absence helj) in the 

 identification of softwoods. 



Hardwoods. (Oaks, Elms, Chestnut, etc.) 

 These are much more complicated in structure, most of 

 them containing all the four elements already referred to. The 

 most conspicuous are the wood pores, technically called vessels. 

 These are hollow tubes made up of cells arranged vertically with 

 open ends set one above the other like empty barrels with their 



