SPRUCE G.N. 8313 



SPRUCE 



Picea excdsa Link Coniferae. Abietineae. 



A soft wood, light in colour and in weight resembling Silver Fir, from 

 which it is difficult to distinguish. Although plainly and definitely 

 striped, the difference in the colour of the Autumn and Spring wood is 

 small. Smell when worked, little or none (dry wood). Lustre crystalline 

 or satiny. 



Structure, as in the Pines, more or less. 



Kesin-canals present, the vertical ones being casual and sometimes 

 absent over long lengths of arc (even as much as 15 inches). When in 

 doubt the horizontal canals must be carefully searched for. 



Reaction of watery extract with potash, none: with perchloride of 

 iron, yellow (otherwise the colour of the perchloride only). 



Rays of two kinds: horizontal resin-canals abundant. They are of 

 the same character as those of the Scots Fir and of the Larch, and of the 

 same slender shape as those of the latter. 



Pits in the cross-field, usually two or more small ones which occupy 

 but a minute portion of the area. 



Ray-tracheids with processes projecting inwards. 



Epithelial cells of the vertical resin-canals, thick-walled, i.e. about 

 as thick as those of the tracheids around them. 



The shavings are soft and silky to the touch. 



Pith large, up to J inch diameter, conspicuous, soft. 



May Se confused with: May be distinguished by: 



Silver Fir (no resin-canals, no Resin-canals of both kinds pre- 



tracheids in the rays). sent: tracheids in the rays. 



Weymouth Pine (one or two Two or several small pits in the 



large pits in the cross-field). cross-field. 



Sapwood of Scots Fir (one large As above, 

 pit in the cross-field). 



