SCOTS FIR G.N. 8309 



The smaller rays are of one row of cells only and do not contain a resin- 

 canal. The larger kind are called "lenticular rays" and the latter, or 

 smaller, "linear rays." The larger rays have two rows of cells, only in 

 the middle height; at the ends they are one-rowed. In point of height 

 they may be of as many as fifteen cells or less, rarely more (at least in 

 this species). 



Pinus sylvestris Linn, may be, and generally is, confused with other 

 species of Pine, with the Douglas Fir, with the Spruce, with the Silver 

 Fir, and with the Larch . It may be distinguished as follows : 



From the Spruce, by the rarity of the vertical resin-canals in that wood 

 which also has more than one (small) pit in the cross-field, and thick- 

 walled epithelial cells. 



From the Larch, which has several small pits in the cross-field, fre- 

 quently in two rows one above the other; smooth walls to the ray- 

 tracheids or edge-cells, and thick-walled epithelial cells. Smell, none 

 when worked (at least when the wood is dry). Reaction with perchloride 

 of iron on watery extract, inky. 



From the Douglas Fir, which, in tangential section, has rays that are 

 rather short, lanceolate or boat-shaped, in the middle of which the resin- 

 canal occupies only a portion of the transverse diameter of the ray 

 (i.e. there are one to two layers of cells between the canal and the 

 surrounding ground-tissue: the tracheids have spiral thickenings. 

 Smell, none when worked (at least when the wood is dry). Reaction as 

 for Larch, inky. 



From the Yew, which has no resin-canals whatever, but has spiral- 

 thickenings in the tracheids. Reaction of watery extract with perchloride 

 of iron, none. 



From the Silver Fir, by the absence of resin-canals of either kind in 

 that wood which has, however, two or more small pits in the cross-field. 



From the Weymouth Pine, which has smooth-walled tracheids and 

 proportionately higher lenticular rays (tangential section). 



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