POPLARS G.N. 6713 



POPLARS 



Populus. Salicacese. 



Diffuse-porous woods of medium weight and hardness and of uniform 

 colour and structure : not easily distinguishable from each other (except 

 as regards Populus alba (syn. P. canescens) which forms a pinkish-brown 

 heartwood). The others are white. P. italica is generally full of knots. 

 P. nigra is fine-grained and very light in weight. All are difficult to 

 smooth in vertical section with cutting tools though they cut cleanly 

 across grain when they appear silvery -grey. 



Transverse section. Boundary a fine line of parenchyma : the varying 

 density of the rings also provides a line of contrast. 



Parenchyma as above, otherwise nil. 



Vessels visible with lens, small, apparently crowded, diminishing a 

 little in size and numbers from the Spring to the Autumn wood. Where 

 widely spaced, as happens in very well-developed rings, there is a ten- 

 dency to form short, loose arcs. 



Rays visible with lens, very fine, numerous, sinuous (wriggling between 

 the vessels) : very regular in spacing, at intervals of the width of a large 

 vessel apart : colourless or of the same colour as the fibres : uniseriate. 



Radial section. Boundaries traceable but not prominent: vessels 

 clearly visible but rather fine: silver-grain hardly visible (except in 

 P. canescens and perhaps in P. nigra). See note to Willow for micro- 

 scopic details. 



Tangential section. As the radial, but the boundaries generally show 

 feeble fringes and sometimes zigzag markings in the cross-grain, as in the 

 Birch but feebler. 



The white-wooded Poplars may be They may be distinguished by: 

 confused with: 



Horse Chestnut (exceedingly fine No certain character, at least as 

 grain, hence smooth surface when regards Populus nigra which is 

 planed: very light weight: often nearly as light in weight and has 

 with a yellow tinge). small pores. From the others their 



coarseness of grain and greater 

 weight are the only distinguishing 

 features. 



Lime and Birch (multiseriate Uniseriate rays at regular inter- 

 rays at rather irregular intervals vals of the width of a large vessel. 

 in transverse section). 



Tulip-tree and Sycamore (rays Rays uniseriate, need lens, 

 very clearly visible: multiseriate). 



s. 33 3 



