MACROSCOPIC STRUCTURE. 2 1 



on account of the obliquity of the cut or the slightly undu- 

 lating course of the rays through the wood ; according to 

 their angle of inclination to the light, the rays appear duller 

 (Fig. 7, S, e) or brighter (Fig. 8) than the surrounding tissue. 

 The annual rings are seen as dark lines on the medullary 

 rays, the tangential parenchyma seen on the transverse section 

 here appears as fine parallel lines. 



Tangential Section. Intersected vessels appear clearly as 

 more or less lengthy grooves ; in a curved or scalloped 

 distribution on the section they mark the annual rings. 

 In the summer- wood these are but slightly marked. The 

 sections of the medullary rays are arranged vertically 

 as long, dark, dull lines, somewhat thicker in their middle 

 parts. 



The sapwood is one to three centimetres broad, light- 

 coloured: the heartwood of variable colour, in freshly cut 

 wood it is somewhat useful for determining the species and 

 country of the wood, but this is not reliable enough for com- 

 mercial purposes. Heartwood of most oaks is dull brown, in 

 red oak (<J. r ultra) and Turkey oak (Q. Cm-is) somewhat 

 redder ; numerous other kinds of oak wood arc known in 

 commerce, e.g., thus stone-oakwood denotes hard quality, 

 while winter and summer oak wood have respectively hard 

 and soft woods, but not specific <1 inferences (such as (J. pcdmi- 

 cnlala and t >. si'sttilijlttra). Llaek or brown oak is a dark 

 valuable natural oakwood, that is well known in England; in 

 Germany, the term is applied to oakwood that has laid long 

 in river-water, or in chalybeate water. Ha/el-oak is very 

 narrow-zoned. The colour of oakwood eventually becomes 

 darker, as do all woods. 



2. Species of Beech (Fagus). 

 (In Europe, America, Asia and New Zealand.) 



Transverse Section. Pores invisible ; on thin transparent 

 sections very fine, very numerous and uniformly distributed. 

 Rays some thick, others fine, always forming bright bands, 

 sometimes lighter, sometimes darker than the surrounding 

 tissue, according to the angle of incidence of the light. 



