:J2 



WRIGHT : THE GENUS DIORPYROS 



of measurements of transverse dimensions of the fibres in 

 the sapwood and heartwood is given below : 



The above table would perhaps lead one to believe that 

 our wet country species had generally larger transverse 

 dimensions than our dry zone species. It is also to be noticed 

 that there is not, in every case, an increase in transverse 

 dimensions as one passes into the sapwood, and that 

 the maximum variation in transverse dimensions for the 

 fibres in the whole of our species is about O006 mm. and for 

 fibres of the same species less than half this amount. 

 The transverse dimensions, thickness of wall, &c., may 

 be greatly modified by individual forces, stress, windage, 

 &c. 



Medullary Rays. These elements are, as far as the genus 

 Diospyros is concerned, the most variable of all the com- 

 ponents of the secondary xylem. Fundamentally they are 

 similar to the wood parenchyma cells since they possess 

 thin cellulose walls and contain abundance of starch, tannin, 

 and oxalate of lime. Their presence in abundance tends to 

 lower the value of the timber, their thin walls and wide 

 lumina rendering shrinking more certain. 



