WRIGHT: THE GENUS DIOSPYROS 
The durability of otir Diospyros timbers is due to the 
nature and percentage number of the elements comprising 
the wood, together with the presence of coloured contents 
partially or wholly filling the elements. In all our Ceylon 
species of Diospyros the cambium divides very elowly, and 
the elements, particularly the fibres, possess small transverse 
dimensions and thick walls ; the percentage number of fibres 
is in every case very high, and that of the tracheal elements 
very low. consequently the xylem is much more durable 
than the majority of our Ceylon timbers. Nevertheless, the 
histological composition of the secondary xylem is only one 
factor in determining the durability of these timbers, the 
infiltrated gums and resin providing a substantial support to 
the otherwise empty elements. The relative durability of 
the outer white sapwood and the central ebony is well seen 
m trunks of trees exposed to the atmosphere and vermin ; 
the sapwood is stripped completely in a few years, leaving 
a smooth black log of ebony which resists the attacks of ants 
and many wood borers. 
J h r i 9 C 0 , ,°r i0 ' 1 ° £ the W00d is *« Chemical 
white wnnrfa TK. v.* P to the red > and 
ebonv . t • WiUte sa P woo, l surrounding the central 
^ o* material 
9 T darj elemente > "* the »f 
Uuejmtenal mcreaeee from witw 
