48 GUIDE TO TIMBERS OF NIGERIA 



others. Smell ? Not likely to soil. The colour deepens 

 very greatly to dark brown. Unwin (1920, p. 416) says, 

 " reddish," and p. 286, " greenish-brown after it has lain in 

 the forest for a few years." 



STRUCTURE. Transverse section. (Prepared with glass- 

 paper.) See PL III,. fig. 1. 



Parenchyma of one kind : (a) abundant and visible to the 

 unaided eye, sheathing the pores as broad margins, but not 

 extending to lateral wings. Proportion of the wood about 

 one-third (including pores). 



Vessels^visible as perforations, large, no apparent diminution 

 in size, but a slight reduction in number outwards towards the 

 ring-boundary, which is represented by a darker-coloured band : 

 this appearance is more probably due to the smaller quantity 

 of P. (a) ; distribution in pronounced oblique lines which 

 change their direction from ring to ring, forming a " herring- 

 bone " pattern ; number per sq. mm. 0-7 ; mostly simple but 

 many groups ; widely isolated ; shape, shortly oval. Contents, 

 dark-coloured. 



Rays just visible on account of their colour, very fine ; of 

 one kind only ; colour distinctly reddish ; fairly regular in size 

 and spacing at intervals of from one to three pore-diameters ; 

 fairly straight, but slightly avoiding the pores ; almost too thin 

 to taper ; proportion of the wood about one-fifth ; number 

 per mm. 8-16. 



Ground-tissue-cells visible with the macroscope ; to the 

 unaided eye the ground appears dark brown ; proportion of 

 the wood about one-fifth. 



Rings apparently well defined, but the true boundary is 

 doubtful ; it may be constituted by the zone of darker- 

 coloured wood poor in pores ; contour (in specimen 

 described) is very irregular, but does not appear to be 

 normal. 



Radial section very brilliant and stripy, but the colour is 

 modified by the pinkish-brown colour of the rays. Vessels 

 contain much rich reddish-brown resin in globules and have 

 shining linings. P. (a) visible with difficulty as borders to 

 the vessels (except in the darker bands). Rays visible as 

 prominent pinkish lines. 



Tangential section as the radial, but the rays tend to dull and 



