80 GUIDE TO TIMBERS OF NIGERIA 



Transverse section. (Prepared with glass-paper.) 



Parenchyma of one (?) kind : (a) sheathing the vessels and 

 extending tangentially to sub-continuous undulating lines 

 occasionally anastomosing, very numerous, at intervals of 

 about 2J-3 times their own width. Colour, light brown ; 

 contains many minute globules of a darker brown. Width 

 very variable from one-half diameter of a large pore to rather 

 more than the long diameter ; number per mm. 2-4. Dis- 

 tribution uniform ; proportion of the section about one-third 

 (including the pores). There are many very fine lines running 

 from ray to ray which may be parenchyma (&), but they are 

 absent over quite considerable areas ; further investigation 

 will be necessary before determining the precise nature of these 

 lines. 



Vessels visible as perforations to the naked eye, large but 

 very variable in size ; very few in numbers, 0-3 per sq. mm., 

 widely isolated ; comparatively few simple vessels; mostly 

 groups, both radial and .nested, of from 2-7. Contents, some 

 yellow globules. Shape, roundish. 



Rays visible to good sight, fine, of a similar colour to the 

 parenchyma (a) but a little lighter ; sub-regular in spacing 

 but fairly regular in size, of one kind only ; at intervals of 

 from three to six times their own width ; fairly straight ; 

 number per mm. 8-10. Proportion of the mass of the wood 

 rather less than one-quarter. 



Ground- tissue-cells just visible with the macroscope in places ; 

 proportion of the mass nearly half. 



Rings not traceable. 



Radial section. Colour brown in alternating striae of darker 

 and lighter tints like machine-ruling ; grain, medium, 

 coarse, but few pores exposed on this section ; those which 

 are seen contain glistening sulphur-coloured globules. Paren- 

 chyma (a) very abundant and even prominent in borders, and 

 tails to the pores, and continuous vertical lines between them. 

 The lines above referred to are occasionally visible with the 

 macroscope as short lengths of a single cell in width. Rays 

 readily visible by reflection, not prominent. 



Tangential section as the radial, but the rays are short, fine, 

 hoary, spindle-shaped lines visible with the lens ; not in 

 parallel ; height up to -5 mm. and one to three cells wide. 



