30 GUIDE TO TIMBERS OF NIGERIA 



or less ; the lines occur chiefly in the denser tissue and are 

 absent in some zones ; in some rings festoons are formed. 



Vessels visible on account of the P. (a) which sheaths them ; 

 rather small, but not diminishing in size outwards to the limit 

 of the ring ; slightly fewer in number in the outer zone ; not 

 very widely isolated, rather crowded in places ; number of 

 pore groups per sq. mm. 912 ; arrangement indefinite, 

 except where there are festoons, and even then the angle of 

 inclination to the radial line is quite indefinite ; simple and 

 in radial groups of 2-3 pores, the groups themselves inclining 

 to dispose themselves radially, a disposition that is sometimes 

 visible to the naked eye. Contents, black. Proportion of 

 the wood, including the P. (a), about one-third. 



Rays not visible except with the lens on account of their 

 brown colour ; and sometimes difficult to find ; fairly regular in 

 size and spacing ; nearly straight and not avoiding the pores ; 

 intervals about 56 times the breadth of a ray ; number per 

 mm. 38. Proportion of the wood, about one-fifth to one-sixth. 



Ground-tissue-cells just visible with macroscope. 



Rings apparently defined, but less distinct with lens ; bound- 

 aries may possibly be the bands of denser tissue ; regular in 

 contour ; the gum-galls may follow the boundary. 



Radial section. Rays visible in certain lights only ; in the 

 right light they are readily visible on account of their lack of 

 lustre. Vessels medium coarse, often twinned, with much 

 black resin and shining linings. P. (a) just visible with lens 

 as tails to the vessels, and an occasional white line visible in 

 certain lights. 



Tangential section as the radial, but the vessels exposed are 

 fewer, though occasionally twinned. Rays need lens and are 

 then visible as fine brown lines somewhat variable in size ; 

 not in parallel ; uni- and multi -seriate ; height up to twenty 

 cells by one to three wide. 



SAPWOOD of Lovoa. " White, comparatively narrow " 

 (Unwin, 1920, p. 327). 



BARK of Lovoa. " Dark brown, becoming rougher with age 

 and scaling to some extent ; yellow-brown and smooth when 

 young " (Unwin, I.e.). " Greyish, .wrinkled on the surface, 

 but not fissured, scaling in small plates " (Chev., I.e.). 



USES, ETC., of Lovoa. " Canoes ; the wood shrinks and 



