18 GUIDE TO TIMBERS OF NIGERIA 



(Empire Timber Ex. 1920), received from the Government of 

 Nigeria. 



GENERAL CHARACTERS. A very light soft wood of an oat- 

 meal colour very much resembling that of Ricinodendron 

 africanus (see that species). Surface dull, warm to the touch ; 

 would soil readily. Very cross- and coarse-grained, open. 

 Shade of the transverse section lighter than that of the other 

 sections. Smell, none. Very absorbent. 



STRUCTURE. (More visible in the tainted portions.) 



Transverse section. (Prepared with the plane.) Parenchyma 

 of one kind only : (a) in small quantity, narrowly sheathing the 

 pores ; visible to the unaided eye in vertical section only. 

 Slightly darker than the ground-tissue. 



Vessels visible as perforations, very large ; not diminishing 

 in size outwards towards the ring boundary, but distinctly 

 fewer in numbers, with a tendency to collect in the inner zone 

 of the ring ; 2-5 per sq. mm. ; a distinct oblique arrangement 

 of the pores ; mostly simple, but a few groups of two or three 

 pores here and there ; widely isolated ; shape, shortly oval ; 

 tyloses abundant ; proportion of the wood, small. 



Rays easily visible though fine ; of one kind only ; straight, 

 except where they avoid the pores ; regular in spacing at 

 intervals of about the smaller diameter of a large pore apart ; 

 colour white or straw -yellow ; denser than the ground-tissue, 

 6-9 per mm. 



Ground-tissue exceedingly lax, the cells can be counted 

 with the aid of the macroscope, and when moistened they 

 swell more than those of the rays. 



Rings traceable with difficulty ; boundary a fine white line, 

 often repeated, and contour regular. 



Radial section. Colour uniform except as to the vessels, 

 which are dark, filled with tyloses and very coarse and straight. 

 P. (a) visible as fine tails to the vessels. Rays easily visible, 

 brownish, darker than the ground-tissue, containing much 

 more red, lustrous resin. Rings hardly traceable. 



Tangential section as the radial, but there are numerous fine 

 parallel lines, possibly septa of the fibres, visible with the 

 macroscope, which need further investigation. Rays visible 

 as a half-tone effect ; height about 20 cells or up to 1-5 mm. ; 

 not in parallel ; the cells contain resin globules. 



