GUIDE TO TIMBERS OF NIGERIA 71 



GENERAL CHARACTERS. A very light, soft wood of a dirty 

 white colour which deepens little if at all on exposure. It 

 may easily be mistaken for the wood of Eriodendron, p. 17, 

 of this series. Surface dull and floury, warm to the touch, 

 very easily soiled. Grain, very coarse and open, fairly straight. 

 Smell of musty nuts, as observed in other species of the same 

 family. Wood exceedingly absorbent. 



STRUCTURE. Very characteristic. 



Transverse section. (Prepared with limited success by all 

 known methods in turn. Description from a surface rubbed 

 down with pumice-stone, controlled by section with a razor.) 



Parenchyma of one kind : (a) obscure and scanty, in con- 

 tact with the vessels. 



Vessels readily visible as perforations, very large, apparently 

 diminishing somewhat in size, but not much in number, towards 

 the outer limit of the ring ; 03 per sq. mm. ; very widely 

 isolated ; many empty spaces exceeding lj sq. mm. in area ; 

 distribution indefinite, but a slight tendency to oblique lines ; 

 simple and in radial and nested groups of 2-5 pores ; shape, 

 oval ; contents, very large tyloses ; proportion of the wood, 

 very small, not more than one-twentieth. 



Rays very fine ; of one kind only ; colour slightly lighter 

 than that of the ground ; regular in size, -but less so in spacing, 

 as many as four to the pore-diam. ; 12-15 per mm. ; extra- 

 ordinarily numerous, occupying nearly half the mass of the 

 wood, hence, from their abundance and close proximity, have 

 sometimes the appearance (to the naked eye) of large or aggre- 

 gate rays. 



Ground- tissue- cells just visible with the lens. 



Rings not prominent but apparently well defined ; con- 

 tour regular. 



Radial section. -Vessels very large, but owing to lack of 

 colour are invisible in certain lights ; often filled with white 

 tyloses and a very small amount of resin. Parenchyma 

 obscure. Rays visible by reflection only ; the ray- cells are 

 smaller than those of the ground-tissue (rare case). 



Tangential section as the radial, but the rays appear as 

 minute spindle-shaped bodies of a pale brown colour which 

 furnishes almost the only colouring matter in the wood ; not 

 in parallel. 



