GUIDE TO TIMBERS OF NIGERIA 77 



colour, pinkish-buff. Proportion of the mass of the wood 

 (including the vessels) about one-sixth. 



Vessels distinctly visible as perforations, large, diminution 

 but little ; occasional mother-and-daughter groups, mostly twos 

 and threes, some fours ; number of vessels per sq. mm. 9-20. 

 Arranged in oblique lines in well-developed rings (visible to 

 naked eye). Shape, slightly oval. Apparently empty ? 



Rays not visible without lens, very fine ; of one kind only ; 

 regular in size, but rather less so in spacing, at intervals of 

 rather more than the width of a ray to six times that width ; 

 weak like silk threads ; number per mm. 15-22 ; proportion of 

 the mass about one- quarter. 



Ground-tissue-cells just visible with macroscope. 



Rings apparently defined, but no definite boundary ; chiefly 

 indicated by denser zones of tissue and a change in the direction 

 of the oblique lines of vessels. 



Radial section rather stripy (roey) in dull and lustrous bands. 

 Grain, very cross, being so much inclined in places as almost to 

 show transverse sections. Parenchyma just visible as hoary 

 boarders and tails to the pores. Vessels with shining linings ; 

 loculi on limit of vision ; empty except for occasional beads of 

 red resin. Rays visible as very narrow, hoary flakes or lines ; 

 from ten to twenty cells high. Rings indicated by the cross- 

 grain only. 



Tangential section as the radial, but the rays are only visible 

 as a matt effect ; not in parallel, being rather in echelon ; 

 mostly uniseriate, multiseriate rays present but rare. The 

 indication of the rings is rather more distinct, being shown up 

 by the loops of dense ground-tissue from which the vessels 

 are absent or rare ; a distinct zigzag arrangement of the vessels 

 in places. 



SAPWOOD well, but not sharply defined from the heart- 

 wood, greyer and less brilliant. The colour of the heart com- 

 mences to be apparent first in the vessels and rays. 



BARK entire, somewhat resembling that of the Silver Fir, 

 whitish with brown patches : lenticels numerous, extended 

 laterally, brown. Texture granular. Of two layers of about 

 equal thickness, the inner being purplish-red in colour and 

 darker ; scleroses (stone-cells) small but abundant. Inner 

 surface covered with much brown bast. Pith ? 



