GUIDE TO TIMBERS OF NIGERIA 59 



species, the parenchyma has been very difficult to find, 

 being absent, or exceedingly obscure. . 



Vessels easily visible to the unaided eye as perforations, very 

 prominent, not much diminution in size, but a little decrease 

 in numbers towards the outer limit of the ring ; widely isolated ; 

 a strong tendency to oblique lines and angles ; few, 4-6 per 

 sq. mm. Simple for the most part, few if any m-and-d pores ; 

 shape, strongly oval ; proportion of the wood relatively small ; 

 tyloses abundant ; contents, occasional red globules. 



Rays visible with lens, very fine ; of one kind ; lighter in 

 shade than the ground ; regular in spacing, about 2-3 to the 

 pore-diam. ; straight ; tapering but little ; number per mm. 

 15-18. 



Ground-tissue-cells not visible with the macroscope, harsh 

 and horny, causing wood to be short and brittle. 



Rings ill defined ; boundary a zone of denser wood ; 

 contour regular. 



Radial section. Grain, coarse, very much inclined, changing 

 in direction ring by ring. P. (a) visible with lens ; contains 

 numerous crystals. Vessels, coarse open grooves with 

 gummy, lustrous linings and many globules of red resin, also 

 tyloses. Rays visible with lens, light in colour, dull. Rings 

 not traceable. 



Tangential section as the radial, but the Parenchyma is doubt- 

 fully traceable. Rays visible with lens as fine, slightly lighter 

 lines ; height about 12-15 cells ; not in parallel ; chiefly 

 uniseriate. 



SAPWOOD. " Slash yellowish- white and rather dirty colour. 

 A mucilage-like latex exudes from the cut ; there is only a 

 slight difference between sap and heartwood " (Unwin, p. 402). 

 " Sap and heartwood not differentiated " (Chevalier, 1909, 

 p. 230). Some of our specimens have a clearly defined sapwood 

 which is much darker than the heartwood. 



BARK. " Slightly rough and scaly, but in an even manner " 

 (Unwin, p. 402, I.e.); "Bark grey, deeply fissured, scaling in 

 large plates" (Chev,, p. 231). 



USES, ETC. " Inlaying " (Unwin, p. 79) ; " very durable 

 indeed, termite -proof both in exposed places and for interior 

 work ; sapwood not quite so durable ; canoes, bridge-build- 

 ing " (p. 403). 



