68 GUIDE TO TIMBERS OF NIGERIA 



brownish, slightly darker than the ground. The rays either 

 split up or are inclined to unite in brush-like tufts (aggrega- 

 tion ?) ; they are otherwise very close here and there, being 

 very irregularly spaced, and also irregular in size. Weak ; 

 many thin ends ; number per mm; 9-12 ; proportion of the 

 wood rather more than one-quarter. 



Ground-tissue-cells visible with the macroscope ; they 

 apparently contain crystals. 



Rings in appearance well denned by a line of contrast in 

 colour ; contour regular except where there is a brush of rays 

 and then a notch appears as in the European Alder, etc. 



Radial section. P. (a) visible on account of its abundance. 

 The Parenchyma of the second kind appears as fine lines 

 (macroscope). Vessels empty with brownish linings. Rays 

 visible as narrow lustrous brownish flakes. Rings not traceable. 



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

 as very fine brown lines not in parallel ; height twelve to 

 fourteen cells ; Hopkinson says, three to eleven cells by one 

 to three rows wide. They occasionally collect to form browner 

 groups. 



NOTE. When the tertiary thickening of the vessels is removed 

 certain muriform bodies are seen. These may be very large 

 pits or anomalous tyloses, and need further investigation. 



SAPWOOD. " Little difference between sapwood and heart- 

 wood. Slash white with yellow spots ; a chalky latex exudes 

 when it is cut, rapidly running down the stem like a streak of 

 whitewash " (Unwin, p. 390). 



BARK. " The white lenticels are very typical of the tree 

 and give it the appearance of having a rust-disease " (ibid., I.e.). 

 Chevalier (1909, p. 121) says, " Bark ashy-grey, scaly, exuding 

 an abundant white latex when cut. This coagulates, forming a 

 resinous material which rapidly hardens." 



USES. ETC. " Is attacked by termites ; not durable in the 

 open " (Unwin, I.e.). 



Density, No. 3007, 0-39, or about 24 Ib. per cu. ft. 

 2829, 0-329 20J 



3289, 0-38 24 



3621, 0-382 24 



Chevalier (I.e.) gives 0-391. 



Conservator's note. " A fairly large tree, plentiful in the 



