THE TIMBERS OF COMMERCE 



Bark. Light-grey, yellow or brown with numerous small 

 shallow fissures : two layers ; about J inch thick. 



Uses, etc. Turnery, brush-backs, etc. May be met with in 

 round logs with bark up to 12 inches in diameter. Splits raggedly 

 and with difficulty. 



Authorities. J. Smith (in). Wiesner (131). Lief. 12, p. 952. 

 Difficult to distinguish from the Ceylon Satin-woods except by 

 the smell (see note to Chloroxylon Swietenia. No. 26.) 



Colour. Yellow to brown : the sap-wood lighter and greyer. 



Anatomical Characters. Transverse section : — 



Pores. Need lens, size 4-5, not much variation : evenly dis- 

 tributed, though there are zones poor in pores here and there : 

 numerous, 18-160 per mm. : single or in loosely-connected 

 radial groups of sometimes as many as 16, but usually not more 

 than 5 : not subdivided : no red resin. 



Rays. Just visible, size 4-6 : undulating rather regularly, but 

 not avoiding the pores : a pore-width or much more apart : 

 numerous, 6-10 per mm. : equidistant : uniform in width : 

 lighter in colour : unusually long. 



Rings. Very clear in the solid, but not so in the transparent 

 section : a few fine concentric lines occasionally equalling or a 

 little broader than the rays. 



Soft-tissue. Abundant in concentric fine lines, size 7 (Ray- 

 scale), also narrowly encircling the pores. 



Pith. Round or angular, 1-3 mm. diameter : rather softer than 

 the wood : light yellow to grey : cells contain many drops of 

 brown resin. 



Radial Section. The pores need lens, being fine, dull lines : 

 the rays are visible in certain lights, and are narrow, dull flakes : 

 the rings appear as inconspicuous lines : no crimson gum-veins. 



Tangential Section. As the Radial, but the rays are minute 

 lines about 0-25 mm. high and the Rings appear as inconspicuous 

 loops. 



Type specimens from commercial sources. Not authenticated, 

 but the wood undoubtedly belongs to the Rutaceae, and is in 

 close agreement with several other species of Zanthoxylum which 

 I have examined. The structure of the whole Order Rutaceae 

 is very uniform. 



No. 22. KNOBTHORN. Zanthoxylum capense. 



Harv. 



Plate II. Fig. 16. 

 Natural Order. Rutaceae. 



Synonyms. Fagarastrum capense. D. Don. Xanthoxylon 

 capense. Harv. 



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