MARACAIBO LIGNUM-VIT^E 



long, undulating : less dense than the ground-tissue, difficult to 

 see in a transparent section : very numerous, 19-23 per mm. a 

 pore-width or less apart. 



Rings. Usually clear on account of a pore-zone of rather larger 

 and more numerous pores. 



Soft-tissue. Doubtful, only isolated cells in the neighbourhood 

 of the pores. 



Pith. ? 



Radial Section. Rather lighter in shade than the above. Pores 

 conspicuous in the sap-wood adjoining the heart : fine green lines, 

 always full of resin : also some with red resin. Rays require the 

 lens, fine, under 0-5 mm. high. Rings appear as indefinite bands 

 of colour. In tangential section the rays are imperceptible with 

 the lens. 



Type specimens from commerical sources checked by specimens 

 in the Museum, Kew. 



No. 17. MARACAIBO LIGNUM-VIT^E Guaia- 

 cum arboreum. DC. 



Natural Order. Zygophylleae. 



Alternative Names. Maracaibo. Guaiacan, Guayaca, Guaya- 

 can in the Amazonas region and Palo Santo in Para (76). 



Source of Supply. Brazil. 



Physical Characters, etc. Dry weight about 69 Ib. per cu. ft. 

 Splits with very great difficulty and with rough fracture. Hard- 

 ness Grade i, the hardest of all woods except its near allies. 

 Smell and taste none. Burns extremely well with a quiet flame, 

 heat expels a yellow resin, embers glow in still air, but consume 

 very slowly. Solution with water none, with alcohol faint 

 yellow. Commercial form, round logs up to 60-70 feet long by 

 1-2 feet diam. 



Grain. Very fine, close and even, the pores make a feathery 

 pattern upon the surface. Surface dull with shining pores when 

 freshly cut, afterwards becoming covered with a bluish-grey 

 exudation which is dry not sticky : scarcely cold to the touch. 



Bark. ? 



Uses, etc. The same as other species of Guaiacum (which see). 

 Easily confused with No. 16, with which it has much in com- 

 mon, but there is considerable difference in the structure. 



Authority. Miers (76). 



Colour of the heart-wood brown. Sap-wood ? 



Anatomical Characters. Transverse section : 



Pores. The groups are readily visible, but the individual pores 

 require the lens : size 5-6, quite uniform : very regularly dis- 



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