WOODS. 



173 



PLATE LXXVL 



FIG. 86. Powdered Guaiacum Wood (x 240). 



cr, Prismatic crystals of calcium oxalate. 



fl, Wood-fibres. 



pi, Wood parenchyma. 



pv, Walls of vessel. 



Ptn, Medullary ray in radial section. 



r'm', The same in tangential section. 



v, Pitted vessels in radial section. 



v', The same in transverse section. 



v", The same in oblique section. 



