BARKS. 



185 



PLATE LXXX. 



Pie. 90. Powdered Alder Buckthorn Bark (x 240) 



col, Collenchyma of the cortex. 



cr, Prismatic and rosette crystals. 



fl, Bast fibres with pitted walls. 



1,1', Bast in longitudinal and transverse section. 



pc, p'c', Cortical parenchyma, in longitudinal and transverse 



section. 



ph, Phellodenn. 



rm, r'm', Medullary ray in tangential and radial section. 

 s,s', Cork, in tangential and transverse section. 

 tc, Rows of crystal cells. 



