BARKS. 



189 



PLATE LXXXII. 



ist "J.'.^-m 



FIG. 92. Powdered Cascarilla Bark (x 240). 



a, starch grains. 



cp, Prismatic or rhombohedral c-ystals. 



cr, Rosette crystals. 



cs, Secretion cells. 



fl, Bast fibres. 



f I', The same, in transverse section. 



I, I', Bast, radial and transverse section. 



pc, cortical parenchyma, longitudinal section. 



p'c', The same, transverse tection. 



ph, Phelloderm. 



rm, r'rn', Medullary ray, radial and transverse section. 



s, Cork cells, showing surface view of the inner wall with 



granular calcareous deposit, 

 s', Phelloderm cells in transverse section. 

 si, Cork cells showing surface view of the outer thickened wall. 

 s'i', The same in section. 

 Is, Superposed secreting cells 

 vg, Sieve-tubes 



