448 



SCIENTIFIC AND APPLIED PHARMACOGNOSY 



diameter; starch grains simple or 2- to 3-compound, the individual 

 grains being spheroidal or polygonal, from 0.005 to 0.020 mm. in 

 diameter and frequently with a central circular point of origin of 



cor 



ph 



FIG. 195. Canella: Transverse section of bark showing tissues of outer bark 

 (su); middle bark or cortical region (cor); and inner bark (ph). K, cork 

 cells; ph, inner layer of periderm showing the cells with their strongly thick- 

 ened, distinctly lamellated, porous and lignified inner walls; o, oil cells with a 

 yellowish oily content; s, collapsed cells of sieve; Kr, rosette aggregates of 

 calcium oxalate; m, medullary rays, each cell having a rosette aggregate of 

 calcium oxalate. After Tschirch. 



growth; numerous stone cells of periderm, about 0.075 mm. in 

 diameter, the inner walls of which are considerably thickened, 



