8o 



BOTANY AND PHARMACOGNOSY. 



Fig. 5 2. Cross-section of bark of Tsuga Canadensis, c, c, c, secondary cork forma- 

 tion; a, dead phloem tissues rich in coloring, resinous and tannin-like substances; s, s, stone 

 cells; m, m, medullary rays; cr, cells containing long prisms of calcium oxalate; ca, cam- 

 bium; st, bands of starch-bearing parenchyma cells. After Bastin. 



