Fig.  44. — Transverse  section  from  stem,  two  years  old,  of  Picea  excelsa, 
magnified  75  diameters.  A,  hypoderma  ;  6,  epidermis;  c,  periderm  layer  in 
formation — its  cells  rich  in  tannin  ;  d,  tannin  cell  in  cortex  ;  e,  secretion  reser- 
voir;^ bast  layer  of  bark  ;  g,  cambium  zone;  h,  secretion  reservoir  in  xylem  ; 
i,  ring  of  growth. 
