Am.  Jour.  Pharm.  \ 
February,  1896.  / 
North  American  Conifer  ce. 
67 
Fig.  9,  part  of  cross-section  of  stem  of  P.  rigida,  magnified  75  diameters  ;  a, 
cutinized  and  very  thick-walled  epidermis  ;  b,  hypodermal  tissue  ;  c,  fissure  ; 
d,  sclerotic  or  stony  tissue  ;  e,  e' ',  tannin  cells  in  middle  bark;  /,  collapsed  sieve 
tissue  in  older  bast;  g,  newer  sieve  tissue  ;  /z,  cambium  zone  ;  i>  tracheids  of 
xylem  ;  k,  ring  of  growth  ;  m,  secretion  reservoir  in  the  wood;  see,  r,  secretion 
reservoir  in  bark. 
This  drawing,  as  well  as  that  of  the  stems  of  P.  Austriaca  and  of  P.  palustris, 
was  made  from  a  specimen  which  had  been  treated  with  a  solution  of  ferric 
chloride  in  absolute  alcohol,  and  is  intended  to  show  the  distribution  of  tannic 
matters. 
