Am.  Jour.  Pharm, 
April,  1896. 
North  American  Conifer ce. 
20 1 
transfusion  tissue  was  of  the  usual  character,  and  the  bundles  which 
it  enclosed  were  each  about  two-  or  three-rayed. 
There  were,  on  the  outer  or  convex  surface  of  the  leaf,  from  ten 
to  fourteen  rows  of  stomata,  and  on  the  concave  or  inner  surface 
from  five  to  seven  rows. 
Fig.  18,  portion  of  cross-section  of  stem  of  Pinus  echinata,  magnified*  100 
diameters.  A,  stone  cells  of  periderm  layer;  b,  fissure;  c,  phellogen  layer, 
rich  in  tannic  matters;  d,  secretion  reservoir  in  cortex;  e,  tannin  cell;  f%  bast 
layer,  containing  secretion  cells;  g,  cambium;  /i,  medullary  ray  in  wood. 
A  cross-section  of  a  twig  of  three  years'  growth  showed  the 
following  structure :  At  the  outside,  a  periderm  composed  of  bands 
of  stony  tissue  alternating  with  bands  of  thin-walled  cells, which  were 
succeeded  interiorly  by  a  phellogen  layer  rich  in  tannic  matters  ;  inter- 
