208 
North  American  Cojiiferce. 
Am.  Jour.  Pharm. 
April,  1896. 
phloem  masses,  and  a  few  were  seen  also  opposite  the  xylem  ends 
of  the  bundles,  about  midway  between  them  and  the  endodermis. 
The  cross-section  of  a  twig  of  two  years'  growth  showed  the  fol- 
lowing structure  :  At  the  exterior,  a  periderm  consisting  of  thickish- 
walled  cells,  which  contained  abundance  of  tannic  and  coloring  mat- 
ters; interior  to  this, a  zone  consisting  of  several  thicknesses  of  cells, 
whose  walls  were  excessively  thickened  and  lignified ;  succeeding  this, 
a  phellogen  layer  rich  in  tannin;  next,  a  thick,  cortical  parenchyma, 
composed  chiefly  of  large,  thin-walled  cells,  elongated  in  a  tangen- 
tial direction,  but  interspersed  with  secretion  reservoirs,  and  con- 
taining also  a  few  scattered  stone  cells ;  a  bast  layer,  composed  of 
Fig.  21,  transverse  section  of  leaf  of  Pinus  Cubensis,  magnified  75  diameters. 
St,  stoma  ;  sec.  r,  secretion  reservoir  ;  f,  sclerenchyma  fibre  ;  /,  lacuna. 
relatively  small  cells,  and  destitute  of  fibrous  or  other  lignified  ele- 
ments, having  its  tissues  mostly  arranged  in  radial  rows  and  inter- 
spersed with  small  secretion  cells;  a  cambium  zone,  which  presented 
no  special  peculiarities;  a  zone  of  xylem  tissues,  whose  structure 
resembled  that  of  the  other  species  of  its  genus ;  and  a  pith  com- 
posed chiefly  of  thin-walled  parenchyma,  containing  numerous  secre- 
tion cells. 
The  tannin  was  similar  in  distribution  to  that  in  Pinus  Taeda, 
and  the  oleoresinous  matters  were  also  similarly  distributed,  though 
they  appeared  to  be  somewhat  less  abundant  in  the  specimens 
studied. 
