Am.  Jour.  Pharm.  > 
September,  1914.  / 
Rhamnus  Purshiana. 
391 
forty  feet  with  a  diameter  of  eighteen  to  twenty  inches.  In  shady 
places  the  tree  grows  tall,  straight,  and  slender,  while  in  open  places 
with  plenty  of  sunlight  it  branches  near  the  base,  attains  greater 
diameter  and  less  height. 
A  mild,  moist  climate  is  necessary  for  the  abundant  growth  and 
large  size  of  the  tree.  In  a  dry  climate  and  higher  altitude  it  occurs 
sparingly  and  in  shrub  form  only.  In  its  most  northern  range,  in 
Southeastern  Alaska,  it  also  grows  as  a  shrub  of  three  to  six  feet  in 
height.  In  certain  sections  of  the  California  coast  it  has  a  height 
of  only  a  few  inches  with  prostrate  stems. 
Reforesting. — Opinion  differs  as  to  the  natural  reforesting  of 
cut-over  areas.  It  is  stated  by  some  that  a  new  growth  always 
springs  up  on  cut-over  areas,  providing  the  bark  is  not  removed  from 
the  stumps;  while  others  claim  that  sprouts  rarely  spring  up  from 
stumps,  because  the  trees  are  usually  cut  while  the  sap  is  running, 
hence  very  little  life  is  left  in  the  stump. 
The  tree  is  a  prolific  seeder ;  seeds  are  of  medium  high  germination 
(often  tardy)  and  of  very  persistent  vitality.  Scattered  seedlings 
are  fairly  abundant  in  moist  forests,  litter  and  mucky  soils  ;  scanty 
in  drier  habitat,  except  in  depressions  where  seeds  have  been  deeply 
covered  by  accident.  (Geo.  B.  Sudworth,  U.  S.  Department  of 
Agriculture,  Forest  Service  Bulletin,  "  Forest  Trees  of  Pacific  Slope," 
1908,  p.  404.) 
Longevity. — The  longevity  has  not  been  fully  determined  for 
large  trees.  Trees  ten  years  old  are  from  six  to  eight  inches  in 
diameter.  Trees  estimated  at  twenty-five  to  forty  years  old  are  fre- 
quently found. 
Cultivation. — For  several  years  the  U.  S.  Department  of  Agri- 
culture has  conducted  experiments  looking  towards  the  cultivation 
of  this  tree,  and  has  succeeded  in  growing  it  from  the  seed  in  moist 
places  near  Washington,  D.  C,  the  trees  in  six  years  from  the  seed 
attaining  a  height  of  ten  to  twelve  feet. 
The  Kew  Gardens  in  England  ten  years  ago  raised  cascara  sagrada 
from  the  seed  collected  in  California,  and  it  has  proved  quite  hardy. 
The  tree  has  also  been  grown  in  Germany,  but  is  said  to  develop  but 
slowly. 
In  the  experiments  conducted  by  the  Department  of  Agriculture  a 
certain  method  of  pruning  has  been  followed  which  forces  the  top  of 
the  tree  into  three  or  four  branches;  one  of  these  branches  may  be 
cut  each  year  for  peeling,  and,  as  another  branch  soon  develops  in  its 
