73 
Structure  of  Iris. 
/Am.  Jour.  Pharm. 
\    February,  1895. 
STRUCTURE  OF  IRIS."" 
By  Kdson  S.  Bastin. 
The  Blue  Flag,  Iris  versicolor,  Limit,  is  one  of  the  commonest  of 
monocotyls  in  the  eastern  United  States.  The  range  of  its  habitat 
is  from  Canada  to  Florida,  and  from  the  Atlantic  as  far  West  as 
Minnesota  and  the  Indian  Territory.  Its  rhizomes  are  horizontally 
creeping,  from  16  to  24  cm.  long,  more  or  less  branched,  and  com- 
posed of  joints,  each  from  3  to  10  cm.  in  length,  and  representing  a 
year's  growth.  Each  joint  at  or  near  its  base  is  cylindrical  or  only 
slightly  flattened,  but  toward  its  apex  is  larger  and  widened  hori- 
Fig.  1. 
zontally.  At  the  anterior  end  on  the  upper  surface  of  each  joint  is  a 
more  or  less  cup-shaped  scar  of  a  flowering  stem.  At  this  end  also 
may  occur  two,  or  sometimes  four,  lateral  branches  arranged  opposite 
each  other  in  pairs.  The  surface  of  the  joints  is  densely  covered 
with  scales  consisting  of  the  fibrous  bases  of  the  decayed  leaves, 
and  from  the  inferior  surfaces,  chiefly  from  the  broader,  flattened 
portion  of  the  joints,  spring  numerous,  sparingly  branching, 
wrinkled  rootlets,  averaging  10  or  12  cm.  long  and  about  1)4  nam. 
in  thickness.  These,  together  with  the  scales,  are  usually  removed 
in  preparing  the  drug  for  market.  The  dried  drug,  therefore,  shows, 
except  occasionally  near  the  apex  of  the  rhizome,  only  the  crowded 
