422 
Structure  of  Podophyllum. 
/Am.  Jour.  Pharru. 
X  September,  1894. 
fact,  probably  to  be  regarded  as  imperfectly  developed  bast  fibres. 
The  cells  contain  starch,  though  not  so  abundantly  as  the  adjacent 
parenchyma  cells  of  the  cortex.  It  must  be  remarked  that  these 
fibres  do  not  occur  in  all  the  bundles. 
Fig.  5  shows  one  of  the  small  bundles,  exterior  to  the  primary 
circle,  magnified  330  diameters.  b,  b,  b,  b,  b  are  the  fibres  in  ques- 
tion; ct  a  sieve-cell ;  dy  dy  d}  ducts  in  the  xylem ;  e,  wood  parenchyma ; 
and  a}  a,  cortical  parenchyma  cells. 
Fig.  5. 
Several  roots  were  examined  with  reference  to  the  structure  of  the 
central  radial  bundle.  In  the  specimens  examined,  the  number  of 
xylem  rays  in  the  bundle  was  found  to  vary  between  three  and  six, 
the  commonest  numbers  being  five  and  six.  The  central  part  is 
sometimes  wholly  parenchymatous  and  sometimes  contains  scattered 
ducts.  The  endodermal  sheath  is  composed  of  quite  regularly  ar- 
ranged cells,  all  somewhat  elongated  in  a  tangential  direction,  and 
having  the  radial  walls  a  little  darker  in  color.    The  pericambium, 
