3§o 
Structure  of  Gelsemium. 
/  Am.  Jour.  Pharm. 
\      August,  1898. 
be  a  diagnostic  feature.  Mr.  Shoemaker  gives  as  a  second  char- 
acter "  the  tendency  of  the  pith  of  the  stem  to  be  penetrated  by 
several  plates  of  large,  thin-walled  cells,  which  divide  the  pith  more 
or  less  perfectly  into  four  portions."  This  layer  of  cells  is  an  internal 
phloem,  similar  to  what  we  find  in  Solanum  Dulcamara  and  many 
other  plants,  and  which  has  been  first  accurately  described  in  gel- 
semium by  Miss  Caroline  Thompson  (Bot.  Gaz.,  1898,  p.  118).  This 
internal  sieve  zone  is  characteristic  for  the  rhizome  and  overground 
stem  of  gelsemium,  distinguishing  them  from  the  root. 
L.  E.  Sayre  {Amer.  Jour.  Pharm.,  1898,  p.  11)  gives  the  charac- 
teristic differences  in  structure  between  the  overground  stem  and 
Fig.  2. — Diagram  of  overground  stem  of  Gelsemium  sempervirens  (L.)  Pers. 
C,  cork;  B,  bast  fibres;  Ca,  cambium;  M,  medullary  rays;  K,  crystals  of 
calcium  oxalate  ;  S,  internal  phloem. 
rhizome  to  be,  that  "  in  the  stem  are  found  comparatively  large 
bundles  of  bast  near  the  wood,  just  outside  the  cambium.  In  the 
rhizome  the  bast  is  arranged  near  the  axillary  layer,  and  in  an  inter- 
rupted ring  rather  than  in  bundles."  These  differences  in  structure 
the  writer,  however,  does  not  find  to  hold.  The  position  and  dis- 
tribution of  the  bast  fibers  in  the  rhizome  and  overground  stem  of 
gelsemium  are  about  the  same.  It  is  possible  that  in  number  the  bast 
fibers  in  the  rhizome  may  exceed  those  of  the  overground  stems, 
still  this  cannot  be  said  to  constitute  a  difference  to  be  relied  upon. 
I  will  describe  the  morphology  of  the  rhizome,  overground  stem 
and  root  of  the  living  material  that  I  examined. 
