382 
Structure  of  Gelsemium. 
Am.  Jour.  Pharm. 
August,  1898. 
cork  the  parenchyma  cells  are  large,  and  contain  numerous  starch 
grains  and  oil  globules.  The  collenchyma  cells  of  the  overground 
stems  with  their  chlorophyll  contents  are  wanting  here.  In  the 
medullary  ray  cells  of  the  inner  bark  are  found  crystals  of  calcium 
oxalate.  The  latter  are  similar  in  size,  shape  and  position  to  those 
found  in  the  overground  stem.  The  bast  fibres  are  long,  silky,  and 
a  little  more  numerous  than  in  the  overground  stem.  Medullary  ray 
cells  are  about  of  the  same  shape,  number  and  composition  as  those 
of  the  overground  stem.  The  internal  phloem,  in  older  plants,  is 
pronounced,  divided  into  four  well-marked  zones,  as  in  the  over- 
ground stem.  It  is  similar  to  that  in  the  overground  stem  in  every 
respect  save  position,  it  being  eccentric  rather  than  central. 
Fig.  4. — Diagram  of  root  of  Gelsemium  sempervirens  (L.)>  Pers.  C,  cork; 
M,  medullary  rays  ;  Ca,  cambium  ;  Ky  crystals  of  calcium  oxalate. 
THE  ROOT. 
The  root  is  quite  long  and  spreading.  It  is  externally  of  a  dirty 
brownish-yellow,  and  internally  {Fig.  4.)  of  a  yellow  color.  The 
thin  epidermis  in  young  roots  is  replaced  by  a  thick  layer  of  cork  in 
the  older  plants,  consisting  of  from  sixteen  to  eighteen  rows  of  cells. 
The  collenchyma  of  the  stem  is  wanting.  Starch  grains  and  oil  glo- 
bules are  distributed  throughout  the  parenchyma  of  the  bark,  as  it  is 
in  the  overground  stem  and  rhizome.  Similar  crystals  of  calcium  ox- 
alate as  already  described  are  found  in  the  medullary  ray  cells  of  the 
inner  bark.  The  medullary  rays  are  similar  to  those  described  in  the 
overground  stem  and  rhizome,  but  we  find  more  secondary  medul- 
lary rays. 
