43°  Gelsemium  Sempervirais,  Ait.  {As™ptembef,bjS 
In  an  older  hypocotyl,  in  which  secondary  growth  has  gone  on 
for  some  time,  the  fundaments  of  two  internal  phloem  patches  may 
be  observed  just  below  the  cotyledonary  node.  The  round  hypo- 
cotyl  becomes  elliptical,  preparatory  to  the  separation  of  the  coty- 
ledons. Five  or  six  large  embryonic  cells  appear  on  the  inner  side 
of  the  wood.  Their  nuclei  are  large,  and  take  a  darker  stain  than 
the  adjoining  cells.  In  short,  the  fundament  of  an  internal  phloem 
patch  has  arisen  in  the  leaf  trace  bundles,  destined  for  the  first, 
third,  fifth  and  succeeding  pairs  of  leaves.  No  such  fundament  is 
demonstrable  in  the  pair  of  bundles  for  the  cotyledons,  second, 
Fig.  4. 
fourth  and  succeeding  pairs  of  leaves.  With  increased  age  these 
embryonic  cells  become  a  mass  of  small,  finely  divided  cells,  so  that 
evidently  the  bundles  for  the  odd  pairs  of  leaves  each  possess  an 
internal  phloem  patch.  Throughout  the  lower  and  middle  portions 
of  the  epicotyl,  or  the  internode  above  the  cotyledons,  the  opposite 
bundles  are  devoid  of  internal  phloem,  but  just  below  the  node 
bearing  the  first  pair  of  leaves,  two  groups  of  embryonic  cells  ap- 
pear in  them,  representing  the  fundaments  of  the  internal  phloem 
patches  for  the  even  pairs  of  leaves.  When  the  node  bearing  the 
second  pair  of  leaves  is  reached,  all  four  patches  of  internal  phloem 
are  clearly  distinguishable.  In  the  bending  out  of  the  leaf  bundles 
into  the  petioles,  the  same  crossing  of  the  internal  phloem  to  the 
exterior  takes  place  in  the  leaves  of  the  seedling  that  has  been  de- 
