544 
Fruit  of  Cocos  Nucifera. 
1  Am.  Jour.  Pharm. 
I  November,  1901. 
sionally  more,  groups  separated  from  each  other  by  a  continuation 
of  the  sheath  (Fig.  5).  Normally  the  xylem  is  near  the  inner  flat 
side  and  the  two  phloem  groups  are  approximately  symmetrical 
with  reference  to  the  shorter  axis  of  the  elliptical  cross  section  ; 
but  often  the  xylem  is  near  one  of  the  narrow  sides  and  the  phloem 
groups  are  symmetrical  with  reference  to  the  longer  axis,  and  still 
more  often  the  arrangement  is  diagonal  or  otherwise  irregular. 
Mohl1  in  1 831  noted  that  the  phloem  in  the  stem  of  Calamus 
was  normally  divided  into  two  distinct  groups,  and  Kny  2  as  well  as 
other  authors  have  since  found  the  same  arrangement  in  a  number 
of  palms.  By  the  study  of  many  sections,  the  writer  has  demon- 
strated that  a  cocoanut  fiber  with  two  phloem,  groups  has  also  a 
double  xylem,  although  in  most  sections  no  separation  is  evident, 
and  the  whole  fiber  consists  of  two  simple  bundles  united  side  by 
side,  which  may  completely  separate  further  on  in  their  course  by 
the  forking  of  the  fiber. 
Serial  sections  cut  through  such  compound  fibers  show  that  at 
the  place  of  forking  the  phloem  groups  are  still  further  separated 
and  the  xylem  also  is  divided  by  bast-fibers,  thus  forming  two  dis- 
tinct bundles  which  pass  into  the  two  branches.  The  phloem  in 
each  branch  is  at  first  entire,  but  further  on,  if  the  branch  is  large 
it  usually  divides,  and  still  further  on  the  whole  bundle  may  split 
up,  with  the  formation  again  of  two  fibers.  Occasionally  a  fiber 
which  has  no  evident  division  of  the  xylem  has  four  groups 
indicating  that  the  fiber  is  composed  of  four  united  bundles,  which, 
on  branching,  form  two  fibers  each  with  a  double  bundle. 
Large  fibers  not  only  fork  but  also  send  off  small  lateral 
branches.  The  rudimentary  bundles  belonging  to  such  branches 
may  often  be  seen  in  cross  sections  of  the  trunk  fiber  below  the 
place  of  branching  {Fig.  5,  a). 
a.  Stegmata  {Figs.  5  and  6,  ste). — As  seen  in  surface  view  these 
are  circular  or  elliptical  cells  from  -008  to  -020  m.m.  in  diameter,, 
which  extend  in  longitudinal  rows  over  the  surface  of  the  fibers. 
Longitudinal  sections  show  that  the  cells  are  biconvex,  fitting  into 
depressions  in  the  bast-fibers,  and  that  the  outer  walls  are  exceed, 
ingly  thin,  while  the  inner  and  side  walls  are  strongly  thickened, 
1  De  Palmarum  Strudura,  Translation  in  Ray  Soc.  Reports  and  Papers, 
1849,  p.  29- 
2  VerhandL  d.  Bot.  Ver.  Prov.  Brandenburg,  Bd.  xxiii,  1881,  pp.  94-109. 
