542  The  Apocynacece  in  Materia  Medica.  {K^S^\^' 
awn.  They  are  always  very  numerous  in  the  follicle,  ascending, 
with  a  micropyle  on  the  outside.  From  the  base,  the  furrow  runs 
the  half  way  up  the  ventral  face,  inserting  itself  in  the  funiculus 
which  crosses  the  yellow  membrane  covering  the  placenta  and 
which  breaks  off  close  to  the  seed  the  moment  of  the  dehiscence  of 
the  fruit. 
The  seed  proper  varies  in  the  dimensions,  form,  color/ surface 
and  the  anatomical  structure.  The  length  is  always  greater  than 
the  breadth,  and  does  not  exceed  but  little  over  two  milli- 
metres. The  thickness  likewise  varies  greatly,  as  also  the  attenua- 
tion toward  the  extremities.  The  shape  varies  within  certain  limits 
by  the  position  or  insertion  of  the  seed  in  the  follicle.  The  dorsal 
face  is  often  more  strongly  convex  than  the  other.  On  the  ventral 
face  toward  the  upper  part  one  sees  ordinarily  the  point  of  insertion 
of  the  funiculus  (hiluiri),  and  in  several  species  a  raphe  more  or  less 
clear.  The  color  varies  from  a  greenish-white  or  yellowish  to  a 
dark  brown,  and  is  often  modified  by  the  hairy  covering.  In  some 
fruits,  dried  by  fire,  the  extremities  become  charred  and  the  color  of 
the  seeds  changed.  The  seeds  are  distinguished  as  those  glabrous 
and  those  villous. 
Glabrous  Seeds. — To  this  group  belong  all  the  Asiatic  species 
and  also  the  rarer  African  species.  Franchet  remarks  that  the  ab- 
sence of  hairs  upon  the  seed  seems  in  correlation  with  a  consider- 
able development  of  the  thread  which  surmounts  the  anther,  and 
with  an  awn  in  which  the  naked  part  is  shorter  than  the  other.  It 
is  likewise  noteworthy  that  Ouabaine  is  extracted  from  a  glabrous 
seed  and  Strophanthine  from  a  villous  seed. 
Villous  Seeds. — The  hairs  on  the  surface  of  these  seeds  are  ordi- 
narily short.  S.  laineux,  of  Zambesi,  being  the  sole  exception  to 
this  rule.  They  are  applied  close  to  the  seed  and  directed  from  the 
base  to  the  top.  The  color  varies,  but  quite  constant  for  the 
same  species.  The  lustre  is  silky  and  brilliant.  Fontaine  says 
that  the  hairs  detach  themselves  very  easily  in  handling  and  strongly 
irritate  the  mucous  membranes  of  the  nostrils  and  the  conjunctiva. 
The  seeds  of  Strophanthus  bear  two  awns ;  the  one  at  the  base 
sessile,  the  other  at  the  summit,  more  or  less  lengthily  aristated. 
The  first  is  very  caducous,  and  not  being  observed  by  some  botanists 
on  this  account,  its  existence  has  been  doubted.  The  upper  awn  is 
always  greatly  developed  and  forms  a  straight  shaft,  rigid  and 
