714  Anatomy  of  Umbelliferous  Fruits.  {ANov^mb^rPhi9ri™' 
endosperm  is  rounded  dorsally,  somewhat  pressed  in  by  the  vittse,  on 
the  inner  side  almost  straight ;  sclerenchyma  fibers  run  at  the  base  of 
the  ribs. 
Under  the  microscope,  the  upper  surface  shows  tangentially 
stretched  cells  with  a  slightly  thickened  cuticle.  Beneath  the  epi- 
dermis of  older  fruits  lies  a  parenchyma  zone  which  is  collapsed  or 
compressed  toward  the  inner  part.  The  middle  portion  of  the  meso- 
carp  is  divided  into  two  distinctly  demarkated  zones.  The  outer  is 
composed  of  large,  rounded,  punctated,  thick-walled  parenchyma 
cells  which  take  the  red  color  with  phloroglucin  and  hydrochloric 
acid,  only  over  the  vittse  lies  a  zone  of  unthickened  collapsed  tissue ; 
on  the  commissural  side,  the  punctuated  tissue  is  small  and  round 
celled.  The  inner  part  is  filled  up  with  strongly  lignified  scleren- 
chyma fibers  which  are  especially  broad  in  the  ribs  (up  to  six  rows 
of  cells  thick)  and  are  extended  in  an  almost  interrupted  row  around 
the  oil  tubes.  A  similar  patch,  also,  lines  in  the  region  of  the  raphe, 
but  is  not  prolonged  over  the  secretory  passages.  Only  the  marginal 
rib-plates  stretch  over  almost  half  of  the  vittse.  The  bast  fibers  are 
long-pointed,  with  small  elliptical  pores  sloping  to  the  left.  The 
pitted  trachea  lie  on  the  boundary  between  the  sclerenchyma  plates 
and  the  thickened  parenchyma  and  are  accompanied  by  thick-walled 
wood  parenchyma.  The  secretory  passages  are  roundish-oval,  up  to 
iiOju.  in  lengthwise  view  and  60 /x  in  transverse  view;  on  the 
commissural  surface  they  are  for  the  greater  part  larger  (up  to  180 
/x  in  longitudinal  section  and  go ^  in  cross  section).  They  border 
on  the  inner  epidermis  and  are  surrounded  by  well  built,  quadrate  or 
weakly  peripherally  stretched  epithelial  cells.  The  seed  coat  is 
greatly  collapsed,  brown-walled,  underdeveloped  on  the  commissural 
surface.  The  thin-walled  endosperm  contains  fixed  oil  and  aleurone. 
Other  CEnanthe  species  resemble  this  one  and  are  differentiated  in 
anatomical  structures  by  the  arrangement  of  the  sclerenchyma  ele- 
ments and  the  wood  parenchyma. 
CEnanthe  Lachenalii  Gmel.-^-The  thickened  wood  parenchyma  is 
found  only  in  the  ribs,  not  in  the  inter-rib  regions.  The  scleren- 
chyma fibers  are  arranged  as  in  0.  Phellandrium. 
CEnanthe  pimpinelloidea. — As  in  O.  Phellandrium  the  scleren- 
chyma plates  are  more  broadly  developed  in  the  ribs,  but  are  ex- 
tended over  the  vittse  in  a  more  layered  band,  up  to  four  rows  broad. 
ZEthusa  Cynapium  L. — The  fruit  of  "  Fools  Parsley "  is  oval, 
4  Mm.  long,  2.5  Mm.  deep  and  2  Mm.  broad,  pale  yellow,  crowned 
