Am  jour  pharm.  |  JSfotes  on  the  Dasheen  and  Chayote. 
August,  19 19.    J  -> 
507 
These  with  their  guard  cells  are  broadly  elliptical  in  outline.  Each  is 
surrounded  by  five  neighboring  cells.  In  cross  section  (Fig.  10)  the 
outer  walls  of  the  epidermal  cells  are  slightly  convex  and  cutinized. 
Beneath  the  outer  epidermis  is  a  zone  of  several  layers  of  paren- 
chymatous cells,  many  of  which  have  lignified  walls.  In  some 
instances  lignification  occurs  in  the  walls  of  the  cells  directly  under- 
neath the  epidermis,  while  in  others  the  lignified  elements  are  sepa- 
Fig.  10.  Transverse  section  through  receptacular  portion  of  Chayote 
fruit  showing  epidermis  (<?),  parenchyma  (p),  latex  tubes  (/),  portion  of 
fibrovascular  bundle  (b),  and  starch  grains  (j).    X  95- 
rated  from  the  epidermis  by  one  to  several  layers  of  cells  with 
non-lignified  walls.  The  next  broadest  zone  of  the  receptacle  is 
composed  of  more  or  less  radially  elongated,  thin-walled  paren- 
chyma cells,  comparatively  small  in  the  outer  region  but  gradually 
becoming  larger  toward  the  center.  Numerous  branched  latex  tubes, 
with  yellowish  contents,  course  irregularly  through  this  region. 
Fibro-vascular  bundles  of  the  bi-cdllateral  type  are  also  to  be  noted. 
The  most  conspicuous  elements  of  these  are  the  spiral  ducts  which 
attain  a  breadth  of  28  microns. 
Carpellary  Portion. — Separating  the  receptacle  from  the  carpel- 
lary  portion  of  the  fruit  may  be  noticed  a  sharply  demarkated  band 
of  cells,  three  layers  thick  (Fig.  13).    Of  these  the  outer  layer  and 
