Am.  Jour.  Pharm. 
August,  19 19. 
L-  }  Notes  on  the  Dasheen  and  Chayote. 
501 
mels  are  marked  by  the  presence  of  numerous  rings  which  represent 
leaf  scars.  When  the  lateral  cormels  are  removed  large  circular  to 
ovate  light  colored  spots  are  exhibited.  The  total  from  one  hill  of 
these  underground  portions  ranges  from  four  to  thirty  pounds. 
The  above  ground  parts  (Fig.  2)  consist  of  several  petiolate, 
auriculate,  peltate,  bright  green  leaves,  three  feet  or  more  long  and 
a  spadix,  which  is  free  and  terminated  by  a  sterile  appendage. 
Histology. — When  examined  microscopically,  sections  of  the 
Trinidad  dasheen  corm  show  the  following  histological  peculiarities, 
passing  from  periphery  toward  the  center. 
Fig.  3.  Two  mother  corms  with  their  lateral  cormels,  the  product  of  an 
11-pound  hill  of  Dasheens.  (Photograph  by  R.  A.  Young  in  Separate  689 
from  U.  S.  Dept.  of  Agric.  Yearbook,  1916.) 
1.  A  zone  of  cork  composed  of  numerous  layers  of  cells  with 
suberized  walls,  varying  in  shape  from  irregular  polygonal  to  rec- 
tangular. 
2.  A  broad  zone  of  phellogen,  composed  of  more  or  less  rectan- 
gular shaped  tangentially  elongated  cells  with  rich  protoplasmic 
contents. 
3.  A  broad  central  matrix,  composed  of  parenchyma  tissue,  the 
cells  of  which  are  mostly  thin  walled  and  abundantly  filled  with 
starch.  The  starch  grains  are  mostly  simple,  but  compound  grains 
composed  of  up  to  eight  units  are  occasionally  met  with.  The 
simple  grains  vary  in  outline  from  rounded  to  irregularly  rounded 
