542 
Fruit  of  Co  cos  Nucifera. 
(Am,  Jour.  Pharm. 
I  Norember,  1901. 
in  making  mats  and  cordage,  and  also  cocoanut  shell,  which  has 
been  used  for  making  knobs  and  other  turned  articles,  were  studied 
by  Wiesner1  nearly  thirty  years  ago,  but  his  work  was  designed 
chiefly  to  distinguish  the  fiber  from  other  commercial  fibers  and  the 
shell  from  the  similar  shell  of  Attalea  funifera. 
Von  Hoehnel 2  describes  briefly  the  histology  of  coir,  but,  like 
Wiesner,  does  not  appear  to  have  understood  the  true  nature  of 
the  stegmata. 
Weiss,3  Engler  and  Prantl,4  and  some  other  authors  refer 
briefly  to  the  microscopic  structure  of  parts  of  the  cocoanut,  but 
their  descriptions  are  of  little  value  in  diagnosis. 
1.  Epicarp. 
The  epicarp  or  epidermal  layer  is  about  -015  m.m.  thick  and  is 
made  up  of  tabular  cells  with  dark  brown  contents.  In  surface 
view  the  cells  are  usually  square,  rectangular  or  triangular,  with 
double  walls  about  -005  m.m.  thick  and  are  arranged  with  some 
regularity  in  rows. 
2.  Mesocarp. 
(a)  Hard  ground  tissue. — This  tissue  consists  of  thick-walled 
cells  which  are  often  tangentially-transversely  elongated.  In  the 
first  few  layers  the  walls  are  about  the  same  thickness  as  in  the 
epidermis,  without  evident  pores,  but  further  inward  they  are  more 
strongly  thickened  (double  walls  often  '015  m.m.  thick)  and  con- 
spicuously  porous.  Still  further  inward  they  pass  into  the  paren- 
chyma of  the  soft  ground  tissue. 
(b)  Bast-fiber  bundles. — In  the  hard  ground  tissue  the  bundles 
have  no  phloem  or  xylem  but  are  composed  entirely  of  bast-fibers 
with  cell  walls  often  thicker  than  the  lumen.  The  number  of 
fibers  seen  in  cross  section  varies  from  two  or  three  up  to  a  hun- 
dred or  more.  Transitional  forms  between  fibrous  and  fibro-vas- 
cular  bundles  occur  further  inward. 
1  Die  Rohstoffe  des  Pflanzen-Reiches,  Leipzig,  1873,  pp.  436  and  789.  (A  new 
edition  is  being  published  in  parts,  but  the  chapters  on  the  cocoanut  have  not 
yet  appeared.) 
2  Die  Microscopie  der  technisch  verwendeten  Faserstoffe,  Leipzig,  1887,  p.  52. 
3  Anatomie  der  Pflanzeny  Wien,  1878,  1  Band. 
4  Die  natiirlichen  PJlanzenfamilien,  II  Theil,  3  Abteilung,  p.  22. 
