AnAigusiPi9cfs^m'}      Histology  of  Hyoscyamus  Muticus.  365 
on  the  under  surfaces.  They  are  lighter  in  color  than  the  rest  of 
the  leaf,  and  running  out  from  the  midrib  are  prominent  veins 
which  terminate  in  the  lobes.  In  color  the  leaves  are  green  or 
yellow-green. 
Surface  views  of  both  upper  and  under  sides  of  the  leaves  show 
cells  with  relatively  even  and  regular  walls  [Fig.  J,  .Fand  and  Fig. 
4.  J).  On  the  veins  the  epidermal  cells  are  elongated  and  sometimes 
pointed,  resembling  prosenchyma  in  form  (Fig.  4,  K).  The  palisade 
Fig.  4  — H,  Epidermis  of  calyx,  outer  surface  ;  J,  epidermis  of  leaf,  under 
surface  ;  K,  epidermis  from  midrib,  under  surface  of  leaf;  M,  epidermis  from 
inner  surface  of  calyx. 
parenchyma  consists  of  a  single  row  of  cells  which  are  filled  with 
protoplasm,  and  contain  numerous  chloroplasts.  They  are  separated 
by  numerous  intercellular  spaces.  The  spongy  parenchyma  is  made 
up  of  several  layers  of  irregular  cells,  between  which  are  large  inter- 
cellular spaces.  These  cells  are  also  rich  in  chloroplasts  and  those 
adjacent  to  the  palisade  frequently  contain  crystals.  Stomata  simi- 
lar in  form  and  size  occur  on  both  the  upper  and  under  surfaces  of 
the  leaves,  and  both  surfaces  are  pubescent. 
