362  Histology  of  Hyoscyamus  Muticus.      { AmAUJ|usMmm' 
STEM. 
The  inflorescence  is  a  dorsi-ventral,  one-sided  raceme,  having  the 
younger  portion  rolled  inward  toward  the  ventral  side.  However, 
the  inflorescence  is  almost  identical  with  that  of  Hyoscyamus  niger, 
which  Tschirch  insists  is  cymose  in  structure  (Anatomischer  Atlas, 
page  168),  and  not  a  close  raceme  or  spike  as  it  is  usually  described. 
The  stems  are  hollow,  cylindrical,  and  longitudinally  wrinkled, 
the  younger  parts  being  flattened  in  drying  and  often  deeply  furrowed 
on  the  ventral  side.    They  are  covered  with  trichomes,  which  are 
Fig.  1. — A,  Cross  section  of  stem,  showing  epidermis  b,  and  cortex  c.  B, 
Cross  section  of  stem  extending  from  the  cortex  e,  to  the  xylem  f,  showing  the 
phloem  at  g.  C,  Portion  of  xylem  showing  ducts  and  wood  fibers  z,  and 
medullary  ray  at  //  d,  wood  fibers,  separated  by  maceration  ;  n,  fragments  of 
ducts  from  powder. 
very  prominent  on  the  younger  parts,  while  the  older  parts  may  be 
almost  smooth.  In  color  they  are  grayish-yellow  to  yellowish- 
brown,  and  as  they  may  be  10  mm.  or  more  in  diameter,  they  show 
externally  characteristics  which  readily  distinguish  them  from  the 
official  Hyoscyamus  niger. 
The  internal  structure  of  the  stem  is  peculiar  and  characteristic. 
