Am.  Jour.  Pharm. 
October,  1894. 
}     Structure  of  Heuchera  Americana. 
469 
as  an  astringent,  and  it  doubtless  merits  the  reputation  it  has 
acquired  as  a  remedy  for  diarrhoea,  aphthse,  menorrhagia,  and  for 
other  disorders  for  which  purely  astringent  remedies  are  employed. 
The  rhizome  is  fleshy,  one-half  or  three-fourths  of  an  inch  thick, 
tuberculate,  and  often  pitted,  from  two  to  four  or  five  inches  long, 
giving  origin  on  its  upper  surface  and  sides  to  several  short  heads 
which  are  cylindrical,  scaly  from  the  numerous  remaining  leaf-bases, 
and  often  terminated  by  a  concave  stem-scar ;  from  the  sides  and 
lower  surface  of  the  rhizome  are  emitted  numerous  roots,  many  of 
which  are  thin,  but  some  of  which  may  in  the  fresh  state  be  as  much 
as  one-third  of  an  inch  in  diameter. 
Fig.  4. 
A  cross-section  of  the  rhizome  shows  a  structure  which  is  repre- 
sented magnified  about  six  diameters  in  Fig.  2.  At  the  outside  is  a 
corky  layer  which  is  rough  and  unequal  in  thickness  from  peeling 
away  at  the  surface ;  interior  to  this  at  b  is  a  rather  thin  bark  com- 
posed wholly  of  soft  tissues,  and  then  a  large  central  cylinder  with 
a  few  wedge-shaped  radiating  xylem  masses  arranged  at  irregular 
distances  apart  but  always  separated  by  broad  masses  of  soft  tissues; 
and  there  is  a  large  central  pith. 
The  cross-section  of  a  root  shows  quite  a  characteristic  structure. 
One  of  the  roots  magnified  about  six  diameters  is  shown  in  cross- 
section  in  Fig.  j.    The  rough,  corky  exterior  bark  is  shown  at  a, 
