116  Note  on  Yerba  and  Raiz  del  Indio.      {^Jrch  Ss!"** 
the  Mexican  Pharmacopoeia  cannot  be  the  parent  plant  of  the  root 
examined  by  Mr.  Voelcker.  It  seems  likely,  however,  that  the  latter 
is  identical  with  a  root,  also  known  by  the  name  canaigre.  At  least 
in  the  "  Report  of  the  Commissioner  of  Agriculture  for  the  year 
1879,"  a  plant  is  figured,  the  leaves  of  which  agree  in  the  main  with 
Mr.  Voelcker' s  description,  as  well  as  the  characteristics  of  the  root 
given  in  the  report  by  Mr.  Wm.  Saunders,  superintendent  of  gardens 
and  grounds  in  Washington,  D.  C,  who  speaks  in  the  Report  (page 
364)  as  follows: 
"In  the  report  of  the  department  for  1878,  at  page  119,  will  be 
found  an  analysis  of  the  above-named  root  (canaigre)1.  The  main 
object  of  the  examination  was  to  determine  the  amount  of  tannic  acid 
contained  in  this  root  which  was  received  from  Texas,  where  it  has 
long  been  used  by  the  Indians  and  others  for  tanning  purposes,  and 
is  said  to  be  used  at  present  by  several  tanneries  in  and  about  San 
Antonio.  From  the  analysis  it  appears  that  the  root  contains  about 
23  per  cent,  of  tannic  acid2,  and  the  fact  that  the  article  is  employed 
in  tanneries  would  seem  to  indorse  its  practical  adaptability  as  a  tan- 
ning material.  Canaigre  is  the  bulbous  root  of  a  kind  of  dock  specifi- 
cally called  Rumex  hymenosepalum  (Torrey).  It  grows  plentifully  in 
sandy  soils  over  a  large  territory  on  both  sides  of  the  Rio  Grande,  and 
from  there  northward  over  a  large  portion  of  Western  Texas.  The 
bulbs  are  produced  in  clusters  like  some  kinds  of  sweet  potatoes,  some 
clusters  weighing  several  pounds,  and  can  be  procured,  it  is  stated,  at 
a  cost  not  exceeding  $1  per  100  pounds.  The  leaves  of  the  plant  are 
somewhat  fleshy  when  in  the  young  state,  when  they  are  greedily 
eaten  by  cattle,  and  occasionally  used  as  a  pot-herb  by  travelers  and 
others." 
The  facts  as  far  as  they  are  accessible  to  me  at  the  present  time, 
point  to  the  identity  of  the  three  samples  of  roots  mentioned  above, 
and  that  they  have  been  derived  from  the  neighborhood  of  the  Rio 
Grande.  From  the  brief  history  given  it  is  not  in  the  least  surprising 
that  in  some  localities  of  Texas  this  root  should  have  become  popularly 
known  as  "raiz  del  indio,"  and  the  herbaceous  plant  yielding  it  as 
"yerba  del  indio,"  which  latter  name  has  long  been  applied  in  the 
interior  of  Mexico  to  a  woody  climber,  the  root  of  which,  doubtless, 
differs  from  the  former  considerably  in  its  morphological  characters, 
1  I  have  not  been  able  to  consult  the  report  containing  this  analysis.— J.M.M. 
2  Mr.  Voelcker  found  2313  per  cent,  of  tannin— J.  M.  M. 
