|22  Distribution  of  Tannin  Plants.  J^&fiS 
order  Santalales  four  families  together  contain  about  fifteen  species 
of  plants  which  produce  tannin,  the  important  ones  being  species  of 
Osyris  and  Fiisanus  from  India,  Central  Africa  and  Australia,  rang- 
ing from  15  to  25  per  cent,  in  tannin  content.  The  order  Ranales 
has  nine  families  which  together  include  a  hundred  species  of  plants 
containing  more  or  less  tannin ;  of  these  the  best  known  are  species 
of  Per  sea  in  Chili,  17  per  cent,  tannin;  Nectandra  in  Brazil,  10  per 
cent,  tannin;  Xesodaphne  in  Australia  and  Litsea  in  India,  both 
yielding  over  7  per  cent,  tannin.  In  the  order  Tubiflorae  a  large  num- 
ber of  tannin  containing  species  is  distributed  among  fourteen  fami- 
lies. The  important  tannin  plants  are  species  of  Bignonia  from 
Guiana,  14  per  cent,  tannin,  of  Erernophila  from  Australia  and  of 
Avicennia  from  the  East  and  the  West  Indies.  Other  orders  in 
which  a  part  of  the  families  have  numerous  species  containing  tannin, 
the  important  ones  of  which  are  largely  confined  to  the  tropics,  are 
the  Contorts,  Aristolochiales,  Rubiales,  Umbelliflora,  Parietales  and 
Malvales. 
No  less  interesting  is  the  distribution  of  those  orders  in  which 
practically  all  the  families  comprise  tannin  bearing  plants.  In  some 
of  these  families  the  occurrence  of  tannin  is  so  general  that  they 
may  be  considered  as  typical  tannin  families.  Examples  of  such  are 
the  Combretacese,  consisting  of  about  240  tropical  species,  one  of 
which  yields  the  myrobalans  of  commerce;  the  Rhizophoracese  which 
contains  about  50  tropical  species  rich  in  tannin,  some  of  which  yield 
the  mangrove  bark;  the  Leguminosse  with  about  6,000  widely  dis- 
tributed species  of  which  many  of  those  rich  in  tannin,  as  the  wattle, 
algarobilla,  ratanhia,  kino  and  divi-divi,  are  tropical,  and  the  Myrta- 
cese  which  has  at  least  100  tannin  species,  the  best  known  of  which 
is  the  Eucalyptus,  native  of  Australia.  Notwithstanding  the  wide 
distribution  of  these  families,  by  far  the  greater  number  of  species 
having  a  high  tannin  content  occur  in  tropical  or  subtropical  regions. 
There  are,  of  course,  some  exceptions,  as,  for  example,  the  Fagaceae, 
to  which  the  oaks  and  chestnuts  belong,  but  in  general  that  portion 
of  the  several  continents  lying  between  the  parallels  of  300  north 
and  south  latitude  must  be  depended  upon  to  furnish  the  bulk  of  the 
supply  of  commercial  tannin. 
An  enumeration  of  the  various  plants  which  have  been  used  for 
tanning  in  different  countries  would  give  only  an  apparent  indication 
of  their  geographic  distribution,  since  a  tannin  plant  frequently 
occurs  in  countries  where  it  finds  little  if  any  use  and  perhaps  more 
