148 
Manganese  Occurring  in  Plants. 
( Am.  Jour.  Pharm. 
I     March,  1886. 
In  a  paper  of  mine2  I  stated  that  the  plants  of  the  natural  order 
Zingiberacese  are  remarkable  for  the  manganese  which  is  to  be  met 
with  in  every  part  of  at  least  most  of  those  plants.  The  smallest 
fragment  of  cardamoms  or  of  their  capsule  yields  an  ash  of  intensely 
green  color,  due  to  manganates.  Other  seeds  or  fruits  which  I  ex- 
amined in  the  same  way  pVoved  free  of  manganese. 
Yet  there  is  another  plant  particularly  remarkable  in  that  respect, 
viz.,  the  curious  Trapa  nutans,  L.,  an  annual  herb  growing  in  a  lim- 
ited number  of  localities  in  several  parts  of  continental  Europe.  It 
lives  in  a  very  interesting  wa^  on  the  bottom  of  swamps,  from  which 
at  the  flowering  time  the  leaves  rise  to  the  surface  of  the  water. 
Gorup-Besanez3  has  shown  that  Trapa  natans,  especially  its  fruit, 
is  comparatively  rich  in  manganese  although  it  grows  in  water  con- 
taining only  an  extremely  small  amount  of  that  metal.  Like  Lami- 
naria  in  the  case  of  iodine,  Trapa  natans  is  possessed  of  the  singular 
power  of  assimilating  manganese  which  it  wants  from  the  water.  It 
would  be  interesting  to  submit  the  plant  under  notice  to  experiments 
in  order  to  ascertain  whether  it  can  perfectly  succeed  without  manga- 
nese, and  to  investigate  whether  other  plants  living  in  the  same  water 
as  Trapa  likewise  absorb  manganese. 
The  seeds,  i.  e.,  the  cotyledons,  of  the  "  water  nut,"  i.  e.,  Trapa 
natans,  are  eaten  in  Upper  Alsatia  and  the  neighboring  districts  of 
France  as  well  as  in  Northern  Italy;  they  were  in  prehistoric  times, 
in  all  probability,  an  item  of  the  food  of  the  inhabitants  of  the  pala- 
fittes  (Pfahlbauten)  of  Switzerland.  The  most  characteristic  fruit  of 
Trapa  is  abundantly  met  with  in  the  remains  of  those  prehistoric  settle- 
ments, thus  showing,  in  the  opinion  of  some  botanists/  that  Trapa 
natans  is  to  be  comprised  among  the  species  which  are  on  the  way  to 
die  out.  A  recent  monograph5  on  Trapa  natans,  however,  is  by  no 
means  in  favor  of  such  a  theory,  considering  that  in  olden  times 
swamps  were  much  more  abundant  in  Europe.  Consequently  the 
conditions  for  the  growth  of  Trapa  were  then  much  more  favorable 
than  they  are  in  our  days. 
There  are,  strangely  enough,  two  species  of  the  same  genus  in  the 
East,  playing  a  most  important  part  in  the  food  of  the  Indian  and 
2  Pharm.  Journal,  iii  (1872),  208. 
3  Liebig's  Annalen  der  Chemie  und  Pharmacie,  cxviii  (1861)  p.  223. 
4  Christ,  Das  Pflanzenleben  der  Schweiz,  Ziirich,  1879,  p.  55,  180,  424,  432. 
5  Tiiggi,  Die  Wassernuss,  Trapa  natans,  Zurich,  1883,  pp.  34,  40. 
