the  Umbelliferae,  the  Compositae,  and  the  Labiatx  ;  whilst  in  about
a  third  the  plants  had  dehiscent  fruits  with  small  seeds,  such  as
are  characteristic  of  the  Cruciferae,  the  Caryophyllaceae,  and  the
Juncaceae.  Plants  with  large  seeds,  such  as  those  of  Nuphar
luteum  and  Convolvulus  arvensis,  make  up  only  six  per  cent,  of
those  of  the  non-buoyant  group,  the  remainder  comprising  plants
with  berries,  such  as  Solanum,  and  others  with  miscellaneous  fruits.
Of  the  80  plants  where  the  seeds  or  fruits  floated  more  than  a
week,  usually  for  several  weeks,  and  often  for  months,  70  per  cent,
possessed  dry,  indehiscent  fruits,  such  as  those  of  Hydrocotyle
vulgaris,  Bidens  cemua,  Lycopus  europaeus,  Carex,  &c.,  whilst  only
6  or  7  per  cent  had  dehiscent  fruits  with  small  seeds,  such  as  we
iind  in  Lysimachia  and  Menyanthes,  the  remainder  being  generally
characterised  by  large  seeds,  such  as  those  of  Convolvulus  sepium,
C.  soldanella.  Iris  pseudacorus,  Calla  palustris,  &c.  It  would  thus
appear  that,  in  so  far  as  buoyancy  is  concerned.  Nature  has  for  the
most  part  ignored  the  small  seed  and  has  confined  herself  mainly
to  the  dry  indehiscent  fruit  We  have  already  seen  that  this
is  also  true  of  the  same  great  sorting-process  in  the  tropical  islands
of  the  Pacific,  and  it  doubtless  applies  all  over  the  world.
