﻿new 
  Flora 
  of 
  Krakatao. 
  143 
  

  

  There 
  is 
  no 
  need 
  to 
  discuss 
  the 
  possibility 
  of 
  the 
  plants 
  

   newly 
  installed 
  at 
  Krakatao 
  having 
  been 
  brought 
  there 
  by 
  

   the 
  intermediation 
  of 
  man. 
  The 
  island 
  is 
  uninhabited, 
  unin- 
  

   habitable, 
  and 
  difficult 
  of 
  access. 
  

  

  Finally, 
  the 
  composition 
  itself 
  of 
  the 
  existing 
  flora 
  of 
  Kra- 
  

   katao 
  is 
  an 
  additional 
  proof 
  that 
  it 
  cannot 
  have 
  derived 
  its 
  

   origin 
  either 
  from 
  the 
  former 
  flora 
  or 
  by 
  the 
  intervention 
  of 
  

   man. 
  

  

  In 
  the 
  second 
  place 
  I 
  think 
  it 
  necessary 
  to 
  say 
  a 
  few 
  words 
  

   on 
  the 
  views 
  generally 
  adopted 
  as 
  to 
  the 
  origin 
  of 
  the 
  floras 
  

   of 
  islands. 
  This 
  question, 
  justly 
  regarded 
  as 
  one 
  of 
  the 
  most 
  

   important 
  in 
  botanical 
  geography, 
  has 
  been 
  treated 
  in 
  a 
  num- 
  

   ber 
  of 
  works 
  and 
  memoirs 
  of 
  great 
  value. 
  It 
  would 
  be 
  out 
  

   of 
  place 
  in 
  this 
  short 
  notice 
  to 
  make 
  numerous 
  quotations 
  ; 
  

   nevertheless 
  I 
  cannot 
  refrain 
  from 
  mentioning 
  the 
  excellent 
  

   memoirs 
  on 
  insular 
  floras 
  and 
  their 
  origin 
  published 
  two 
  years 
  

   ago 
  by 
  Mr. 
  W. 
  Botting 
  Hemsley 
  of 
  Kew. 
  In 
  these 
  memoirs, 
  

   which 
  together 
  form 
  the 
  first 
  volume 
  of 
  the 
  " 
  Botany 
  " 
  part 
  

   of 
  the 
  celebrated 
  ' 
  Challenger 
  ' 
  Reports, 
  Mr. 
  Hemsley 
  has 
  

   brought 
  together 
  and 
  discussed 
  all 
  the 
  data 
  bearing 
  on 
  the 
  

   subject. 
  

  

  Everything 
  to 
  be 
  found 
  in 
  literature 
  on 
  the 
  origin 
  of 
  insular 
  

   floras 
  has 
  reference 
  to 
  coral-islands 
  : 
  these 
  are 
  the 
  only 
  ones 
  

   for 
  which 
  direct 
  observations 
  have 
  been 
  possible 
  up 
  to 
  the 
  

   present 
  time. 
  

  

  When 
  one 
  of 
  these 
  islands 
  has 
  begun 
  to 
  rise 
  above 
  the 
  

   level 
  of 
  the 
  sea, 
  seeds 
  carried 
  by 
  ocean-currents 
  from 
  distant 
  

   shores 
  strike 
  against 
  the 
  growing 
  island. 
  Arrested 
  for 
  good 
  

   and 
  all 
  in 
  their 
  passive 
  course 
  these 
  seeds 
  germinate 
  and 
  give 
  

   birth 
  to 
  the 
  first 
  vegetation 
  of 
  the 
  island. 
  That 
  seeds 
  and 
  

   fruits 
  may 
  play 
  this 
  role 
  of 
  first 
  colonizing 
  agent 
  they 
  must 
  

   be 
  able 
  to 
  float 
  for 
  a 
  long 
  time 
  in 
  the 
  sea 
  and 
  must 
  not 
  lose 
  

   their 
  germinative 
  power. 
  These 
  two 
  qualities 
  being 
  rarely 
  

   united, 
  the 
  number 
  of 
  plants 
  which 
  land 
  on 
  one 
  of 
  these 
  new 
  

   coral-islands 
  is 
  very 
  restricted. 
  It 
  is 
  always 
  the 
  same 
  plants, 
  

   generally 
  trees, 
  to 
  which 
  the 
  role 
  of 
  first 
  colonizing 
  agent 
  

   reverts 
  ; 
  there 
  are 
  at 
  the 
  most 
  thirty 
  species 
  in 
  all 
  which 
  come 
  

   under 
  consideration. 
  

  

  Once 
  the 
  isle 
  is 
  provided 
  with 
  some 
  trees 
  a 
  second 
  colonizing 
  

   agent 
  intervenes. 
  It 
  is 
  birds, 
  and 
  amongst 
  them 
  especially 
  

   oceanic 
  pigeons 
  (frequently 
  Carpophaga 
  oceanica), 
  which 
  now 
  

   act 
  this 
  role, 
  by 
  coming 
  to 
  rest 
  on 
  the 
  trees 
  after 
  their 
  long 
  

   flight. 
  Being 
  frugivorous, 
  they 
  deposit 
  on 
  the 
  island 
  with 
  their 
  

   excrement 
  the 
  seeds 
  of 
  many 
  plants, 
  which 
  are 
  not 
  long 
  in 
  

   constituting 
  a 
  new 
  and 
  important 
  element 
  of 
  this 
  flora 
  in 
  statu 
  

   nascendi. 
  Ocean-currents 
  and 
  birds 
  are 
  thus 
  the 
  two 
  agents 
  

  

  