﻿Ii6 
  M. 
  Treub 
  on 
  the 
  

  

  transported 
  by 
  the 
  wind 
  across 
  an 
  arm 
  of 
  the 
  sea 
  ; 
  even 
  though 
  

   very 
  narrow 
  *. 
  

  

  Lastly, 
  the 
  great 
  number 
  of 
  species 
  of 
  ferns 
  constitutes 
  the 
  

   most 
  interesting 
  result 
  of 
  the 
  inquiry. 
  Amongst 
  these 
  eleven 
  

   species 
  of 
  ferns 
  there 
  are 
  only 
  two, 
  Acrostichum 
  aureum 
  and 
  

   Nephrolejpis 
  exaltata, 
  which 
  are 
  widely 
  distributed 
  over 
  the 
  

   islands 
  of 
  the 
  hot 
  regions. 
  For 
  these 
  two 
  species, 
  which 
  

   probably 
  prefer 
  a 
  soil 
  more 
  or 
  less 
  impregnated 
  with 
  saline 
  

   matters, 
  Krakatao 
  can 
  offer 
  some 
  advantages 
  in 
  this 
  respect; 
  

   for 
  the 
  nine 
  other 
  species 
  this 
  is 
  not 
  the 
  case. 
  

  

  But 
  more 
  than 
  that. 
  In 
  order 
  to 
  judge 
  of 
  the 
  relative 
  

   importance 
  of 
  plants 
  belonging 
  to 
  different 
  groups 
  in 
  the 
  re- 
  

   stocking 
  of 
  a 
  country, 
  the 
  point 
  in 
  question 
  in 
  the 
  first 
  place 
  

   is 
  not 
  the 
  number 
  of 
  species 
  but 
  the 
  number 
  of 
  individuals. 
  

   Looking 
  at 
  it 
  from 
  this 
  point 
  of 
  view, 
  I 
  can 
  formulate 
  the 
  

   result 
  of 
  the 
  inquiry 
  made 
  at 
  Krakatao 
  thus 
  : 
  — 
  

  

  Three 
  years 
  after 
  the 
  eruption 
  the 
  new 
  flora 
  of 
  Krakatao 
  was 
  

   composed 
  almost 
  entirely 
  of 
  Ferns. 
  The 
  Phanerogams 
  were 
  

   only 
  found 
  isolated, 
  here 
  and 
  there 
  on 
  the 
  shore 
  or 
  on 
  the 
  moun- 
  

   tain 
  itself 
  

  

  It 
  is 
  therefore 
  ferns 
  to 
  which 
  the 
  role 
  reverts 
  of 
  preparing 
  

   the 
  earth 
  for 
  the 
  phanerogamic 
  vegetation, 
  which 
  in 
  time 
  

   will 
  cover 
  the 
  island 
  again 
  as 
  it 
  covered 
  it 
  before 
  the 
  eruption. 
  

  

  There 
  is 
  nothing 
  at 
  all 
  astonishing 
  in 
  the 
  fact 
  that 
  nume- 
  

   rous 
  spores 
  of 
  ferns 
  fall 
  on 
  Krakatao, 
  since 
  the 
  wind 
  carries 
  

   even 
  tiie 
  seeds 
  of 
  phanerogams 
  over 
  the 
  island 
  ; 
  but 
  what 
  is 
  

   almost 
  incomprehensible 
  to 
  any 
  one 
  on 
  the 
  spot 
  is 
  how 
  the 
  

   ferns 
  and 
  their 
  prothallia 
  succeed 
  in 
  living 
  under 
  such 
  disad- 
  

   vantageous 
  conditions. 
  Chemically 
  and 
  physically 
  the 
  vol- 
  

   canic 
  matter 
  which 
  covers 
  Krakatao 
  constitutes 
  one 
  of 
  the 
  

   most 
  arid 
  of 
  soils. 
  To 
  give 
  an 
  idea 
  of 
  the 
  chemical 
  compo- 
  

   sition 
  presented 
  to 
  plants 
  by 
  this 
  substratum, 
  I 
  reproduce 
  the 
  

   result 
  of 
  two 
  analyses 
  according 
  to 
  M. 
  Verbeek 
  \ 
  : 
  — 
  

  

  No. 
  7 
  a. 
  No. 
  9 
  a. 
  

  

  Si 
  2 
  61-30 
  68-99 
  

  

  TiO 
  a 
  112 
  0-82 
  

  

  Al 
  2 
  U 
  3 
  17-77 
  16-07 
  

  

  Fe 
  2 
  3 
  4-39 
  2-63 
  

  

  Fe 
  O 
  171 
  1-10 
  

  

  MnO 
  0-41 
  0-28 
  

  

  Ca 
  O 
  343 
  3-16 
  

  

  MgO 
  232 
  1-08 
  

  

  K 
  2 
  O 
  2-51 
  1-83 
  

  

  Na 
  3 
  498 
  404 
  

  

  * 
  The 
  distances 
  of 
  Krakatao 
  from 
  Sibesia, 
  Sumatra, 
  and 
  Java 
  are 
  10, 
  

   20, 
  and 
  21 
  miles. 
  The 
  two 
  small 
  islands 
  " 
  Lang 
  eiland 
  " 
  and 
  " 
  Verlaten 
  

   eiland," 
  which 
  were 
  completely 
  laid 
  waste 
  at 
  the 
  time 
  of 
  the 
  eruption, 
  

   were 
  absolutely 
  uninhabited 
  at 
  the 
  period 
  of 
  my 
  visit 
  to 
  Krakatao. 
  

  

  t 
  R. 
  D. 
  M. 
  Verbeek, 
  ' 
  Krakatao,' 
  Batavia, 
  1885-86, 
  p. 
  309. 
  

  

  