﻿new 
  Flora 
  of 
  Krakatao. 
  147 
  

  

  M. 
  Verbeek 
  adds 
  : 
  " 
  the 
  dark-coloured 
  ash 
  no. 
  7 
  a 
  is 
  pro- 
  

   bably 
  the 
  most 
  basic, 
  the 
  pumice 
  no. 
  9 
  a 
  the 
  most 
  acid 
  product 
  

   of 
  those 
  cast 
  out 
  by 
  Krakatao 
  in 
  1883." 
  It 
  has 
  been 
  said 
  of 
  

   the 
  island 
  of 
  Ascension 
  that 
  the 
  soil 
  resembles 
  powdered 
  

   glass. 
  It 
  is 
  clear 
  that 
  the 
  same 
  thing 
  might 
  be 
  said 
  of 
  Kra- 
  

   katao. 
  

  

  As 
  for 
  the 
  physical 
  conditions, 
  the 
  pumice-stone 
  and 
  the 
  

   greyish-coloured 
  ashes 
  which 
  cover 
  Krakatao 
  are 
  continually 
  

   heated 
  by 
  a 
  scorching 
  sun, 
  without 
  there 
  being 
  any 
  trace 
  of 
  

   shade. 
  

  

  With 
  the 
  assistance 
  of 
  my 
  friend 
  Dr. 
  Burck 
  I 
  made, 
  in 
  the 
  

   laboratory 
  of 
  the 
  garden 
  at 
  Buitenzorg, 
  sowings 
  of 
  the 
  fern- 
  

   spores 
  brought 
  back 
  from 
  Krakatao 
  on 
  all 
  kinds 
  of 
  substratum. 
  

   We 
  wished 
  to 
  see 
  whether 
  the 
  prothallia 
  and 
  young 
  plants 
  of 
  

   these 
  ferns 
  presented 
  any 
  special 
  adaptations 
  which 
  would 
  

   enable 
  them 
  to 
  overcome 
  conditions 
  so 
  little 
  favourable 
  as 
  

   those 
  offered 
  by 
  the 
  soil 
  of 
  Krakatao. 
  During 
  an 
  examina- 
  

   tion 
  which 
  was 
  of 
  necessity 
  brief 
  * 
  nothing 
  revealed 
  the 
  

   presence 
  of 
  special 
  adaptations 
  either 
  in 
  the 
  prothallia 
  or 
  in 
  

   the 
  young 
  plants. 
  

  

  To 
  the 
  mind 
  of 
  one 
  verifying 
  on 
  the 
  spot 
  the 
  predominance 
  

   of 
  ferns 
  at 
  Krakatao 
  the 
  following 
  questions 
  immediately 
  

   present 
  themselves. 
  How 
  can 
  the 
  fern-spores 
  germinate 
  

   under 
  such 
  conditions 
  ? 
  are 
  there 
  not 
  plants 
  of 
  a 
  lower 
  order 
  

   there, 
  which 
  cover 
  the 
  pumice-stone 
  and 
  the 
  ash 
  with 
  a 
  thin 
  

   layer, 
  enabling 
  the 
  spores 
  to 
  germinate 
  ? 
  In 
  the 
  first 
  place 
  

   1 
  thought 
  of 
  small 
  lichens 
  ; 
  but 
  I 
  did 
  not 
  succeed 
  in 
  finding 
  

   a 
  single 
  lichen 
  on 
  the 
  whole 
  island. 
  But 
  here 
  and 
  there 
  on 
  

   the 
  surface 
  of 
  the 
  ash 
  and 
  of 
  the 
  pumice 
  a 
  glaucous 
  or 
  greenish 
  

   layer 
  could 
  be 
  distinguished, 
  which 
  evidently 
  arose 
  from 
  Algas. 
  

   A 
  minute 
  examination 
  with 
  the 
  lens 
  showed 
  that 
  the 
  same 
  

   thing 
  existed 
  nearly 
  everywhere, 
  though 
  in 
  a 
  less 
  pronounced 
  

   degree. 
  I 
  then 
  collected 
  samples 
  of 
  the 
  superficial 
  layer 
  of 
  

   the 
  soil 
  of 
  Krakatao 
  from 
  several 
  places 
  in 
  order 
  to 
  exa- 
  

   mine 
  them 
  at 
  Buitenzorg. 
  

  

  It 
  appears 
  that 
  the 
  ash 
  and 
  the 
  pumice 
  composing 
  the 
  soil 
  of 
  

   Krakatao 
  are 
  covered 
  almost 
  everywhere 
  with 
  a 
  thin 
  layer 
  of 
  

   (Jonfervoid 
  A 
  Igce. 
  

  

  I 
  have 
  proved 
  the 
  presence 
  on 
  Krakatao 
  of 
  six 
  species 
  of 
  

   these 
  Confervoid 
  Algas, 
  to 
  wit 
  : 
  one 
  Tolypothrix^ 
  one 
  Ana- 
  

   bana 
  : 
  one 
  Synqyloca, 
  and 
  three 
  species 
  of 
  Lyngbya. 
  I 
  shall 
  

   distinguish 
  provisionally 
  the 
  last 
  three 
  species 
  by 
  the 
  following 
  

   names 
  : 
  — 
  

  

  * 
  In 
  consequence 
  of 
  the 
  indisposition 
  which 
  compelled 
  me 
  to 
  return 
  

   for 
  some 
  time 
  to 
  Europe. 
  

  

  