﻿450 
  Transactions. 
  — 
  Botany, 
  

  

  up 
  Olio 
  side 
  of 
  a 
  rulge 
  to 
  descciicl 
  on 
  tlie 
  other. 
  The 
  central 
  cone, 
  which 
  

   forms 
  but 
  a 
  small 
  part 
  of 
  the 
  whole, 
  consists 
  of 
  loose 
  cinders 
  and 
  ashes, 
  into 
  

   which 
  the 
  feet 
  sink 
  at 
  every 
  step 
  of 
  the 
  ascent. 
  The 
  island 
  may 
  therefore 
  

   be 
  regarded 
  as 
  a 
  huge 
  filter, 
  through 
  which 
  the 
  rain 
  percolates, 
  so 
  that 
  a 
  

   perenuial 
  stream 
  or 
  even 
  a 
  spring 
  is 
  an 
  impossibility 
  ; 
  in 
  fact, 
  the 
  island 
  is 
  

   entirely 
  destitute 
  of 
  water, 
  except 
  the 
  small 
  quantity 
  that 
  during 
  rainy 
  

   weather 
  accumulates 
  in 
  rock-cavities, 
  and 
  which 
  is 
  speedily 
  evaporated. 
  The 
  

   formation 
  of 
  surface 
  soil 
  is 
  impossible 
  under 
  such 
  conditions, 
  since 
  the 
  

   comminuted 
  particles 
  of 
  rock 
  or 
  ash 
  are 
  washed 
  into 
  the 
  interstices 
  of 
  the 
  

   rocks 
  by 
  every 
  shower, 
  or 
  blown 
  away 
  by 
  every 
  breeze. 
  

  

  Yet 
  under 
  these 
  antagonistic 
  conditions, 
  less 
  favourable 
  on 
  the 
  whole 
  to 
  

   vegetable 
  life 
  than 
  even 
  the 
  pumice-covered 
  plains 
  of 
  the 
  Taupo 
  district, 
  we 
  

   find 
  a 
  flora 
  comprising 
  fully 
  one-seventh 
  of 
  the 
  entire 
  number 
  of 
  flowering 
  

   plants 
  and 
  ferns 
  indigenous 
  to 
  the 
  colony 
  always 
  exhibiting 
  extreme 
  luxu- 
  

   riance 
  of 
  foliage, 
  although 
  its 
  larger 
  members 
  arc 
  greatly 
  dwarfed 
  in 
  stature, 
  

   and 
  at 
  certain 
  periods 
  of 
  the 
  year 
  presenting 
  an 
  amount 
  of 
  floral 
  splendour 
  

   which 
  finds 
  no 
  counterpart 
  in 
  the 
  southern 
  portions 
  of 
  the 
  colony. 
  

  

  In 
  many 
  places 
  the 
  chasms 
  and 
  depressions 
  are 
  occupied 
  by 
  a 
  most 
  

   luxuriant 
  growth 
  of 
  Mosses, 
  Hepaticse, 
  and 
  Lichens, 
  the 
  most 
  frequent 
  of 
  

   which 
  are 
  Htjpnum 
  furfiirosum, 
  Chandonanllms 
  squarrosiis, 
  Pohjoius 
  clavifjcr, 
  

   Trichocolea 
  tomentclla, 
  Sendtjiera 
  flagelUfera, 
  Cladonia 
  ramjerijina, 
  C. 
  cornu- 
  

   copoides, 
  etc. 
  On 
  the 
  dry 
  exposed 
  rocks, 
  liacovnirium 
  lamnjinosxim. 
  forms 
  

   large 
  patches, 
  which 
  become 
  brittle 
  during 
  intervals 
  of 
  dry 
  weather, 
  but 
  

   revive 
  with 
  the 
  first 
  showers 
  : 
  this 
  is 
  the 
  only 
  locality 
  in 
  which 
  it 
  descends 
  to 
  

   the 
  sea-level 
  in 
  New 
  Zealand. 
  Growing 
  amongst 
  the 
  cool 
  mosses 
  are 
  several 
  

   delicate 
  ferns, 
  IlijmcnopJnjUum 
  sanguinoJcntnm, 
  H. 
  varum, 
  H. 
  midtifidum, 
  

   and 
  especially 
  Trichomanes 
  reniforme. 
  Other 
  ferns 
  of 
  coarser 
  growth 
  are 
  not 
  

   uncommon, 
  while 
  Clieilaiithes 
  sieberi, 
  a 
  characteristic 
  plant 
  of 
  the 
  Auckland 
  

   volcanic 
  district, 
  is 
  plentiful 
  on 
  the 
  driest 
  rocks. 
  One 
  of 
  the 
  most 
  interesting 
  

   plants 
  on 
  the 
  island 
  is 
  the 
  tropical 
  Psiluiinn 
  triqvclnnii, 
  which 
  occurs 
  in 
  

   abundance, 
  usually 
  springing 
  from 
  the 
  face 
  of 
  rocks. 
  Dendrobium 
  cunning- 
  

   liamii 
  produces 
  its 
  beautiful 
  flowers 
  in 
  greater 
  profusion 
  and 
  of 
  larger 
  size 
  

   than 
  I 
  have 
  seen 
  them 
  elsewhere, 
  and 
  the 
  fragrant 
  Earina 
  mucrovata 
  is 
  

   abundant. 
  There 
  is 
  a 
  sprinkling 
  of 
  grasses 
  comprising 
  eight 
  or 
  ten 
  species, 
  

   with 
  a 
  few 
  common 
  herbaceous 
  plants, 
  but 
  the 
  most 
  interesting 
  feature 
  of 
  

   the 
  flora 
  is 
  the 
  occurrence 
  of 
  Metrosideros 
  iomentosa, 
  ill. 
  robusta, 
  Griselinia 
  

   lucida, 
  PiUosporum 
  crassifolium, 
  Knlghtla 
  cxcclsa, 
  and 
  other 
  trees, 
  often 
  in 
  a 
  

   diminutive 
  condition, 
  but 
  laden 
  with 
  glossy 
  foliage 
  of 
  the 
  greatest 
  luxuriance, 
  

   and 
  flowers 
  of 
  deeper 
  and 
  brighter 
  tints 
  than 
  are 
  produced 
  under 
  ordinary 
  

   conditionSd 
  

  

  On 
  the 
  clay 
  cliffs 
  of 
  the 
  adjacent 
  islands, 
  Metrosideros 
  toinentosa 
  attains 
  a 
  

  

  