﻿Gr. 
  M. 
  Thomson, 
  — 
  On 
  the 
  Fertilization 
  of 
  some 
  New 
  Zealand 
  OrcJiids. 
  425 
  

  

  of 
  the 
  anther, 
  and 
  is 
  slightly 
  viscid. 
  The 
  pollen-masses, 
  four 
  in 
  number, 
  

   are 
  very 
  incoherent. 
  From 
  their 
  inconspicuous 
  colour, 
  the 
  fact 
  of 
  their 
  being 
  

   very 
  frequently 
  closed, 
  and 
  the 
  extreme 
  incoherence 
  of 
  their 
  pollen, 
  I 
  am 
  

   inclined 
  to 
  think 
  that 
  the 
  flowers 
  of 
  this 
  plant 
  are 
  always 
  self-fertilized, 
  I 
  

   examined 
  39 
  flowers, 
  and 
  found 
  that 
  the 
  pollinia 
  were 
  present 
  in 
  all 
  of 
  

   them, 
  but 
  in 
  the 
  more 
  advanced 
  some 
  of 
  the 
  pollen 
  was 
  scattered 
  over 
  the 
  

   stigmas, 
  and 
  the 
  ovaries 
  appeared 
  well-developed. 
  

  

  Tribe 
  Neotte^, 
  

   (9.) 
  Thehjmitra 
  longifolia. 
  

  

  The 
  fertihzation 
  of 
  this 
  orchid 
  is 
  treated 
  of 
  in 
  Fitzgerald's 
  "Australian 
  

   Orchids," 
  and 
  quoted 
  by 
  Darwin. 
  All 
  the 
  parts 
  of 
  the 
  perianth, 
  including 
  

   the 
  labellum, 
  are 
  similar 
  in 
  colour 
  and 
  shape. 
  The 
  column 
  is 
  nearly 
  erect, 
  

   and 
  slightly 
  hooded 
  at 
  the 
  apex. 
  On 
  its 
  front 
  margin, 
  and 
  a 
  little 
  below 
  

   the 
  apex, 
  a 
  projection 
  occurs 
  on 
  each 
  side, 
  bearing 
  a 
  tuft 
  of 
  exquisitely 
  

   beautiful 
  feathery 
  hairs. 
  These 
  are 
  the 
  auricles 
  or 
  staminodia 
  which 
  

   represent 
  two 
  out 
  of 
  the 
  three 
  stamens 
  of 
  the 
  inner 
  whorl, 
  the 
  third 
  being 
  

   the 
  only 
  stamen 
  fully 
  developed. 
  In 
  this 
  flower 
  they 
  form 
  a 
  very 
  con- 
  

   spicuous 
  feature, 
  but 
  I 
  do 
  not 
  know 
  their 
  function, 
  if 
  any. 
  Placed 
  quite 
  in 
  

   at 
  the 
  back 
  and 
  near 
  the 
  base 
  of 
  the 
  column, 
  are 
  the 
  two 
  persistent 
  anther 
  

   lobes. 
  In 
  very 
  young 
  buds 
  these 
  contain 
  the 
  pollinia, 
  but 
  as 
  they 
  apx^roach 
  

   maturity 
  they 
  become 
  attached 
  to 
  the 
  back 
  of 
  the 
  stigma, 
  which 
  stands 
  

   forward 
  a 
  slight 
  distance 
  from 
  the 
  column. 
  The 
  pollinia 
  are 
  composed 
  of 
  

   four 
  sheets 
  or 
  plates 
  of 
  white, 
  powdery, 
  very 
  incoherent 
  pollen. 
  The 
  

   rostellum 
  is 
  hardly 
  viscid 
  at 
  all, 
  nor 
  would 
  this 
  be 
  of 
  any 
  use 
  to 
  the 
  plant, 
  

   as 
  it 
  is 
  seldom, 
  if 
  ever, 
  visited 
  by 
  insects. 
  The 
  flowers 
  are 
  seldom 
  found 
  

   open, 
  and 
  as 
  a 
  rule 
  are 
  probably 
  self- 
  fertilized. 
  I 
  presume 
  that 
  the 
  pollen 
  

   grains 
  emit 
  their 
  tubes 
  to 
  the 
  upper 
  surface 
  of 
  the 
  stigma, 
  but 
  I 
  never 
  

   succeeded 
  in 
  detecting 
  this. 
  

  

  (10.) 
  Prasophjllum 
  colensoi. 
  

  

  The 
  flowers 
  are 
  small 
  and 
  greenish-brown 
  in 
  colour. 
  The 
  base 
  of 
  the 
  

   ovary 
  is 
  sheathed 
  by 
  a 
  short 
  truncate 
  bract 
  ; 
  the 
  very 
  short 
  pedicel 
  is 
  not 
  

   twisted, 
  so 
  that, 
  as 
  in 
  Thehjmitra, 
  the 
  labellum 
  appears 
  in 
  its 
  normal 
  position 
  

   above 
  the 
  flower. 
  All 
  the 
  parts 
  of 
  the 
  perianth 
  are 
  similar 
  in 
  form 
  and 
  

   colour. 
  The 
  column 
  is 
  very 
  short 
  and 
  erect, 
  with 
  the 
  anther 
  placed 
  at 
  the 
  

   back. 
  At 
  each 
  side 
  rises 
  a 
  small 
  two-lobed 
  appendage, 
  representing 
  a 
  

   staminodium 
  or 
  imperfect 
  stamen 
  about 
  half 
  the. 
  height 
  of 
  the 
  column. 
  

   The 
  stigma.tic 
  surface 
  is 
  broadly 
  triangular, 
  and 
  is 
  protected 
  in 
  front 
  by 
  the 
  

   labellum, 
  and 
  latterly 
  by 
  the 
  staminodia. 
  The 
  pollen 
  grains 
  are 
  usually 
  

   found 
  adhering 
  to 
  the 
  back 
  of 
  the 
  siigma, 
  some 
  on 
  its 
  upper 
  edge. 
  When 
  

   examined 
  under 
  the 
  microscope, 
  some 
  of 
  these 
  were 
  found 
  to 
  have 
  

   emitted 
  a 
  mass 
  of 
  short 
  tubes. 
  The 
  pollinia 
  are 
  two 
  in 
  number, 
  and 
  the 
  

  

  a24 
  

  

  