﻿44 
  Elementary 
  Species 
  

  

  from 
  one 
  locality 
  may 
  be 
  grown, 
  and 
  all 
  will 
  ex- 
  

   hibit 
  exactly 
  the 
  same 
  markings. 
  Most 
  of 
  these 
  

   forms 
  are 
  of 
  very 
  local 
  occurrence. 
  The 
  most 
  

   beautiful 
  of 
  all, 
  the 
  ornatissima, 
  is 
  found 
  only 
  in 
  

   Jemtland, 
  the 
  aurobadia 
  only 
  in 
  Soderinanland, 
  

   the 
  anopetala 
  in 
  other 
  localities 
  in 
  the 
  same 
  

   country, 
  the 
  roseola 
  near 
  Stockholm, 
  and 
  the 
  

   yellow 
  lutescens 
  in 
  Finmarken. 
  

  

  The 
  researches 
  of 
  Wittrock 
  included 
  only 
  a 
  

   small 
  number 
  of 
  elementary 
  species, 
  but 
  every 
  

   one 
  who 
  has 
  observed 
  the 
  violets 
  in 
  the 
  central 
  

   parts 
  of 
  Europe 
  must 
  be 
  convinced 
  that 
  many 
  

   dozens 
  of 
  constant 
  forms 
  of 
  the 
  typical 
  Viola 
  

   tricolor 
  might 
  easily 
  be 
  found 
  and 
  isolated. 
  

  

  We 
  now 
  come 
  to 
  the 
  field 
  pansy, 
  the 
  Viola 
  ar- 
  

   vensis, 
  a 
  very 
  common 
  weed 
  in 
  the 
  grain-fields 
  

   of 
  central 
  Europe. 
  I 
  have 
  already 
  mentioned 
  

   its 
  small 
  corolla, 
  surpassed 
  by 
  the 
  lobes 
  of 
  the 
  

   calyx 
  and 
  its 
  capacity 
  of 
  self-fertilization. 
  It 
  

   has 
  still 
  other 
  curious 
  differentiating 
  charac- 
  

   ters; 
  the 
  pollen 
  grains, 
  which 
  are 
  square 
  in 
  

   V. 
  tricolor, 
  are 
  five-sided 
  in 
  V. 
  arvensis. 
  

   Some 
  transgressive 
  fluctuating 
  variability 
  may 
  

   occur 
  in 
  both 
  cases 
  through 
  the 
  admixture 
  

   of 
  pollen-grains. 
  Even 
  three-angled 
  pollen- 
  

   grains 
  are 
  seen 
  sometimes. 
  Other 
  marks 
  are 
  

   observed 
  in 
  the 
  form 
  of 
  the 
  anthers 
  and 
  the 
  

   spur. 
  

  

  There 
  seem 
  to 
  be 
  very 
  many 
  local 
  subspecies 
  

  

  