﻿Elementary 
  Species 
  in 
  Nature 
  39 
  

  

  varieties, 
  the 
  attributes 
  of 
  the 
  latter 
  with 
  the 
  

   peculiarities 
  of 
  the 
  former 
  species. 
  

  

  Besides 
  the 
  lutea, 
  there 
  are 
  some 
  other 
  spe- 
  

   cies, 
  nearly 
  allied 
  to 
  tricolor, 
  as 
  for 
  instance, 
  

   cornuta, 
  calcarata, 
  and 
  attaica, 
  which 
  are 
  com- 
  

   bined 
  with 
  it 
  under 
  the 
  head 
  of 
  Melanium 
  as 
  a 
  

   subgenus, 
  and 
  which 
  together 
  constitute 
  a 
  syste- 
  

   matic 
  unity 
  of 
  undoubted 
  value, 
  but 
  ranging 
  be- 
  

   tween 
  the 
  common 
  conceptions 
  of 
  genus 
  and 
  

   species. 
  These 
  forms 
  are 
  so 
  nearly 
  allied 
  to 
  

   the 
  heartsease 
  that 
  they 
  have 
  of 
  late 
  been 
  made 
  

   use 
  of 
  in 
  crosses, 
  in 
  order 
  to 
  widen 
  the 
  range 
  

   of 
  variability 
  of 
  garden-pansies. 
  

  

  Viola 
  tricolor 
  is 
  a 
  common 
  European 
  weed. 
  

   It 
  is 
  widely 
  dispersed 
  and 
  very 
  abundant, 
  grow- 
  

   ing 
  in 
  many 
  localities 
  in 
  large 
  numbers. 
  It 
  is 
  

   an 
  annual 
  and 
  ripens 
  its 
  seeds 
  freely, 
  and 
  if 
  op- 
  

   portunity 
  is 
  afforded, 
  it 
  multiplies 
  rapidly. 
  

  

  Viola 
  tricolor 
  has 
  three 
  subspecies, 
  which 
  

   have 
  been 
  elevated 
  to 
  the 
  rank 
  of 
  species 
  by 
  

   some 
  authors, 
  and 
  which 
  may 
  here 
  be 
  called, 
  for 
  

   brevity's 
  sake, 
  by 
  their 
  binary 
  names. 
  One 
  is 
  

   the 
  typical 
  V. 
  tricolor, 
  with 
  broad 
  flowers, 
  vari- 
  

   ously 
  colored 
  and 
  veined 
  with 
  yellow, 
  purple 
  

   and 
  white. 
  It 
  occurs 
  in 
  waste 
  places 
  on 
  sandy 
  

   soil. 
  The 
  second 
  is 
  called 
  V. 
  arvensis 
  or 
  the 
  

   field-pansy; 
  it 
  has 
  small 
  inconspicuous 
  flowers, 
  

   with 
  pale 
  yellowish 
  petals 
  which 
  are 
  shorter 
  

   than 
  the 
  sepals. 
  It 
  pollinates 
  itself 
  without 
  the 
  

  

  