﻿Elementary 
  Species 
  in 
  Nature 
  59 
  

  

  portance. 
  Among 
  the 
  range 
  of 
  elementary 
  spe- 
  

   cies 
  those 
  should 
  be 
  used 
  which 
  not 
  only 
  pos- 
  

   sess 
  the 
  desired 
  advantages 
  in 
  the 
  highest 
  de- 
  

   gree, 
  but 
  which 
  promise 
  the 
  best 
  results 
  in 
  other 
  

   respects 
  or 
  their 
  earliest 
  attainment. 
  The 
  

   fuller 
  our 
  knowledge 
  of 
  the 
  elementary 
  species 
  

   constituting 
  the 
  systematic 
  groups, 
  the 
  easier 
  

   and 
  the 
  more 
  reliable 
  will 
  be 
  the 
  choice 
  for 
  the 
  

   breeder. 
  Many 
  Californian 
  wild 
  flowers 
  with 
  

   bright 
  colors 
  seem 
  to 
  consist 
  of 
  large 
  numbers 
  

   of 
  constant 
  elementary 
  forms, 
  as 
  for 
  instance, 
  

   the 
  lilies, 
  godetias, 
  eschscholtias 
  and 
  others. 
  

   They 
  have 
  been 
  brought 
  into 
  cultivation 
  many 
  

   times, 
  but 
  the 
  minutest 
  distinction 
  of 
  their 
  ele- 
  

   mentary 
  forms 
  is 
  required 
  to 
  attain 
  the 
  highest 
  

   success. 
  

  

  In 
  concluding, 
  I 
  will 
  point 
  out 
  a 
  very 
  interest- 
  

   ing 
  difficulty, 
  which 
  in 
  some 
  cases 
  impedes 
  the 
  

   clear 
  understanding 
  of 
  elementary 
  species. 
  It 
  

   is 
  the 
  lack 
  of 
  self-fertilization. 
  It 
  occurs 
  in 
  

   widely 
  distant 
  families, 
  but 
  has 
  a 
  special 
  inter- 
  

   est 
  for 
  us 
  in 
  two 
  genera, 
  which 
  are 
  generally 
  

   known 
  as 
  very 
  polymorphous 
  groups. 
  

  

  One 
  of 
  them 
  is 
  the 
  hawkweed 
  or 
  Hieracium, 
  

   and 
  the 
  other 
  is 
  the 
  dandelion 
  or 
  Taraxacum 
  

   officinale. 
  Hawkweeds 
  are 
  known 
  as 
  a 
  genus 
  

   in 
  which 
  the 
  delimitation 
  of 
  the 
  species 
  is 
  al- 
  

   most 
  impossible. 
  Thousands 
  of 
  forms 
  may 
  be 
  

   cultivated 
  side 
  by 
  side 
  in 
  botanical 
  gardens, 
  ex- 
  

  

  