﻿Retrograde 
  Varieties 
  127 
  

  

  they 
  are 
  evidently 
  derived 
  from 
  it 
  and 
  limited 
  

   to 
  it. 
  And 
  this 
  is 
  so 
  true 
  that 
  nobody 
  claims 
  

   the 
  grade 
  of 
  elementary 
  species 
  for 
  white 
  roses 
  

   or 
  white 
  brambles, 
  but 
  everyone 
  recognizes 
  that 
  

   forms 
  diverging 
  from 
  the 
  nearest 
  species 
  by 
  

   a 
  single 
  character 
  only, 
  are 
  to 
  be 
  regarded 
  as 
  

   varieties. 
  

  

  This 
  general 
  conviction 
  is 
  the 
  basis 
  on 
  which 
  

   we 
  may 
  build 
  up 
  a 
  more 
  sharply 
  defined 
  distinc- 
  

   tion 
  between 
  elementary 
  species 
  and 
  varieties. 
  

   It 
  is 
  an 
  old 
  rule 
  in 
  systematic 
  botany, 
  that 
  no 
  

   form 
  is 
  to 
  be 
  constituted 
  a 
  species 
  upon 
  the 
  

   basis 
  of 
  a 
  single 
  character. 
  All 
  authors 
  agree 
  

   on 
  this 
  point; 
  specific 
  differences 
  are 
  derived 
  

   from 
  the 
  totality 
  of 
  the 
  attributes, 
  not 
  from 
  one 
  

   organ 
  or 
  one 
  quality. 
  This 
  rule 
  is 
  intimately 
  

   connected 
  with 
  the 
  idea 
  that 
  varieties 
  are 
  de- 
  

   rived 
  from 
  species. 
  The 
  species 
  is 
  the 
  typical, 
  

   really 
  existing 
  form 
  from 
  which 
  the 
  variety 
  has 
  

   originated 
  by 
  a 
  definite 
  change. 
  In 
  enumer- 
  

   ating 
  the 
  different 
  forms 
  the 
  species 
  is 
  distin- 
  

   guished 
  by 
  the 
  term 
  of 
  genuine 
  or 
  typical, 
  often 
  

   only 
  indicated 
  as 
  a 
  or 
  the 
  first; 
  then 
  fol- 
  

   low 
  the 
  varieties 
  sometimes 
  in 
  order 
  of 
  their 
  

   degree 
  of 
  difference, 
  sometimes 
  simply 
  in 
  alpha- 
  

   betical 
  order. 
  In 
  the 
  case 
  of 
  elementary 
  species 
  

   there 
  is 
  no 
  real 
  type; 
  no 
  one 
  of 
  them 
  predom- 
  

   inates 
  because 
  all 
  are 
  considered 
  to 
  be 
  equal 
  in 
  

   rank, 
  and 
  the 
  systematic 
  species 
  to 
  which 
  they 
  

  

  