﻿234 
  Retrograde 
  Varieties 
  

  

  strengthened, 
  not 
  indeed 
  to 
  the 
  restoration 
  of 
  

   the 
  tinge 
  of 
  the 
  species, 
  but 
  at 
  least 
  so 
  far 
  as 
  

   to 
  leave 
  no 
  doubt 
  as 
  to 
  the 
  identity 
  of 
  the 
  visi- 
  

   ble 
  color 
  of 
  the 
  species 
  and 
  the 
  latent 
  or 
  sub- 
  

   latent 
  one 
  of 
  the 
  variety. 
  

  

  I 
  made 
  such 
  an 
  experiment 
  with 
  the 
  peach- 
  

   leaved 
  harebell 
  or 
  Campanula 
  persicifolia. 
  The 
  

   white 
  variety 
  of 
  this 
  species, 
  which 
  is 
  often 
  met 
  

   with 
  in 
  our 
  gardens, 
  shows 
  a 
  very 
  pale 
  bluish 
  

   hue 
  when 
  cultivated 
  in 
  large 
  quantities, 
  which 
  

   however 
  is 
  subject 
  to 
  individual 
  variations. 
  I 
  

   selected 
  some 
  plants 
  with 
  a 
  decided 
  tinge, 
  

   flowered 
  them 
  separately, 
  sowed 
  their 
  seeds, 
  

   and 
  repeated 
  this 
  during 
  two 
  generations. 
  The 
  

   result 
  was 
  an 
  increase 
  of 
  the 
  color 
  on 
  the 
  tips 
  

   of 
  the 
  segments 
  of 
  the 
  corolla 
  in 
  a 
  few 
  in- 
  

   dividuals, 
  most 
  of 
  them 
  remaining 
  as 
  purely 
  

   white 
  as 
  the 
  original 
  strain. 
  But 
  in 
  those 
  few 
  

   plants 
  the 
  color 
  was 
  very 
  manifest, 
  individually 
  

   variable 
  in 
  degree, 
  but 
  always 
  of 
  the 
  same 
  blue 
  

   as 
  in 
  the 
  species 
  itself. 
  

  

  Many 
  other 
  instances 
  could 
  be 
  given. 
  

   Smooth 
  varieties 
  are 
  seldom 
  absolutely 
  so, 
  and 
  

   if 
  scattering 
  hairs 
  are 
  found 
  on 
  the 
  leaves 
  or 
  

   only 
  on 
  some 
  more 
  or 
  less 
  concealed 
  parts, 
  they 
  

   correspond 
  in 
  their 
  character 
  to 
  those 
  of 
  the 
  

   species. 
  So 
  it 
  is 
  with 
  prickles, 
  and 
  even 
  the 
  

   thornless 
  thorn-apple 
  has 
  fruits 
  with 
  surfaces 
  

   far 
  from 
  smooth. 
  The 
  thornless 
  horse-chest- 
  

  

  