﻿498 
  Mutations 
  

  

  suit 
  showed 
  that 
  no 
  further 
  selection 
  could 
  be 
  

   of 
  any 
  avail, 
  and 
  that 
  I 
  had 
  succeeded 
  in 
  purify- 
  

   ing 
  the 
  21-rayed 
  grandiflorum 
  variety. 
  

  

  It 
  is 
  from 
  this 
  grandiflorum 
  that 
  I 
  have 
  finally 
  

   produced 
  my 
  double 
  variety. 
  In 
  the 
  year 
  1896 
  

   I 
  selected 
  from 
  among 
  the 
  above 
  quoted 
  1500 
  

   plants, 
  500 
  with 
  terminal 
  heads 
  bearing 
  21 
  or 
  

   more 
  rays. 
  On 
  these 
  I 
  counted 
  the 
  rays 
  of 
  all 
  

   the 
  secondary 
  heads 
  about 
  the 
  middle 
  of 
  August 
  

   (1896) 
  and 
  found 
  that 
  they 
  had, 
  as 
  a 
  rule, 
  

   retrograded 
  to 
  lower 
  figures. 
  On 
  many 
  thou- 
  

   sands 
  of 
  heads 
  only 
  two 
  were 
  found 
  having 
  22 
  

   rays. 
  All 
  others 
  had 
  the 
  average 
  number 
  of 
  21 
  

   or 
  even 
  less. 
  I 
  isolated 
  the 
  individual 
  which 
  

   bore 
  these 
  two 
  heads, 
  allowed 
  them 
  to 
  be 
  fertil- 
  

   ized 
  by 
  insects 
  with 
  the 
  pollen 
  of 
  some 
  of 
  the 
  

   best 
  plants 
  of 
  the 
  same 
  group, 
  but 
  destroyed 
  the 
  

   remainder. 
  

  

  This 
  single 
  exceptional 
  plant 
  has 
  been 
  the 
  

   starting 
  point 
  of 
  my 
  double 
  variety. 
  It 
  was 
  not 
  

   remarkable 
  for 
  its 
  terminal 
  head, 
  which 
  exhib- 
  

   ited 
  the 
  average 
  number 
  of 
  rays 
  of 
  the 
  21-rayed 
  

   race. 
  Nor 
  was 
  it 
  distinguished 
  by 
  the 
  average 
  

   figure 
  for 
  all 
  its 
  heads. 
  It 
  was 
  only 
  selected 
  

   because 
  it 
  was 
  the 
  one 
  plant 
  which 
  had 
  some 
  

   secondary 
  heads 
  with 
  one 
  ray 
  more 
  than 
  all 
  the 
  

   others. 
  This 
  indication 
  was 
  very 
  slight, 
  and 
  

   could 
  not 
  have 
  been 
  detected 
  save 
  by 
  the 
  

   counting 
  of 
  the 
  rays 
  of 
  thousands 
  of 
  heads. 
  

  

  