﻿500 
  Mutations 
  

  

  converted 
  into 
  rays. 
  This 
  conversion 
  is 
  ob- 
  

   viously 
  the 
  true 
  mark 
  of 
  the 
  doubling, 
  and 
  be- 
  

   fore 
  traces 
  of 
  it 
  are 
  found, 
  no 
  assertion 
  what- 
  

   ever 
  can 
  be 
  given 
  as 
  to 
  the 
  issue 
  of 
  the 
  pedigree- 
  

   experiment. 
  

  

  Three 
  more 
  years 
  were 
  required 
  before 
  this 
  

   first, 
  but 
  decisive 
  trace 
  was 
  discovered. 
  During 
  

   these 
  years 
  I 
  subjected 
  my 
  strain 
  to 
  the 
  same 
  

   sharp 
  selection 
  as 
  has 
  already 
  been 
  described. 
  

   The 
  chosen 
  ancestor 
  of 
  the 
  race 
  had 
  flowered 
  in 
  

   1896, 
  and 
  the 
  next 
  year 
  I 
  sowed 
  its 
  seeds 
  only. 
  

   From 
  this 
  generation 
  I 
  chose 
  the 
  one 
  plant 
  with 
  

   the 
  largest 
  number 
  of 
  rays 
  in 
  its 
  terminal 
  head, 
  

   and 
  repeated 
  this 
  in 
  the 
  following 
  year. 
  

  

  The 
  consequence 
  was 
  that 
  the 
  average 
  num- 
  

   ber 
  of 
  rays 
  increased 
  rapidly, 
  and 
  with 
  it 
  the 
  

   absolute 
  maximum 
  of 
  the 
  whole 
  strain. 
  The 
  

   average 
  came 
  up 
  from 
  21 
  to 
  34. 
  Brighter 
  and 
  

   brighter 
  crowns 
  of 
  the 
  yellow 
  rays 
  improved 
  

   my 
  race, 
  until 
  it 
  became 
  difficult 
  and 
  very 
  time- 
  

   consuming 
  to 
  count 
  all 
  the 
  large 
  rays 
  of 
  the 
  bor- 
  

   ders. 
  The 
  largest 
  numbers 
  determined 
  in 
  the 
  

   succeeding 
  generations 
  increased 
  by 
  leaps 
  from 
  

   21 
  to 
  34 
  in 
  the 
  first 
  year, 
  and 
  thence 
  to 
  48 
  and 
  66 
  

   in 
  the 
  two 
  succeeding 
  summers. 
  Every 
  year 
  I 
  

   was 
  able 
  to 
  save 
  enough 
  seed 
  from 
  the 
  very 
  best 
  

   plant 
  and 
  to 
  use 
  it 
  only 
  for 
  the 
  continuance 
  of 
  

   the 
  race. 
  Before 
  the 
  selected 
  plants 
  were 
  al- 
  

   lowed 
  to 
  open 
  the 
  flowers 
  from 
  which 
  the 
  seed 
  

  

  