﻿Unbalanced 
  Crosses 
  263 
  

  

  them 
  has 
  as 
  yet 
  not 
  been 
  made. 
  Unfortunately 
  

   many 
  of 
  the 
  better 
  systematists 
  are 
  in 
  the 
  habit 
  

   of 
  throwing 
  all 
  these 
  interesting 
  forms 
  to- 
  

   gether, 
  and 
  of 
  omitting 
  their 
  descriptive 
  study. 
  

   I 
  have 
  made 
  a 
  large 
  number 
  of 
  crosses 
  be- 
  

   tween 
  such 
  undescribed 
  types 
  and 
  as 
  a 
  rule 
  

   got 
  constant 
  hybrid 
  races. 
  Only 
  one 
  or 
  two 
  

   exceptions 
  could 
  be 
  quoted, 
  as 
  for 
  instance 
  the 
  

   Oenothera 
  brevistylis, 
  which 
  in 
  its 
  crosses 
  al- 
  

   ways 
  behaves 
  as 
  a 
  pure 
  retrogressive 
  variety. 
  

   Instead 
  of 
  giving 
  an 
  exhaustive 
  survey 
  of 
  

   hybrids, 
  I 
  simply 
  cite 
  my 
  crosses 
  between 
  

   lamarckiana 
  and 
  biennis, 
  as 
  having 
  nearly 
  the 
  

   aspect 
  of 
  the 
  last 
  named 
  species, 
  and 
  remaining 
  

   true 
  to 
  this 
  in 
  the 
  second 
  generation 
  without 
  

   any 
  sign 
  of 
  reversion 
  or 
  of 
  splitting. 
  I 
  have 
  

   crossed 
  another 
  elementary 
  species, 
  the 
  Oeno- 
  

   thera 
  hirtella 
  with 
  some 
  of 
  my 
  new 
  and 
  with 
  

   some 
  older 
  Linnean 
  species, 
  and 
  got 
  several 
  

   constant 
  hybrid 
  races. 
  Among 
  these 
  the 
  off- 
  

   spring 
  of 
  a 
  cross 
  between 
  muricata 
  and 
  hirtella 
  

   is 
  still 
  in 
  cultivation. 
  The 
  cross 
  was 
  made 
  in 
  

   the 
  summer 
  of 
  1897 
  and 
  last 
  year 
  (1903) 
  I 
  grew 
  

   the 
  fourth 
  generation 
  of 
  the 
  hybrids. 
  These 
  

   had 
  the 
  characters 
  of 
  the 
  muricata 
  in 
  their 
  nar- 
  

   row 
  leaves, 
  but 
  the 
  elongated 
  spikes 
  and 
  rela- 
  

   tively 
  large 
  flowers 
  of 
  the 
  hirtella 
  parent, 
  and 
  

   remained 
  true 
  to 
  this 
  type, 
  showing 
  only 
  slight 
  

   fluctuations 
  and 
  never 
  reverting 
  or 
  segregating 
  

  

  