﻿648 
  Mutations 
  

  

  conies 
  as 
  prominent 
  as 
  it 
  must 
  once 
  have 
  been 
  in 
  

   the 
  ancestors, 
  and 
  is 
  still 
  in 
  that 
  part 
  of 
  their 
  

   offspring, 
  which 
  has 
  not 
  become 
  changed 
  in 
  this 
  

   respect. 
  Thus 
  the 
  proof 
  of 
  our 
  assertion 
  of 
  

   systematic 
  atavism 
  is, 
  in 
  this 
  case, 
  not 
  obtained 
  

   by 
  the 
  inspection 
  of 
  the 
  adult, 
  but 
  by 
  the 
  investi- 
  

   gation 
  of 
  the 
  conditions 
  in 
  an 
  early 
  stage. 
  

   It 
  remains 
  to 
  be 
  explained 
  how 
  the 
  twisting 
  may 
  

   finally 
  be 
  caused 
  by 
  this 
  incipient 
  grouping 
  of 
  

   the 
  leaves. 
  Before 
  doing 
  so, 
  it 
  may 
  be 
  as 
  well 
  

   to 
  state 
  that 
  the 
  case 
  of 
  the 
  teasel 
  is 
  not 
  an 
  iso- 
  

   lated 
  one, 
  and 
  that 
  the 
  same 
  conclusions 
  are 
  

   supported 
  by 
  the 
  valerian, 
  and 
  a 
  large 
  num- 
  

   ber 
  of 
  other 
  examples. 
  In 
  early 
  spring 
  some 
  

   rosettes 
  show 
  a 
  special 
  condition 
  of 
  the 
  

   leaves, 
  indicating 
  thereby 
  at 
  once 
  their 
  atavism 
  

   and 
  their 
  tendency 
  to 
  become 
  twisted 
  as 
  soon 
  

   as 
  they 
  begin 
  to 
  expand. 
  The 
  Sweet 
  William 
  

   or 
  Dianthus 
  barbatus 
  affords 
  another 
  instance 
  ; 
  

   it 
  is 
  very 
  interesting 
  because 
  a 
  twisted 
  race 
  

   is 
  available, 
  which 
  may 
  produce 
  thousands 
  of 
  

   instances 
  developed 
  in 
  all 
  imaginable 
  degrees, 
  

   in 
  a 
  single 
  lot 
  of 
  plants. 
  Viscaria 
  oculata 
  

   is 
  another 
  instance 
  belonging 
  to 
  the 
  same 
  fam- 
  

  

  ily. 
  

  

  The 
  bedstraw 
  (Galium) 
  also 
  includes 
  many 
  

   species 
  which 
  from 
  time 
  to 
  time 
  produce 
  twist- 
  

   ed 
  stems. 
  I 
  have 
  found 
  them 
  myself 
  in 
  Holland 
  

   on 
  Galium 
  verum 
  and 
  G. 
  Aparine. 
  Both 
  seem 
  

  

  