﻿634 
  Mutations 
  

  

  The 
  scapes 
  are 
  not 
  absolutely 
  lacking, 
  but 
  only 
  

   reduced 
  to 
  almost 
  invisible 
  rudiments. 
  

  

  Relying 
  upon 
  this 
  conclusion 
  we 
  infer 
  that 
  all 
  

   of 
  the 
  three 
  elementary 
  species 
  have 
  umbels, 
  

   some 
  pedunculate 
  and 
  the 
  others 
  not. 
  On 
  this 
  

   point 
  they 
  agree 
  with 
  the 
  majority 
  of 
  the 
  allied 
  

   species 
  in 
  the 
  genus 
  and 
  in 
  other 
  genera, 
  as 
  for 
  

   instance 
  in 
  Androsace. 
  Hence 
  the 
  conclusion 
  

   that 
  the 
  common 
  ancestors 
  were 
  perennial 
  

   plants 
  with 
  a 
  rootstock 
  bearing 
  their 
  flowers 
  

   in 
  umbels 
  or 
  whorls 
  on 
  scapes. 
  Lacking 
  in 
  the 
  

   Primula 
  veris, 
  these 
  scapes 
  must 
  obviously 
  have 
  

   been 
  lost 
  at 
  the 
  time 
  of 
  the 
  evolution 
  of 
  this 
  

   form. 
  

  

  Proceeding 
  on 
  this 
  line 
  of 
  speculation 
  we 
  at 
  

   once 
  see 
  that 
  a 
  very 
  adequate 
  opportunity 
  for 
  

   systematic 
  atavism 
  is 
  offered 
  here. 
  According 
  

   to 
  our 
  general 
  conception 
  the 
  apparent 
  loss 
  of 
  a 
  

   scape 
  is 
  no 
  proof 
  of 
  a 
  corresponding 
  internal 
  

   loss, 
  but 
  might 
  as 
  well 
  be 
  caused 
  simply 
  by 
  

   the 
  reduction 
  of 
  the 
  scape-growing 
  capacity 
  to 
  

   a 
  latent 
  or 
  inactive 
  state. 
  It 
  might 
  be 
  awak- 
  

   ened 
  afterwards 
  by 
  some 
  unknown 
  agency, 
  and 
  

   return 
  to 
  activity. 
  

  

  Now 
  this 
  is 
  exactly 
  what 
  happens 
  from 
  time 
  

   to 
  time. 
  In 
  Holland 
  the 
  acaulescent 
  primrose 
  

   is 
  quite 
  a 
  common 
  plant, 
  filling 
  the 
  woods 
  in 
  the 
  

   spring 
  with 
  thousands 
  of 
  clusters 
  of 
  bright 
  yel- 
  

   low 
  flowers. 
  It 
  is 
  a 
  very 
  uniform 
  type, 
  but 
  in 
  

  

  