﻿700 
  Mutations 
  

  

  saw 
  it, 
  seventeen 
  years 
  ago. 
  How 
  long 
  had 
  

   it 
  been 
  so? 
  Had 
  it 
  commenced 
  to 
  mutate 
  after 
  

   its 
  introduction 
  into 
  Europe, 
  some 
  time 
  ago, 
  or 
  

   was 
  it 
  already 
  previously 
  in 
  this 
  state! 
  It 
  

   is 
  as 
  yet 
  impossible 
  to 
  decide 
  this 
  point. 
  Per- 
  

   haps 
  the 
  mutable 
  state 
  is 
  very 
  old, 
  and 
  dates 
  

   from 
  the 
  time 
  of 
  the 
  first 
  importation 
  of 
  the 
  

   species 
  into 
  Europe. 
  

  

  Apart 
  from 
  all 
  such 
  considerations 
  the 
  period 
  

   of 
  the 
  direct 
  observations, 
  and 
  the 
  possible 
  

   duration 
  of 
  the 
  mutability 
  through 
  even 
  more 
  

   than 
  a 
  century, 
  would 
  constitute 
  only 
  a 
  moment, 
  

   if 
  compared 
  with 
  the 
  whole 
  geologic 
  time. 
  

   Starting 
  from 
  this 
  conception 
  the 
  pedigree 
  of 
  

   our 
  mutations 
  must 
  be 
  considered 
  as 
  only 
  one 
  

   small 
  group. 
  Instead 
  of 
  figuring 
  a 
  fan 
  of 
  mu- 
  

   tants 
  for 
  each 
  year, 
  we 
  must 
  condense 
  all 
  the 
  

   succeeding 
  swarms 
  into 
  one 
  single 
  fan, 
  as 
  might 
  

   be 
  done 
  also 
  for 
  Draba 
  verna 
  and 
  other 
  poly- 
  

   morphous 
  species. 
  In 
  Oenothera 
  the 
  main 
  stem 
  

   is 
  prolonged 
  upwards 
  beyond 
  the 
  fan; 
  in 
  the 
  

   others 
  the 
  main 
  stem 
  is 
  lacking 
  or 
  at 
  least 
  

   undiscernible, 
  but 
  this 
  feature 
  manifestly 
  is 
  only 
  

   of 
  secondary 
  importance. 
  We 
  might 
  even 
  pre- 
  

   fer 
  the 
  image 
  of 
  a 
  fan, 
  adjusted 
  laterally 
  to 
  

   a 
  stern, 
  which 
  itself 
  is 
  not 
  interrupted 
  by 
  this 
  

   branch. 
  

  

  On 
  this 
  principle 
  two 
  further 
  considerations 
  

   are 
  to 
  be 
  discussed. 
  First 
  the 
  structure 
  of 
  the 
  

  

  