﻿LECTURE 
  XVIII 
  

  

  NEW 
  SPECIES 
  OF 
  OENOTHERA 
  

  

  In 
  our 
  experiments 
  on 
  the 
  origin 
  of 
  peloric 
  

   varieties 
  and 
  double 
  flowers 
  we 
  were 
  guided 
  in 
  

   the 
  choice 
  of 
  our 
  material 
  by 
  a 
  survey 
  of 
  the 
  

   evidence 
  already 
  at 
  hand. 
  We 
  chose 
  the 
  types 
  

   known 
  to 
  be 
  most 
  commonly 
  produced 
  anew, 
  

   either 
  in 
  the 
  wild 
  state 
  or 
  under 
  the 
  conditions 
  

   of 
  cultivation. 
  In 
  both 
  instances 
  our 
  novelty 
  

   was 
  a 
  variety 
  in 
  the 
  ordinary 
  sense 
  of 
  the 
  word. 
  

   Our 
  pedigree-culture 
  was 
  mainly 
  an 
  experi- 
  

   mental 
  demonstration 
  of 
  the 
  validity 
  of 
  conclu- 
  

   sions, 
  which 
  had 
  previously 
  been 
  deduced 
  from 
  

   such 
  observations 
  as 
  can 
  be 
  made 
  after 
  the 
  ac- 
  

   cidental 
  birth 
  of 
  new 
  forms. 
  

  

  From 
  these 
  facts, 
  and 
  even 
  from 
  these 
  pedi- 
  

   gree-experiments, 
  it 
  is 
  scarcely 
  allowable 
  to 
  

   draw 
  conclusions 
  as 
  to 
  the 
  origin 
  of 
  real 
  spe- 
  

   cies. 
  If 
  we 
  want 
  to 
  know 
  how 
  species 
  originate, 
  

   it 
  is 
  obviously 
  necessary 
  to 
  have 
  recourse 
  to 
  

   direct 
  observation. 
  The 
  question 
  is 
  of 
  the 
  high- 
  

   est 
  importance, 
  both 
  for 
  the 
  theory 
  of 
  descent, 
  

   and 
  for 
  our 
  conception 
  of 
  the 
  real 
  nature 
  of 
  

  

  516 
  

  

  