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  I 
  

  

  / 
  

  

  1 
  

  

  

  Species 
  and 
  Varieties 
  

  

  Their 
  Origin 
  by 
  

   Mutation 
  

  

  Lectures 
  Delivered 
  at 
  the 
  University 
  of 
  

  

  California 
  

  

  by 
  

  

  Hugo 
  DeVries 
  

  

  Professor 
  of 
  Botany 
  in 
  the 
  University 
  of 
  Amsterdam 
  

  

  Edited 
  by 
  

   Daniel 
  Trembly 
  MacDougal 
  

  

  Director 
  Department 
  of 
  Botanical 
  Research, 
  Carnegie 
  Institution 
  

  

  of 
  Washington 
  

  

  Second 
  Edition, 
  

   Corrected 
  and 
  Revised 
  

  

  CHICAGO 
  

   The 
  Open 
  Court 
  Publishing 
  Company 
  

  

  LONDON 
  

  

  Kegan 
  Paul, 
  Trench, 
  Triibner 
  & 
  Co., 
  Ltd. 
  

  

  1906 
  

  

  