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  Elementary 
  Species 
  

  

  But 
  by 
  means 
  of 
  crossing 
  with 
  other 
  species 
  

   and 
  especially 
  with 
  the 
  Japanese 
  plums, 
  the 
  

   hardy 
  qualities 
  of 
  the 
  beach-plum 
  have 
  been 
  

   united 
  with 
  the 
  size, 
  flavor 
  and 
  other 
  valuable 
  

   qualities 
  of 
  the 
  fruit, 
  and 
  a 
  group 
  of 
  new 
  plums 
  

   have 
  been 
  produced 
  with 
  bright 
  colors, 
  ovoid 
  and 
  

   globular 
  forms 
  which 
  are 
  never 
  flattened 
  and 
  

   have 
  no 
  suture. 
  The 
  experiments 
  were 
  not 
  fin- 
  

   ished, 
  when 
  I 
  visited 
  Mr. 
  Burbank 
  in 
  July, 
  1904, 
  

   and 
  still 
  more 
  startling 
  improvements 
  were 
  said 
  

   to 
  have 
  been 
  secured. 
  

  

  I 
  may 
  perhaps 
  be 
  allowed 
  to 
  avail 
  myself 
  of 
  

   this 
  opportunity 
  to 
  point 
  out 
  a 
  practical 
  side 
  of 
  

   the 
  study 
  of 
  elementary 
  species. 
  This 
  always 
  

   appears 
  whenever 
  wild 
  plants 
  are 
  subjected 
  to 
  

   cultivation, 
  either 
  in 
  order 
  to 
  reproduce 
  them 
  as 
  

   pure 
  strains, 
  or 
  to 
  cross 
  them 
  with 
  other 
  al- 
  

   ready 
  cultivated 
  species. 
  The 
  latter 
  practice 
  

   is 
  as 
  a 
  rule 
  made 
  use 
  of 
  whenever 
  a 
  wild 
  spe- 
  

   cies 
  is 
  found 
  to 
  be 
  in 
  possession 
  of 
  some 
  quality 
  

   which 
  is 
  considered 
  as 
  desirable 
  for 
  the 
  culti- 
  

   vated 
  forms. 
  In 
  the 
  case 
  of 
  the 
  beach-plum 
  

   it 
  is 
  the 
  hardiness 
  and 
  the 
  great 
  abundance 
  of 
  

   fruits 
  of 
  the 
  wild 
  species 
  which 
  might 
  profit- 
  

   ably 
  be 
  combined 
  with 
  the 
  recognized 
  qualities 
  

   of 
  the 
  ordinary 
  plums. 
  Now 
  it 
  is 
  manifest, 
  that 
  

   in 
  order 
  to 
  make 
  crosses, 
  distinct 
  individual 
  

   plants 
  are 
  to 
  be 
  chosen, 
  and 
  that 
  the 
  variability 
  

   of 
  the 
  wild 
  species 
  may 
  be 
  of 
  very 
  great 
  im- 
  

  

  