﻿608 
  Mutations 
  

  

  nated 
  in 
  horticulture 
  as 
  varieties, 
  though 
  ob- 
  

   viously 
  they 
  are 
  of 
  quite 
  another 
  nature 
  than 
  

   the 
  varieties 
  reproduced 
  by 
  seed. 
  Secondly, 
  a 
  

   large 
  number, 
  no 
  doubt 
  the 
  greater 
  number 
  

   of 
  novelties, 
  are 
  of 
  hybrid 
  origin. 
  Here 
  we 
  

   may 
  discern 
  two 
  cases. 
  Hybrids 
  may 
  be 
  

   produced 
  by 
  the 
  crossing 
  of 
  old 
  types, 
  either 
  

   of 
  two 
  old 
  cultivated 
  forms 
  or 
  newlv 
  intro- 
  

  

  ' 
  

  

  duced 
  species, 
  or 
  ordinarily 
  between 
  an 
  old 
  

   and 
  an 
  introduced 
  variety. 
  Such 
  novelties 
  are 
  

   excluded 
  from 
  our 
  present 
  discussion. 
  Sec- 
  

   ondly, 
  hybrids 
  may 
  be 
  produced 
  between 
  a 
  true, 
  

   new 
  mutation 
  and 
  some 
  of 
  the 
  already 
  existing 
  

   varieties 
  of 
  the 
  same 
  species. 
  Examples 
  of 
  this 
  

   obvious 
  and 
  usual 
  practice 
  will 
  be 
  given 
  further 
  

   on, 
  but 
  it 
  must 
  be 
  pointed 
  out 
  now 
  that 
  by 
  such 
  

   crosses 
  a 
  single 
  mutation 
  may 
  produce 
  as 
  many 
  

   novelties 
  as 
  there 
  are 
  available 
  varieties 
  of 
  the 
  

   same 
  species. 
  

  

  Summarizing 
  these 
  introductory 
  remarks 
  we 
  

   must 
  lay 
  stress 
  on 
  the 
  fact 
  that 
  only 
  a 
  small 
  part 
  

   of 
  the 
  horticultural 
  novelties 
  are 
  real 
  mutations, 
  

   although 
  they 
  do 
  occur 
  from 
  time 
  to 
  time. 
  If 
  

   useful, 
  they 
  are 
  as 
  a 
  rule 
  isolated 
  and 
  multiplied, 
  

   and 
  if 
  necessary, 
  improved 
  by 
  selection. 
  They 
  

   are 
  in 
  many 
  instances, 
  as 
  constant 
  from 
  seed 
  as 
  

   the 
  unavoidable 
  influence 
  of 
  vicinisin 
  allows 
  

   them 
  to 
  be. 
  Exact 
  observations 
  on 
  the 
  origin, 
  

   or 
  on 
  the 
  degree 
  of 
  constancy, 
  are 
  usually 
  lack- 
  

  

  