﻿LECTURE 
  XXVII 
  

  

  INCONSTANCY 
  OF 
  IMPROVED 
  RACES 
  

  

  The 
  greater 
  advantages 
  of 
  the 
  asexual 
  multi- 
  

   plication 
  of 
  extremes 
  are 
  of 
  course 
  restricted 
  to 
  

   perennial 
  and 
  woody 
  plants. 
  Annual 
  and 
  bi- 
  

   ennial 
  species 
  cannot 
  as 
  a 
  rule, 
  be 
  propagated 
  

   in 
  this 
  way, 
  and 
  even 
  with 
  some 
  perennials 
  hor- 
  

   ticulturists 
  prefer 
  the 
  sale 
  of 
  seeds 
  to 
  that 
  of 
  

   roots 
  and 
  bulbs. 
  In 
  all 
  these 
  cases 
  it 
  is 
  clear 
  

   that 
  the 
  exclusion 
  of 
  the 
  individual 
  variability, 
  

   which 
  was 
  shown 
  to 
  be 
  an 
  important 
  point 
  in 
  

   the 
  last 
  lecture, 
  must 
  be 
  sacrificed. 
  

  

  Seed-propagation 
  is 
  subject 
  to 
  individual 
  as 
  

   well 
  as 
  to 
  fluctuating 
  variability. 
  The 
  first 
  

   could 
  perhaps 
  be 
  designated 
  by 
  another 
  term, 
  

   embryonic 
  variability, 
  since 
  it 
  indicates 
  the 
  

   fluctuations 
  occurring 
  during 
  the 
  period 
  of 
  

   development 
  of 
  the 
  germ. 
  This 
  period 
  begins 
  

   with 
  the 
  fusion 
  of 
  the 
  male 
  and 
  female 
  elements 
  

   and 
  is 
  largely 
  dependent 
  upon 
  the 
  vigor 
  of 
  these 
  

   cells 
  at 
  the 
  moment, 
  and 
  on 
  the 
  varying 
  qualities 
  

   they 
  may 
  have 
  acquired. 
  It 
  comprises 
  in 
  the 
  

   main 
  the 
  time 
  of 
  the 
  ripening 
  of 
  the 
  seed, 
  and 
  

  

  770 
  

  

  