﻿454 
  Ever-sporting 
  Varieties 
  

  

  Dimorphism 
  is 
  of 
  universal 
  occurrence 
  in 
  the 
  

   whole 
  vegetable 
  kingdom. 
  In 
  some 
  cases 
  it 
  is 
  

   typical, 
  and 
  may 
  easily 
  be 
  discerned 
  from 
  ex- 
  

   treme 
  flutuating 
  variability. 
  In 
  others 
  the 
  con- 
  

   trast 
  is 
  not 
  at 
  all 
  obvious, 
  and 
  a 
  closer 
  

   investigation 
  is 
  needed 
  to 
  decide 
  between 
  the 
  

   two 
  possibilities. 
  Sometimes 
  the 
  adaptive 
  qual- 
  

   ity 
  is 
  evident, 
  in 
  other 
  cases 
  it 
  is 
  not, 
  A 
  large 
  

   number 
  of 
  plants 
  bear 
  two 
  kinds 
  of 
  leaves 
  linked 
  

   with 
  one 
  another 
  by 
  intermediate 
  forms. 
  Often 
  

   the 
  first 
  leaves 
  of 
  a 
  shoot, 
  or 
  those 
  of 
  accident- 
  

   ally 
  strong 
  shoots, 
  exhibit 
  deviating 
  shapes, 
  

   and 
  the 
  usefulness 
  of 
  such 
  occurrences 
  seems 
  to 
  

   be 
  quite 
  doubtful. 
  The 
  elongation 
  of 
  stems 
  and 
  

   linear 
  leaves, 
  and 
  the 
  reduction 
  of 
  lateral 
  or- 
  

   gans 
  in 
  darkness, 
  is 
  manifestly 
  an 
  adaptation. 
  

   Many 
  plants 
  have 
  stolons 
  with 
  double 
  adapta- 
  

   tions 
  which 
  enable 
  them 
  to 
  retain 
  their 
  char- 
  

   acter 
  of 
  underground 
  stems 
  with 
  bracts 
  or 
  to 
  

   exchange 
  it 
  for 
  the 
  characteristics 
  of 
  erect 
  

   stems 
  with 
  green 
  leaves 
  according 
  to 
  the 
  outer 
  

   circumstances. 
  In 
  some 
  shrubs 
  and 
  trees 
  the 
  

   capacity 
  of 
  a 
  number 
  of 
  buds 
  to 
  produce 
  either 
  

   flowers 
  or 
  shoots 
  with 
  leaves 
  seems 
  to 
  be 
  in 
  

   the 
  same 
  condition. 
  The 
  capacity 
  of 
  producing 
  

   spines 
  is 
  also 
  a 
  double 
  adaptation, 
  active 
  on 
  

   dry 
  and 
  arid 
  soil 
  and 
  latent 
  in 
  a 
  moist 
  climate 
  

   or 
  under 
  cultivation, 
  as 
  with 
  the 
  wild 
  and 
  cul- 
  

   tivated 
  apple, 
  and 
  in 
  the 
  experiments 
  of 
  Lo- 
  

  

  