﻿176 
  Retrograde 
  Varieties 
  

  

  strict 
  methods 
  of 
  criticism 
  very 
  few 
  instances 
  

   will 
  be 
  found 
  that 
  satisfy 
  legitimate 
  demands. 
  

   On 
  this 
  ground 
  it 
  is 
  by 
  far 
  safer 
  in 
  the 
  present 
  

   state 
  of 
  our 
  knowledge, 
  to 
  accept 
  bud-variations 
  

   only 
  as 
  direct 
  proofs 
  of 
  true 
  atavism. 
  And 
  

   even 
  these 
  may 
  not 
  always 
  be 
  relied 
  on, 
  as 
  some 
  

   hybrids 
  are 
  liable 
  to 
  split 
  up 
  in 
  a 
  vegetative 
  

   way, 
  and 
  in 
  doing 
  so 
  to 
  give 
  rise 
  to 
  bud-varia- 
  

   tions 
  that 
  are 
  in 
  many 
  respects 
  apparently 
  sim- 
  

   ilar 
  to 
  cases 
  of 
  atavism. 
  But 
  fortunately 
  such 
  

   instances 
  are 
  as 
  yet 
  very 
  rare. 
  

  

  After 
  this 
  discussion 
  it 
  would 
  be 
  bold 
  indeed 
  

   to 
  give 
  instances 
  of 
  seed-atavism, 
  and 
  I 
  believe 
  

   that 
  it 
  will 
  be 
  better 
  to 
  refrain 
  wholly 
  from 
  do- 
  

   ing 
  so. 
  

  

  Many 
  instances 
  of 
  so-called 
  atavism 
  are 
  of 
  

   purely 
  morphologic 
  nature. 
  The 
  most 
  interest- 
  

   ing 
  cases 
  are 
  those 
  furnished 
  by 
  the 
  forms 
  

   which 
  some 
  plants 
  bear 
  only 
  while 
  young, 
  and 
  

   which 
  evidently 
  connect 
  them 
  with 
  allied 
  species, 
  

   in 
  which 
  the 
  same 
  features 
  may 
  be 
  seen 
  in 
  the 
  

   adult 
  state. 
  Some 
  species 
  of 
  the 
  genus 
  Acacia 
  

   bear 
  bipinnate 
  leaves, 
  while 
  others 
  have 
  no 
  

   leaves 
  at 
  all, 
  but 
  bear 
  broadened 
  and 
  flattened 
  

   petioles 
  instead. 
  The 
  second 
  type 
  is 
  presumed 
  

   to 
  be 
  descended 
  from 
  the 
  first 
  by 
  the 
  loss 
  

   of 
  the 
  leaflets 
  and 
  the 
  modification 
  of 
  the 
  stalks 
  

   into 
  flat 
  and 
  simple 
  phyllodes. 
  But 
  many 
  of 
  

   them 
  are 
  liable 
  to 
  recall 
  this 
  primitive 
  form 
  

  

  