﻿136 
  Retrograde 
  Varieties 
  

  

  finer 
  species 
  of 
  garden-plants, 
  as 
  Sophora 
  jap- 
  

   onica, 
  nave 
  given 
  rise 
  to 
  weeping 
  varieties, 
  and 
  

   the 
  yew-tree 
  or 
  Taxus 
  has 
  a 
  fastigiate 
  form 
  

   which 
  is 
  much 
  valued 
  because 
  of 
  its 
  ascending 
  

   branches 
  and 
  pyramidal 
  habit. 
  So 
  it 
  is 
  with 
  

   the 
  pyramidal 
  varieties 
  of 
  oaks, 
  elms, 
  the 
  bas- 
  

   tard-acacia 
  and 
  some 
  others. 
  

  

  It 
  is 
  generally 
  acknowledged 
  that 
  these 
  forms 
  

   are 
  to 
  be 
  considered 
  as 
  varieties 
  on 
  the 
  ground 
  

   of 
  their 
  occurrence 
  in 
  so 
  wide 
  a 
  range 
  of 
  species, 
  

   and 
  because 
  they 
  always 
  bear 
  the 
  same 
  attrib- 
  

   utes. 
  The 
  pendulous 
  forms 
  owe 
  their 
  peculiar- 
  

   ity 
  to 
  a 
  lengthening 
  of 
  the 
  branches 
  and 
  a 
  loss 
  

   of 
  their 
  habit 
  of 
  growing 
  upwards 
  ; 
  they 
  are 
  too 
  

   weak 
  to 
  retain 
  a 
  vertical 
  position 
  and 
  the 
  re- 
  

   sponse 
  to 
  gravity, 
  which 
  is 
  ordinarily 
  the 
  cause 
  

   of 
  the 
  upright 
  growth, 
  is 
  lacking 
  in 
  them. 
  As 
  

   far 
  as 
  we 
  know, 
  the 
  cause 
  of 
  this 
  weeping 
  habit 
  

   is 
  the 
  same 
  in 
  all 
  instances. 
  The 
  fastigiate 
  

   trees 
  and 
  shrubs 
  are 
  a 
  counterpart 
  of 
  the 
  weep- 
  

   ing 
  forms. 
  Here 
  the 
  tendency 
  to 
  grow 
  in 
  a 
  

   horizontal 
  direction 
  is 
  lacking, 
  and 
  with 
  it 
  the 
  

   bilateral 
  and 
  symmetric 
  structure 
  of 
  the 
  

   branches 
  has 
  disappeared. 
  In 
  the 
  ordinary 
  

   yew-tree 
  the 
  upright 
  stem 
  bears 
  its 
  needles 
  

   equally 
  distributed 
  around 
  its 
  circumference, 
  

   but 
  on 
  the 
  branches 
  the 
  needles 
  are 
  inserted 
  in 
  

   two 
  rows, 
  one 
  to 
  the 
  left 
  and 
  one 
  to 
  the 
  right. 
  

   All 
  the 
  needles 
  turn 
  their 
  upper 
  surfaces 
  up- 
  

  

  