﻿268 
  Retrograde 
  Varieties 
  

  

  is 
  a 
  hybrid 
  sundew 
  between 
  D. 
  anglica 
  and 
  D. 
  

   rotundifolia. 
  Primula 
  variabilis 
  is 
  a 
  hybrid 
  

   between 
  the 
  two 
  common 
  primroses, 
  P. 
  offici- 
  

   nalis 
  and 
  P. 
  grandiflora. 
  The 
  willow-herb 
  

   (Epilobium), 
  the 
  self-heal 
  (Brunella) 
  and 
  the 
  

   yellow 
  pond-lilies 
  (Nuphar) 
  afford 
  other 
  in- 
  

   stances 
  of 
  constant 
  wild 
  hybrids. 
  

  

  Macfarlane 
  has 
  discovered 
  a 
  natural 
  hybrid 
  

   between 
  two 
  species 
  of 
  sundew 
  in 
  the 
  swamps 
  

   near 
  Atco, 
  N. 
  J. 
  The 
  parents, 
  D. 
  intermedia 
  

   and 
  D. 
  filiformis, 
  were 
  growing 
  abundantly 
  all 
  

   around, 
  but 
  of 
  the 
  hybrid 
  only 
  a 
  group 
  of 
  eleven 
  

   plants 
  was 
  found. 
  A 
  detailed 
  comparison 
  of 
  

   the 
  hybrid 
  with 
  its 
  parents 
  demonstrated 
  a 
  

   minute 
  blending 
  of 
  the 
  anatomical 
  peculiarities 
  

   of 
  the 
  parental 
  species. 
  

  

  Luther 
  Burbank 
  of 
  Santa 
  Rosa, 
  California, 
  

   has 
  produced 
  a 
  great 
  many 
  hybrid 
  brambles, 
  

   the 
  qualities 
  of 
  which 
  in 
  many 
  respects 
  surpass 
  

   those 
  of 
  the 
  wild 
  species. 
  Most 
  of 
  them 
  are 
  

   only 
  propagated 
  by 
  cuttings 
  and 
  layers, 
  not 
  

   being 
  stable 
  from 
  seed. 
  But 
  some 
  crosses 
  be- 
  

   tween 
  the 
  blackberry 
  and 
  the 
  raspberry 
  (R. 
  

   fruticosus 
  and 
  R. 
  idaeus) 
  which 
  bear 
  good 
  

   fruit 
  and 
  have 
  become 
  quite 
  popular, 
  are 
  so 
  

   fixed 
  in 
  their 
  type 
  as 
  to 
  reproduce 
  their 
  com- 
  

   posite 
  characters 
  from 
  seed 
  with 
  as 
  much 
  regu- 
  

   larity 
  as 
  the 
  species 
  of 
  Rubus 
  found 
  in 
  nature. 
  

   Among 
  them 
  are 
  the 
  " 
  Phenomenal 
  and 
  the 
  

  

  