﻿206 
  Stork: 
  Studies 
  in 
  the 
  genus 
  Taraxacum 
  

  

  matured 
  in 
  wet 
  or 
  cold 
  weather 
  often 
  lack 
  the 
  distinct 
  red 
  color. 
  

   It 
  would 
  seem 
  then 
  that 
  to 
  be 
  sure 
  in 
  all 
  cases 
  of 
  the 
  identity 
  of 
  a 
  

   plant, 
  one 
  must 
  resort 
  to 
  cultures. 
  In 
  fact, 
  so 
  polymorphous 
  

   are 
  many 
  of 
  the 
  species 
  of 
  this 
  genus 
  that 
  it 
  would 
  be 
  desirable 
  

   to 
  grow 
  the 
  species 
  together 
  In 
  order 
  to 
  determine 
  just 
  what 
  

   typical 
  forms 
  result 
  under 
  certain 
  uniform 
  environmental 
  condi- 
  

   tions. 
  From 
  what 
  the 
  writer 
  has 
  seen 
  of 
  some 
  herbarium 
  material 
  

  

  palust 
  

  

  form 
  

  

  + 
  

  

  under 
  cultivation. 
  Fernald 
  (3) 
  speaks 
  of 
  the 
  difficulty 
  at 
  times 
  

   of 
  separating 
  T. 
  palustre 
  from 
  T. 
  vulgare 
  and 
  says 
  the 
  former 
  

   occurs 
  in 
  "damp 
  sheltered 
  situations, 
  especially 
  roadside 
  ditches 
  

   and 
  similar 
  spots," 
  and 
  it 
  is 
  in 
  such 
  situations 
  that 
  a 
  variety 
  of 
  

   T. 
  viUgare 
  can 
  at 
  times 
  be 
  found 
  having 
  more 
  or 
  less 
  the 
  characters 
  

   usually 
  ascribed 
  to 
  T. 
  palustre. 
  Herbarium 
  material 
  has 
  been 
  

   studied 
  of 
  American 
  plants 
  named 
  T. 
  lividiim 
  (Waldst. 
  & 
  Kit.) 
  

   Heller, 
  T. 
  mexicanum 
  DC, 
  T. 
  oblanceolatum 
  A. 
  Nelson, 
  T. 
  officinale 
  

   alpinum 
  Koch, 
  and 
  T. 
  laevigatum 
  (Willd.) 
  DC; 
  and 
  similar 
  diffi- 
  

   culties 
  are 
  presented. 
  Sears 
  (11) 
  concludes 
  that 
  the 
  last 
  of 
  these 
  

  

  permu 
  

  

  varym 
  

  

  The 
  plants 
  should 
  be 
  seen 
  growing 
  side 
  by 
  side. 
  Dahlstedt 
  

   (2) 
  says 
  r, 
  erythrospermtim 
  belongs 
  to 
  the 
  T. 
  laevigatum 
  group, 
  

   and 
  that 
  if 
  the 
  whole 
  group 
  were 
  to 
  be 
  made 
  one 
  collective 
  

  

  f 
  as 
  having 
  priority. 
  In 
  the 
  

   [■raph 
  of 
  the 
  eenus, 
  Handel- 
  

  

  name 
  

  

  mono 
  

  

  Mazzetti 
  

  

  from 
  

  

  region 
  and 
  Canada, 
  and 
  placed 
  most 
  of 
  them 
  under 
  definite 
  

  

  European 
  species. 
  

  

  writer 
  

  

  from 
  

  

  of 
  the 
  species 
  of 
  Taraxacum 
  found 
  in 
  America, 
  in 
  order 
  that 
  he 
  

   might 
  grow 
  these 
  together 
  under 
  similar 
  environmental 
  conditions 
  

   and 
  make 
  some 
  definite 
  determinations 
  as 
  to 
  just 
  how 
  far 
  soil 
  and 
  

   climate 
  are 
  responsible 
  for 
  the 
  varietal 
  and 
  specific 
  or 
  supposed 
  

   specific 
  differences 
  in 
  this 
  genus. 
  Moreover, 
  such 
  a 
  collection 
  of 
  

   plants 
  in 
  culture 
  would 
  make 
  possible 
  further 
  cytologlcal 
  and 
  

   genetical 
  studies 
  which 
  It 
  Is 
  planned 
  to 
  carry 
  out. 
  The 
  cultures 
  

  

  