﻿Elementary 
  Species 
  in 
  Nature 
  55 
  

  

  can 
  only 
  be 
  recognized 
  by 
  comparative 
  experi- 
  

   mental 
  studies. 
  

  

  Though 
  the 
  evidence 
  already 
  given 
  might 
  be 
  

   esteemed 
  to 
  be 
  sufficient 
  for 
  our 
  purpose, 
  I 
  

   should 
  like 
  to 
  introduce 
  a 
  few 
  more 
  examples; 
  

   two 
  of 
  them 
  pertain 
  to 
  American 
  plants. 
  

  

  The 
  Ipecac 
  spurge 
  or 
  Euphorbia 
  Ipecacu- 
  

   anha 
  occurs 
  from 
  Connecticut 
  to 
  Florida, 
  

   mainly 
  near 
  the 
  coast, 
  preferring 
  dry 
  and 
  sandy 
  

   soil. 
  It 
  is 
  often 
  found 
  by 
  the 
  roadsides. 
  Ac- 
  

   cording 
  to 
  Britton 
  and 
  Brown's 
  "Illustrated 
  

   Flora' 
  ' 
  it 
  is 
  glabrous 
  or 
  pubescent, 
  with 
  several 
  

   or 
  many 
  stems, 
  ascending 
  or 
  nearly 
  erect 
  ; 
  with 
  

   green 
  or 
  red 
  leaves, 
  which 
  are 
  wonderfully 
  

   variable 
  in 
  outline, 
  from 
  linear 
  to 
  orbicular, 
  

   mostly 
  opposite, 
  the 
  upper 
  sometimes 
  whorled, 
  

   the 
  lower 
  often 
  alternate. 
  The 
  glands 
  of 
  the 
  

   involucres 
  are 
  elliptic 
  or 
  oblong, 
  and 
  even 
  the 
  

   seeds 
  vary 
  in 
  shape. 
  

  

  Such 
  a 
  wide 
  range 
  of 
  variability 
  evidently 
  

   points 
  to 
  the 
  existence 
  of 
  some 
  minor 
  types. 
  

   Dr. 
  John 
  Harshberger 
  has 
  made 
  a 
  study 
  of 
  

   those 
  which 
  occur 
  in 
  the 
  vicinity 
  of 
  Whitings 
  in 
  

   New 
  Jersey. 
  His 
  types 
  agree 
  with 
  the 
  descrip- 
  

   tion 
  given 
  above. 
  Others 
  were 
  gathered 
  by 
  

   him 
  at 
  Brown's 
  Mills 
  in 
  the 
  pinelands, 
  New 
  

   Jersey, 
  where 
  they 
  grew 
  in 
  almost 
  pure 
  sand 
  in 
  

   the 
  bright 
  sunlight. 
  He 
  observed 
  still 
  other 
  

   differentiating 
  characters. 
  The 
  amount 
  of 
  seed 
  

  

  