﻿80 
  Elementary 
  Species 
  

  

  trial 
  value. 
  Clover 
  exhibits 
  many 
  varieties, 
  

   which 
  have 
  been 
  cultivated 
  indiscriminately, 
  

   and 
  often 
  in 
  motley 
  mixtures. 
  The 
  flower- 
  

   heads 
  may 
  be 
  red 
  or 
  white, 
  large 
  or 
  small, 
  cylin- 
  

   dric 
  or 
  rounded, 
  the 
  leaves 
  are 
  broader 
  or 
  nar- 
  

   rower, 
  with 
  or 
  without 
  white 
  spots 
  of 
  a 
  curious 
  

   pattern. 
  They 
  may 
  be 
  more 
  or 
  less 
  hairy 
  and 
  

   so 
  forth. 
  Even 
  the 
  seeds 
  exhibit 
  differences 
  in 
  

   size, 
  shape 
  or 
  color, 
  and 
  of 
  late 
  Martinet 
  has 
  

   shown, 
  that 
  by 
  the 
  simple 
  means 
  of 
  picking 
  out 
  

   seeds 
  of 
  the 
  same 
  pattern, 
  pure 
  strains 
  of 
  clover 
  

   may 
  be 
  obtained, 
  which 
  are 
  of 
  varying 
  cultural 
  

   value. 
  In 
  this 
  way 
  the 
  best 
  subspecies 
  or 
  va- 
  

   rieties 
  may 
  be 
  sought 
  out 
  for 
  separate 
  cultiva- 
  

   tion. 
  Even 
  the 
  white 
  spots 
  on 
  the 
  leaflets 
  have 
  

   proved 
  to 
  be 
  constant 
  characters 
  corresponding 
  

   with 
  noticeable 
  differences 
  in 
  yield. 
  

  

  Flax 
  is 
  another 
  instance. 
  It 
  was 
  already 
  cul- 
  

   tivated, 
  or 
  at 
  least 
  made 
  use 
  of 
  during 
  the 
  

   period 
  of 
  the 
  lake-dwellers, 
  but 
  at 
  that 
  time 
  it 
  

   was 
  a 
  species 
  referred 
  to 
  as 
  Linum 
  angusti- 
  

   folium, 
  and 
  not 
  the 
  Linum 
  usitatissimum, 
  which 
  

   is 
  our 
  present 
  day 
  flax. 
  There 
  are 
  now 
  many 
  

   subspecies, 
  elementary 
  species, 
  and 
  varieties 
  

   under 
  cultivation. 
  The 
  oldest 
  of 
  them 
  is 
  known 
  

   as 
  the 
  " 
  springing 
  flax," 
  in 
  opposition 
  to 
  the 
  

   ordinary 
  " 
  threshing 
  flax.' 
  It 
  has 
  capsules 
  

   which 
  open 
  of 
  themselves, 
  in 
  order 
  to 
  dissemin- 
  

   ate 
  the 
  seeds, 
  while 
  the 
  ordinary 
  heads 
  of 
  the 
  

  

  