﻿680 
  Mutations 
  

  

  These 
  narrow 
  lateral 
  lobes 
  heighten 
  the 
  abnor- 
  

   mal 
  aspect 
  of 
  the 
  whole 
  spike. 
  

  

  They 
  are 
  only 
  produced 
  at 
  a 
  somewhat 
  ad- 
  

   vanced 
  stage 
  of 
  the 
  development 
  of 
  the 
  palet, 
  

   are 
  united 
  to 
  one 
  another 
  and 
  to 
  the 
  central 
  

   part 
  by 
  strong 
  veins, 
  which 
  form 
  transversal 
  

   anastomoses 
  at 
  their 
  insertion. 
  The 
  length 
  of 
  

   these 
  awns 
  is 
  very 
  variable, 
  and 
  this 
  quality 
  is 
  

   perhaps 
  the 
  most 
  striking 
  of 
  the 
  whole 
  variety. 
  

   Often 
  they 
  reach 
  only 
  1--2 
  mm., 
  or 
  the 
  major- 
  

   ity 
  may 
  become 
  longer 
  and 
  attain 
  even 
  1 
  cm., 
  

   while 
  here 
  and 
  there, 
  between 
  them, 
  longer 
  ones 
  

   are 
  inserted, 
  extending 
  in 
  some 
  instances 
  even 
  

   as 
  far 
  as 
  3 
  cm. 
  from 
  the 
  spike. 
  Their 
  trans- 
  

   verse 
  position 
  in 
  such 
  cases 
  is 
  strikingly 
  con- 
  

   trasted 
  with 
  the 
  ordinary 
  erect 
  type 
  of 
  the 
  

   awns. 
  

  

  These 
  lateral 
  lobes 
  are 
  to 
  be 
  regarded, 
  from 
  

   the 
  morphologic 
  point 
  of 
  view, 
  as 
  differentiated 
  

   parts 
  of 
  the 
  blade 
  of 
  the 
  leaf. 
  Before 
  they 
  are 
  

   formed, 
  or 
  coincidently 
  with 
  the 
  beginning 
  of 
  

   their 
  development, 
  the 
  summit 
  of 
  the 
  central 
  

   lobe 
  becomes 
  hollow, 
  and 
  the 
  development 
  of 
  

   the 
  supernumerary 
  flower 
  commences. 
  In 
  dif- 
  

   ferent 
  varieties, 
  and 
  especially 
  in 
  the 
  most 
  re- 
  

   cent 
  crosses 
  of 
  them, 
  this 
  development 
  is 
  ex- 
  

   cessively 
  variable. 
  

  

  The 
  accidental 
  flower 
  arises 
  at 
  some 
  distance 
  

   beneath 
  the 
  summit 
  of 
  the 
  scale, 
  on 
  its 
  middle 
  

  

  