﻿Genetics 
  of 
  1 
  ' 
  Rogues 
  " 
  among 
  Culinary 
  Peas 
  (Pisum 
  sativum). 
  187 
  

  

  they 
  may 
  be 
  reckoned 
  as 
  of 
  two 
  kinds 
  : 
  (1) 
  those 
  in 
  which 
  none 
  of 
  the 
  

   leaflets 
  have 
  points 
  ; 
  and 
  (2) 
  those 
  in 
  which 
  pointed 
  leaflets 
  sooner 
  or 
  later 
  

   appear. 
  This 
  in 
  practice 
  forms 
  a 
  convenient 
  distinction 
  which 
  can 
  almost 
  

   always 
  be 
  applied. 
  The 
  two 
  groups 
  thus 
  distinguished 
  on 
  somatic 
  characters 
  

   differ 
  essentially 
  in 
  their 
  genetic 
  properties 
  : 
  " 
  non-pointed 
  " 
  plants 
  give 
  on 
  

   self-fertilisation 
  what 
  in 
  previous 
  publications 
  we 
  have 
  called 
  A 
  families, 
  

   consisting 
  predominantly 
  of 
  types, 
  or 
  at 
  least 
  non-pointed 
  plants, 
  but 
  the 
  

   " 
  pointed 
  " 
  give 
  B 
  families 
  containing 
  predominantly 
  rogues. 
  Families 
  in 
  

   which 
  the 
  proportion 
  of 
  the 
  two 
  kinds 
  approaches 
  equality 
  occur 
  but 
  rarely. 
  

  

  Intermediate 
  plants 
  of 
  composite 
  or 
  mosaic 
  nature 
  are 
  not 
  very 
  uncommon, 
  

   and 
  the 
  mosaicism 
  may 
  be 
  of 
  varying 
  extent. 
  In 
  extreme 
  cases, 
  a 
  whole 
  

   branch 
  may 
  differ 
  from 
  the 
  main 
  stem, 
  and 
  a 
  " 
  pointed 
  " 
  branch 
  giving 
  a 
  

   B 
  family 
  may 
  arise 
  from 
  a 
  " 
  non-pointed 
  " 
  main 
  stem 
  giving 
  an 
  A 
  family, 
  or 
  

   vice 
  versd. 
  The 
  adequate 
  discussion 
  of 
  these 
  irregularly 
  composite 
  plants 
  

   must 
  be 
  deferred. 
  

  

  We 
  have 
  been 
  chiefly 
  occupied 
  with 
  a 
  study 
  of 
  the 
  genetic 
  peculiarities 
  

   connected 
  with 
  the 
  gradual 
  and 
  regular 
  assumption 
  of 
  the 
  rogue 
  characters 
  

   by 
  the 
  intermediate 
  plants 
  which 
  sooner 
  or 
  later 
  acquire 
  pointed 
  leaflets. 
  

   From 
  the 
  fact 
  that 
  the 
  change 
  was 
  progressive, 
  we 
  surmised 
  that 
  if 
  the 
  

   position 
  of 
  origin 
  of 
  the 
  seeds 
  on 
  such 
  plants 
  were 
  determined, 
  it 
  would 
  be 
  

   found 
  that 
  the 
  few 
  non-pointed 
  plants 
  which 
  they 
  produce 
  would 
  be 
  found 
  

   to 
  come 
  predominantly 
  from 
  seeds 
  in 
  the 
  lower 
  pods, 
  and 
  the 
  pointed 
  from 
  

   the 
  upper 
  pods. 
  As 
  the 
  result 
  of 
  a 
  preliminary 
  trial 
  we 
  found 
  that 
  this 
  rule 
  

   was 
  in 
  fact 
  followed, 
  and 
  this 
  observation 
  was 
  published* 
  at 
  the 
  end 
  of 
  1915. 
  

   Further 
  experience 
  has 
  abundantly 
  confirmed 
  it. 
  

  

  But 
  the 
  converse 
  conclusion 
  which 
  we 
  also 
  announced 
  at 
  the 
  same 
  time, 
  

   to 
  the 
  effect 
  that 
  in 
  the 
  case 
  of 
  A 
  families 
  containing 
  only 
  a 
  small 
  number 
  of 
  

   rogues 
  these 
  come 
  predominantly 
  from 
  the 
  upper 
  pods, 
  has 
  proved 
  to 
  be 
  

   erroneous. 
  In 
  families 
  where 
  the 
  pointed 
  plants 
  are 
  proportionally 
  few, 
  the 
  

   seeds 
  from 
  which 
  they 
  come 
  are 
  not 
  derived 
  from 
  any 
  particular 
  level 
  on 
  the 
  

   parent 
  plants, 
  and 
  the 
  observation 
  on 
  which 
  we 
  relied 
  was 
  only 
  an 
  accident 
  

   of 
  the 
  special 
  case. 
  

  

  Since 
  the 
  publication 
  of 
  these 
  first 
  results 
  the 
  work 
  has 
  been 
  continued 
  

   along 
  several 
  lines. 
  Having 
  established 
  the 
  fact 
  stated 
  above, 
  that 
  in 
  the 
  

   B 
  families 
  the 
  non-pointed 
  plants 
  come 
  chiefly 
  from 
  the 
  bottom 
  pods, 
  we 
  

   endeavoured 
  to 
  ascertain 
  more 
  exactly 
  the 
  positions 
  from 
  which 
  they 
  do 
  

   come. 
  Choosing, 
  therefore, 
  a 
  number 
  of 
  intermediate 
  plants 
  which 
  we 
  

   thought 
  likely 
  to 
  throw 
  B 
  families, 
  we 
  emasculated 
  each 
  flower 
  on 
  the 
  

   stems 
  in 
  succession, 
  as 
  far 
  as 
  possible, 
  pollinating 
  them 
  from 
  type 
  plants 
  

   * 
  ' 
  Proc. 
  Roy. 
  Soc.,' 
  B, 
  vol. 
  89, 
  p. 
  174. 
  

  

  Q 
  2 
  

  

  