﻿Systematic 
  Atavism 
  639 
  

  

  castrum, 
  being 
  limited 
  to 
  the 
  base 
  of 
  the 
  spike, 
  

   and 
  decreasing 
  in 
  size 
  from 
  the 
  lower 
  flowers 
  

   upward. 
  Connected 
  with 
  these 
  atavistic 
  bracts 
  

   is 
  a 
  feature 
  of 
  minor 
  importance, 
  which 
  how- 
  

   ever, 
  by 
  its 
  almost 
  universal 
  accompaniment 
  of 
  

   the 
  bracts, 
  deserves 
  our 
  attention, 
  as 
  it 
  is 
  indica- 
  

   tive 
  of 
  another 
  latent 
  character. 
  As 
  a 
  rule, 
  the 
  

   bracts 
  are 
  grown 
  together 
  with 
  their 
  axillary 
  

   flower-stalk. 
  This 
  cohesion 
  is 
  not 
  complete, 
  nor 
  

   is 
  it 
  always 
  developed 
  in 
  the 
  same 
  degree. 
  

   Sometimes 
  it 
  extends 
  over 
  a 
  large 
  part 
  of 
  the 
  

   two 
  organs, 
  leaving 
  only 
  their 
  tips 
  free, 
  but 
  on 
  

   other 
  occasions 
  it 
  is 
  limited 
  to 
  a 
  small 
  part 
  of 
  

   the 
  base. 
  But 
  it 
  is 
  very 
  interesting 
  that 
  this 
  

   same 
  cohesion 
  is 
  to 
  be 
  seen 
  in 
  the 
  shepherd's 
  

   purse, 
  in 
  the 
  wormseed 
  and 
  in 
  the 
  cabbage, 
  as 
  

   well 
  as 
  in 
  the 
  case 
  of 
  the 
  Erucastrum 
  and 
  most 
  

   of 
  the 
  other 
  observed 
  cases 
  of 
  atavistic 
  bracts. 
  

   This 
  fact 
  suggests 
  the 
  idea 
  of 
  a 
  common 
  origin 
  

   for 
  these 
  anomalies, 
  and 
  would 
  lead 
  to 
  the 
  

   hypothesis 
  that 
  the 
  original 
  ancestors 
  of 
  the 
  

   whole 
  family, 
  before 
  losing 
  the 
  bracts, 
  exhibited 
  

   this 
  peculiar 
  mode 
  of 
  cohesion. 
  

  

  Bracts 
  and 
  analogous 
  organs 
  afford 
  similar 
  

   cases 
  of 
  systematic 
  atavism 
  in 
  quite 
  a 
  number 
  

   of 
  other 
  families. 
  Aroids 
  sometimes 
  produce 
  

   long 
  bracts 
  from 
  various 
  places 
  on 
  their 
  

   spadix, 
  as 
  may 
  be 
  seen 
  in 
  the 
  cultivated 
  

   greenhouse 
  species, 
  Antliuriiim 
  scherzerianum. 
  

  

  