﻿638 
  Mutations 
  

  

  stalks, 
  but 
  are 
  limited 
  to 
  the 
  lowermost 
  part 
  of 
  

   the 
  raceme, 
  adorning 
  a 
  few, 
  often 
  ten 
  or 
  twelve, 
  

   and 
  rarely 
  more 
  flower-stalks. 
  Moreover 
  they 
  

   exhibit 
  a 
  feature 
  which 
  is 
  indicative 
  of 
  the 
  pres- 
  

   ence 
  of 
  an 
  abnormality. 
  They 
  are 
  not 
  all 
  of 
  the 
  

   same 
  size, 
  but 
  decrease 
  in 
  length 
  from 
  the 
  base 
  

   of 
  the 
  raceme 
  upward, 
  and 
  finally 
  slowly 
  dis- 
  

   appear. 
  

  

  Besides 
  these 
  rare 
  cases 
  there 
  are 
  quite 
  a 
  

   number 
  of 
  cruciferous 
  species 
  on 
  record, 
  which 
  

   have 
  been 
  observed 
  to 
  bear 
  bracts. 
  Penzig 
  

   in 
  his 
  valuable 
  work 
  on 
  teratology 
  gives 
  a 
  

   list 
  of 
  33 
  such 
  genera, 
  many 
  of 
  them 
  repeat- 
  

   ing 
  the 
  anomaly 
  in 
  more 
  than 
  one 
  species. 
  

   Ordinary 
  cabbages 
  are 
  perhaps 
  the 
  best 
  known 
  

   instance, 
  and 
  any 
  unusual 
  abundance 
  of 
  nour- 
  

   ishment, 
  or 
  anomalous 
  cause 
  of 
  growth 
  seems 
  

   to 
  be 
  liable 
  to 
  incite 
  the 
  development 
  of 
  bracts. 
  

   The 
  hedge 
  garlic 
  or 
  garlic 
  mustard 
  (Alliaria), 
  

   the 
  shepherd's 
  purse, 
  the 
  wormseed 
  or 
  Ery 
  si- 
  

   mum 
  cheiranthoides 
  and 
  many 
  others 
  afford 
  

   instances. 
  In 
  my 
  cultures 
  of 
  Heeger's 
  shep- 
  

   herd's 
  purse, 
  the 
  new 
  species 
  derived 
  at 
  Lan- 
  

   dau 
  in 
  Germany 
  from 
  the 
  common 
  shepherd's 
  

   purse, 
  the 
  anomaly 
  was 
  observed 
  to 
  occur 
  more 
  

   than 
  once, 
  showing 
  that 
  the 
  mutation, 
  which 
  

   changed 
  the 
  fruits, 
  had 
  not 
  in 
  the 
  least 
  affected 
  

   this 
  subordinate 
  anomalous 
  peculiarity. 
  In 
  all 
  

   these 
  cases 
  the 
  bracts 
  behave 
  as 
  with 
  the 
  Eru- 
  

  

  