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  Mutations 
  

  

  have 
  arisen 
  at 
  once, 
  and 
  hence 
  the 
  conclusion 
  

   that 
  the 
  ascidia 
  of 
  Nepenthes 
  are 
  also 
  originally 
  

   due 
  to 
  a 
  sudden 
  mutation. 
  Interrupted 
  leaves, 
  

   with 
  an 
  ascidium 
  on 
  a 
  naked 
  prolongation 
  of 
  the 
  

   midvein, 
  are 
  by 
  no 
  means 
  limited 
  to 
  the 
  Croton 
  

   varieties. 
  As 
  stray 
  anomalies 
  they 
  have 
  often 
  

   been 
  observed, 
  and 
  I 
  myself 
  had 
  the 
  oppor- 
  

   tunity 
  of 
  collecting 
  them 
  on 
  magnolia, 
  on 
  clover 
  

   and 
  on 
  some 
  other 
  species. 
  They 
  are 
  additional 
  

   evidence 
  in 
  support 
  of 
  the 
  explanation 
  given 
  

   above. 
  

  

  In 
  the 
  same 
  way 
  double 
  ascidia 
  may 
  be 
  made 
  

   use 
  of 
  to 
  explain 
  the 
  foliar 
  cups 
  of 
  the 
  teasels 
  

   and 
  some 
  other 
  plants, 
  as 
  for 
  instance, 
  some 
  

   European 
  snakeroots 
  (Eryngium 
  maritimum 
  

   and 
  E. 
  campestre), 
  or 
  the 
  floral 
  leaves 
  of 
  the 
  

   honeysuckle. 
  The 
  leaves 
  on 
  the 
  stems 
  of 
  the 
  

   teasels 
  are 
  disposed 
  in 
  pairs, 
  and 
  the 
  bases 
  of 
  

   the 
  two 
  leaves 
  of 
  each 
  pair 
  are 
  connate 
  so 
  as 
  

   to 
  constitute 
  large 
  cups. 
  We 
  have 
  already 
  men- 
  

   tioned 
  these 
  cups, 
  and 
  recall 
  them 
  in 
  the 
  present 
  

   connection 
  to 
  use 
  them 
  as 
  a 
  prototype 
  of 
  the 
  

   double 
  ascidia. 
  These 
  are 
  constituted 
  of 
  two 
  op- 
  

   posite 
  leaves, 
  accidentally 
  connated 
  at 
  their 
  base 
  

   or 
  along 
  some 
  part 
  of 
  their 
  margins. 
  If 
  the 
  

   leaves 
  are 
  sessile, 
  the 
  analogy 
  with 
  the 
  teasels 
  

   is 
  complete, 
  as 
  shown, 
  for 
  instance, 
  in 
  a 
  case 
  

   of 
  Cotyledon, 
  a 
  crassulaceous 
  plant 
  which 
  is 
  

  

  