﻿Taxonomic 
  Anomalies 
  671 
  

  

  lobes, 
  the 
  deeper 
  the 
  ascidium 
  will 
  become. 
  It 
  

   should 
  be 
  added 
  that 
  this 
  explanation 
  of 
  the 
  dif- 
  

   ferent 
  shapes 
  of 
  ascidia 
  is 
  of 
  general 
  validity. 
  

  

  Ascidia 
  of 
  the 
  snake-plantain 
  or 
  Plantago 
  

   lanceolata 
  are 
  narrow 
  tubes, 
  because 
  the 
  leaves 
  

   are 
  oblong 
  or 
  lanceolate, 
  while 
  those 
  of 
  the 
  

   broad 
  leaved 
  species 
  of 
  arrowhead, 
  as 
  for 
  in- 
  

   stance, 
  the 
  Sagittaria 
  japonica, 
  are 
  of 
  a 
  conical 
  

   shape. 
  

  

  From 
  the 
  evidence 
  of 
  the 
  lime-tree 
  we 
  may 
  

   conclude 
  that 
  normal 
  peltate 
  leaves 
  may 
  have 
  

   originated 
  in 
  the 
  same 
  way. 
  And 
  from 
  the 
  fact 
  

   that 
  pitchers 
  are 
  one 
  of 
  the 
  most 
  frequent 
  

   anomalies, 
  we 
  may 
  conclude 
  that 
  the 
  chance 
  of 
  

   producing 
  peltate 
  leaves 
  must 
  have 
  been 
  a 
  very 
  

   great 
  one, 
  and 
  wholly 
  sufficient 
  to 
  account 
  for 
  

   all 
  observed 
  cases. 
  In 
  every 
  instance 
  the 
  pre- 
  

   viously 
  existing 
  shape 
  of 
  the 
  leaf 
  must 
  have 
  de- 
  

   cided 
  whether 
  peltate 
  or 
  pitcher-like 
  leaves 
  

   would 
  be 
  formed. 
  As 
  far 
  as 
  we 
  can 
  judge 
  pel- 
  

   tate 
  anomalies 
  are 
  quite 
  uninjurious, 
  while 
  as- 
  

   cidia 
  are 
  forms 
  which 
  must 
  impede 
  the 
  effect 
  of 
  

   the 
  light 
  on 
  the 
  leaf, 
  as 
  they 
  conceal 
  quite 
  an 
  

   important 
  part 
  of 
  the 
  upper 
  surface. 
  In 
  this 
  

   way 
  it 
  is 
  easily 
  conceivable 
  that 
  peltate 
  leaves 
  

   are 
  a 
  frequent 
  specific 
  character, 
  while 
  ascidia 
  

   are 
  not, 
  as 
  they 
  only 
  appear 
  in 
  the 
  special 
  cases 
  

   of 
  limited 
  adaptation, 
  as 
  in 
  the 
  instances 
  of 
  the 
  

   so 
  called 
  pitcher-plants. 
  The 
  genera 
  Nepenthes, 
  

  

  