﻿396 
  G. 
  R. 
  Wieland 
  on 
  the 
  Cycadophyta. 
  

  

  In 
  this 
  new 
  classification, 
  then, 
  it 
  is 
  primarily 
  aimed 
  

   to 
  give 
  dne 
  homogeneity 
  to 
  the 
  grouping 
  of 
  the 
  Mesozoic 
  

   Cycadophyta. 
  This 
  cannot 
  be 
  done 
  if 
  the 
  term 
  Bennet- 
  

   titales, 
  as 
  first 
  used 
  and 
  defined, 
  is 
  retained. 
  While 
  it 
  

   would 
  take 
  us 
  far 
  afield 
  to 
  discuss 
  at 
  full 
  length 
  the 
  ques- 
  

   tions 
  of 
  mere 
  priority 
  relating 
  to 
  the 
  use 
  of 
  Bennettitales, 
  

   there 
  are 
  simple 
  and 
  good 
  reasons 
  for 
  letting 
  this 
  name 
  

   fall 
  into 
  disuse. 
  As 
  already 
  noted 
  the 
  boundaries 
  are 
  

   greatly 
  extended 
  ; 
  there 
  are 
  now 
  without 
  much 
  question 
  

   several 
  groups 
  ranking 
  as 
  high 
  as 
  the 
  Cycadales 
  within 
  

   the 
  Cycadophyta 
  ; 
  while 
  the 
  Bennettitales 
  as 
  used, 
  neither 
  

   expressed 
  such 
  relationship 
  nor 
  gave 
  sufficient 
  recognition 
  

   to 
  the 
  vegetative 
  equivalence 
  between 
  the 
  silicified 
  stems, 
  

   at 
  first 
  the 
  only 
  ones 
  included, 
  and 
  the 
  existing 
  cycads. 
  

   It 
  was 
  this 
  latter 
  fact 
  that 
  largely 
  influenced 
  the 
  retention 
  

   of 
  the 
  fossil 
  cycads 
  in 
  the 
  Cycadales 
  in 
  both 
  Volumes 
  I 
  

   and 
  II 
  of 
  my 
  American 
  Fossil 
  Cycads. 
  Approach 
  from 
  

   the 
  paleontologic 
  side 
  led 
  to 
  the 
  same 
  comparisons 
  with 
  

   cycads 
  that 
  had 
  obtained 
  for 
  seventy 
  years 
  ; 
  although 
  it 
  

   was 
  freely 
  admitted 
  at 
  all 
  points 
  that 
  the 
  discussions 
  of 
  

   relationship 
  must 
  be 
  inherently 
  tentative. 
  

  

  The 
  vegetative 
  characters 
  of 
  the 
  Cycadeoids 
  bear 
  such 
  a 
  

   general 
  resemblance 
  to, 
  and 
  present 
  so 
  many 
  points 
  of 
  

   agreement 
  with 
  those 
  of 
  the 
  cycads, 
  that 
  an 
  ancient 
  con- 
  

   tact 
  is 
  indicated. 
  The 
  facts 
  were 
  summed 
  up 
  in 
  the 
  

   American 
  Fossil 
  Cycads, 
  Vol. 
  I, 
  page 
  226 
  et 
  seq.; 
  and 
  

   the 
  additions 
  to 
  our 
  knowledge 
  of 
  the 
  anatomy 
  since 
  made 
  

   confirm 
  rather 
  than 
  disprove 
  a 
  degree 
  of 
  vegetative 
  affin- 
  

   ity. 
  It 
  is 
  difficult 
  to 
  admit 
  that 
  such 
  a 
  complete 
  similarity 
  

   is 
  in 
  entirety 
  the 
  end 
  result 
  of 
  homoplasy. 
  All 
  recognize, 
  

   however, 
  that 
  the 
  reproductive 
  organs 
  must 
  indicate 
  an 
  

   exceedingly 
  ancient 
  separation 
  — 
  perhaps 
  even 
  mid 
  to 
  

   early 
  Paleozoic. 
  Scott 
  says 
  : 
  

  

  "It 
  is 
  a 
  striking 
  fact 
  that 
  in 
  their 
  reproductive 
  organs, 
  that 
  

   is 
  to 
  say, 
  in 
  the 
  very 
  characters 
  on 
  which 
  systematists 
  are 
  accus- 
  

   tomed 
  to 
  rely, 
  the 
  Bennettitese 
  differ 
  toto 
  coelo 
  from 
  the 
  Cyca- 
  

   daceae. 
  The 
  organisation 
  of 
  the 
  flower 
  is 
  so 
  different 
  from 
  that 
  

   of 
  the 
  cones 
  of 
  any 
  recent 
  Cycad 
  that 
  it 
  is 
  difficult 
  to 
  determine 
  

   with 
  any 
  certainty 
  the 
  homologies 
  of 
  the 
  parts 
  in 
  the 
  two 
  groups. 
  

   It 
  is, 
  of 
  course, 
  possible 
  that 
  future 
  palaeontological 
  discoveries 
  

   may 
  reveal 
  the 
  existence 
  of 
  types 
  of 
  fructification 
  intermediate 
  

   between 
  those 
  of 
  Cycadales 
  and 
  Bennettitales 
  ; 
  at 
  present, 
  how- 
  

   ever, 
  it 
  seems 
  as 
  if 
  their 
  development 
  had 
  followed 
  different 
  

   lines 
  from 
  a 
  very 
  early 
  stage." 
  

  

  