﻿398 
  G. 
  R. 
  Wieland 
  on 
  the 
  Cycadophyta. 
  

  

  opteris 
  and 
  Macrotaeniopteris 
  (not 
  necessarily 
  all 
  

   forms), 
  Ctenis, 
  Pseudoctenis, 
  Ptilozamites. 
  

  

  Reasons 
  for 
  this 
  grouping 
  are, 
  however, 
  neither 
  lack- 
  

   ing 
  nor 
  solely 
  inferred. 
  Thomas 
  and 
  Bancroft 
  (1913) 
  

   have 
  shown 
  that 
  Nilssonia, 
  Taniopteris, 
  and 
  Ptilozamites 
  

   have 
  characteristic 
  stomata 
  suggesting 
  the 
  existence 
  of 
  

   a 
  provisional 
  great 
  group 
  — 
  the 
  Nilssoniales. 
  The 
  facts 
  

   they 
  adduced, 
  position 
  of 
  the 
  genera 
  in 
  time, 
  certain 
  leaf 
  

   features, 
  and 
  the 
  probability 
  of 
  departure 
  in 
  the 
  fructifi- 
  

   cation 
  from 
  Wielandiella, 
  led 
  me 
  to 
  use 
  this 
  classification 
  

   (1916). 
  But 
  reasons 
  for 
  such 
  a 
  wide 
  separation 
  are 
  less 
  

   evident. 
  The 
  fact 
  that 
  Tceniopteris 
  vittata 
  leaves 
  of 
  the 
  

   Yorkshire 
  coast, 
  which 
  are 
  hardly 
  distinguishable 
  from 
  

   some 
  of 
  the 
  smaller 
  Nilssonia 
  foliage, 
  pertain 
  to 
  small 
  

   fruits 
  not 
  remote 
  from 
  Wielandiella, 
  is 
  important 
  

   (Thomas, 
  1915). 
  This 
  new 
  type, 
  Williams 
  oniell 
  a, 
  thus 
  

   falls 
  into 
  the 
  better 
  defined 
  Microfloras, 
  and 
  at 
  the 
  same 
  

   time 
  suggests 
  that 
  Tseniopterids 
  in 
  general, 
  and 
  doubtless 
  

   Macrotseniopterids, 
  are 
  truly 
  cycadeoid. 
  It 
  accordingly 
  

   seems 
  preferable 
  to 
  drop 
  the 
  term 
  Nilssoniales 
  1 
  and 
  so 
  

   leave 
  the 
  several 
  genera 
  in 
  question 
  as 
  the 
  terminal 
  

   family 
  of 
  the 
  apocycadeoids, 
  or 
  Holophyt^:. 
  

  

  This 
  family 
  group 
  appears 
  to 
  have 
  its 
  most 
  striking 
  

   development 
  in 
  the 
  Rhaetic, 
  and 
  attention 
  has 
  elsewhere 
  

   been 
  called 
  to 
  the 
  fact 
  that 
  while 
  many 
  macrophyllous 
  

   forms 
  occur 
  in 
  the 
  Trias 
  of 
  Virginia 
  and 
  North 
  Carolina, 
  

   microphyllous 
  forms 
  are 
  a 
  feature 
  in 
  the 
  Rhaetic 
  of 
  

   Argentina. 
  There 
  too 
  the 
  Ptilozamites 
  types 
  are 
  seen. 
  

  

  Evidently 
  there 
  was 
  an 
  ancient 
  line 
  which 
  led 
  toward 
  

   the 
  Cycadales, 
  Hemicycadales, 
  and 
  Ginkgoales 
  — 
  the 
  Para- 
  

   cycadales 
  it 
  might 
  be 
  called. 
  As 
  members 
  of 
  a 
  group, 
  

   leading 
  toward 
  the 
  Ginkgoales, 
  yet 
  in 
  all 
  probability 
  but 
  

   slightly 
  removed 
  (if 
  at 
  all), 
  from 
  the 
  Hoiophytse, 
  there 
  

  

  1 
  Thomas, 
  H. 
  Hamshaw. 
  On 
  Williamsoniella, 
  a 
  New 
  Fruit 
  Type 
  of 
  

   Bennettitean 
  Flower. 
  Phil. 
  Trans. 
  Koy. 
  Soc, 
  vol. 
  207, 
  p. 
  113. 
  

  

  [In 
  giving 
  my 
  classification 
  of 
  the 
  Cycadales 
  (Amer. 
  Fos. 
  Cy., 
  vol. 
  II, 
  

   p. 
  26), 
  I 
  was 
  unaware 
  of 
  this 
  important 
  paper. 
  While 
  on 
  the 
  other 
  hand 
  

   my 
  inclusion 
  of 
  a 
  great 
  group 
  Dioonitales 
  was 
  a 
  lapsus 
  calami, 
  due 
  to 
  

   having 
  after 
  a 
  time 
  overlooked 
  the 
  later 
  notes 
  of 
  Nathorst 
  on 
  Dioonites 
  

   s/it 
  ridbilis. 
  These 
  leaves 
  are, 
  as 
  recalled, 
  associated 
  with 
  what 
  at 
  first 
  

   suggested 
  ;t 
  decompounded 
  spore 
  or 
  anthera/ngium 
  ; 
  found 
  on 
  later 
  study 
  

   h> 
  bettered 
  methods 
  to 
  U'long 
  to 
  a 
  lax 
  seed 
  cone 
  of 
  the 
  Beania 
  type. 
  The 
  

   so-called 
  Urania 
  is 
  rather 
  difficult 
  to 
  place 
  anywhere, 
  though 
  more 
  cycadeous 
  

   than 
  cycadeoid. 
  Seward 
  (Fossil 
  Botany, 
  p. 
  502) 
  notes 
  the 
  resemblance 
  of 
  

   this 
  two 
  sec. 
  led 
  megasporophyll 
  type 
  to 
  abnormally 
  paired 
  Ginkgo 
  seeds; 
  

   and 
  I 
  called 
  attention 
  to 
  a 
  certain 
  sporophyll 
  resemblance 
  between 
  Zami- 
  

   ostrobus 
  or 
  Stenorrachus 
  of 
  Nathorst 
  and 
  Cycadeoidea 
  (Am. 
  Fos. 
  Cy., 
  vol. 
  

   I. 
  |, 
  232).] 
  

  

  