﻿G. 
  R. 
  Wieland 
  on 
  the 
  Cycadophyta. 
  408 
  

  

  for 
  uniting 
  these 
  two 
  Cycadalean 
  lines 
  anywhere 
  in 
  post- 
  

   Paleozoic 
  time 
  ; 
  and 
  what 
  is 
  true 
  of 
  them 
  is 
  true 
  of 
  all 
  

   the 
  main 
  Cycadophytan 
  types. 
  Thus 
  Pseudocycas 
  sug- 
  

   gests 
  relationship 
  to 
  the 
  Cycadese, 
  just 
  as 
  does 
  Podoza- 
  

   mites 
  to 
  the 
  Zamise 
  ; 
  though 
  both 
  are 
  clearly 
  old. 
  So 
  too 
  

   the 
  borderline 
  frond 
  type 
  Stangerites. 
  . 
  

  

  Coining 
  to 
  the 
  Pericycadeoid 
  division 
  of 
  the 
  hemi- 
  

   cycads, 
  the 
  macroflorous 
  Cycadeoideas 
  persist 
  nearly 
  as 
  

   long 
  as 
  the 
  cycads 
  — 
  being 
  last 
  found 
  in 
  the 
  Upson 
  shale 
  

   of 
  Texas, 
  high 
  up 
  in 
  the 
  Upper 
  Cretaceous, 
  and 
  not 
  known 
  

   earlier 
  than 
  the 
  Jura. 
  Taking 
  the 
  record 
  as 
  it 
  stands, 
  the 
  

   Microflora 
  are 
  an 
  older 
  line 
  than 
  the 
  Cycadeoideae, 
  but 
  

   generalized 
  in 
  the 
  sense 
  that 
  so 
  far 
  as 
  appears, 
  they 
  tend 
  

   less 
  to 
  extreme 
  types. 
  Pteropliyllnm, 
  with 
  an 
  exceedingly 
  

   long 
  history, 
  must 
  be 
  hemicycadeoid. 
  The 
  Permian- 
  

   Carboniferous 
  Plagiozamites 
  5 
  is 
  an 
  old 
  cosmopolitan 
  

   form 
  (incertce 
  sedis) 
  of 
  short 
  range. 
  Tceniopteris, 
  Nils- 
  

   sonia, 
  Ctenis, 
  are 
  hemicycads 
  of 
  longer 
  range, 
  unless 
  the 
  

   slightly 
  net-veined 
  Ctenis 
  be 
  excepted. 
  The 
  very 
  fact 
  of 
  

   extinction 
  implies 
  that 
  these 
  genera 
  reached 
  a 
  degree 
  of 
  

   specialization 
  ; 
  but 
  it 
  is 
  improbable 
  that 
  they 
  bore 
  heavy 
  

   cones. 
  Entirely 
  too 
  little 
  consideration 
  has 
  been 
  given 
  

   the 
  possibility 
  that 
  many 
  of 
  these 
  leaf 
  types 
  may 
  be 
  those 
  

   of 
  forest-making 
  trees, 
  flowered 
  like 
  the 
  magnolias. 
  

   Much 
  less 
  has 
  it 
  been 
  noted 
  that 
  with 
  only 
  a 
  slight 
  inner- 
  

   vation, 
  — 
  invasion 
  of 
  a 
  marginal 
  veinule, 
  in 
  any 
  bladed 
  

   type 
  with 
  well 
  separated 
  pinnate 
  venation 
  netted 
  types 
  

   could 
  easily 
  arise. 
  Recall 
  once 
  more 
  that 
  leaf-hiatus 
  

   between 
  T 
  umbo 
  a 
  and 
  Gnetum 
  gnemon. 
  

  

  In 
  the 
  Permian 
  the 
  several 
  Cycadophyte 
  lines 
  are 
  more 
  

   uncertain, 
  but 
  shown 
  as 
  discrete. 
  Using 
  these 
  terms 
  in 
  

   a 
  purely 
  adjective 
  sense, 
  there 
  must 
  be 
  the 
  Eocycad, 
  

   Eocycadeoid, 
  and 
  the 
  Apocycadeoid 
  groups. 
  Finally 
  the 
  

   pro- 
  or 
  hemiangiosperm 
  arrow 
  has 
  the 
  position 
  laid 
  

   down, 
  except 
  that 
  the 
  head 
  representing 
  the 
  actual 
  

   appearance 
  of 
  the 
  angiosperms 
  might 
  be 
  placed 
  at 
  the 
  

   close 
  of 
  the 
  Jura. 
  

  

  Not 
  to 
  add 
  theory 
  to 
  theory 
  ; 
  but 
  rather 
  to 
  give 
  a 
  simple 
  

   form 
  of 
  expression 
  to 
  basic 
  conceptions 
  sometimes 
  over- 
  

   looked, 
  a 
  second 
  diagram 
  has 
  been 
  arranged 
  to 
  show 
  the 
  

   Cycadophyta 
  in 
  their 
  larger 
  relationships. 
  As 
  plotted, 
  

   the 
  object 
  is 
  first 
  to 
  accentuate 
  the 
  very 
  earliest 
  appear- 
  

  

  5 
  See 
  the 
  paper 
  by 
  Harvey 
  Bassler; 
  A 
  Cycadophyte 
  from 
  the 
  North 
  

   American 
  Coal 
  Measures, 
  this 
  Journal, 
  vol. 
  42* 
  pp. 
  21-26, 
  July, 
  1916. 
  

  

  