﻿LECKENBY 
  OOLITIC 
  PLANTS. 
  81 
  

  

  As 
  the 
  venation 
  and 
  fructification 
  ofPecopteris 
  unclans 
  and 
  P.poly- 
  

   podioides 
  resemble 
  each 
  other, 
  I 
  propose 
  to 
  refer 
  these 
  species 
  to 
  

   Polypodites, 
  and 
  to 
  reserve 
  the 
  genus 
  Phlebopteris 
  for 
  those 
  species 
  

   having 
  a 
  distinct 
  areola, 
  although 
  the 
  genus 
  is 
  again 
  capable 
  of 
  sub- 
  

   division 
  into 
  two 
  sections 
  — 
  one 
  containing 
  those 
  species 
  in 
  which, 
  as 
  

   in 
  P. 
  contigua, 
  the 
  sori 
  are 
  placed 
  externally 
  to 
  the 
  areola 
  ; 
  and 
  the 
  

   other 
  for 
  species, 
  like 
  the 
  following, 
  in 
  which 
  the 
  sori 
  are 
  placed 
  in 
  

   the 
  centre 
  of 
  the 
  areola 
  and 
  close 
  to 
  the 
  midrib. 
  

  

  18. 
  Phleboptekis 
  Woodwardii, 
  nobis. 
  PI. 
  VIII. 
  fig. 
  6. 
  

  

  Frond 
  unknown 
  ; 
  leaflets 
  long 
  and 
  narrow, 
  ivith 
  a 
  thickened 
  midrib, 
  

   grooved 
  on 
  each 
  side, 
  and 
  from 
  which 
  spring 
  rows 
  of 
  veins 
  form- 
  

   ing 
  pentagonal 
  areola?, 
  which 
  hi- 
  or 
  tri-furcate 
  towards 
  the 
  edges. 
  

   Fructification 
  — 
  stellate 
  sori, 
  in 
  the 
  centre 
  of 
  the 
  areola;. 
  

   The 
  magnified 
  portion 
  figured 
  represents 
  a 
  species 
  in 
  which, 
  as 
  

   before 
  stated, 
  the 
  sori 
  are 
  placed 
  within 
  an 
  areola, 
  which 
  in 
  the 
  one 
  

   before 
  us 
  is 
  pentagonal. 
  It 
  has 
  hitherto 
  been 
  found 
  only 
  in 
  frag- 
  

   ments, 
  although 
  tolerably 
  plentiful. 
  The 
  arrangement 
  of 
  the 
  nerves 
  

   and 
  the 
  disposition 
  of 
  the 
  sori 
  are 
  so 
  remarkable 
  as 
  to 
  leave 
  no 
  doubt 
  

   of 
  its 
  being 
  a 
  distinct 
  species. 
  Their 
  connexion 
  with 
  a 
  feeding-vein 
  

   is 
  obscure. 
  

  

  19. 
  Fucoides 
  erectus, 
  Bean, 
  MS. 
  PI. 
  XI. 
  figs. 
  3 
  a, 
  3 
  6. 
  

  

  Frond 
  expanding, 
  somewhat 
  fan-sluiped, 
  erect, 
  dichotomously 
  branched; 
  

   branches 
  cleft 
  irregularly 
  and 
  longitudinally 
  at 
  their 
  summits, 
  form- 
  

   ing 
  lobes 
  ivhich 
  are 
  obtusely 
  pointed, 
  sometimes 
  truncate, 
  a 
  cluster 
  of 
  

   veins 
  forming 
  a 
  midrib 
  from 
  which 
  spread 
  numerous 
  secondary 
  ones. 
  

   Fructification 
  in 
  one 
  or 
  more 
  rows 
  of 
  ovate 
  vesicles, 
  immersed 
  in 
  the 
  

   frond. 
  

  

  The 
  fronds 
  of 
  this 
  species 
  are 
  broader 
  than 
  those 
  of 
  Fucoides 
  

   arcuatus, 
  and 
  are 
  not 
  incurved. 
  It 
  is 
  only 
  in 
  finely 
  -preserved 
  spe- 
  

   cimens 
  that 
  the 
  venation 
  and 
  fructification 
  can 
  be 
  observed. 
  The 
  

   example 
  figured 
  is 
  from 
  the 
  beds 
  at 
  Cloughton 
  AVyke. 
  It 
  occurs 
  

   also 
  at 
  Gristhorpe. 
  

  

  EXPLANATION 
  OF 
  PLATES 
  VIII.-XI. 
  

  

  Illustrative 
  of 
  the 
  Oolitic 
  Plants 
  of 
  Scarborough. 
  

  

  Plate 
  VIII. 
  

   Fig. 
  1. 
  Cycadites 
  zamioides; 
  portion 
  of 
  a 
  frond, 
  natural 
  size. 
  

  

  2. 
  Pterophyllum 
  medianum 
  ; 
  portion 
  of 
  a 
  frond, 
  natural 
  size. 
  

  

  3. 
  angustifolium 
  ; 
  portion 
  of 
  a 
  frond, 
  natural 
  size. 
  

  

  4. 
  Otopteris 
  lanceolata 
  ; 
  portion 
  of 
  a 
  frond, 
  natural 
  size. 
  

  

  5. 
  graphica 
  ; 
  portion 
  of 
  a 
  frond, 
  natural 
  size. 
  

  

  6. 
  Phlebopteris 
  Woodwardii 
  ; 
  portion 
  of 
  a 
  leaflet, 
  magnified 
  3 
  diameters. 
  

  

  Plate 
  IX. 
  

  

  Fig. 
  1. 
  Otopteris 
  tenuata\ 
  portion 
  of 
  a 
  frond, 
  natural 
  size. 
  

  

  2. 
  Pterophyllum 
  minus 
  ; 
  two 
  fronds, 
  showing 
  variation 
  in 
  their 
  division, 
  

  

  three-fourths 
  the 
  natural 
  size. 
  

  

  3. 
  comptum 
  ; 
  portion 
  of 
  a 
  young 
  frond, 
  two-thirds 
  the 
  natural 
  size. 
  

  

  4. 
  PalxBozamia 
  pecten 
  : 
  a, 
  portions 
  of 
  fronds, 
  stems, 
  and 
  a 
  flower, 
  one- 
  

  

  half 
  the 
  natural 
  size 
  ; 
  b, 
  portion 
  of 
  a 
  frond, 
  magnified 
  2 
  diameters. 
  

   VOL. 
  XX. 
  PART 
  I. 
  O 
  

  

  