﻿2 
  

  

  Mr. 
  E. 
  Beer 
  and 
  Dr. 
  A. 
  Arber. 
  On 
  the 
  

  

  habit, 
  habitat, 
  and 
  systematic 
  position," 
  including 
  both 
  Vascular 
  Cryptogams 
  

   and 
  Angiosperms. 
  Miss 
  Prankerd 
  considers, 
  like 
  nearly 
  all 
  of 
  those 
  who 
  

   have 
  written 
  upon 
  this 
  subject, 
  that 
  the 
  plurality 
  of 
  nuclei 
  arises 
  by 
  amitosis. 
  

   With 
  regard 
  to 
  the 
  ultimate 
  fate 
  of 
  the 
  nuclei, 
  she 
  does 
  not 
  believe 
  it 
  

   probable 
  either 
  that 
  all 
  the 
  nuclei 
  but 
  one 
  degenerate 
  in 
  each 
  cell, 
  or 
  that 
  

   they 
  fuse 
  with 
  one 
  another. 
  She 
  is 
  inclined 
  to 
  suppose 
  that 
  walls 
  may 
  

   ultimately 
  be 
  formed 
  between 
  the 
  daughter 
  nuclei 
  which 
  have 
  arisen 
  by 
  

   amitosis. 
  

  

  In 
  the 
  same 
  issue 
  of 
  the 
  ' 
  Annals 
  of 
  Botany 
  ' 
  as 
  that 
  in 
  which 
  Miss 
  

   Prankerd's 
  account 
  appeared, 
  we 
  published 
  a 
  preliminary 
  statement 
  of 
  our 
  

   results 
  upon 
  the 
  same 
  subject.* 
  It 
  is 
  unnecessary 
  to 
  refer 
  to 
  this 
  at 
  length, 
  

   but 
  we 
  may 
  recall 
  that 
  we 
  recorded 
  a 
  plurality 
  of 
  nuclei 
  in 
  the 
  young 
  

   parenchymatous 
  tissues 
  of 
  76 
  species, 
  chiefly 
  Angiosperms, 
  but 
  including 
  also 
  

   a 
  Gymnosperm 
  and 
  a 
  Vascular 
  Cryptogam. 
  This 
  phenomenon 
  seemed 
  to 
  us 
  

   so 
  widespread 
  that 
  we 
  suggested 
  the 
  possibility 
  that 
  a 
  binucleate 
  or 
  multi- 
  

   nucleate 
  stage 
  might 
  often 
  intervene 
  as 
  a 
  normal 
  phase 
  of 
  development 
  

   between 
  the 
  meristematic 
  and 
  adult 
  conditions. 
  The 
  main 
  difference 
  between 
  

   our 
  results 
  and 
  those 
  of 
  previous 
  writers 
  is 
  that, 
  according 
  to 
  our 
  observa- 
  

   tions, 
  the 
  plurality 
  of 
  nuclei 
  normally 
  arises 
  by 
  karyokinesis 
  and 
  not 
  by 
  

   amitosis. 
  Moreover, 
  there 
  are 
  certain 
  peculiarities 
  in 
  the 
  phenomena 
  

   associated 
  with 
  this 
  mitosis 
  to 
  which 
  we 
  called 
  attention 
  in 
  our 
  note, 
  and 
  

   which 
  we 
  propose 
  to 
  describe 
  more 
  fully 
  in 
  the 
  present 
  paper. 
  

  

  The 
  Occurrence 
  of 
  the 
  Multinucleate 
  Phase. 
  

  

  Binucleate 
  or 
  multinucleate 
  cells 
  have 
  been 
  observed 
  by 
  us 
  in 
  the 
  vege- 
  

   tative 
  tissues 
  of 
  177 
  species 
  representing 
  60 
  families. 
  They 
  have 
  been 
  found 
  

   in 
  each 
  of 
  the 
  five 
  classes 
  of 
  living 
  Pteridophyta 
  (e.g., 
  Equisetum, 
  Plate 
  1, 
  

   fig. 
  25, 
  and 
  Lygodium, 
  Plate 
  1, 
  fig. 
  28), 
  and 
  are 
  of 
  very 
  general 
  occurrence 
  in 
  

   the 
  Gymnosperms 
  {e.g., 
  Larix, 
  Plate 
  1, 
  fig. 
  23, 
  and 
  Cryptomeria, 
  Plate 
  1, 
  

   fig. 
  27), 
  Monocotyledons, 
  and 
  Dicotyledons. 
  The 
  cases 
  in 
  which 
  we 
  have 
  

   observed 
  them 
  are 
  enumerated 
  in 
  the 
  following 
  list. 
  An 
  asterisk 
  before 
  the 
  

   name 
  of 
  a 
  species 
  denotes 
  that 
  it 
  is 
  a 
  case 
  in 
  which 
  " 
  phragmospheres 
  " 
  

   have 
  been 
  observed 
  (see 
  p. 
  10). 
  All 
  the 
  observations 
  were 
  made 
  on 
  our 
  

   own 
  preparations, 
  except 
  in 
  the 
  case 
  of 
  those 
  species 
  to 
  which 
  the 
  initials 
  

   (E.S.) 
  are 
  appended 
  ; 
  these 
  have 
  been 
  examined 
  in 
  the 
  late 
  Miss 
  Ethel 
  

   Sargant's 
  collection 
  of 
  seedling 
  slides. 
  

  

  * 
  Beer, 
  E., 
  and 
  Arber, 
  A., 
  " 
  On 
  the 
  Occurrence 
  of 
  Binucleate 
  and 
  Multinucleate 
  Cells 
  

   in 
  Growing 
  Tissues," 
  'Ann. 
  Bot., 
  ! 
  vol. 
  29, 
  pp. 
  597-8 
  (1915). 
  

  

  