﻿I890.J 
  

  

  BOTANICAL 
  GAZETTE. 
  

  

  175 
  

  

  The 
  principal 
  points 
  in 
  regard 
  to 
  cell 
  division 
  in 
  

   01 
  the 
  roots 
  of 
  these 
  plants 
  

   have 
  already 
  been 
  thor- 
  

  

  oucrhly 
  discussed 
  by 
  Goe- 
  

   bel' 
  - 
  - 
  

  

  the 
  apices 
  

  

  and 
  DeBar\ 
  

  

  and 
  

  

  will 
  not 
  be 
  repeated 
  here. 
  

  

  Fig. 
  

  

  I 
  

  

  no 
  

  

  represents 
  the 
  

   apex 
  of 
  the 
  root 
  of 
  Mar- 
  

   silia 
  in 
  longitudinal 
  sec- 
  

   tion. 
  Underneath 
  the 
  

   dermatogen 
  is 
  a 
  single 
  

  

  layer 
  of 
  hypodermal 
  cells, 
  

   which 
  has 
  a 
  common 
  ini- 
  

   tial 
  cell 
  with 
  the 
  dermat- 
  

   ogen. 
  This 
  hypodermal 
  

   ''''3'er(h, 
  fig. 
  ,), 
  divides 
  

   more 
  by 
  tangential 
  

   ^lls 
  but 
  remains 
  a 
  sin- 
  

   gle 
  layer. 
  

  

  GoebeP 
  represents 
  the 
  

   ransmon 
  from 
  the 
  bulky 
  

   ^"'fal 
  cells 
  into 
  the 
  long 
  

   narrow 
  cells 
  of 
  the 
  ple- 
  

   ^0"^e 
  cylinder, 
  as 
  taking 
  

   P^^^e 
  very 
  abruptly, 
  at 
  

   r^ 
  the 
  6th 
  ^ 
  

  

  ^ 
  he 
  species 
  figured 
  was 
  

  

  about 
  

  

  segment. 
  

  

  \ 
  

  

  Fig. 
  1. 
  

  

  ence 
  "^ 
  V 
  ; 
  ^^''^^I'^fo^^a, 
  I 
  have 
  noticed 
  a 
  marked 
  differ- 
  

   when 
  ihe^^ 
  f 
  }e 
  ti^ansition 
  is 
  very 
  gradual. 
  From 
  the 
  time 
  

  

  ,.^..-i^i"^^'^ 
  ^^^^^ 
  ^^^^ 
  ^"t 
  off, 
  the 
  three 
  tissues, 
  dermat- 
  

  

  ^?en 
  npr"n 
  ^^^ 
  *^"' 
  ^^^^ 
  tnree 
  tissues, 
  < 
  

  

  ^j^puibiemand 
  plerome, 
  are 
  distinctly 
  different. 
  

  

  base 
  nf 
  .r^^^'^^P 
  ^s 
  formed 
  from 
  seijments 
  cut 
  off 
  fr 
  

  

  

  segm 
  

  

  After 
  

  

  om 
  the 
  

  

  everv 
  

  

  three 
  

  

  seg- 
  

  

  the 
  sides 
  of 
  this 
  cell, 
  there 
  is 
  one 
  cutoff 
  

  

  ""ea 
  into 
  1 
  • 
  l 
  1"^ 
  basal 
  segment 
  is, 
  in 
  the 
  first 
  place, 
  di- 
  

  

  P^^'Pendici 
  /' 
  '^^ 
  "^^" 
  quadrants, 
  bv 
  walls 
  which 
  are 
  nearly 
  

   segment 
  % 
  ^^ 
  ^^^^^ 
  ^^^^^^' 
  ^"^ 
  t^" 
  ^^^^ 
  outer 
  surface 
  of 
  the 
  

  

  ^'vided 
  "k, 
  f\, 
  ^ 
  ^^- 
  ^■) 
  Each 
  of 
  these 
  cells 
  is 
  similarly 
  

   __ 
  "^i 
  uut 
  there 
  T« 
  mi.r^u 
  i^„„ 
  „ 
  -^ 
  

  

  Won, 
  1887 
  

  

  • 
  GOIBE, 
  

  

  ^i^e 
  IS 
  much 
  less 
  regularit}^ 
  in 
  the 
  position 
  of 
  

  

  pp. 
  265 
  ^2Z&~t- 
  ^^^^^^^^^^*^" 
  ^"^ 
  Special 
  Morphology 
  of 
  Plants- 
  English 
  Edi- 
  

  

  of 
  the 
  Phanerogams 
  and 
  Ferns. 
  Englisli 
  Edition, 
  

  

  *'' 
  pp. 
  17-2o~ 
  °''**''^^i^e 
  Anatomy 
  

  

  1- 
  c. 
  p. 
  2Zi. 
  

  

  