﻿^30 
  BOTANICAL 
  GAZETTE. 
  [September, 
  

  

  large 
  enough 
  to 
  be 
  readily 
  visible, 
  in 
  the 
  vast 
  majority 
  of 
  

   cases 
  the 
  exceedingly 
  delicate 
  fibrilkv 
  penetrating 
  the 
  middle 
  

   lamella; 
  required 
  for 
  demonstration 
  the 
  highest 
  powers 
  of 
  the 
  

   microscope, 
  and 
  the 
  most 
  delicate 
  manipulation. 
  

  

  Potato-scab, 
  a 
  bacterial 
  disease: 
  H. 
  L. 
  Bolley.-Bv 
  

   special 
  arrangement, 
  this 
  paper, 
  which 
  belonged 
  to 
  the 
  Sec- 
  

   tion 
  anH 
  will 
  so 
  appear 
  in 
  the 
  volume 
  of 
  Proceedings, 
  was 
  

  

  e 
  Botanical 
  Club, 
  and 
  appears 
  in 
  that 
  connec- 
  

  

  tion 
  and 
  will 
  

   read 
  before 
  the 
  

   tion 
  in 
  our 
  report. 
  

  

  The 
  development 
  and 
  function 
  of 
  the 
  so-called 
  cyf 
  

   " 
  knees,'' 
  ivitk 
  • 
  - 
  -^ 
  -/ 
  -'-^ 
  

  

  tree: 
  W. 
  P. 
  

  

  of 
  the 
  

   Dr. 
  Wilson 
  has 
  for 
  several 
  years 
  

  

  been 
  investigating 
  this 
  subject, 
  both 
  by 
  means 
  of 
  numerous 
  

   cultures 
  and 
  by 
  the 
  examination 
  of 
  great 
  cypress 
  tracts 
  in 
  

   -t^lorida. 
  He 
  described 
  four 
  methods 
  by 
  which 
  the 
  " 
  knees" 
  

   aie 
  tormed, 
  and 
  demonstrated 
  that 
  their 
  formation 
  always 
  

   Had 
  to 
  do 
  with 
  the 
  presence 
  of 
  water, 
  so 
  that 
  they 
  could 
  be 
  

   pioduced 
  at 
  will 
  in 
  cultures. 
  The 
  cvpress 
  was 
  originally 
  a 
  

   aiy 
  ground 
  tree 
  and 
  this 
  structure 
  was 
  an 
  adaptation 
  to 
  a 
  

   watery 
  habitat. 
  The 
  "knees" 
  are 
  rapidiv 
  formed 
  in 
  the 
  

   presence 
  of 
  water, 
  and 
  gradually 
  rot 
  away 
  and 
  disappear 
  

   ^^hen 
  water 
  is 
  withdrawn. 
  A 
  large 
  and 
  Vecently 
  drained 
  

   cy 
  pi 
  ess 
  region 
  m 
  Florida 
  gave 
  the 
  author 
  manv 
  proofs 
  ot 
  

   f 
  r!n 
  f^}\^^ 
  between 
  the 
  presence 
  of 
  water 
  and^the 
  forma- 
  

  

  f 
  ^nrH. 
  /f^'- 
  ', 
  ^^ 
  '^^"^« 
  Clear 
  enough, 
  therefore, 
  that 
  the 
  

   tunction 
  of 
  the 
  "knees 
  " 
  is 
  the 
  aeration 
  of 
  the 
  root-structures, 
  

   sUdpf 
  ^^V^' 
  illustrated 
  by 
  a 
  series 
  of 
  photographiclantern 
  

   the 
  dp'vJ 
  presence 
  or 
  absence 
  of 
  water 
  not 
  only 
  affected 
  

   a 
  w^r 
  P^^^ 
  of 
  "knees," 
  but 
  the 
  wdiole 
  habit 
  of 
  the 
  tree 
  

   whl 
  in 
  ^',^^'>' 
  g*"«und 
  trees 
  are 
  tall 
  and 
  sparsely 
  branched, 
  

   wa 
  exroS-'' 
  f^"^' 
  ^'^ 
  ^^^^P^^t 
  and 
  flat-topped.' 
  The 
  paper 
  

   ^Z^^T.f^^^^^' 
  'f^'^^''^''^^ 
  and 
  bearing- 
  as 
  it 
  does 
  upon 
  a 
  

   t 
  wiTsoontP^'tr 
  f 
  ^J^^t' 
  't 
  i« 
  a 
  gratification 
  to 
  know 
  that 
  

   remarks 
  Lfn 
  P^.^J'^^e^ 
  and 
  amply 
  illustrated, 
  the 
  author 
  

  

  soS:^^^^:tllS^obt:ed" 
  '^-'^ 
  '" 
  ^ 
  bnef 
  summary 
  of 
  

  

  N. 
  iTwoT' 
  'tk 
  ''' 
  '^'' 
  Senus 
  Rhynchosfora 
  in 
  N- 
  M' 
  

   of 
  which 
  he 
  h^T/ 
  ''''^^^^ 
  outlined 
  the 
  grouping 
  of 
  species. 
  

  

  ^- 
  -mart: 
  by 
  aT^xhib^^^; 
  ^^^"""^^^ 
  ^^"^>^' 
  ^"^ 
  '^"' 
  

  

  -^ 
  '^^ 
  ^-"^hibit 
  of 
  specimens. 
  

  

  N. 
  l'bhSo4 
  ' 
  tT 
  ^""" 
  e/ 
  Vacciniacec. 
  from 
  BoU^ 
  

   group 
  of 
  eDinh..;~r^ 
  "^"^ 
  genus 
  belongs 
  to 
  the 
  remarka^' 
  

   them 
  an 
  fn 
  Ten^i'/^'"^'' 
  ^^^ 
  ^^ 
  ^ts 
  narrow 
  leaves 
  differs 
  fron^ 
  

  

  general 
  appearance. 
  

  

  