﻿172 
  BOTANICAL 
  GAZETTE. 
  [J^l}'? 
  

  

  a 
  glairy 
  fluid 
  exuding 
  from 
  the 
  tips 
  of 
  vigorous 
  hypha^, 
  and 
  

   I 
  have 
  studied 
  this 
  same 
  Botrytis 
  growing 
  upon 
  Lilium 
  lon- 
  

   giflorum 
  and 
  have 
  observed 
  the 
  same 
  phenomena. 
  

  

  Last 
  autumn 
  mv 
  attention 
  was 
  called 
  to 
  a 
  rot 
  of 
  the 
  sweet 
  

   potato 
  in 
  which 
  Rhizopus 
  nigricans 
  (Mucor 
  stolonifer) 
  was 
  

   present 
  ; 
  yet 
  if 
  spores 
  of 
  this 
  fungus 
  were 
  sown 
  upon 
  a 
  sHce 
  

   of 
  healthy 
  sweet 
  potato 
  the}' 
  produced 
  no 
  effect, 
  the 
  spores 
  

   not 
  even 
  germinating 
  ; 
  while 
  if 
  a 
  bit 
  of 
  the 
  mycelium 
  were 
  

   placed 
  in 
  a 
  similar 
  position, 
  rapid 
  growth 
  of 
  the 
  fungus 
  and 
  

   decomposition 
  of 
  the 
  potato 
  followed. 
  If 
  the 
  slice 
  had 
  been 
  

   previously 
  killed 
  by 
  boiling, 
  the 
  spores 
  germinated 
  readily, 
  

   producing 
  the 
  same 
  results 
  as 
  the 
  bit 
  of 
  mycelium. 
  Rhizo- 
  

   pus 
  behaves 
  in 
  the 
  same 
  way 
  in 
  cultures 
  made 
  upon 
  Irish 
  po- 
  

   tatoes, 
  beets, 
  turnips, 
  carrots, 
  apples, 
  pears, 
  and 
  quinces. 
  

   De 
  Bary 
  remarked 
  this 
  peculiarity 
  in 
  Sclerotinia, 
  and 
  thought 
  

   that 
  it 
  was 
  due 
  to 
  the 
  fact 
  that 
  the 
  fungus 
  required 
  to 
  be 
  

   nourished 
  as 
  a 
  saprophyte 
  in 
  order 
  to 
  become 
  facultative 
  as 
  

   a 
  parasite. 
  The 
  habit 
  of 
  the 
  Botrvtis 
  of 
  the 
  lilv 
  disease 
  is 
  

   shghtly 
  different. 
  Its 
  spores 
  germinate 
  readilv 
  in 
  a 
  drop 
  d 
  

   distilled 
  water 
  if 
  the 
  temperature 
  be 
  f^worable,'' 
  but 
  then 
  they 
  

   are 
  large 
  and 
  contain 
  considerable 
  reserve 
  material 
  stored 
  

   in 
  them 
  ; 
  while 
  the 
  conidia 
  of 
  the 
  before-mentioned 
  fungi 
  are 
  

   small 
  and 
  require 
  external 
  nourishment 
  in 
  order 
  to 
  be 
  able 
  

  

  to 
  grow. 
  

  

  The 
  following 
  experiment 
  illustrates 
  this 
  point, 
  and 
  also 
  

   connects 
  the 
  Rhizopus 
  definitely 
  watb 
  the 
  origin 
  of 
  the 
  dis- 
  

   ease. 
  A 
  hanging 
  drop 
  culture 
  of 
  Rhizonus 
  was 
  made 
  in 
  a 
  

  

  drop 
  of 
  ste 
  

   freely. 
  When 
  

  

  trom 
  which 
  the 
  drop 
  depended 
  was 
  inverted 
  and 
  placed 
  in 
  the 
  

   middle 
  of 
  a 
  slice 
  of 
  healthy 
  sweet 
  potato. 
  This 
  w^as 
  left 
  over 
  

   night, 
  and 
  in 
  the 
  morning 
  it 
  was 
  found 
  that 
  the 
  hyphae 
  were 
  

   leachmg 
  oyer 
  the 
  edge 
  of 
  the 
  coverslip 
  and 
  producing 
  decay 
  

   wherever 
  they 
  touched. 
  . 
  ^ 
  ^ 
  

  

  As 
  De 
  Bary 
  found 
  with 
  Sclerotinia 
  that 
  the 
  liquid 
  

  

  Rhizopus 
  

  

  Slil 
  "^""f 
  ?^i 
  f'""" 
  ^ 
  thoroughlv 
  rotten 
  potato 
  and 
  filtered- 
  

   soon 
  l^^^^i% 
  yegetable 
  tissue 
  immersed 
  in 
  this 
  fluid 
  were 
  

   mad/fii?"- 
  ''''.^ 
  .'"^'"P'^^^d. 
  Other 
  experiments 
  were 
  

   rmh;b 
  r""^ 
  the 
  iquid 
  through 
  a 
  porcelain 
  filter, 
  and 
  (to 
  

   entnel^^ 
  ehmmate 
  the 
  chance 
  of 
  bacterial 
  action) 
  adding 
  a 
  

  

  drnnofo 
  •• 
  '""^^^^o* 
  bacterial 
  action) 
  aaaiu^ 
  - 
  

  

  ?!:^Llf5!I^!lXi!!^bli^^ 
  3^,,,,, 
  of 
  the 
  liquid. 
  The 
  

  

  ' 
  ""''"^^^^^^^^^^^^^^^^^^^^^^^ 
  Jan.. 
  1890. 
  '^ 
  

  

  