﻿1890,] 
  BOTANICAL 
  GAZETTE. 
  32 
  1 
  

  

  for 
  the 
  growth 
  of 
  the 
  mildew 
  than 
  the 
  ordinary 
  stem 
  or 
  leaf. 
  

   The 
  same 
  mildew 
  has 
  been 
  common 
  upon 
  the 
  Ampelopsis 
  

   tricuspidata, 
  causing 
  the 
  portions 
  of 
  the 
  attached 
  leaves 
  to 
  

   turn 
  a 
  rich 
  red 
  upon 
  the 
  upper 
  side 
  as 
  if 
  prematurely 
  

   ripening. 
  While 
  at 
  Liberty, 
  New 
  York, 
  the 
  Plasmopara 
  

   was 
  found 
  in 
  abundance 
  upon 
  a 
  cultivated 
  plant 
  of 
  Ampe- 
  

   lopsis 
  quinquefolia 
  growing 
  upon 
  a 
  trellis 
  with 
  no 
  grapevines 
  

   or 
  other 
  Virginia 
  creeper 
  plants 
  within 
  a 
  long 
  distance. 
  No 
  

   signs^ 
  of 
  the 
  mildew 
  were 
  upon 
  the 
  fruit. 
  A 
  few 
  plants 
  

   growing 
  upon 
  the 
  ground 
  in 
  a 
  wood 
  lot 
  at 
  Cold 
  Spring 
  Har 
  

   bor, 
  Long 
  Island, 
  had 
  nearlj^ 
  every 
  leaf 
  attacked, 
  and 
  here 
  

   as 
  noted 
  for 
  the 
  A. 
  tricusoidata 
  the 
  foliage 
  had 
  turned 
  in 
  

  

  Jul} 
  

  

  The 
  coloration 
  was 
  

  

  so 
  strong 
  and 
  constant 
  that 
  it 
  served 
  as 
  a 
  guide 
  in 
  collecting 
  

   specimens. 
  

  

  Abundant 
  specimens 
  of 
  Plasmopara 
  eniosfora 
  Schroet. 
  

   were 
  found 
  in 
  early 
  May 
  upon 
  ErJgeron 
  Canadense, 
  which 
  

   was 
  the 
  first 
  time 
  the 
  writer 
  had 
  succeeded 
  in 
  taking 
  this 
  

   pecuhar 
  and 
  abbreviated 
  species. 
  

  

  Plasmopara 
  Geranli 
  (Pk.) 
  Bed. 
  is 
  becoming 
  the 
  most 
  

   common 
  species 
  in 
  the 
  vicinity 
  of 
  New 
  Brunswick, 
  especially 
  

   upon 
  the 
  Geranium 
  Carolinianum, 
  which 
  it 
  covers 
  in 
  early 
  

   spring. 
  It 
  establishes 
  itself 
  upon 
  the 
  seedlings 
  of 
  this 
  winter 
  

   annual 
  in 
  late 
  autumn. 
  No 
  oospores 
  seem 
  to 
  form 
  in 
  this 
  

   host 
  and 
  there 
  is 
  no 
  particular 
  reason 
  for 
  their 
  presence 
  as 
  

   |he 
  mildew 
  passes 
  the 
  winter 
  in 
  the 
  tissue 
  of 
  the 
  host 
  which 
  

   IS 
  better 
  than 
  in 
  the 
  form 
  of 
  oospores. 
  

  

  Bremia 
  Lactuas 
  Regel 
  (Peronospora 
  gangliformisD 
  By.) 
  

   \vas 
  abundant 
  upon 
  Lactuca 
  Canadensis 
  in 
  some 
  parts 
  of 
  the 
  

   state, 
  and 
  weakened 
  materially 
  the 
  vigor 
  if 
  not 
  shortened 
  the 
  

   ^"e 
  of 
  this 
  weed. 
  However, 
  in 
  the 
  greenhouses 
  it 
  worked 
  

   some 
  damage 
  to 
  the 
  lettuce 
  crop 
  during 
  the 
  winter 
  months. 
  

  

  Peronospora 
  -parasitica 
  D'By. 
  has 
  a 
  list 
  of 
  a 
  score 
  ot 
  

   '^osts 
  all 
  in 
  the 
  same 
  order 
  (Crucifer^). 
  It 
  was 
  found 
  in 
  

   early 
  spring 
  particularly 
  abundant 
  upon 
  Cardamme 
  hirsuta 
  

   ?nd 
  C. 
  laciniata. 
  On 
  May 
  17th, 
  it 
  was 
  met 
  with 
  upon 
  the 
  

   eaves 
  of 
  Hesperis 
  matronalis 
  and 
  several 
  times 
  afterwards 
  

   ^Pon 
  the 
  same 
  host, 
  which 
  as 
  far 
  as 
  determined 
  is 
  a 
  new 
  one 
  

   ^0 
  America. 
  In 
  like 
  manner 
  on 
  June 
  4th 
  it 
  was 
  taken 
  upon 
  

   ™any 
  of 
  the 
  outer 
  leaves 
  of 
  the 
  common 
  cabbage. 
  iNo 
  

   Sr'''^ 
  of 
  this 
  host 
  is 
  made 
  by 
  American 
  writers 
  upon 
  the 
  

  

  tn 
  ^^''"'"'^^pora 
  ViolcB 
  D'By. 
  did 
  not 
  prove 
  so 
  destructive 
  

   ;o 
  the 
  cultivated 
  violets 
  as 
  was 
  feared 
  last 
  winter, 
  andcli.- 
  

   ^^sed 
  plants 
  from 
  several 
  greenhouses 
  fail 
  now 
  to 
  conhrm 
  

  

  