642- 
Report  on  Wheat-Mildew. 
Now  in  the  fen  country,  which  may  be  termed  the  natural 
home  of  mildew,  the  barberry  is  a scarce  tree,  and  it  is 
probably  only  to  be  found  in  a few  ornamental  gardens.  If  a 
single  tree  infects  a whole  field,  and  if  with  the  removal  of  that 
tree  the  disease  disappears,  might  we  not  expect  to  find  that 
districts  which  had  no  such  tree  would  at  least  enjoy  a partial 
immunity?  Instead  of  this,  they  are  peculiarly  susceptible 
to  the  disease.  Is  there  not  some  reason  to  suppose  that  some 
plant  other  than  the  barberry  is  capable  of  fulfilling  the  office  of 
a foster-parent,  or  that  the  fungus  can  maintain  life  for  more 
than  one  season  without  passing  through  that  stage  of  existence 
which  is  passed  on  the  barberry  ? There  seems  a reasonable 
probability  that  both  these  questions  may  be  answered  in  the 
affirmative.  A few  months  ago,  when  I asked  whether  any 
other  plant  could  supply  the  place  of  the  barberry,  I was  told 
that  it  was  exceedingly  improbable  ; that  all  the  different  species 
of  CEcidium  frequenting  English  plants  had  been  identified,  and 
that  it  was  very  unlikely  that  one  which  could  be  connected 
with  mildew  had  been  overlooked.  In  the  paper  to  which  I 
have  so  often  referred,  Mr.  Plowright  gave  a list  of  the  varieties  of 
barberry  on  which  the  CEcidium  of  Puccinia  graminis  is  found.* * 
Having  observed  in  1882  that  the  berries  of  Berberis  aqui- 
folium  (syn.  Mahonia  aquifolium — a variety  of  the  barberry  not 
included  in  the  list  referred  to)  on  some  shrubs  in  my  garden 
were  covered  with  a suspicious-looking  rust,  I mentioned  this  to 
Mr.  Plowright,  and  on  the  31st  of  May  1883, 1 supplied  him  with 
some  berries  which  appeared  to  me  to  be  infected  with  CEcidium. 
Upon  examination  they  were  found  to  be  covered  with  this 
rust.  A wheat-plant  grown  in  water,  under  glass,  in  Mr. 
Plowright’s  study,  was  infected  from  one  of  these  berries,  and 
on  the  19th  of  June  he  sent  me  a portion  of  the  plant  with  well- 
developed  Uredo  linearis  upon  it.  Later  on  I found  specimens 
of  the  same  rust  on  the  leaf  and  leaf-stalk  of  the  Mahonia.  Now 
hedge  by  the  side  of  the  Paris  and  Lyons  Railway,  ■which  was  said  to  have  pro- 
duced mildew,  and  the  removal  of  a portion  of  it  (1  kilometre  in  length)  was  so 
beneficial  that  “ the  whole  hedge  was  then  removed  and  the  disease  disappeared  ” 
(Rev.  J.  Du  Port,  ‘On  the  Fungoid  Diseases  of  Cereals,’  Transactions  of  tho 
Norfolk  and  Norwich  Naturalists’  Society,  1880). 
* The  following  is  the  list : — 
Berberis  vulgaris.  B.  Aristala. 
„ ilicifolia.  „ amarensis. 
„ canadensis.  „ atropurpurea. 
„ nepalensis.  Mahonia 1 glauca. 
1 (In  Loudon’s  Encyclopedia  of  trees  and  shrubs,  1842,  this  variety  is  classed  in  the 
Berberis  subdivision  (as  distinguished  from  the  Mahonia)  under  the  name  of  Berberis 
dealbatu. — W.  C.  L.) 
