451 
November  13,  1902. 
JOURNAL  OF  HORTICULTURE  A  XD  COTTAGE  GARDENER. 
Societies. 
R.H.S.,  Scientific  Commitee,  Noy.  4'h. 
Present:  Dr.  M.  T.  Masters,  in  the  chair ;  Messrs.  Worsley, 
Baker,  Michael,  Saunders,  Bowles,  Odell,  and  Hooper;  Drs. 
Rendle  and  Cooke;  Rev.  G.  Henslow,  Hon.  See. 
Er<iut,  V revalence  of. — Mr.  Hooper  observed  that  this  disease 
was  particularly  abundant  this  season,  and  exhibited  specimens 
in  Cocksfoot  and  Rye  Grass.  It  generally  is  frequent  in  wet 
autumns. 
Apple  Trees  in  Blossom. — He  also  referred  to  the  occurrence 
of  flowers  on  Apple  trees,  a  fact,  elsewhere  noted  in  the  papers, 
due  to  the  mildness  of  the  weather.  Dr.  Masters  observed  that 
when  such  flowers  occurred  on  spurs,  they  were  dissociating  next 
year’s  buds;  but  on  terminal  shorts  they  were  additional  growths. 
Tomatoes  and  Bordeaux  Mixture. — He  also  called  attention  to 
the  advantage  of  using  this  fungicide,  which  were  shown  by  out¬ 
door  Tomatoes  having  completely  failed  when  left  to  themselves; 
but  those  sprayed  bore  at  least  half  a  crop  this  autumn. 
Crocus ,  taic  car. — Mr.  Bowles  showed  a  blossom  of  C.  speciosus 
var.  Aitchisoni,  which  bore  a  fine  pale-coloured  flower;  the 
country  was  not  known  whence  it  was  received. 
Cypripedium  Malformed. — Mr.  Saunders  showed  a  drawing  of 
a  flower  having  the  labellum  erect  and  one  additional  petal. 
Dr.  Masters  undertook  to  add  further  details. 
Apple  Leaf  Black  Mould. — Dr.  M.  C'.  Cooke  reported  as  follows 
upon  the  Apple  leaves  submitted  for  examination  :  “  They  were 
badly  diseased  with  the  attack  of  a  black  mould  new  to  the 
British  Isles.  The  leaves  were  dead  or  dying  at  the  ends  of  the 
branches,  and  the  under  surface  sprinkled  on  the  dead  parts 
with  black  dots,  which  proved  to  be  the  tufts  of  eonidia  pro¬ 
duced  by  Coniothecium  Ouestieri  (Desm),  which  was  found  and 
described  in  France  in  1857  on  leaves  c-f  Cornus  sanguinea.  The 
eonidia  are  brown,  very  variable  both  in  form  and  size,  and 
muriformly  septate,  clustered  in  glomerules,  and  mixed  with  a 
few  slender  threads.  This  parasite  has  appeared  so  seldom  that 
no  experiments  have  been  made  upon  it,  but  it  is  recommended 
to  strip  off  and  burn,  and  sweep  from  the  ground  all  fallen  leaves, 
so  as  to  prevent  the  diffusion  of  the  pest.  Even  when  this  is 
done,  if  there  is  any  foliage  left,  it  should  be  sprayed  with  one 
of  the  copper  solutions  to  destroy  the  germinating  powers  of 
the  eonidia.” 
Flax  Wilt- — Dr.  Cooke  communicated  the  following  paper  : 
“  Since  the  last  meeting  of  the  Committee  I  have  learnt  that 
experiments  have  been  undertaken  in  the  N.  Dakota  experi¬ 
mental  station  (bulletin  No.  50)  to  ascertain  the  cause  of  the 
disease  known  as  ‘Flax  wilt’  and  ‘Flax  sick  soil,’  a  disease 
which  appears  to  be  known  in  Ireland,  as  well  as  in  Belgium, 
Germany,  and  other  Flax-producing  countries  of  Europe.  I 
may  premise  that  it  has  long  been  known  that  Flax  cannot  be 
grown  continuously  for  any  long  period  upon  the  §ame  soil, 
because  then  the  soil  becomes  ‘sick’  and  the  Flax  seedlings 
die  off  and  do  not  produce  a  crop.  The  cause  of  this  has  hitherto 
been  a  mystery,  mostly  attributed  to  the  exhaustion  of  the 
soil.  The  result  of  these  experiments  appears  to  be,  not  the 
exhaustion  of  any  of  the  chemical  constituents  of  the  soil,  but 
the  prevalence  of  a  minute  fungus  in  the  soil,  which  preys  upon 
the  debris  of  the  previous  year’s  crop,  and  attacks  the  young 
seedlings  of  the  new  year,  causing  them  to  wilt  and  die.  ,  The 
name  of  this  new  fungus  is  Fusarium  lini.  Apart  from  the  eluci¬ 
dation  of  this  particular  disease,  I  think  that  the  subject  must 
be  of  interest  to  this  committee,  since  there  is  no  reason  for 
supposing  that  this  is  a  solitary  instance  of  the  phenomenon, 
and  that  other  cases  of  failure  in  successive  crops,  and  of  the 
wilting  of  seedlings,  may  possibly  be  due,  in  like  manner,  to  the 
presence  of  fungus  mycelium  and  eonidia  in  the  soil,  so  difficult 
to  determine,  and  sometimes  attributed  to  exhaustion  of  the 
soil.  The  methods  adopted  in  this  instance  may  serve  as  a  guide 
to  the  course  to  be  pursued  in  similar  instances,  and  although 
they  may  entail  considerable  labour,  appear  to  offer  an  adequate 
reward.  At  any  rate,  this  communication  justifies  the  action  of 
the  Department  of  Agriculture  of  the  United  States  in  estab¬ 
lishing  experiment  stations,  where  these  problems  may  be  solved 
at  the  expense  of  the  State.  In  the  present  case  it  is  recom¬ 
mended  that  cultivators  should  cease  growing  Flax  year  after 
year  upon  the  same  land,  and  that  at  least  three  other  crops 
should  intervene  between  Flax  crops:  and  that  as  much  of  the 
old  Flax  straw  and  stubble  as  possible  which  remains  on  the 
ground  should  be  burnt  forthwith,  and  that  the  Flax  seed,  before 
sowing,  should  be  cleaned  and  treated  with  formaldehyde,  accord¬ 
ing  to  instructions.” 
Tumour  of  Potato  Tubers. — Dr.  Cooke  supplied  the  following 
additional  facts  upon  this  disease,  lately  reported  upon  :  “  It 
was  attributed  to  a  newly  described  fungus  under  the  name  of 
Chrysophlyctis  endobiotica.  Although  at  the  time  I  advocated 
its  decided  affinity  to  the  tumour  of  Beetroot.  More  recently 
specimens  have  been  sent  to  Berlin,  with  the  result  that  Dr. 
Magnus  has  not  only  confirmed  this  affinity,  but  has  demon¬ 
strated  that  it  is  the  same  species,  which  is  known  as  CEdomyces 
leproides  (Trabut),  so  that  the  ‘  Beetroot  tumour  ’  and  the 
'  Potato  tumour  ’  are  caused  by  the  same  fungus.  This  should 
be  noticed,  since  the  form  on  Potatoes  has  for  two  years  been 
destructive  in  several  localities  in  the  British  Isles,  and  is  quite 
capable  of  infesting  Beetroot  in  like  manner.” 
Iris  Black  Mould. — Dr.  Cooke  also  reports  upon  diseased  Irises 
sent  to  the  Committee  :  “  Since  the  last'  meeting  a  plant  of  Iris 
ochroleuca  has  been  submitted  to  me  for  examination.  The 
roots  were  in  a  perfectly  sound  condition,  but  the  leaves  were 
affected  in  a  similar  manner  to  those  of  other  specimens  sent  to 
the  Committee  recently,  and  of  which  I  find  no  record  in  the 
reports  of  our  meetings.  As  this  disease  is  apparently  common, 
it  is  advisable  that  some  allusion  should  be  made  to  it  for  refer¬ 
ence  on  a  future  occasion.  The  leaves  turn  yellow  and  sickly, 
and  then  brown,  dying  towards  the  tips.  Upon  these  brown 
patches  occur  sooty  or  blackish  spots,  often  of  considerable 
extent,  rather  velvety  under  a  lens;  which  manifest  the  appear¬ 
ance  of  a  black  mould  (Heterosporium).  The  tissue  beneath  is 
permeated  by  mycelium,  and  the  mouldy  spots  are  often  an 
inch  or  more  in  length,  occasionally  bounded  by  a  darker  line. 
The  threads,  or  eonidiophores,  are  erect,  brown,  septate,  nodu- 
’ost,  often  flexuous,  and  of  an  olive  colour  (70  —  90  X  10  -  14 
At  the  apex,  or  laterally,  the  eonidia  are  produced,  either  singly 
cr  two  or  more  together,  and  are  large,  elliptical  or  oblong,  with 
from  one  to  three  septa,  or  cross  divisions,  with  the  ends  obtuse 
or  rounded.  The  whole  surface  is  granular,  or  warted,  and  of  a 
1  a’e  olive  colour  (35  -  70  x  14  —  20  ^  .  When  mature 
these  eonidia  are  capable  of  germination  from  each  individual 
cell,  so  that  each  conidium  may  be  regarded  as  compound,  and 
equivalent  in  reproductive  power  to  as  many  eonidia  as  there 
are  cells  in  the  original  conidium.  It  occurs  on  the  leaves  of 
Iris,  Freesia.  Antholyza,  and  Hemerocallis,  and  is  known,  not 
only  in  Europe,  but-  at  the  Cape,  New  Zealand,  and  the  United 
States  of  America ;  and  will  be  found  described  in  Massee’s 
‘  Plant  'Diseases,’  pages  321  and  440,  and  figured  in  this  Journal 
on  plate  v..  fig.  90.  Spraying  with  potassium  sulphide  is  reported 
to  check  the  disease,  and  all  diseased  leaves  should  be  cut  off  and 
burnt.  If  these  precautions  are  attended  to,  and  the  foliage  is 
not  watered,  the  disease  may  be  controlled.  Also  spraying  with 
ammoniacal  copper  solution  checks  the  disease,  after  clearing 
away  diseased  leaves.” 
Crabs  with  Sedums. — Mr.  Saunders  reported  as  follows  on 
some  specimens  sent  by  Mr.  Maynard,  Wymondham,  Norfolk  : 
“  The  grubs  sent  with  the  enclosed  letter  are  the  grubs  of  one 
of  the  weevils,  either  the  black  Vine  weevil  (Otiorhynchus  sul- 
catus)  or  the  clay-coloured  weevil  (O.  picipes),  but  the  grubs 
of  these  species  are  so  much  alike  that  it  is  almost  impossible 
to  tell  them  apart.  However,  as  the  life  history  of  both  is 
exactly  the  same,  it  does  not  make  much  difference,  from  a  cul¬ 
tivator’s  point  of  view.  The  parent  weevils  lay  their  eggs  at 
the  roots  of  various  soft-rooted  plants,  Sedums,  Primulas,  Be¬ 
gonias,  Cyclamens,  and  Ferns  being  great  favourites.  The 
weevils  themselves  are  also  very  destructive  to  the  foliage  and 
tender  shoots  of  Vines  and  many  other  plants,  particularly  Ferns 
and  Dracaenas.  I  do  not  know  of  any  means  of  killing  the  grubs  but 
picking  them  out  from  among  the  roots.  Any  insecticide  that 
would  kill  the  grubs  would  certainly  be  equally  .destructive  to 
the  plant.  The  beetles  are  not  often  seen,  as  they  feed  at  night 
and  hide  themselves  very  carefully  during  the  day.  They  may 
be  caught  by  putting  a  white  cloth  under  the  plant  that  they  are 
attacking  before  it  becomes  dark.  If  the  plant  is  in  a  pot  it  is 
better,  if  possible,  to  lay  it  on  its  side;  then,  after  it  has  been 
dark  for  an  hour  or  so,  throw  a  strong  light  suddenly  upon  the 
plant.  This  will  generally  cause  the  weevils  to  fall  off,  when 
they  will  easily  be  seen  on  the  cloth  ;  if  they  do  not  fall,  give 
them  a  jarring  shake,  and  search  it  well.  Small  bundles  of  dry 
moss  or  hay  make  good  traps  ;  they  should  be  laid  on  the  soil 
in  pots  near  the  stems  of  the  plants,  or,  in  the  case  of  creepers, 
tied  on  to  the  stems  or  shoots,  so  that  when  the  weevils  are  seek¬ 
ing  shelter  they  should  find  one  close  at  hand.  These  traps 
should  be  examined  every  morning.  These  weevils  are  either 
black,  and  about  half  an  inch  in  length,  or  of  a  dull,  pale,  yel¬ 
lowish-brown  colour,  and  about  a  quarter  of  an  inch  in  length, 
according  to-  the  species.”  A  vote  of  thanks  was  recorded  to 
Dr.  Cooke  and  Mr.  Sanders  for  their  valuable  papers. 
Partial  Separation  of  Parental  Characters  in  a  Hybrid 
Orchid.- — Mr.  Hurst  sent  a  flower  with  the  following  communi¬ 
cation  :  “  A  plant  of  Paphiopedilum  x  Canhami  (P.  superbiens  x 
P.  villosum),  which  hitherto  has  always  produced  normal  flowers 
with  me,  has  now  produced  the  curious  flower  exhibited.  One 
side  of  the  lip  or  slipper  is  normal  in  colour,  being  evidently  a 
fair  blend  between  the  parent  species.  The  other  side  of  the 
lip  may  be  divided  into  three  distinct  areas:  (1)  a  narrow  band 
of  rich  brown  purple,  as  in  the  parent  P.  superbiens;  (2)  a  broad 
band  of  greenish  yellow,  as  in  the  parent  P.  villosum;  (3)  the 
remainder  of  the  lin  being  a  normal  blend  between  the  two 
parents.  We  have  here  evidently  a  partial  separation  of  the 
mixed  ‘  blood  ’  of  the  parent  species,  the  result  being  a  mosaic 
rather  than  a  blend.  It  is  interesting  to  note  that  the  hairs 
within  the  lip  are  sharply  separated,  as  in  the  colour,  and  there 
is  also  a  slight  tendency  to  separation  in  the  colour  of  the  dorsal 
sepal  and  the  petals.  Whether  this  partial  ‘sport’  will  prove 
permanent  remains  to  be  seen,  though  it  is  not  very  likely.  We 
