October  21,  1897. 
JOURNAL  OF  HORTICULTURE  AND  COTTAGE  GARDENER. 
381 
highly  fed  has  invited  disease,  but  the  parasite  did  not  begin  on  the  fine 
leaves,  but  on  the  weaker  from  the  Eoyal  county.  See  its  fac- simile  at  L, 
under  side  of  the  leaf,  natural  size.  It  is  just  half  the  size  of  the  leaf  of 
the  specimen  from  Somerset  and  from  Kent.  One  has  leaves  little  thicker 
thao  ordinary  writing  paper,  and  the  other  stout,  elastic,  strong,  and 
tenacious  as  shoe  leather.  So  much  for  robustness  as  the  predis)iosing 
cause  of  attack. 
The  fungus.  Chrysanthemum  ieaf-nist  (Trichobasis  chrysanthemi), 
produces  dark  brown  pustules  on  the  under  side  of  the  leaves  of  the 
Chrysanthemum  sinense  vars.  (most  on  the  Incurved  sections),  as  shown 
at  L,  some  small  (y),  others  larger  (A)  and  isolated,  not  a  few  in 
groups  (0,  and  often  becoming  confluent  (to).  The  jmstules  contain  a 
number  of  spores  (if),  very  dark  brown  or  nearly  black,  echinulate 
(very  short  bristles),  with  always  one  (n)  transparent  spot,  sometimes 
two  (o),  free,  attached  at  first  by  a  short  peduncle  {p),  and  caducous 
(spores  falling  very  early).  In  some  cases  the  spores  are,  or  appear, 
concatenate  (chained),  as  shown  at  q.  All  the  spores  are  uredo,  or 
summer  ;  at  least,  I  only  found  the  miserable  apology  for  a  teleiitospore 
(shown  at  r)  on  August  26th,  1897. 
These  uredo  or  summer  spores  germinate  at  once  on  a  clean,  healthy 
leaf  of  a  Chrysanthemum  (almost  every  one  on  the  under  side)  with  the 
greatest  freedom  in  presence  of  moisture,  but  seem  baffled  on  the  upper 
side  of  the  leaf,  either  by  the  sunlight  or  dryness.  Some  spores  there  do 
not  even  attempt  to  grow,  but  appear  to  thicken  their  outer  coat, 
becoming  as  if  warted,  and  losing  the  transparent  spot,  getting  round,  and 
apparently  capable  of  retaining  vitality  for  a  considerable  time.  I  have 
some  collected  on  August  26th  now  (October  11th)  quite  sound,  and  these, 
when  placed  on  the  leaves  from  Somerset  with  a  little  moisture  on  them, 
pushed  germinal  tubes  and  bored  right  into  the  leaves  without  the  least 
difficul  ty. 
The  effect  of  the  entrance  into  the  leaves  of  the  germinal  tubes  of  the 
fungus  spoi’es  is  to  produce  the  pustules  before  mentioned  on  the  under 
side,  these  being  at  first  pale  green,  then  yellowish,  afterwards  light 
brown,  getting  darker  as  the  sjmres  form,  and  growing  outwards  push 
through  the  destroyed  epidermis.  The  germinal  tube  once  inside  the 
tissues  divides,  forming  mycelium  hyphm  very  densely,  which  push  in 
the  intercellular  spaces  of  the  cells,  abstract  their  contents,  and  take 
their  place.  The  hyphse  form  a  perfect  net  of  threads,  and  push  out 
growths  so  plenteously  as  to  render  the  spores  very  crowded,  sipieezing 
each  other  into  odd  shapes,  the  younger  pushing  off  the  heads  of  the 
older  in  order  to  take  their  place.  Thus  the  spores  are  shed  in  myriads, 
and  it  is  only  a  question  of  a  Chrysanthemum  leaf  being  seized  for  the 
work  in  new  generations  to  proceed  with  astounding  rapidity. 
The  effect  is  to  destroy  the  lower  substance  of  the  leaf  to  the  extent 
of  the  pustules,  such  leaves  becoming  brown  and  dying  more  or  less  as 
the  tissues  are  affected  right  through,  pale  spots  appearing  on  the  upper 
surface,  as  shown  in  part  of  a  leaf  at  N,  these  being  at  first  pale  green, 
afterwards  yellow,  and  then  brown.  The  plants  are  weakened  in  conse¬ 
quence  of  the  attack,  and  if  the  parasite  is  left  to  run  its  course  unchecked 
they  may  be  ruined. 
How  the  teleutospores  behave  I  do  not  know  ;  but  as  gardeners  cut 
off  the  old  Chrysanthemum  stems  in  good  time  to  get  strong  suckers,  by 
burning  these  stems  the  resting  spores  are  consumed.  There  are  very 
few  of  them.  The  fungus  can,  however,  be  continued  without  them.  The 
uredo  form  of  many  Tuccinia  certainly  lives,  especially  on  IMugworts  and 
on  Thistles,  over  the  winter,  and  is  more  likely  to  do  so  on  Chrys¬ 
anthemums  protected  from  frost,  which  means  that  the  uredo  stage  of 
the  fungus  may  live  on  the  cuttings. 
This  brings  us  to  the  question  of  battling  with  the  foe.  Kill  the  spores. 
Badly  infested  plants  should  be  burned,  and  others  syringed  from  tip  to  toe 
with  sulphide  of  potassium,  J  oz.  to  a  gallon  of  water,  or  permanganate  of 
potash,  1  oz.  to  3  gallons  of  water,  laying  the  plants  on  their  sides,  and 
doing  the  woi’k  thoroughly,  so  as  not  to  leave  a  spore  uni-eached.  The 
suphide  smells  nauseously,  and  discolours  paint  ;  the  permanganate  dis¬ 
colours  the  flowers. 
Bordeaux  mixture  at  quarter  strength  should  also  be  mentioned  as  a 
preventive  and  remedy  in  early  stages  of  attack  ;  sulphate  of  copper, 
lb.  :  best  chalk  lime,  freshly  burned,  light  lumps,  lb.  ;  water, 
22  gallons.  Dissolve  the  sulphate  in  I  gallon  of  cold  water  in  a  tub 
or  earthen  vessel.  Slake  the  lime  in  another  in  a  gallon  of  water,  and 
when  cold  pour  through  a  coarse  bag  into  the  sul[)hate  of  copper  solution 
slowly;  stir,  then  add  the  remainder  of  the  water.  Apply  with  a  spraying 
apparatus,  wetting  the  under  side  of  the  leaves  particularly,  but  all  parts 
of  the  plant.  It  will  kill  the  spores  on  whichjt  rests  and  enter  the  open 
pustules,  but  not  those  unruptured,  therefore  repeat  occasionally.  It  is 
a  mild  and  safe  application. 
There  is  the  question  of  cuttings.  To  make  sure  they  are  clean  dip 
them  before  insertion  in  the  weak  Bordeaux  mixture  advised.  This  will 
coat  them  with  a  thin  film  of  the  poison,  and  while  there  no  fungus  can 
push  its  germinal  tube  and  take  possession  of  the  leaves.  “  What  a 
bother,”  some  will  say.  Well,  the  enemy  has  come,  and  should  be  con¬ 
quered.  The  advertised  fungicides  containing  sulphate  of  copper  can  always 
be  had.  Use  them  in  good  time,  and  repeatedly,  and  their  value  will  be 
proved  in  vanquishing  this  insidious  enemy  of  the  Chrysanthemum — 
G.  Abbey. 
Specimens  of  diseased  Chrysanthemum  leaves  were  recently  sub¬ 
mitted  by  a  New  .lersey  florist  to  Dr.  llalsted  for  examination  and  advice 
as  to  the  course  of  treatment  to  be  pursued.  His  reply  is  as  follows  :  — 
“1'here  is  a  genuine  rust  upon  the  cultivated  Chrysanthemum  sent  by 
the  correspondent,  and  it  probably  is  the  Puccinia  tanaceti,  71.(7.  There 
is  doubt  as  to  the  species,  because  only  the  uredospores  have  been  found 
upon  the  leaves  examined,  but  these  agree  in  size  and  shape  with  those  of 
P.  tanaceti,  and  furthermore  this  species  is  found  upon  a  species  of 
Chrysanthemum  as  shown  by  an  herbarium  specimen. 
“  The  florist  has  written  me  that  he  may  lose  his  whole  crop  from  this 
rust.  It  appears  upon  the  foliage  in  small  brown  s]iots,  which  consist  of 
hea]>s  of  spores  borne  upon  the  tips  of  threads  that  have  pushed  through 
the  skin  of  the  leaf.  The  Carnation  rust  is  not  unlike  this  in  general 
appearance,  but  the  final  spores  are  very  different,  provided  the 
Chrysanthemum  rust  proves  to  be  as  suspected. 
“  Growers  of  Chrysanthemums  should  look  to  their  plants,  and  if  any 
find  the  rust  it  ought  to  be  dealt  with  summarily,  for  the  enemy  is  a 
serious  one.  The  rust  fungus  sends  its  threads  all  through  the  plant 
before  the  spores  are  produced,  and  therefore  spraying  may  not  prove  a 
Fig.  57.  —  Chrysanthemum  Leae-rust  Fungus  [Trichobasis 
(Uredo)  Chrysanthemi,  with  final  stage  —  Puccinia 
CHRYSANTHEMiE,  AND  OTHER  IIUSTS,] 
References. — A,  Part  of  affected  leaf  of  Chrysanthemum  (October  9th) ; 
a,  small  pustules  of  fungus;  b,  pustules  confluent  or  run  together.  B, 
Trichobasis  (Uredo)  Chrysanthemi  spores  ;  c,  usual  form  ;  d,  concatenate 
type.  (7,  summer  spore  germinating ;  e,  germinal  tube.  1),  teleuto- 
spore  found  in  first  pustule  examined.  E,  mature  teleutospore  =  Puccinia 
Chrysanthemm.  F,  young  leaf  of  Artemisia  vulgaris  (October  9th), 
showing  ;  /,  small  pustules  ;  g,  pustules  become  confluent  or  run  together. 
(?,  uredospores  =  Trichobasis  (Uredo)  Artemisia?.  E,  teleutospore  = 
Puccinia  Artemisiic.  J,  small  leaf  of  Carduus  vulgaris;  h,  pustules  of 
-  root  fungus;  «,  pustules  confluent.  J,  uredospores  =  Trichobasis  (Uredo) 
Cichoracearum  or  Heraclei.  K,  teleutospore  =  Puccinia  Cichoracearum. 
L,  Chrysanthemum  leaf  (August  26th)?  j,  small  pustules;  A,  large 
pustules  isolated  ;  7,  clustered  pustules  ;  to,  pustules  confluent.  31,  uredo¬ 
spores  from  pustule  ;  n,  spores  with  transparent  spot  in  centre ;  o,  spores 
with  two  spots ;  p,  spore  on  peduncle ;  r,  miniature  teleutospore,  the 
uredospore  =  Trichobasis  (Uredo)  Chrysanthemi.  W,  part  leaf  of  Chrys¬ 
anthemum,  showing  spots  on  upper  surface,  and  corresponding  to  pustules 
on  the  under  side.  All  the  leaves  or  parts  natural  size,  and  all  the  fungi 
enlarged  260  diameters. 
satisfactory  remedy  for  it.  All  affected  leaves  should  be  picked  off  and 
burned. — Byron  D.  IIalsted,  Experiment  Station,  New  Brunswick, 
N.J."  (in  “  American  Gardening.”) 
[As  will  be  seen  by  the  above  record,  attention  was  first  called  to  the 
Chrysanthemum  rust  ^\mg\x&\n  the  Journal  of  Horticulture.  Mr.  Abbey’s 
illustrations  are  from  actual  specimens  found  in  the  different  leaves 
examined.  Is  the  American  parasite  the  same  under  a  different  name?] 
