May  26,  1898. 
JOURNAL  OJi'  HORTICULTURE  AND  COTTAGE  GARDENER, 
house  described  in  my  lecture  is  a  low  span,  running  north  and  south, 
with  a  sunk  path  in  centfe,  150  long  by  15  wide,  18  inches  deep  at 
the  sides.  It  is  ventilated  tK6  same  as  the  others,  but  with  this 
difference,  that  the  board  is,  pot  continuous,  opening  two  sashes  and 
missing  one ;  2  inches  is  the’’, most  the  ventilators  have  been  opened 
in  this  house  up  till  now  (May  16th). 
I  may  say  that  the  roofs  are  glazed  with  foreign  glass,  13  inches 
wide.  We  do  not  trouble  much  with  thermometers  in  the  houses,  but 
I  know  that  on  no  day  this  season  has  the  temperature  exceeded  90°. 
— D.  Buchanan,  Forth  Vineyards,  Kippen. 
[Very  different  are  the  surrounding  conditions  of  the  vineries  in 
charge  of  Mr.  W.  Taylor  and  those  of  Messrs.  D  &  W.  Buchanan. 
There  appears  to  be,  by  comparison,  an  extreme  of  exposure  in  the 
one  case  and  of  shelter  in  the  other.  A  warmer  air  bath  we  could  not 
very  well  imagine  than  in  and  around  Mr.  Chaffin’s  structures,  which 
nestle  at  the  foot  of  a  southern  tree  and  shrub  clad  declivity,  trees 
also  affording  shelter,  if  we  remember  rightly,  from  the  east  and  west. 
It  is  a  veritable  sun  trap,  and  an  ideal  spot,  we  should  imagine,  for 
“  red  spider.”  The  Kippen  ventilators  would  be  inadequate  for  the 
vineries  at  Bath.] 
“SILVER  LEAF”  IN  PEACH  TREE. 
The  shoots  submitted  by  “  Gardener,”  on  page  434,  last  week,  were 
similar  in  appearance  to  many  Plum  leaves,  and  commonly  regarded  as 
due  to  the  action  of  frost.  In  the  case  now  in  question  the  trees  were 
grown  under  glass,  and  instead  of  Plum  the  affected  leaves  were  of 
Peaches  Everyone  growing  Peaches  against  walls,  especially  in  elevated 
and  cold  districts,  knows  the  only  too  familiar  “  blister,”  and  its  being 
mostly,  if  not  entirely,  confined  to  outdoor  trees.  Eew  attribute  it  to 
anything  but  cold  winds,  particularly  easterly,  inasmuch  as  protection 
and  warmth  prevent  to  a  great  extent  attack  by  the  blister  fungus. 
That  is  the  general  opinion  of  gardeners,  but  is  not  fully  endorsed  by 
fuiigologists. 
So  far  as  I  know  “silver  leaf”  has  not  been  observed  on  Peach  trees 
outdoors,  or  on  Plum  trees  under  glass.  The  affection  may  be  found  on 
Portugal  Laurels  occasionally,  the  trees  ultimately  collapsing  or  losing 
their  leaves.  This  has  been  attributed  to  fungus  at  the  roots.  I  have 
examined  many  specimens  of  “  silver  leaf,”  from  Sloe  up  to  Green  Gage 
Plum,  from  Bird  Cherry  (Cerasus  padus)  up  to  Bigarreau  Napoleon 
Cherry,  and  down  again  to  Portugal  Laurels,  but  have  not  been  able  to 
detect  any  parasitic  micro-organism.  Similar  result  has  attended  the 
scrutiny  of  Birch  and  Hornbeam  leaves  affected  with  “silver  leaf  ”  until 
browned.  Why?  Perhaps  this  case  of  “silver  leaf”  in  Peach  leaves 
may  afford  a  clue. 
The  shoots  of  Peach  trees,  now  to  be  referred  to,  were  cut  from 
“  a  house  facing  east  and  stanffing  on  limestone,  the  fruits  setting  well, 
but  falling  off  before  they  attain  any  size.”  The  leaves  are  quite  silvery 
on  the  upper  surface,  a  fair  sample  being  shown  in  the  illustration,  fig.  8.5, 
at  A,  and  on  the  under  side  pale  or  yellowish  green.  Beyond  the 
“silver”  there  was  nothing  abnormal  about  them— no  malformation, 
swollen,  distorted,  thickened,  twisted,  or  curled  parts.  A  section  through 
the  tissue  revealed  nothing  beyond  the  normal  form  (B).  The  “silver” 
was  but  skin  deep  (a),  epidermal  cells  somewhat  more  contracted  than 
usual  (6),  and  those  underlying  considerably  rounder  than  ordinary  (c). 
No  fungoid  hypha  presented  itself,  the  intercellular  spaces  being  quite 
free  from  foreign  bodies.  This  might  be  attributed  to  faulty  ventilation. 
Well,  I  have  seen  many  instances  of  bad  air-giving,  but  never  any 
producing  “silver  leaf”  in  any  plant  under  glass. 
Upon  further  examination  I  noticed  that  some  of  the  leaves  had 
brown  spots  on  them,  and  one  leaf  in  particular  was  dead  at  its  extremity, 
being  curled  up,  as  injured  tissues  and  dead  parts  usually  are.  I  thought 
it  a  mere  cause  of  water  having  hung  on  the  leaf  and  destroyed  the  part, 
but  the  browning  ran  into  the  “  silver,”  and  had  the  appearance  shown 
at  C.  Making  a  section  where  the  brown  joined  the  silver,  the  tissues 
were  seen  as  represented  at  B,  The  silver  epidermis  (d)  was  tinged  with 
ellow  ;  beneath  the  cuticle  and  inner  surface  were  minute  yeast-like 
odies  (e),  and  these  prevaded  the  intercellular  spaces  of  the  subjacent 
cells  (/).  The  slice  was  from  the  upper  surface  or  silver  side  of  the  leaf. 
Turning  the  leaf  over  the  under  side,  shown  at  E,  had  the  yellowish 
green  hue  before  mentioned,  and  on  the  brown  part  a  sprinkling  of  white 
bloom.  This  was  the  very  thing  I  had  striven  to  find  for  years.  Bodies 
were  seen  on  the  slide,  and  at  once  recognised  as  Ascomyces  species,  as 
had  also  been  the  mycelial  hyphse.  A  section  gave  the  result  shown  at  F. 
It  was  regarded  as  a  form  only  of  Peach  leaf  blister  fungus  (Ascomyces 
deformans),  but  there  was  no  deformed  living  leaf,  no  blister,  swelling,  or 
anything  of  that  kind,  merely  the  silver  leaf,  and  where  the  fruits 
appeared  a  browning  and  destruction  of  the  tissues. 
The  ascus  (^g)  contains  eight  spores,  and  these  are  liberated  by  an 
opening  (A).  In  many  cases,  however,  the  spores  germinate  in  the  ascus, 
producing  buds  or  conidia,  and  then  appear  manv-spored.  The 
discharged  spores  (»)  soon  germinate  and  produce  secondary  spores,  like 
yeast,  by  gemmation  or  budding  (G^). 
I  offer  no  explanation  of  the  phenomena,  suffice  to  state  the  facts  as 
observed  and  leave  others  to  speculate.  It  may  be  remarked,  however, 
that  the  case  is  very  distinct  from  leaf-ldister,  but  the  fungus  is  practi¬ 
cally  the  same.  The  mycelial  hypha  is  pushed  beneath  the  cuticle  and 
the  epidermis,  and  the  nutritive  or  vegetative  hypha  runs  or  buds  between 
the  formative  cells  of  the  host-plant,  abstracting  their  contents  and 
utilising  their  substance  to  purposes  of  its  own. 
The  fungus  does  not  (at  least  this  torm  of  it)  blister  the  leaves,  but 
appears  the  same  as  that  found  sometimes  on  the  browned  foliage  <jf 
“  bird’s  nests  ”  or  “  witches’  besoms  ”  in  Plum,  Cherry,  and  Bird  Cherry, 
and  the  blister  form  is  the  “  bladder  ”  found  on  young  fruits  of  those 
trees,  known  as  “  bladder-plum  ”  fungus  (Ascomyces  pruni).  A  very 
closely  allied  species  causes  silver  leaf  in  Potentillas,  but  yellowish  spots 
also  appear,  and  on  these  “fruits  '  (A.  potentillae)  are  produced. 
The  mycelium  of  the  parasite  spreads  through  the  intercellular  spaces 
of  the  tissues  of  young  shoots  in  the  spring,  being  perennial,  but  how  it 
can  give  rise  to  “silver  leaf”  passes  my  understanding,  the  suppression  of 
the  chlorophyll  on  the  upper  surface  of  the  leaf  and  not  lower,  or  only  to 
a  limited  extent,  being  more  a  chemical  than  organic  characteristic.  In 
Fig.  85. — Silver  Leap  on  Peach  Trees  under  Glass. 
'References.— A,  Peach  tree  leaf,  upper  side,  showing  “silver  leaf”  (natural  size). 
B,  part  section  of  upper  surface  of  leaf  enlarged  260  diameters  ;  a,  cuticle  = 
“silver  leaf;”  ft,  epidermal  cells;  c,  formative  cells.  C,  upper  surface  of 
small  leaf,  showing  both  silver  leaf  and  browned  (natural  size).  D,  section 
of  portion  of  lirowned  part,  enlarged  260  diameters  ;  d,  silver  cuticle  ;  «,  yeast 
like  bodies  ;  /,  hyphpe  in  inter-cellular  spaces.  E,  under  side  of  leaf  (natural 
size).  F,  section  through  part  of  browned  portion  of  leaf,  enlarged  260  times, 
showing  fungus  =  Ascomyces  deformans  var. ;  g,  ascus  containing  eight  sjiores  ; 
ft,  spores  escaping  by  apical  opening  ;  i,  spores  germinating.  G,  spores  pro¬ 
ducing  secondary  growths  by  gemmation  (budding),  enlarged  520  diameters. 
the  case  of  some  Plums  the  silver  or  cuticle  covering  peels  off,  and  it  also 
occurs  with  various  other  plants  that  have  been  damaged  by  an  overdose 
of  tobacco  or  nicotine,  a  new  one  being  formed.  I  must,  however,  leave 
the  matter  for  the  research  which  the  subject  merits,  theory  being  of  little 
use  without  facts. — G.  Abbey. 
THE  LATE  MR.  GLADSTONE, 
Quite  fitting  and  appropriate  is  it  that  a  record  of  the  death  on  the 
morning  of  the  i9th  inst.,  of  the  greatest  commoner  of  the  century  should 
be  inscribed  in  these  pages,  of  which,  as  far  as  his  multifarious  duties 
allowed,  he  was  a  reader.  An  instance  of  the  keen  discernment  of  ,Mr. 
Gladstone  may  be  mentioned.  About  ten  years  ago  we  published  a  short 
note,  the  first  of  its  kind  that  appeared  in  our  columns  over  a  period  of 
forty  years,  describing  an  example  of  success  in  transforming  barren 
Pear  trees  into  productive  Apple  trees  by  grafting.  Detecting  the  note, 
and  foreseeing,  as  the  deceased  gentleman  thought,  a  practical  method  of 
improving  our  fruit  supply,  he  cited  the  case  in  one  of  his  famous 
speeches.  While  knowing  of  instances  of  success  in  establishing  Apples 
on  Pear  stocks,  we  could  not  regard  them  as  more  than  facts  of  an 
interesting  nature,  and  so  stated  at  the  time.  Mr.  Gladstone  was  unques¬ 
tionably  anxious  to  develop  what  he  called  “small  cultures.”  In 
turning  to  one  of  his  post-cards  we  find  these  words  : — 
“  As  regards  this  small  culture  in  its  many  branches,  1  am  more  and 
more  of  opinion  that,  though  in  each  particular  detail  the  results  might 
appear  secondary,  the  aggregate  effect  would  be  a  great  benefit  to  our 
agriculturists,  and  if  we  could  also  gain  a  still  greater  increase  in  the 
supply  of  milk,  be  a  most  valuable  boon  to  the  health  and  comfort  of  our 
population.” 
