'May  1,  1902. 
379 
JOURNAL  OF  HOPi,TICULTURE  AND  COTTAGE  GARDENER. 
Laelia  x  Latona. 
This  is  a  peerless  species  of  Orchid,  undoubtedly  one  of  the 
•most  beautiful  of  all  spring  flowering  kinds,  and  not  very  difficult 
ix>  entice  into  flower.  Messrs.  J.  Veitch  and  Sons,  Limited,  have 
shown  some  splendid  plants  of  it  at  recent  meetings  of  the  Royal 
Horticultural  Society  in  the  Drill  Hall,  and  other  collections  are 
seen  te  be  graced  with  it  also.  The  plant  is  still  comparatively 
rare,  however,  and  fetches  a  good  price  per  plant — that  is,  five 
guineas  for  stout  plants.  This  hybrid  re.sulted  from  crossing 
L.  purpurata  with  L.  cinnabarina,  both  of  which  have  been 
very  frequently  used  for  crosses,  and  the  latter  was  in  this  case 
■the  seed  parent.  The  flowers  are  from  4in  to  5in  in  diameter. 
The  sepals  and  petals  are  similar  and  of  a  uniform  light  orange- 
yellow  ;  the  lip  is  narrow,  scarcely  lobed,  convolute  over  the 
column  to  beyond  the  middle,  whitish  at  the  base,  the  remainder 
red-pui^ple  bordered  with  orange-yellow.  The  margin  of  the 
apical  spreading  lobe  is  much  undulated.  The  hybrid  received  a 
First  Class  Certificate  in  1892. 
The  Week’s  Cultural  Notes. 
Disa  grandiflora  is  a  beautiful  and  showy  species  that  unfor¬ 
tunately  is  not  everywhere  a  success.  It  is  very  annoying  tO'  the 
grower  who  has  given  a  grent  deal  of  care  and  thought  to  its 
culture  and  then  been  unsuccessful,  to  go  to  places  where 
apparently  little  trouble  is  taken  with  it,  but  excellent  results 
obtained.  In  some  cases  I  am  convinced  the  plants  are  ruined 
by  coddling.  They  like  ample  root  and  atmospheric  moisture,  it 
is  true,  but  its  native  habitat  is  the  Table  Mountain  at  the  Cape, 
■  and  it  also  likes  an  abundant  supply  of  fresh  air;  must  have  it, 
in  fact,  if  it  is  going  to  be  a  success. 
Grown  dose  to  a  greenhouse  door  kept  constantly  open  in 
summer,  I  have  seen  this  striking  Orchid  doing  remarkably  well, 
and  such  a  position  may  be  recommended.  Frequent  dampings 
•of  the  stages,  floor,  and  overhead  the  plants  will  be  required,  and 
fairly  heavy  shading  during  the  day,  to  keep  the  temperature 
•down.  Otherwise  let  the  plants  rough  it,  so  to  speak,  and  they 
will  be  all  the  better  for  it.  There  is  even  yet  time  for  a  little 
re-arrangement  of  the  compost  should  this  be  necessary,  but  by 
now  the  roots  and  growth  will  both  be  active,  and  the  less  the 
plants  are  pulled,  about  tlie  better. 
Tliey  must  be  kept  growing  now  without  a  check  right  up  to 
the  flowering  time,  and  this  will  ensure  a  beautiful  display.  A 
word  of  caution  as  to  insects  may  be  necessary.  If  thrips  are  on 
the  plants  at  the  time  the  flowers  are  opening,  they  will  quite 
ruin  their  appearance  by  eating  their  way  over  the  petals.  Try, 
then,  to  have  them  perfectly  free  of  these  insects.  Take  them 
singly  and  place  them  in  a  moderately  deep  vessel  of  water ;  this 
will  have  the  effect  of  driving  out  any  insect  from  the  compost. 
Then  sponge  the  leaves  and  stems  with  a  reliable  insecticide  used 
according  to  directions,  or  with  a  solution  of  softsoap  and  tobacco 
water. 
.Do  this  time  after  time  if  the  insects  are  not  all  killed,  for 
only  a  few  left  and  the  plant  will  soon  be  overrun  again.  Should 
D.  grandiflora  continue  unsatisfactory,  there  are  other  species  in 
the  genus  that  may  be  substituted  for  it,  though  none  of  them  are 
so  showy.  The  be.st  substitute  is  undoubtedly  that  splendid 
hybrid  raised  by  Messrs.  Veitch  from  D.  grandiflora  and  D.  race- 
mosa,  riz.,  D.  Veitchi.  It  is  almost  equally  showy  to  D.  grandi¬ 
flora,  and  will  thrive  where  this  does  not,  and  as  it  is  now  fairly 
cheap,  plants  are  within  the  reach  of  all  growers. — H.  R.  R. 
Sale  of  Orchids. 
Messrs.  Pi'otheroe  and  Morris,  on  April  25,  sold  at  the  Central 
Auction  Rooms,  67  and  68,  Cheapside,  E.C.,  a  collection  of 
established  Orchids.  Some  of  the  lots  realised  ver^'  high  prices, 
among  which  may  be  mentioned  the  following: — 07lontoglossum 
crispum,  two  old  bulbs,  two  leaf  bulbs,  strong  plant,  a  superb 
variety,  finely  blotched  and  spotted  on  sepals  and  petals,  grand 
lip — 150  guineas;  ditto,  two  old  bulbs,  two  leaf  bulbs,  fine  plant, 
very  dark  claret  spots  on  sepals  and  petals — 60  guineas ;  ditto, 
roseum,  very  good  plant,  fine  flower,  and  densely  six)tted  petals 
with  minute  spots — 50  guineas. 
Hydrocyanic  Gas  for  Fumigation.* 
The  Chemicals  Used. 
1.  Cyanide  of  potassium;  2.  sulphuric  acid;  3.  water. 
The  cyanide  must  be  practically  chemically  pure  and 
guaranteed  98  to  99  per  cent.  It  costs  from  15d.  to  18d.  per  lb., 
depending  on  quantity  purchased  at  one  time.  I  have  found  in 
my  experience  that  the  251b  package  is  the  most  convenient,  as 
it  is  put  up  ill  tin  cans  with  screw  tops,  and  can  be  conveniently 
handled  by  most  nursei’ymen.  I  find  that  cyanide  broken  into 
lumps  about  the  size  of  small  hickoiy  nuts  gives  the  best  results. 
It  can  be  procured  in  small  liimiis  by  notifying  the  manufacturers 
in  advance. 
'ITie  be.st  grade  of  commercial  sulphuric  acid,  specific  gravity 
1.83,  should  be  procured.  x\cid  used  in  the  manufacture  of 
fertilisers,  commonly  called  “  chamber  acid,”  should  not  be  used. 
I  have  secured  an  excellent  grade  at  a  penny  a  lb.  by  the  carboy. 
Of  course,  these  chemicals  are  subject  to  change  in  price.  It 
must  be  borne  in  mind  that  the  acid  cannot  be  placed  in  vessels  of 
any  kind,  except  those  made  of  earthenware.  I  have  found  that 
an  ordinaiy  pickle  jar  or  crock,  holding  from  2qt  to  4qt,  is 
best  adapted  for  the  chemicals.  Sometimes  a  large  snuff  jar  is 
needed  in  a  large  house.  The  cyanide  should  be  weighed  out 
and  Avrapped  in  strong  paper  bags,  and  kept  packed  in  the  can 
ready  for  use.  A  gla.ss  beaker,  holding  at  least  8oz,  with  the 
ounce  mark  on  the  side,  for  measuring  acid  and  water,  is  very 
necessary.  This  method  Avill  not  admit  of  any  guessAAmrk,  and 
the  chemicals  must  be  prepared  strictly  in  accordance  Avith 
figures  giA'en  for  any  enclosure.  A  bottle  AA'ith  glass  stopper,  or  a 
chinaAAare  pitcher,  should  be  kept  on  hand  for  the  acid.  With  a 
pail  of  Avater  and  a  tin  cup  the  equipment  is  complete. 
Making  the  Gas. 
1.  Measure  the  acid  in  the  glass  beaker  and  pour  it  into  the 
jar.  2.  Measure  the  AA'ater  and  pour  this  on  the  acid.  3.  Drop 
in  a  bag  of  cyanide,  bag  and  all,  close  the  door  quickly,  lock  it, 
and  leave  the  desired  length  of  time' — half  an  hour  or  more,  as 
above  stated.  In  the  meantime  the  foreman  shoidd  see  that 
nobody  enters  or  loiters  about  the  house,  as  the  fumes  are  highly 
poisonous.  One  man  should  alAAays  be  held  responsible  for 
fumigation  of  nui'sery  stock,  and  keep  time,  so  that  the  house 
can  be  opened  and  thoroughly  Amntilated  later. 
There  is  a  slight  formation  of  steam  AA’hen  the  AA-ater  is  poured 
on  the  acid,  but  this  is  not  dangerous.  On  the  other  hand,  Iioaa  - 
ever,  AA'hen  the  bag  of  cyanide  is  dropped  into  the  liquids  there  is 
a  bubbling  and  hissing  similar  to  that  produced  by  a  piece  of 
redhot  iron  in  cold  AAater.  There  is  a  dense  cloud  of  so-called 
steam  giA-mn  olf,  Avliich  in  itself  is  one  of  the  most  deadly, 
*  The  article  is  takeu  (for  the  beiietif  of  a  correspondent)  from  the  .Tournal  of 
the  Royal  Horticultural  Society,  and  is  by  Rrof.  W.  G.  .Johnson,  New  York. 
