540 
December  21,  lf-99. 
JOURNAL  OF  HORTICULTURE  AND  COTTAGE  GARDENER. 
The  flowers  are  often  4  inches  across,  and  of  a  brilliant  purplish  crimson 
colour,  the  front  lobe  dark  purplish  crimson,  while  the  side  lobes  that 
enclose  the  column  are  pure  white,  which  makes  a  striking  contrast. 
L.  a.  venusta  is  the  preceding  glorified,  being  deeper  in  colour,  also 
larger.  A  plant  in  flower  with  me  at  the  present  moment  is  carrying  six 
beautiful  flowers.  L.  a.  grandiflora  is  perhaps  the  largest  of  the  whole 
family,  and  may  be  best  desciibed  as  a  gigantic  flower,  being  nearly 
6  inches  across,  and  of  the  same  colour  as  the  type. — J.  Barker, 
Hessle. 
Orchids  and  Orchid  Hunting. 
The  last  meeting  of  the  autumn  session  of  the  Birmingham  Gar¬ 
deners’  Association,  the  President  (Professor  W.  Hillhouse  of  Mason’s 
College)  entertained  the  members  with  a  highly  interesting  and 
instructive  lecture  from  notes,  entitled  “Orchids  and  Orchid  Hunting.” 
The  Professor — in  his  usual  fluent  and  comprehensive  style — traced  the 
history  of  the  Orchids,  at  least  from  the  time  of  Linnaeus,  and  to 
whom  only  about  seventy  species  and  varieties  were  known,  whereas 
about  5000  species  and  about  400  varieties  have  been  discovered  since 
that  period.  The  lecture  was  illustrated  with  a  series  of  lantern 
slide  photographs,  chiefly  to  show  the  anatomy  and  characteristic 
organisation  of  the  numerous  genera  and  their  variants. 
The  geographical  distribution  of  the  various  species  was  minutely 
described,  and  illustrated  by  means  of  coloured  maps  thrown  upon  the 
screen.  Adverting  to  local  cultivators  of  Orchids,  the  chief  collections 
were  said  to  be  at  the  present  time  Mr.  Joseph  Chamberlain’s,  Mr. 
J.  H.  Kenrick’s,  Edgbaston,  and  at  the  Botanical  Gardens,  Edgbaston, 
and  where  Mr.  Latham  is  continually  adding  to  his  stock. 
In  the  short  discussion  which  followed  one  of  the  members,  in 
reference  to  the  occasional  misnaming  of  Orchids,  observed  that  the 
new  hybrid  Orchid  Sophro  -  Cattleya  Cbamberlaini  triumphans 
(exhibited  by  Mr.  J.  Smith,  grower  to  Mr.  Chamberlain  at  Highbury), 
and  honoured  with  an  “award  of  merit,”  had  been — at  least  in  two 
of  the  London  dailies  and  the  “  Birmingham  Daily  Mail  ” — erroneously 
spelt  as  follows: — Scyphro- Cattleya,  and  that  Chamberlainiana  was 
given  as  a  generic  name,  and  he  thought  that  such  errors  should  be 
corrected  forthwith,  and  thus  save  confusion  in  plant  names. 
A  vote  of  thanks,  proposed  by  the  Chairman  (Mr.  W.  B.  Latham), 
and  seconded  by  Mr.  W.  Spinks,  was  unanimously  accorded  to  the 
lecturer,  who  remarked  in  response  that  he  regretted,  owing  to  so 
numerous  demands  on  his  time,  his  inability  to  attend  the  meetings 
oftener. 
IRIS  SCSI  AN  A. 
For  many  years  there  has  been  a  hesitancy  among  gardeners  to 
cultivate  this  glorious  Iris.  One  of  my  friends  who  believed  it  was 
impossible  to  “  do  ”  it  out  of  doors  has  gone  the  extreme  length  of 
subjecting  it  to  treatment  as  a  greenhouse  pot  plant.  During  the  last 
three  years  it  has  flowered  regularly,  the  stock  having  been  planted 
perhaps  five  years,  and  required  at  least  a  couple  of  years  to  gain 
strength  to  flower.  From  my  experience  with  the  plant  1  conclude 
your  correspondent’s  treatment  is  not  likely  to  be  a  success. 
It  commences  growth  in  October,  and  we  have  only  to  refer  to  old 
writers  to  discover  that  this  month  has  always  been  the  one  when 
growth  commenced.  Gilbert  (“  Florists’  Vade-Mecum  ”)  tells  how 
some  seventeenth  century  growers  lifted  the  plants  annually  in  order 
to  better  insure  bloom,  but  they  were  again  planted  in  August  and 
September,  the  positions  chosen  being  at  the  base  either  of  a  west  or  a 
south  wall.  I  should  not  hesitate  to  defer  planting  stock  of  a  flowering 
size  much  later,  but  it  must  be  remembered  that  growth  springing 
from  the  sides  of  the  older  ones  r<  quires  a  few  years  to  attain  to  a 
flowering  size,  and  late  planting  must  consequently  be  detrimental ; 
while  spring  planting  is,  I  should  say,  treatment  that  ought  to  be 
avoided  as  being  altogether  inimical. 
Our  plants  are  growing  in  a  strong  soil  imported  to  form  a  good 
rooting  medium  for  Roses.  When  planted,  some  light  compost  was 
added  to  assist  the  plants  in  establishing  themselves  more  quickly. 
They  are  also  annually  surface-dressed  with  cow  manure,  supple¬ 
mented  by  a  little  artificial  in  early  spring,  and  as  they  are  planted 
quite  close  to  the  base  of  a  south  wall  so  warm  that  Lonicera 
fragrantissima  trained  to  the  bricks  above  them  is  flowering  when  I 
write,  it  is  apparent  they  do  not  object  to  a  hot  position. 
The  plants  vary  considerably  in  growth.  At  present  one  has 
foliage  15  inches  in  length,  another  a  foot,  and  a  third  from  3  to 
6  inches.  They  are  covered  with  a  thick  mass  of  dried  fern  fronds, 
which  will  be  removed  directly  the  frost  gives,  leaving,  however,  a  few 
pieces  among  the  foliage. 
With  regard  to  the  value  of  stones  when  placed  under  the  roots, 
have  they  ever  been  proved  of  general  use  ?  I  know  a  case  where  the 
most  elaborate  arrangements  with  flagstones  and  frames  resulted  in 
failure.  To  employ  them  when  the  plants  succeed  perfectly  under 
conditions  requiring  neither  stones,  frames,  or  anything  beyond  a 
strong  fertile  soil  and  a  warm  exposure,  is  surely  a  superfluous 
proceeding. — R.  P.  B. 
MICRO-ORGANISMS  AND  THEIR  WORK  IN  THE 
GARDEN. 
We  live,  says  Dr.  G.  Norman,  in  a  world  teeming  with  life,  both 
animal  and  vegetable.  The  first  question  we  are  led  to  ask,  therefore, 
is  to  which  of  these  orders  do  bacteria  or  micro-organisms  belong  ? 
Now  the  differences  between  animals  and  vegetables,  even  so  low 
down  in  the  scale  of  life  as  micro-organisms,  are  chiefly  two — first  there 
is  a  difference  in  structure  and  development,  and  secondly  there  is  a 
difference  in  diet.  r 
A  plant  secures  its  nourishment  from  much  simpler  elements  than 
is  the  case  with  animals.  For  example,  plants  obtain  their  carbon 
from  the  carbonic  acid  gas  in  air  and  water.  This  they  are  able  to 
do  as  regards  the  carbon  by  means  of  the  green  colouring  matter, 
known  to  chemists  as  chlorophyll,  by  the  aid  of  which  with  the 
assistance  of  sunlight  carbonic  acid  is  decomposed  in  the  chlorophyll 
cells,  the  oxygen  passes  back  into  the  atmosphere,  while  the  carbon 
is  stored  in  the  plant  in  the  form  of  starch  and  other  organic  com¬ 
pounds.  The  supply  of  carbon  in  the  non-chlorophyllous  plants,  amongst 
which  we  may  include  micro-organisms,  is  obtained  from  the  different 
forms  of  carbohydrates,  better  known  as  starch,  sugar,  and  gum. 
Many  of  the  bacteria  also  have  the  capacity  of  using  organic  matter 
in  the  soil,  converting  such  into  water,  carbonic  acid,  nitrogen  gas, 
and  ammonia.  The  necessary  hydrogen  comes  from  water,  and  their 
nitrogen  from  the  soil,  chiefly  in  the  form  of  nitrates.  From  the  soil, 
too,  bacteria  obtain  other  necessary  salts,  of  which  lime  is  perhaps  the 
chief.  Now  all  these  substances  are  in  an  elementary  condition,  and  as 
such  plants  can  absorb  them.  Animals,  on  the  other  hand,  are  only 
able  to  utilise  compound  food  products  which  have  been,  so  to  speak, 
prepared  for  them.  For  example,  we  may  mention  the  albuminoids 
and  proteids.  They  cannot  directly  feed  upon  the  elementary  substances 
forming  the  diet  of  plants.  Further,  micro-organisms,  by  their 
structure  and  tissues  of  cellulose,  and  by  their  life  history  and  mode 
of  growth,  unmistakeably  proclaim  themselves  to  be  of  the  vegetable 
kingdom. 
The  presence  of  bacterial  micro-organisms  in  the  soil  is  consider¬ 
ably  affected  by  it s  geological  and  physical  conditions.  Surface  soils 
and  those  rich  in  organic  matter  (humus)  contain  the  largest  number 
of  micro-organisms.  Virgin  soils  contain  much  fewer  than  cultivated 
soils,  and  these  latter  again,  fewer  than  composted  soils.  In  rich 
garden  ground  the  number  of  organisms  augments  with  the  activity 
of  cultivation  and  the  richness  of  the  fertilisers  employed. 
In  all  soils  the  maximum  number  of  organisms  occur  in  the 
summer  months,  and  these  are  most  active  during  warm  weather. 
Consequently  they  are  both  more  numerous  and  more  active  in  well 
prepared  soils  in  a  greenhouse  or  conservatory,  or  even  in  a  closed 
Irame,  than  they  are  in  the  open  garden.  At  the  same  time  the 
conditions,  doubtless,  which  more  than  all  others  control  the  quantity 
and  activity  of  the  contained  micro-organisms,  are  the  degree  and 
quality  of  the  organic  matter  or  humus  in  the  soil. 
The  quantity  and  quality  of  organic  matter  present  in  garden 
soils  have  a  direct  effect  upon  bacteria,  and  these  conditions  are  con¬ 
siderably  enhanced  by  the  applications  of  farmyard  and  stable  manure. 
To  enable  us  to  appreciate  the  work  which  the  “economic  bacteria” 
perform  in  the  garden,  it  will  be  advisable  to  consider  shortly  the 
place  they  occupy  in  the  economy  of  Nature. 
The  threefold  functions  of  plant  life  are  maturation,  assimilation, 
and  reproduction ;  in  other  words,  the  food  of  plants,  the  digestive 
and  storage  power  of  plants,  and  the  various  means  they  adopt  for 
multiplying  and  increasing  their  species. 
Respecting  the  nutrition  of  plant  life,  it  is  obvious  that,  like 
animals,  they  must  feed  and  breathe  to  maintain  life.  Plant  food 
is  of  three  kinds — namely,  water,  chomical  substances,  and  gas. 
Water  is  an  actual  necessity  to  the  plant,  not  only  as  a  direct  food 
and  food  solvent,  but  as  a  vehicle  of  important  inorganic  materials. 
The  hydrogen  of  the  organic  matter  is  obtained  from  the  decom¬ 
position  of  the  water  which  permeates  every  part  of  the  plant,  and  is 
derived  by  it  from  the  soil,  the  rainfall,  and  other  aqueous  deposits  of 
the  atmosphere.  The  chief  chemical  substances  of  which  vegetable 
life  is  constituted  are  six  in  number — viz.,  potash,  magnesia,  lime, 
iron,  phosphoric  acid,  and  sulphur.  These  inorganic  elements  do  not 
enter  the  plant  as  such,  but  combined  with  other  substances,  or 
dissolved  in  water. 
The  gases  essential  to  plants  are  four — viz.,  carbonic  acid, 
hydrogen,  oxygen,  and  nitrogen.  The  leaves  absorb  the  carbonic 
acid  from  the  atmosphere,  under  the  influence  of  sunlight ;  the 
hydrogen  is  obtained  trom  the  water  ;  oxygen  is  absorbed  through 
the  roots  from  the  interstices  of  the  soil.  The  fourth  gas,  nitrogen, 
which  constitutes  more  than  two-thirds  of  the  air  we  breathe,  is 
doubtless  the  most ■  important  food  required  by  plants,  and  it  is  the 
most  expensive  to  buy. 
Yet,  although  this  is  so,  the  plant  cannot  absorb  or  obtain  its 
nitrogen  in  the  same  manner  in  which  it  acquires  its  carbon — namely, 
from  the  atmosphere  through  the  leaves ;  nor  can  the  plant  take 
