74 
JOURNAL  OF  HORTICULTURE  AND  COTTAGE  GARDENER, 
July  25,  1901. 
gradually  rather  than  to  make  violent  changes  in  the  tempi  rature  with 
this  end  in  view.  A  few  weeks’  exposure  to  the  open  air  in  late 
summer  is  an  advantage,  provided  the  growths  are  properly  finished, 
but  not  otherwise. 
Cirrbopetalums. 
The  pretty  flowers  of  these  Orchids  are  produced  in  compact, 
round  umbels  on  thin  wiry  scapes  ;  many  of  them  are  rich  and 
telling  in  colour,  and  they  form  a  very  interesting  genus.  Their 
culture  presents  no  special  difficulty  provided  sufficient  heat  is  at 
command,  but  they  are  seldom  satisfactory  in  a  cool  house.  They 
grow  freely  in  [a  compost  of  equal  parts  of  peat  and  moss  with  a 
sprinkling  of  charcoal  and  potsherds.  Only  about  one-third  of  the 
depth  of  the  pot  is  needed  for  compost,  the  rest  being  filled  with 
crocks  for  drainage.  During  the  summer  months  the  roots  must  be 
very  liberally  watered  on  hot  days,  sometimes  as  often  as  twice  ;  but 
in  winter,  when  at  rest,  far  less  is  needed,  though  nothing  like  tl  e 
drying  off  practised  with  Dendrobiums  and  similar  kinds  i- 
admissible.  The  point  is  to  study  the  plants  and  the  weather.  A 
plant  that  shows  the  least  s;gn  of  shrivelling  should  at  once  be 
watered,  and  more  moisture  will  be  necessary  on  cold,  bright  days, 
when  the  fires  have  to  be  pushed,  than  when  damp  and  close  or 
foggy.  Shade  in  summer,  and  all  the  light  possible  in  winter,  will 
insure  their  being  satisfactory.  There  is  a  large  cumber  of  species  in 
the  genus  known  to  botanists,  but  only  a  few  of  these  are  generally 
grown.  One  of  the  mcst  distinctive  of  the  species  is  C.  Cumingi, 
which  has  been  known  in  collections  since  1841.  It  is  one  of  the 
many  rarities  imported  from  the  Philippine  Islands  by  Mr.  CnmiDg, 
after  whom  it  was  named  by  Dr.  Lindley.  It  flowers  readily  in 
early  spring. — H.  R.  R. 
Town  Trees. 
The  trees  in  our  large  towns  have  many  adverse  influences  to 
contend  against,  such  as — 1,  Over-drained  soil  due  to  the  wide  and 
deep  trenches  made  for  laying  sewage,  gas,  water,  and  other  pipes, 
the  roads  or  streets  being  cut  lengthwise  and  crosswav  by  a  series  of 
loosened  earth  trenches,  which,  however  firmly  rammed,  accelerate 
the  downward  passage  of  water,  and  equally  retard  its  ascent  by 
capillary  attraction  in  droughty  periods.  2,  Poor  or  stubborn  soil, 
in  consequence  of  the  removal  of  the  ameliorated  surfacing  mould 
a  foot  or  more  in  depth  to  make  room  for  laying  down  the  roadway 
and  footpath  materials.  3,  The  exclusion  of  air  and  water  to  the 
roots  by  the  impermeable  road  coverings  ;  the  rain  water,  instead  of 
sinking  into  the  soil,  being  conveyed  off  as  rapidly  as  circumstance- 
admit  by  surface  water-drains.  4,  The  heat  reflected  from  the  large 
areas  of  slate  and  tile,  brick  and  stonework.  5,  Coal  smoke  ami 
gaseous  impurities  arising  from  factories  and  chimneys.  ^ 
Of  the  five  adverse  influences,  the  effect  of  drought  at  the  roots 
and  the  beat  of  the  atmosphere  is  clearly  marked  upon  several  species 
of  trees  in  hot  weather.  To  these  attention  may  be  usefully  drawn  as 
a  lesson  that  ought  not  to  be  neglected  by  corporations  and  those  in 
charge  of  streets,  squares,  and  gardens;  for,  although  the  heat  and 
drought  has  been  somewhat  excessive  this  year,  trees  in  large  towD? 
are  always,  as  was  remarked  to  by  Sir  Herbert  Maxwell  in  the  “  Times,” 
and  quoted  in  the  Journal  of  Horticulture  of  September  28th,  1893, 
exposed  to  greater  summer  beat  and  drought  than  those  in  the 
country. 
Lime  Trees. 
The  trees  which  have  suffered  most  are  the  commonest,  the  Lime 
taking  precedence.  It  is,  perhaps,  the  most  tractable  of  all  trees  for 
submitting  to  manipulation  of  its  head,  being  made  to  form  a  screen 
of  determinate  height  and  breadth,  hedge,  arbour,  or  mop-shaped,  and 
kept  thereto  for  an  indefinite  period.  Another  reason  of  the  prevalence 
of  the  Lime  in  towns  is  that  of  its  being  planted  at  a  time  when  the 
sites  were  not  confined,  and  soot,  and  smoke,  and  noxious  gases  did 
not  abound.  But  owing  to  the  exodus  of  the  population  from  rural  to 
suburban  and  urban  districts,  and  the  advance  of  the  country  in 
industrial  energy  and  progress,  these  open  town  situations  have  become 
more  or  less  confined  by  the  erection  of  dwellings  and  factories,  the 
smoke  and  lumes  correspondingly  more  demonstrable,  the  soil  moisture 
reduced  proportionably,  and  the  air  heat  and  concomitant  drought 
relatively  increased.  Thus,  in  the  course  of  a  few  years,  towns  com¬ 
paratively  rural  become  decidedly  urban,  and  where  once  the  Lime 
throve  and  retained  its  foliage  in  health  up  to  October  or  later,  it 
now  turns  sere  in  August,  and  is  more  or  less  leafless  early  in 
September.  As  the  smoke  and  fumes  increase  with  that  of  summer 
heat,  and  the  soil  moisture  diminish,  the  Lime  shows  marked  signs 
of  distress,  the  tops  of  the  branches  dying  off,  and  sooner  or  later  the 
whole  tiee  succumbs  to  the  adverse  influences  ;  avenue  trees  the 
soonest,  and  the  topped,  because  annually  or  frequently  rejuvenated, 
the  latest;  yet  all  “get  smaller  by  degrees  and  beautifully  less.” 
In  the  country-like  town  of  St.  Albans,  where  the  Lime  is 
practically  the  only  public  road  or  street  tree,  a  convincing  proof 
exists  of  town  planters  being  v<ry  circumspect  in  selecting  species 
for  subjection  to  the  impurities  of  a  town  atmosphere,  not  only  in  the 
smokiest,  but  even  in  the  most  countrified.  Now  there  are  the  Lime 
and  Limes,  to  which  I  may  first  revert  in  respect  of  their  doings  in 
1899,  these  being  similar  to  those  of  1893.  The  common  Lime 
(Tilia  vulgaris  or  europaea)  was  seriously  distressed  in  August,  red 
spider  (Tetranychus  tiliarum)  having  put  in  appearance  and  indicated  its 
presence  by  browning,  curling,  and  falling  of  some  foliage.  Many  of 
the  trees  were  almost,  and  seme  quite,  leafless  on  the  9th  of 
September,  very  few  being  decently  clad  in  summer  garb,  the  most 
retaining  remnants  only  of  brown  or  sere  foliage. 
The  broad-leaved  Lime  (T.  platyphyllus)  has  a  much  finer 
general  contour,  is  hardier,  and  less  subject  to  attacks  of  red  spider, 
as  well  as  retains  its  foliage  later,  than  the  common  Lime.  Hardier 
still  is  the  red  or  orange  twigged  variety  (T.  p.  aurantia),  it  doing 
better  than  any  other  species  or  variety  in  an  exposed  position 
500  feet  above  sea  level ;  for,  remember,  Limes  are  trees  of  the  plain, 
moisture  loving,  but  not  on  cold,  heavy,  wet  soils,  alluvial  flats  being 
more  to  Lime  tree  taste.  Better  still  for  bold  contour  and  beauty  of 
appearance  is  the  petiolate,  sometimes  called  white,  Lime  (T.  petiolaris). 
It  has  an  erect  stem  and  leafy  pendulous  branches,  very  handsome, 
retaining  the  foliage  longer  and  freer  from  red  spider.  The  leaves  are 
large,  dark  green  above,  silvery  beneath,  the  flowers  yellowish  green, 
large  and  fragrant  ;  bees  make  it  “a  hive,"  as  the  species  flowers  just 
after  the  commoner  broad-leaved  and  common  Limes  are  nearly  past. 
Hence  the  Limes  in  variety  give  a  long  bee  season. 
,  The  white  or  silver  Lime  appears  less  hardy  than  the  petiolate 
form.  It  (T.  argentea)  has  the  foliage  browned  more  or  less  in 
exposed  situations  by  late  spring  frosts.  The  foliage  is  bold,  some¬ 
what  round  or  cordate,  pale  green,  shining  and  smooth  above,  white 
downy  beneath,  and  the  yellowish  white  flowers  are  very  fragrant. 
When  ruffled  by  wind  the  tree  has  a  very  silvery  appeirance.  The 
leafage  suffers  less  from  red  spider  and  reflected  t  wn  heat  than  the 
other  species  of  Lime,  but  the  s'lver  Lime  appears  too  tender  for 
any  than  sheltered  and  warm  situations  in  this  country. 
The  American  Basswood,  or  Whitewocd  (T.  americana)  grows 
freely,  but  not  so  Btrongly  as  the  broad-leaved  Lime,  the  deeply 
cordate  abruptly  acuminate  smooth  leaves  berng  sharply  serrated,  and 
turn  yellowish-brown  in  decay.  It  appears  to  stand  town  heat  better 
than  the  broad-leaved  and  common  Limes,  but  the  specimens  noticed 
have  not  been  in  very  adverse  influences  of  smoke  and  fumes.  No- 
observation  has  been  given  of  the  American  white  Basswood  or  variable 
leaved  Lime  (T.  heterophylla)  in  smoky  districts,  its  large  leaves,  4  to 
8  inches  in  diameter,  being  green  and  shining  above,  very  white  and 
velvety  tomentose  beneath  ;  and  evidence  has  not  been  forthcoming 
of  the  very  large  leaved  and  vigorous  growing  Blech’s  Lime 
(T.  platyphyllus  Blechiana). 
The  heart-leaved  Lime  (T.  cordata),  though,  perhaps,  a  native  of 
this  country,  like  the  broad-leaved,  contends  less  effectively  against 
smoke,  fumes,  town  heaf,  and  drought  than  the  common  Lime,  although 
its  leaves  are  quite  as  smooth  above  and  not  more  pubescent  in  the 
axils  of  the  veins  beneath.  As  compared  with  the  broad-leaved  and 
common  Limes,  the  heart -leaved,  generally  with  leaves  smaller  than 
either,  is  a  small  tree,  and  flowers  last  of  the  three.  Of  all  the  Limes, 
the  heart-leaved  appears  least  able  to  resist  the  adverse  influences  of 
coal  smoke  and  reflects  i  heat,  the  leaves  curling  up  in  July,  and  red 
spider  turning  them  quite  brown.  There  are  often  singularly  ruddy 
by  mid- August,  and  fall  by  the  end  of  the  month,  the  trees  being 
leafless  early  in  September. 
I  have  dwelt  at  length  upon  the  Limes,  as  they  appear  most 
generally  selected  for  town  planting,  probably  owiDg  to  early  ideas 
derived  from  the  Low  Countries ;  but  of  all  trees  they  are  the  least 
commendable  for  planting  in  smoky  districts.  In  towns  of  a  decidedly 
rural  character,  with  wide  streets,  and  the  surface  coverings  not 
impermeable  to  air  and  rain,  Limes  may,  and  do,  succeed,  providing 
the  district  or  site  be  not  noted  for  dryness  of  soil  and  aridity  of 
atmosphere.  Under  dry  earth  and  arid  atmospheric  conditions. 
Limes  suffer  from  aphis  attacks  in  the  early  summer,  especially  after 
east  winds  have  blown,  and  the  pavement  beneath  the  spread  of  their 
heads  is  coated  over  with  honeydew,  the  filthy  excreta  of  these  pests, 
affording  a  nidus  for  black  fungus,  Fumago  vagans,  and  may-be  for 
microbes.  Then  the  foliage  is  coated  on  the  upper  surface  by  the 
insects  sucking  the  life  Hood  from  the  under  side  of  superjacent 
leaves,  clogging  it  with  glue-like  substance,  anon  turning  black,  and 
giving  the  trees  a  woelul  aspect.  Apart  from  red  spider,  which 
certainly  follows  if  the  season  is  dry,  the  leaves  so  affected  ripen  and 
fall  prematurely,  so  that  Lime  trees  seldom,  from  one  cause  or  the 
other,  can  be  depended  upon  to  retain  foliage  pleasing  to  the  eyes 
after  August,  and  sometimes  not  even  in  that  month. — G.  Abbey. 
