May  1,  1902. 
JOURNAL  OF  HORTICULTURE  AND  COTTAGE  GARDENER. 
383 
Clematis  montana  over  an  Archway. 
Aldrovanoca  and  the  Bladderwort. 
Aldrovanoca  vesiculosa  i.s  an.  aquatic  found  in  Europe, 
Australia,  and  India.  Each  leaf  has  two  semicircular  lobes,  but  it 
is  not  known  whether  it  is  strictly  insectivorous,  although  in 
an  Australian  variety  a  beetle  was  found  partly  dissolved.  A 
slide  was  thrown  on  the  screen  depicting  the  capturing  apparatus 
of  Venus’s  Fly  Tray  and  Aldrover,  which  takes  much  longer  to 
dissolve  the  insect  caught. 
The  Bladdeiuvmrt,  which  might  be  oftener  grown,  is  an  aquatic, 
and,  when  dead,  the  products  of  decomposition  are  sucked  in  by 
the  rod-shaped  cells.  It  is  also  known  to  grow  in  the  concave 
leaves  of  a  Tillandsia,  likewuse  amongst  Mosses,  Liverworts,  and 
vegetable  mould,  but  the  process  is  similar.  Toothwort  is  a 
parasite  on  forest  trees ;  it  kills  the  Poplar,  but  does  not  injure 
the  Oak.  By  the  formation  of  suckers  it  fastens  by  means  of 
a  gummy  secretion  to  the  trees.  The  leaves  have  chambers.  The 
moment  the  glands  are  stimulated  they  send  out  protoplasmic 
thi-eads.  These  hold  any  insect,  and,  though  no  digestive 
secretion  has  been  found,  yet  the  appearance  of  claws,  legs, 
bristles,  &c.,  is  suggestive  of  a  charnel  house.  The  inference  is, 
therefore,  that  they  must  be  absorbed.  Bartsia  alpina  has  a 
wide  habitat.  The  plant  is  of  a  sombre  dark  violet  hue,  and 
the  name  was  given  by  Linnaeus  in  memory  of  the  death  of  his 
friend  Bartsch.  The  chief  feature  is  the  subterranean  shoots 
having  root  buds.  Owing  to  the  formation  of  the  scales  there 
are  a  great  number  of  ducts  by  virtue  of  the  overlapping  of  the 
scales,  and  though  no  digestive  fluid  has  been  found,  it  is  sug¬ 
gested  that  it  acts  similar  to  the  Toothwort.  The  reason  of  its 
acquiring  this  habit  is  due  tO'  its  "^hort  vegetative  season,  as  it 
is  an  inhabitant  of  the  Arctic  zone,  and_  the  summer  lasts  only 
about  two  months.  A  number  of  other  slides  having  been  shown, 
and  ably  dealt  Avith,  the  lecture  was  brought  to  a  close  Avith  the 
remark  that  while  some  plants  took  nitrogen  in  the  form  of 
protoplasm,  and  Avere  able  to  convert  it  into  soluble  form,  other 
plants  required  to  have  it  applied  artificially  by  hand  in  the  form 
of  nitrate. — A.  O’Neill. 
The  Dahlia  Anal.ysis. 
We  had  hoped  to  publish  Mr.  Mawley’s  analysis  of  Dahlia 
varieties  in  the  present  number,  but  its  preparation  requires 
longer  time.  We  Avill  publish  this  useful  and  important  guide  to 
the  varieties  of  this  increasingly  popular  floAver  in  our  next, 
May  8,  which  will  also  contain  articles  by  experts  on  all  sections 
of  the  Dahlia,  with  interesting  illustrations.  Extra  copies  are 
being  dispersed  to  growers. 
Rev.  Prof.  G.  Henslow,  M.A. 
After  a  four-months  absence  at  Cape  Town,  the  Rev.  Professor 
George  Henslow,  M.A.,  V.M.H.,  has  returned  again  to  80,  Hol¬ 
land  Park,  London,  W.,  and  has  resumed  his  secretarial  duties  cf 
the  Scientific  Committee  (R.H.S.),  kindly  undertaken  by  Dr. 
M.  T.  Masters  during  his  absence.  M’^e  hope  to  see  and  hear  Mr. 
Henslow  at  his  floral  demonstrations  in  the  Drill  Hall  again 
before  very  long. 
R.H.S.  Journal. 
The  quarterly  Journal  (vol.  xxau.  part  4)  of  the  Royal  Horti¬ 
cultural  Society  reached  us  on  the  morning  of  going  to  pres.s. 
Advances  are  still  made  in  the  amount  and  arrangement  of  the 
matter  contained,  and  among  other  more  apparent  features  Ave 
notice  a  complete  index,  numerous  original  illustrations,  especially 
in  connection  with  the  essay  on  Mangoes,  and  two  coloured 
plates^ — no  less! — illustrating  Carnation  diseases.  The  “  Common 
Place  Notes  ”  and  the  “  Abstracts  ”  from  current  periodicals  Ave 
find  highly  useful.  Alas!  hoAvever,  the  awful  trouble  of  having  to. 
cut  the  pages,  and  aa'b  are  so  busy. 
Hardy  Plants  on  Arches  and  Rockeries. 
The  groups  of  Geraniums,  Malva  moschata  alba,  Aspidiums, 
and  other  plants  illustrated  on  page  390,  represent,  though  rather 
indistinctly,  a  corner  in  Mr.  Arnott’s  Rosedean  garden  near  Dum¬ 
fries;  and  the  small-floAvered  Clematis  illustrated  on  the  opposite 
page  shows  hoAv  the  OAvner  bedecks  his  archways.  C.  montana  is 
very  useful  for  such  positions,  and  perhaps  the  Traveller’s  Joy 
(C.  Vitalba)  would  be  equally  as  serAuceable  in  a  like  situation. 
The  naturalising  of  plants  in  groups  of  a  sufficient  size  to  make 
a  massive  display  is  the  most  effective  form  of  gardening,  and  one 
that  should  be  folloAved.  Even  the  commonest  plants  have  a  dis¬ 
tinct  character  and  interest,  which  is  only  seen  at  its  fullest 
when  there  are  a  number  of  representatives  in  one  group. 
Colonial  Exhibition  in  the  Royal  Exchange. 
On  Saturday  next  the  Colonial  Exhibition,  Avhich  has  been 
held  in  the  Royal  Exchange,  London,  since  March  10,  closes. 
The  admission  has  been  free,  and  thousands  of  visitors  have  gone 
there,  seen,  read,  and  heard  of  the  resources  of  part  of  the  British 
Empire,  and  must  have  been  the  better  for  the  education  thus, 
received.  The  Colonies  represented  are  Canada,  North  Bbrneo,. 
Rhodesia,  and  Western  Australia.  The  raAV  products  and  many 
manufactured  articles  derived  out  of  these  countries  have  formed 
the  show.  Rhodesia  and  Canada  were  face  to  face  on  opposite 
sides  of  the  Exchange,  and  perhaps  the  latter,  with  her  minerals 
and*  timbers,  engaged  the  greater  amount  of  space.  Rhodesian 
minerals  and  gold  were  largely  shown,  and  model  gold  cleaning 
or  extracting  machines  were  constantly  at  Avork.  Photographs  o*’ 
native  scenes  and  mining  settlements  were  numerous  and  very 
interesting.  North  Borneo  tobacco,  rice,  sago,  gutta  percha- 
coffee,  beeswax,  pepper,  edible  birds^-nests,  rattans,  hemp,  coal 
and  gold  formed  a  most  pleasurable  exhibition  from  that  State 
and  the  grapes,  Avines,  Jarrah,  Karri,  Tuart,  and  other  woods, 
as  well  as  a  collection  of  wild  floArer  paintings  in  the  Western 
Australia  section  were,  together  with  the  cereals,  very  interest¬ 
ing.  The  West  Indian  Islands  were  represented  by  tropical 
fruits,  sweet  potatoes,  yams,  and  spices.  Various  companies 
interested  in  parts  of  individual  Colonies  presented  illustiated 
portfolios  to  certain  of  the  visitors,  and  the  ofiicial  guide  Avas  a. 
valuable  book  by  itself. 
