8
THE ESSEX FIELD CLUB.
From Mount Nuolja, 3,900 ft., Torne Traske
Sphaerophorus coralloides Pers. Cladonia pyxidata Fr.
Platysma nivale Nyl. Cetraria islandica Ach.
Cetraria aculeata Fr. Parmelia saxatilis Ach.
Squamaria nimbosa Fr. Solorina crocea Ach.
Lecanora ventosa Ach.
Many lichens can withstand great extremes of temperature, but, at
the same time, identical species grow and fruit abundantly where the
climate is extremely rigorous and also where the temperature in the
depth of winter is seldom far below the freezing point. We find that
most of the species now exhibited grow in such climates as those of Swedish
Lapland, Central and North European Russia, at a height of from 7,000
to 10,000 feet in the Alps, and in the south-western parts of Great Britain
and Ireland almost down to the sea level. The lichens in this respect
conform with Alpine flowering plants. Alpines come down to the sea
level in Ireland, and various suggestions have been made to account for
this. On the occasion of the International Phytogeographical excursion
in Britain 1912, Professor Rubel suggested that it was a question of humid-
ity. Professor Massart specifies among the features that struck him
during the excursion, the mildness of the climate, and the presence of
subalpine and alpine species, at low altitudes. Quite recently, January
1914, Mrs. Henshaw in a paper on the flora of Vancouver Island, read
to the Linnean Society, stated that some alpine plants came down to a
low level near the sea in parts of the island.
Among the very interesting exhibits now on view in the Central Hall
of the Natural History Museum, South Kensington, is one of animal
and vegetable life in the Antarctic, showing some of the results of the
Scott Expedition, 1910. There are a few lichens : one of them, Placodium
murorum, is a plant that is quite common in Cornwall and Devon ; it is
also found in the Epping Forest area.
In noting the distribution of lichens on tree trunks of our woods, it
becomes quite evident that many species prefer either the south-east)
south or south-west aspect. This may be owing to a preference for
intense light. It would be very interesting to know whether the lichens
on the birch trunks in high latitudes are more evenly distributed on ac-
count of the fact that during the season when growth is possible the sun
has a greater sweep round the trunks of trees than anything we get in
England. No comparison, as far as one knows, has been made on the
distribution of lichens on tree trunks in the south of England and in
northern Scotland.
CONVERSAZIONE.
Saturday, 21st February 1914.
On the occasion of the conversazione at the Municipal Technical In-
stitute, the Museum was thrown into the general exhibition space, and
some special subjects were illustrated, under the direction of the Curators,
Mr. W. Cole and Mr. H. Whitehead, B.Sc., and some members of the
Essex Field Club. The Curators arranged in the Museum a set of Bee-
hives and Bee-keepers' appliances, and products, intended to illustrate