THE ESSEX FIELD CLUB
HEADQUARTERS:
THE PASSMORE ED WARDS MUSE UM,
ROMFORD ROAD, STRATFORD,
LONDON, E15 4LZ
NEWSLETTER NO. 15 November 1995
FOCUS ON FRESHWATER ALGAE
"There are a sort of men whose visages
"Do cream and mantle like a standing pond"
-The Merchant of Venice, act 1, scene 1, lines 88-89
Some ponds can indeed produce a mantle of green scum, or their water may be entirely
green. It is also noticeable how green many trees and fences are in damp weather, as may
also be concrete or tarmac paths, tiles, flower pots etc. These manifestations are due to
members of the very large and heterogeneous group of the freshwater algae. Yet, apart
from the decorative desmids and the intricately patterned diatoms, they have had
comparatively few enthusiasts in this country, and as a consequence the occurrence and
distribution of the British species is very poorly known. There is no mapping scheme,
nor are there more than a few county lists.
The plate gives a slight idea of the diversity of algae which are to be found in local ponds
and rivers. Most of them are clearly visible with a school-type microscope. There are
very many more genera than those illustrated, and some of those genera have dozens or
even hundreds of species, many of which are badly described. There is plenty of work for
an interested amateur, but one of the chief drawbacks is the need for numbers of large and
expensive German monographs when dealing with the smaller species.
As the Field Club's recorder for freshwater algae I am prepared to look at any samples
members care to send me. Please indicate details of the collecting site, with grid
reference if possible. Water samples from ponds etc. may be sent in polyhtene bottles or
in small plastic (PET) drinks bottles, or even in tubes for a less complete list. Bits of
filamentous algae or encrusted higher plant material etc. can be included, but do please
remember to leave an air space. Plant material should not be packed tightly in a tube or it
will go bad.