Botanical records - problems and solutions
Ken Adams 63 Wroth's Path, Baldwin's Hill, Loughton, Essex IG10 1 SH
As most of you will be aware, the Botany Group has been accumulating additional
botanical records for the county ever since publication of the 2nd Flora of Essex in 1974.
A small team of us have recently been gradually transferring these to MapMate, and
backing them up onto the BSBI database with some 96,000 accumulated so far. You
may have noticed however that my CUK, which enables other botanists with the MapMate
program installed on their computer to send in records by web synchronization, is not
publicized in EFC literature. There are several botanists systematically recording areas
of the county who do send in their records in this way, but I also receive potential
records as paper or Excel lists. The problem I have is that there are numerous amateur
botanists out there in Essex who attempt to identify plants using popular Floras such as
Keeble Martin, and Blarney & Fitter, and duly send me lists, but it is obvious from the
lists that they are not identifying plants critically enough for me to be able to use all, or
sometimes any of their records. There is a popular misconception that if a plant is generally
common, then the identification is probably correct, or worse still, that it doesn't really
matter. It does matter, however, because we are trying to decipher the patterns of
distribution of plants, common as well as rare. A further problem that I have is that
unless we have accurate national grid square references that actually contain the site of
plant, the record is not only inadequate for a National Database, but I can't use it for a
dot map, or correlate it with a soil type, - let alone refind it.
Critical Identification
Let's take some examples. What is the commonest weed of arable land, waste ground,
pavement cracks and wall bases? Well - in most areas now it's most likely to be Guernsey
Fleabane, - Conyza sumatrensis. It has swept across Essex in the last ten years and is
now everywhere in vast quantities. If you have not heard of it, it means you have probably
been misidentifying it as Canadian Fleabane, Conyza canadensis, - which seems to be
far less frequent nowadays. Similarly, among the aquatics Nuttall's Waterweed Elodea
nuttallii has largely ousted Canadian Pondweed Elodea canadensis. Yet another
newcomer is the American Duckweed, Lemna minuta. It is now our commonest
Duckweed, staying on the surface throughout the winter and overtopping other species.
It also seems to be able to tolerate a wider range of light intensities than our native
duckweeds. It's a species, however, that is not in most of the picture book floras and is
liable to be erroneously recorded by the unwary as Lemna minor. Other anomalies also
stand out from several people's lists. Most arable land, gardens and allotments will
support abundant Atriplex prostrata and Atriplex patula, but many people just look at
the leaf shape and mistake these common weeds for Good King Henry, Chenopodium
bonus-henricus, which has so far eluded me in Essex. Atriplex differs from Chenopodium
in having separate male and female flowers, the latter having triangular fleshy bracts.
Essex Field Club Newsletter No. 55, January 2008 9