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RARE PARASITIC FUNGUS FOUND IN ESSEX
On the Essex Field Club meeting to Rowney Wood on 11th May 1996 Chris Romer,
Martin Gregory, Tim Pyner and Tony Boniface found Taphrina johansonii Sadeback
growing on the female catkins of what we thought at first was a willow. On closer
examination Tony Boniface identified it as an aspen which was confirmed by Tim Pyner.
The fungus causes the fruits of the aspen to enlarge and turn bright yellow.
Martin Gregory recollected having seen a photograph of the fungus in Fungi of
Switzerland Volume I. Tony Boniface confirmed this and located a description of it in
British Cup Fungi by Dennis. Tim Pyner, Jerry Bowdrey and eventually Brian Spooner at
Kew confirmed the identification.
The Kew collections contain two previously collected specimens both found in Scotland.
Martin and Pam Ellis have published a record in Suffolk at Thrandeston by Peter
Wanstall. Bruce Ing knows of no other record of the fungus in the British Isles.
The fungus is conspicuous and easily recognised on aspen. Maybe it is more frequent but
unobserved at the top of taller trees. Never dismiss your finds as common. Rarities are
still to be found.
Tony Boniface
ESSEX FIELD CLUB VISIT TO THORLEY FLOOD POUND ON 23RD JUNE 1996
Insect Report
This year has been generally poor for invertebrates, and so it was with some interest that
we set off with nets around the Thorley Flood Pound, just on the Essex side of the River
Stort, our boundaiy with Hertfordshire. The site is a reserve area for winter flood water
from the Stort (owned by the Environment Agency - formerly the National Rivers
Authority), and is typically flooded in January/February when its principal interest is in
the birds. Throughout the summer, it normally retains a soggy nature, but the hot summer
of 1995 and the mini-drought of 1996 seems to have taken their toll. The level of water
in the few remaining dykes was lower than usual and has allowed terrestrial plants to
encroach the margins making them difficult to see (at least that's what the horse told me!)*.
In spite of this evident drying out, the Flood Pound managed to produce some good
insects on the day. The soldier fly Nemotelus pantherinus was taken in huge numbers -
mostly males, and just a few females. This small fly is only known in Essex from three
other recent records, all in the south of the county. The best fly of the day, another soldier
fly, Oxycera nigricornis (formerly Oxycera formosa), was taken in a sweep net by 13 year
old Rosemary Plant - perhaps the Club's youngest entomologist! This species is only
otherwise known in Essex from Sawbridgeworth Marsh Nature Reserve in the same ten-
kilometre grid square, just a couple of kilometres further down the River Stort.
Hoverflies were extremely poorly represented, reflecting the national picture in what is an
abysmal year. Chrysogaster hirtella was numerous sitting on grass stems and other
vegetation; almost all the specimens examined were females. Several Neoascia tenur, a
typical wetland hoverfly, were collected. At nearby Sawbridgeworth Marsh, this species
displays abnormal characteristics in that the bases of the front femora are yellow rather
than the usual black. This variation is constant within the population and it is currently
under investigation in case a new and as yet undetected species is involved. One specimen
from Thorley had the same atypical characters, but the rest of the sample was normal.