16
species was seen on trees (in unpolluted areas
a site like this could support well over 100
species on trees), but some lichens rare in
the county were seen. The dull yellow crustose
species Candelariella xanthostigma was seen at
the base of a fine old pollarded Field Maple.
There is an old unlocalised record of this
species from grid square TQ39 where it is
unlikely to have persisted, but the Hatfield
Forest record is the first recent one. Another
good find was Pertusaria coccodes, a grey
crustose lichen with rather globose isidia
that grows on rough bark. There are records
made by Francis Rose from the Braintree and
Sampford squares, but I had not seen it in
Essex before. It was growing on two moribund
Ash trees which I believe have since been
cleared and on an Oak which is worn smooth by
being climbed upon by children. Other interesting
species seen were Phlyctis argena, Pertusaria
albescens, Ramalina farinacea and Calicium viride.
Lastly, an interesting old record: an 18th
century piece of timber from the Elizabethan
mansion of Rochford Hall was found to have bark
on it, upon which lichens could be seen. These
were kindly identified by Brian Coppins of
Edinburgh Botanic Gardens as Pertusaria leioplaca
and Lecanora chlarotera. Other microfungi
on the bark suggested that the timber was Ash.
It was probably local in origin. Lecanora
chlarotera is uncommon in north Essex. There
are no recent records for Pertusaria leioplaca.
Thanks are due to the Curator of Passmore Edwards
Museum for permission to look at his lichens.