REGIONAL MEETINGS - Natural History Museum

However, we quickly found two of the species for which the wood is well known –
Hymenophyllum tunbrigense and H. wilsonii. These two filmy ferns have an interesting
distribution in Cumbria, H. wilsonii being widespread, particularly in the Lake District,
while, apart from a recently discovered site in the far north of the county, H. tunbrigense is
more or less confined to Eskdale, where it is frequent. The two grow close together on crags
at this lower end of Milkingsteads Wood but elsewhere in the wood H. tunbrigense is much
the more common. There was considerable opportunity to compare the round, toothed
indusium of H. tunbrigense with the more oval, untoothed indusium of H. wilsonii, but our
investigations revealed nothing suggesting hybridisation between the two. We now
penetrated further into the wood to find one of the rare ferns of Cumbria – Dryopteris
aemula. The scarcity of this plant in Cumbria (there are only four sites) is puzzling since it
often thrives in damp westerly woodland of which Cumbria has an abundance.
Milkingsteads Wood has long been known as the home of this fern but of late its numbers
have been much reduced with only a handful of plants growing in a gully on a craggy
buttress. However, a few more plants had been found shortly before this meeting and others
were discovered during the meeting itself, growing close together on the same craggy
buttress and appearing to be in good health and, encouragingly, of varying ages.
Other ferns seen during the morning included Athyrium filix-femina, Blechnum spicant,
Dryopteris dilatata, D. filix-mas, D. affinis (subspp. affinis and borreri), abundant Oreopteris
limbosperma, Phegopteris connectilis, Polypodium interjectum, P. vulgatum and, of course,
Pteridium aquilinum.
Lunch was taken, according to taste, either by the cars or in the handily-placed King George
IV, after which the group moved on to Cumbria’s best Pilularia globulifera site, Flass Tarn
in Wasdale (35/129034). This site also provides a mystery in that, for some years, Pilularia
has thrived in either the main tarn or in a subsidiary pool a short distance away, never in
both. At a visit made to this spot in 2002 most of the Pilularia was in the subsidiary pool
with the main tarn seeming to have lost most of its plants as a result of the dense growth of
Carex rostrata. However, on this occasion the main tarn held an excellent colony growing
densely all the way round the edges, in some places almost forming a sward. Any hopes that
the same situation would apply in the subsidiary pool were swiftly dashed when it was
found that the pool itself had disappeared, leaving only a slightly damp hollow! Our hopes
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photo: M.S. Porter
Dryopteris aemula in Milkingsteads Wood, Eskdale