Field Meeting at Folkestone

Abstract

Eighteen members attended, although not all were present at the same time. We were made most welcome by the Folkestone Natural History Society, and in addition we received an unsolicited favourable notice in a local newspaper (Anon., 1963). The Folkestone district is more humid than the rest of Kent, the mean annual rainfall being 29.1 in. (73.9 cm.) compared with about 25 in. (63.6 cm.) elsewhere, and the Meyer precipitation/saturation deficit quotient lies between 200 and 300 instead of below 200 as in the rest of the county (Perring and Walters, 1962). Measurements of atmospheric pollution are not available, but the degree of pollution, though not entirely negligible, can be assumed to be low. The comparative moistness and cleanness of the air accounts for the presence of some foliose lichens-Parmelia physodes, P. sulcata, P. glabratula-on street trees in the residential parts of the town, which is an unusual phenomenon in southeast England. Corticolous species were looked for in the following localities : Mersham-le-Hatch (nat. grid 61/0640). A group of common species occurred here which were found again repeatedly in other places-namely,

Field and Study Notes

“…Atmospheric pollution appeared to be an unlikely cause, since the frequency of the toxiphobous species Ramalina farinacea (L.) Ach. and Usnea in the area and the rich and varied lichen flora (see Brightman, 1965) indicated low pollution levels, and new major sources were unknown. Moreover, the nature of the uniform discoloration differed from that occurring when thalli are affected by pollution, which in Parmelia species takes the form of marginal bleaching, leaving the centre of the lobes retaining approximately their original colour (Gilbert, O. L., Lichens Killed by Air Pollution.…”