Six lichens of the Lecanora varia group

The Lecanora varia group consists of some 13 species, of which six are discussed; an indented key is presented. L. conizaeoides was first collected c 1862; it occurs where the air is polluted with sulphur dioxide, and it spread first throughout England apparently along the railway network. It is now in decline. Non-sorediate thalli belong to f. variola, a new combination. The lichen forms the association Lecanoretum conizaeoidis, a table of whose sociology is included. Lecanora coriensis, also a new combination, is a sterile leprose lobed lichen from Asia and Australia. Newly described is L. ecorticata, a leprose lichen from Britain and Canada. The combination L. strobilina subsp. strobilinoides is made for a geographical race of limited distribution. L. varia is confined to the Old World, and is replaced by L. densa in North America; their distribution indicates that the Atlantic Ocean acts as a barrier to the spread of lichens. L. laxa is subsumed under L. densa. L. vinetorum is a rare species of walls which has colonized trees and vineyard frames sprayed with copper fungicides.