This paper reassesses the southern temperate South American and Australasian species of Nephroma, analyses their chemistry and provides a key to the 14 species and three varieties accepted. N. occultum from North America is also discussed due to its close relationship to N. microphyllum and N. papillosum. Three pairs of morphotypes are described for the first time: N. analogicum-N. chubutense, N. kuehnemannii-N. microphyllum and N. skottsbergii-N. papillosum. N. papillosum sp. nov. and N. skottsbergii sp. nov. from Chile and Argentina are newly described. N. lobuligerum and N. lepidophyllum are reduced to varietal rank. N. lyallii is placed in synonymy with N. plumbeum and a new combination N. plumbeum var. isidiatum (J. Murray) F. J. White & P. James is made.

The genus Haematomma Massal. (type species: H. ochroleucum (Necker) Laundon) includes the pantropical and subtropical H. puniceum group, but differs in a range of characters including ascus structure, paraphyses, and chemistry from Ophioparma Norman (type species: Ophioparma ventosa (L.) Norman). The differences are such that a new family Ophioparmaceae Rogers & Hafellner is described with Ophioparma as its type genus, and the circumscription of the family Haematommaceae Hafellner is emended to take these changes into account. The combination Rosellinula kalbii (Hafellner) comb. nov. is proposed.

Caloplaca lucifuga Thor sp. nov. is described and reported from Denmark, England, France, Germany, Italy and Sweden. It is only found sterile and is mainly characterized by its endophloedic, sorediate thallus, chemistry and habitat. In Sweden, the species is found in dense wooded pastures dominated by Quercus robur, growing on the bark of very old trunks of Quercus robur or, rarely, Tilia cordata. Outside Sweden, it is found also on Castanea sativa, Fagus sylvatica and Ulmus glabra.

A new species of Sarrameana, S. tasmanica Vězda & Kantvilas, is described from Tasmania. The taxonomic relationship of this species with S. paradoxa Vězda & P. James from New Caledonia is discussed.

Two-years' observation of Athelia arachnoidea lesions in the field showed that they are long-lived perennial structures. In the Sheffield area, central parts of lesions become recolonized by Lecanora conizaeoides only after secondary infection by the lichen parasite Lichenoconium erodens followed by an invasion of the green alga Desmococcus naegelii. A. arachnoidea is active only during the winter months probably as a result of the higher humidity. The role of the sclerotia remains obscure.