Thirteen species of the lichen genus Sticta (Schreber) Ach., are recognized in the New Zealand flora viz.: S. babingtonii, S. caliginosa, S. colinii sp. nov., S. cinereoglauca, S. filix, S. fuliginosa, S. lacera, S. latifrons, S. limbata, S. martinii, S. squamata, S. subcaperata and S. sublimbata. A key to species, synonymy and typification, descriptions of all taxa, biogeographical affinities and distribution maps are presented. Sticta livida is excluded from the New Zealand flora.

Arhothelium saxicolum Makhija & Patwardhan sp. nov. is described from India. It occurs abundantly only on basaltic rock and is restricted to the northern parts of Western Ghats, South-West India.

Two corticolous species of the lichen genus Xanthoria, X. alfredi S. Kondratyuk & Poelt from Russian and Chinese Far East and X. aphrodites Kalb, Poelt & S. Kondratyuk from Cyprus are described. Morphological characters, in particular the presence of true rhizines within Xanthoria and their differences from hapters are indicated. Xanthoria novozelandica Hillmann is the first species of Xanthoria in which oil paraphyses have been found. A key to the treated species, including X. novozelandica and Xanthoria sp. from western North America is provided. The ecology and distribution of described species are discussed. Xanthoria alfredi and X. ulophyllodes probably constitute a typical species pair; X. alfredi and X. aphrodites are relict endemics.

The effects of simulated sulphuric acid rain were investigated, under controlled laboratory conditions, on the surface structure and n-alkane composition of the lichen Pseudevernia furfuracea. Thalli were collected from Larix decidua bark in a wood in a Piedmont alpine valley and treated with three concentrations of H2SO4. The response to simulated acid rain was a clear change in the quantitative alkane composition, with a decreasing trend observed for C28 and C30 with increasing sulphuric acid concentration. From a morphological point of view, a progressive reduction of the surface amorphous layer was observed as a consequence of the exposure of thalli to the acid rain treatments.