A new species, Lecania belgica, is described and illustrated. It is a saxicolous lichen known only from the type locality in Belgium. It is characterized by apothecia with pruinose, irregularly undulating discs, relatively short ascospores, and by having 12–16 spores in the asci. It was found on mortar together with Diplotomma alboatrum.

Caloplaca tropica Y. Joshi & Upreti, is described as new to science and belongs to the Sideritis group in the lichen genus Caloplaca. Caloplaca hueana (section Cocciniodiscus), C. squamosa (Squamosa group) and C. pollinii are reported for the first time from India.

Loxospora lecanoriformis Lumbsch, A. W. Archer & Elix is described from deeply shaded trunks of Doryphora sassafras Endl. in temperate rainforest in north-eastern New South Wales. This species is characterized by large, lecanorine apothecia, mostly unbranched paraphyses, non-amyloid asci and large, thin-walled, simple, ellipsoid ascospores. Molecular data has established that this taxon is related to Loxospora ochrophaea (Tuck.) R. C. Harris.

Ramalina species are among the most abundant lichens on the Galapagos Isles. A total of fifteen species have been distinguished, four of which are described as new here: Ramalina darwiniana, R. fragilis, R. furcellangulida and R. polyforma. These new species are considered to be endemic to the Galapagos whereas previous reports refer to relatively common, more widely distributed species. Several other species are reported here for the first time from the Galapagos.

Opegrapha invadens Etayo on Pannaria farinosa and Plectocarpon usneaustralis Etayo on corticolous Usnea sp. are described as new from southern Chile.

A taxonomic investigation of Lethariella smithii and L. zahlbruckneri has established that they are conspecific. Three chemical races are recognized: race 1 containing norstictic acid, race 2 norstictic acid and placodiolic acid, and race 3 placodiolic acid as major medullary substances.

Chlorophyll a fluorescence was measured every three months from December 2003 to December 2004 in ten, randomly selected thalli of the epiphytic lichen Punctelia subrudecta (Nyl.) Krog occurring in a deciduous, thermophilous downy oak wood in southern Tuscany (central Italy). In situ measurements were carried out with a photosynthesis yield analyser Mini-PAM (Walz, Effeltrich, Germany) on the same measuring points of 30-minute dark-adapted, fully hydrated thalli. The results show a remarkable seasonal change in Fo, Fm, and Fv/Fm, probably caused by a long-term physiological-structural adaptation of the photobiont to the gradual modification of the climatic conditions of each measurement period and the light regime of the understorey. However, P. subrudecta is also sensitive to rapid changes in microclimatic conditions as the PSII functionality is affected by the light regime of the days preceding the field measurements. Some critical observations on the statistical analysis of chlorophyll a fluorescence parameters are also made.

The in-vitro growth rate of soredia from the epiphytic lichen species Physcia tenella was tested at different concentrations of phenols added in an in vitro experiment designed to evaluate the allelopathic effects of bark derived substances in stem flow. The conditions used were designed to resemble those found on bark of Populus×canadensis, as this tree species has been widely used for lichen mapping studies in Germany. Bark phenolic glycosides, flavonoids and tannins undergo hydrolytic decomposition in stem flow, resulting in a variety of monomeric phenolic acids, aldehydes and alcohols. Eleven phenolic substances of different biosynthetic origin in the concentration range between 10−6 M and 10−3 M in the culture medium were tested. IC50 values were calculated for each substance. Inhibition was highest for catechol, substituted phenolic glycosides, benzoic and ellagic acids, moderate for flavonoids, gallic acid, salicylic alcohol, salicylic aldehyde and low for salicylic acid. The tests show that bark phenols in natural concentrations inhibit soredial growth of the test species Physcia tenella and therefore have an influence on the growth of lichens on trees.