Fifty-six known lichenicolous, non-lichenized Opegrapha (Roccellaceae, Arthoniales) species (containing some undescribed taxa) are listed here, five of which are known from Caloplaca (Teloschistaceae, Teloschistales). Opegrapha vulpina, a new lichenicolous fungus on endolithic Caloplaca subg. Pyrenodesmia (Caloplaca erodens and rarely C. albopruinosa), is described from Europe. A second new species, Opegrapha hellespontica, lichenicolous on Caloplaca aurantia, is described from the European part of Turkey. Two possible sibling species of Opegrapha rupestris s. l. lichenicolous on Caloplaca cirrochroa and C. variabilis s. l., respectively, are discussed in the paper, but have not been described.

We describe Calicium sequoiae as a new species of lichenized Ascomycota from north-western California, USA. The species is distinguished morphologically from other known members of Calicium by its stalks that react I+ blue, mature ascospores that are ornamented with spiral ridges, and apothecia that produce prominent white pruina. It is also the only Calicium known to produce thamnolic acid as a major secondary substance. Sequences from the ITS-region showed C. sequoiae to be unique among calicioid Physciaceae, and phylogenetic analysis positioned it close to C. adspersum, C. chlorosporum, C. lenticulare, Cyphelium notarisii, and C. tigillare. Thus far, Calicium sequoiae has been collected only from old-growth redwood (Sequoia sempervirens) forests, where it occurred on thick, fibrous bark of large redwood trees. A key to the 12 species of Calicium known from the Pacific Northwest is provided.

The new lichen genus Myochroidea is described to accommodate four species of the Lecidea leprosula group. Myochroidea is characterized by a crustose, areolate, minutely crenate to almost coralloid or indistinct, grey-brown to olive-brown thallus, reddish brown apothecia with an often persistent margin, moderately branched and anastomosing paraphyses with often swollen, pigmented apical cells, asci of the Micarea-type, and colourless, one-celled, fusiform to broadly ellipsoid ascospores. The new combinations Myochroidea leprosula (Arnold) Printzen, T. Sprib. & Tønsberg comb. nov., M. porphyrospoda (Anzi) Printzen, T. Sprib. & Tønsberg comb. nov., M. rufofusca (Anzi) Printzen, T. Sprib. & Tønsberg comb. nov. and the new species M. minutula Printzen, T. Sprib. & Tønsberg are published. Lecidea porphyroplaca Hinteregger & Poelt is a synonym of M. rufofusca. Descriptions of the four species and an identification key are provided. Myochroidea leprosula and M. rufofusca are reported as new to North America.

The new species Parmeliella subfuscata A. Dube & Makhija, belonging in the P. mariana group, is described. It is recognized by its squamulose, loosely attached, spreading, brownish thallus with cylindrical, branched isidia, indistinct, black prothallus of slightly projecting rhizohyphae, and its apothecia with an unusual, fresh green coloured epithecium and proper exciple. It is so far known only from the type locality in Maharashtra, India.

Australian records of Scoliciosporum are reviewed. The new species, Jarmania scoliciosporoides Kantvilas, is described, based on Tasmanian material previously referred to Scoliciosporum pruinosum (P. James) Vězda; the systematic position of these two taxa is considered. Two further species recorded previously, S. compactum Körber and S. umbrinum (Ach.) Arnold, are discussed and all records united under the latter name; S. umbrinum is reported from Tasmania for the first time.

The new genus Vahliella is recognized as a genus since molecular studies have shown that the subgenus Micropannaria of Fuscopannaria differs so much from this genus that it cannot even be placed in the Pannariaceae. While its family position remains unclear, it is certainly best established as a genus, as it is recognizable also on morphological and chemical characters. Unlike the mainly warm-temperate genus Fuscopannaria, it is restricted to cold-temperate regions. Presently it is known to contain eight species, a key to which is given. The following new combinations are introduced: Vahliella adnata (P. M. Jørg. & Upreti), Vahliella atlantica (P. M. Jørg. & P. W. James), Vahliella californica (Tuck.), Vahliella globuligera (Fryday & P. M. Jørg.), Vahliella hookerioides (P. M. Jørg.), Vahliella labrata (P. M. Jørg.), Vahliella leucophaea (Vahl), Vahliella saubinetii (Mont.).

We have studied and tried to clarify the application of names of all the lichenicolous fungi described by Carlos Spegazzinii. Several of these names have not previously been treated by mycologists currently specializing in lichenicolous fungi. Verruculina gen. nov. is introduced with V. sigmatospora (Speg.) Etayo (syn. Metanectria sigmatospora) as type, and the new combination Scutula nephromatis (Speg.) Etayo (syn. Patellea nephromatis) is made. Material of several species, Diplosporium caudatum (on Punctelia), Pleurotus lichenicolus (on Usnea), Pyrenopeziza lichenicola (on Flavoparmelia), Selenosporium lichenicola (on Candelaria) and Vermiculariella lichenicolum (on Physcia and Peltigera), could not be located in Spegazzini’s collections in La Plata (LPS), therefore these names remain to be clarified.

Nineteen lichens new to sub-Antarctic Heard Island are recorded. Three species are described as new: Gyalideopsis heardense Øvstedal, Mycobilimbia subbyssoidea Øvstedal and Psoroma absconditum Øvstedal. Altogether the total number of lichen species recorded on the island is now 90.

The distribution of different ecological groups of lichens (acidophytes, ‘nitrophytes’, indifferent species) was compared on 1–24 year-old twigs of Abies sibirica sampled in the ‘pristine’ West Sayan and the polluted East Sayan Mountains (Krasnoyarsk District, South Siberia, Russia) to test their value as indicators of current pollution effects. Bark pH of twigs and bark chemistry (N, S, Ca, Mg, Al, Fe) were measured, and a preliminary estimate of emissions in the Krasnoyarsk District from livestock animal populations was calculated. In both regions, an unusually high twig bark pH and an abnormal species composition for A. sibirica canopy were found (e.g. Physcia aipolia, P. dubia, P. tenella, Phaeophyscia sp., Melanelia exasperatula and Candelariella vitellina), with P. tenella (East Sayan) and M. exasperatula (West Sayan) as dominants. The results confirm that the distribution of lichen species on Abies sibirica twigs is a valuable indicator of current changes in atmospheric conditions.

Alectorioid and foliose lichens were weighed from full-size branches of Picea abies cut at two canopy heights in 100 trees in an old subalpine forested area in eastern Norway. The mean lichen biomass per branch decreased from 46 to 37 g moving upwards from 2–3 to 5–6 m canopy height. The lichen biomass correlated strongly with branch size variables, branch diameter alone explaining 48 of the variation in lichen biomass per branch (n=200). The alectorioid/foliose biomass ratio increased from 0·149 at 2–3 m to 0·316 at 5–6 m. Site factors reflecting openness of the canopy were computed for the branch at 2–3 m in all trees. The alectorioid/foliose biomass ratio increased significantly with the indirect site factors, suggesting that light, or factors associated with light, determine the balance between these two growth forms in tree canopies. Within the alectorioid biomass component, genera with usnic acid (Alectoria, Usnea) decreased with height, whereas the genus Bryoria with melanic pigments increased. According to the literature, dark melanic pigments have higher visible light screening efficiency than the yellowish usnic acid. Such patterns suggest a functional role for cortical pigments in the niche differentiation of alectorioid lichens.