Four new species of Caloplaca are described from Antarctica: C. buelliae is parasitic on Buellia, C. iomma has a characteristic deep reddish orange colour on the apothecia, C. psoromatis is parasitic on Psoroma and Pannaria, and C. siphonospora is a parasitic species of mosses, very similar to C. nivalis, but with much shorter spores.

Field experiments were conducted to test the effect of some agrochemicals on the growth of Cladonia furcata. Mineral fertilizer had no direct effect on lichen growth. In contrast, organic manure promoted the length of podetia. A lethal effect was recorded in the case of calcium cyanamide. In addition to direct effects of agrochemicals, indirect effects were also recorded.

Rhizocarpon (subgenus Phaeothallus) santessonii sp. nov. is described from Norway. The species grows immersed in the areolae of Tremolecia atrata when young and later develops autonomous areolae. The species is further characterized by a yellowish grey thallus containing an unidentified pigment, a non-amyloidmedulla, and 1-septate spores which are persistently colourless or become unevenly brownwith age.

Five new species of Rimularia, all endemic to Tasmania, are described, discussed and illustrated: Four species are saxicolous: R. albotessellata Kantvilas (containing pannarin): R. aspicilioides Kantvilas (containing 2′-O–methylperlatolic acid and with apothecia with a thalline margin); R. circumgrisea Kantvilas (containing norstictic acid, and with ascospores 8·5–14·0×5·0–6·5 µm); and R. coppinsiana Kantvilas (containing bourgeanic acid and with ascospores 10–19×7–12 µm). The corticolous R. asteriphila Kantvilas lacks lichen substances, contains Sedifolia-grey pigment and has ascospores 10–15×7–10 µm. The widespread R. psephota (Tuck.) Hertel & Rambold, with which several of the new taxa are compared, is also described, based on Tasmanian collections. Several chemical compounds, including bourgeanic acid, pannarin and 2′–O–methylperlatolic acid, are recorded for the genus for the first time. A key to the 12 species currently recorded for Tasmania is presented.

Lichens are colourful organisms owing to numerous combinations of algal and fungal pigments (as reviewed by Rikkinen 1995). Colour is often used in taxonomic studies to aid species identification but it is sometimes over-used as a characteristic to discriminate related genera such as, Xanthoparmelia and Neofuscelia (Poelt & Leuckert 1993). However, colour variations within species can be significant (Solhaug et al. 2003) because of spatial (Gauslaa & Solhaug 2001; Gauslaa & Ustvedt 2003) and temporal variations (Gauslaa & McEvoy 2005) in environmental factors. There are few experimental studies on lichen colours so far; as a result we do not know the relative importance of genetic versus environmental factors. Our study aimed to assess the effect of ultraviolet radiation (UVR) on the colour of the widespread foliose lichen Xanthoparmelia stenophylla (Ach.) Ahti & D. Hawksw. (until recently known as X. somloensis (Gyeln.) Hale, see Ahti & Hawksworth 2005). Usnic acid is responsible for the yellowish appearance of its upper cortex, but other colour variations are also mentioned in taxonomic literature (Brodo et al. 2001). More specifically, we wanted to discover if UVR and the photosynthate ribitol supplied by the photobiont would cause changes in pigmentation in a Xanthoparmelia species. These factors have been shown to induce and stimulate the synthesis of the orange parietin in Xanthoria parietina (Solhaug & Gauslaa 2004; Solhaug et al. 2003).

Bryoria araucana sp. nov. is described from Chile on the basis of morphological, chemical and molecular data. It has a grey to dark greyish brown pendent thallus with the base usually black, branching angles mainly obtuse, terminal branches with few lateral branchlets acutely inserted, fumarprotocetraric acid, and often protocetraric and confumarprotocetraric acids. It is morphologically similar to the Northern Hemisphere B. trichodes, but lacks soralia and has inconspicuous concolorous or slightly darker pseudocyphellae. Bryoria glabra is also reported for the first time from the Southern Hemisphere. New phylogenetic data based on ITS, mtSSU and MCM7 analyses suggest that Bryoria sect. Bryoria is polyphyletic and needs revision.

Enterographa sorediata is a corticolous, crustose lichen endemic to the southern part of Great Britain where it is confined to old-growth woodlands. This lichen is rarely fertile and mainly characterized by a sorediate thallus producing protocetraric acid. However, phylogenetic analyses using nuLSU, RPB2 and nuITS sequences suggest that E. sorediata belongs to the genus Syncesia and is conspecific with S. myrticola. This is corroborated by the chemistry and the recent observation of a thallus with both fully developed S. myrticola-like apothecia and soralia. This provides further evidence of the difficulties involved in correctly placing sorediate sterile morphs of crustose lichens into particular genera without using molecular data. An updated distribution map of S. myrticola for Great Britain and Ireland is provided, showing that the sorediate morph extends more inland whereas the fertile morph is more coastal.

Bacidia rosellizans S. Ekman is described as new to science. Morphologically, the new species is similar to the type species of the genus, B. rosella (Pers.) De Not., particularly in the pale pink and pigment-deficient apothecia and in having the proper exciple and upper part of the hymenium inspersed with minute crystals that consist at least partly of atranorin. Bacidia rosellizans, however, differs in having a thin whitish thallus, smaller apothecia and a thinner apothecial margin, a dense layer of crystals along the excipular rim, shorter and narrower ascospores with fewer septa, and septate conidia. Whereas B. rosella is a species occurring in the nemoral zone of Europe and possibly northernmost Africa and parts of Asia (but not North America), B. rosellizans is found mainly on Populus and Salix in taiga. This species is currently known from Sweden, Russia, Canada and the USA. It was erroneously treated as Bacidia rosella in a monograph of North American corticolous species of Bacidia and Bacidina by Ekman (in Opera Botanica 127, 1996).

The new species, Mycocalicium llimonae, is described based on specimens collected from cones of Pinus halepensis in the west of the Iberian Peninsula. The new taxon is compared with the other species of the genus Mycocalicium in the Iberian Peninsula, particularly Mycocalicium subtile, and also with other genera in the Mycocaliciaceae.

Stigmidium humidum is described from Spain and Turkey on Thelenella muscorum (Fr.) Vain. (syn Chromatochlamys muscorum (Fr.) H. Mayrhofer & Poelt). The species is the first Stigmidium s. str. species on a host lichen of the family Thelenellaceae and is compared with other species with ‘Type a’ pseudoparaphyses.

Two new species of Micarea are described from South Africa: M. almbornii Coppins, on loose sandstone from Stellenbosch (Western Cape) and M. endoviolascens Coppins, on damp soil from Transvaal. A note is given on Lecidea geïna Stizenb.

The passive uptake of ammonium ions to extracellular cation binding sites has been demonstrated for a range of lichen species. The possible competitive effect of other cations on ammonium binding is discussed. Binding of uncharged gaseous ammonia to exchange sites was also shown. The rapid loss of exchangeable ammonium from extracellular sites has been demonstrated and, because the greatest losses occur in living material, intracellular uptake is inferred. The labile nature of bound ammonium means that transfer of material to the laboratory for analysis may result in the underestimation of the amount bound.

Descriptions are provided for two new species, Mycomicrothelia lateralis Sipman from Norfolk Island and M. triangularis Aptroot from Puerto Rico, both characterized by lateral ostioles and uniseriate ascospores. Based on the examination of additional fresh material, the genus Ornatopyrenis is included in Mycomicrothelia and the new combination Mycomicrothelia queenslandica (Müll. Arg.) Sipman & Aptroot is made. Ornatopyrenis muriformis Aptroot is proposed as a synonym of M. decipiens (Müll. Arg.) R. C. Harris.

Nematodes were found to be abundant in a collection of Cladonia glauca from Ireland. Irregular tuberculate galls on the podetia were probably due to a species tentatively referred to Nothanguina. Aphelenchoides lichenicola sp. nov. and Ottolenchus cabi sp. nov. are described; the former may feed on the fungal component, while the latter probably parasitizes the algal partner. The separation of Ottolenchus from Tylenchus is discussed and six new combinations into Ottolenchus are proposed. Further nematodes found in the sample included species of the genera Belondira, Chilwoodius and Discotnyctus (all Dorylaimida), and a juvenile Rotylenchulus (Hoplolaimidae); this last probably a contaminant. These observations on a single collection suggest that lichens may have a rich and specialized nematode fauna.

Aspicilia crespiana Rico is described as a new species from central Spain and Sardinia (Italy). In central Spain it is common and has a well-defined ecology. It is found at middle to high altitudes (from 400 to 1900 m), overgrowing mosses on exposed and horizontal to more or less vertical siliceous rocks. Closely related to the A. contorta (Hoffm.) Kremp. complex, A. crespiana differs in its muscicolous habit and thallus development, consisting of a network of lichenized squamules interlinked by fungal rhizomorphs.

Twenty lichens and a cyanobacterium grow as epiphytes on both shoreline and inland coconut palms (Cocos nucifera) on Caye Caulker, Belize, with a difference in distribution of these epiphytes between shoreline and inland trees. Nine epiphytes were also collected from mangrove (Rhizophora mangle): seven lichens, one moss, and one cyanobacterium.

All species of Antarctic Acarosporaceae (s. lat., including Biatorellaceae) with yellow thalli are revised. Four genera, Acarospora, Biatorella, Biatorellopsis, Eklundia, and ten species, all of them endemic, were previously reported from Antarctica. Our results indicate that in Antarctica Acarospora subgen. Xanthothallia s. str. includes only two species, A. gwynnii Dodge and A. flavocordia sp. nov.; Biatorella does not occur in Antarctica, the species described by Dodge belonging instead in Candelariella; the genus Eklundia is a synonym of Candelariella; Biatorellopsis does not occur in Continental Antarctica, and the genus is a synonym of Pleopsidium; Pleopsidium is represented in Antarctica by one species, P. chlorophanum, which was treated under very different generic and specific names by earlier authors. Altogether, the number of species of yellow Acarosporaceae known from Antarctica is reduced from ten to three, distributed in two genera: Acarospora and Pleopsidium. The two Acarospora species, A. gwynnii and A. flavocordiaare apparently endemic to Antarctica, whereas P. chlorophanum is a widespread bipolar lichen. A comprehensive list of synonyms and a key are provided.