Oliver Gilbert was a pioneer, an outstanding field botanist and inspirational scientist. He worked in the broad fields of urban and lichen ecology and had almost 40 years of teaching and research experience within universities. Above all he was very approachable, an excellent teacher and fun to be with. Oliver was a leading figure in the British Lichen Society serving as BLS Bulletin Editor (1980–89 except 1987), President (1976–77) and was a frequent Council Member. He was elected an Honorary Member in 1997 and received the prestigious Ursula Duncan Award in January 2004. Oliver had an exceptional ability to find rare and interesting lichens and plant communities that others had overlooked and he constantly challenged conventional wisdom that particular habitats were uninteresting, especially urban habitats. His ecological ‘field craft’ skills were equally legendary. Passion for field work and British Lichen Society field meetings led him to organize a small grant awards scheme to stimulate others to attend field meetings and to submit their results for publication in the BLS Bulletin.

Micarea hypoviolascens sp. nov. (Pilocarpaceae) is described from an ancient woodland in western Scotland. It is the second species within Micarea known to have the olivaceous, K+ deep violet pigment (Sedifolia-grey) in the hypothecium.

Strigula muscicola Berger, Coppins, Cl. Roux & Sérus. is described as new to science; it is a muscicolous species with aggregated ascomata and 3-septate ascospores, growing in subalpine habitats in Austria, Norway and Scotland.

Lecidea hercynica Hauck & Schmull is described as a new species from Germany. It is characterized by a poorly developed or bullate to verrucose, areolate thallus on whitened spots of the substratum, numerous plane to yellowish brown to black, convex apothecia with a persistent margin, Micarea type-like asci, and by the presence of atranorin and protocetraric acid. It does not belong to Lecidea s. str., but is provisionally placed in Lecidea s. lat. until a taxonomic treatment of the whole group has been carried out. Lecidea hercynica is widespread in high-elevation forests of Picea abies in the Harz Mountains, where it grows preferably on decorticated wood in open situations.

Tetramelas phaeophysciae, a new obligately lichenicolous species occurring in Scandinavia, Iceland and Greenland, is described, and the closely related Buellia pulverulenta, together with B. triphragmioides, are transferred to Tetramelas. Phylogenetic reconstructions based on sequence data from nITS1-5.8S-ITS2 rDNA, using Bayesian inference and parsimony analyses, support the segregation of the new species from B. pulverulenta as well as the segregation of Tetramelas and Diplotomma from Buellia s. str.

The new genus Lambinonia Sérus. & Diederich is introduced for the lichenicolous hyphomycete Melanconium strigulae Elenkin & Woron. This species forms dark sporodochia on the surface or at the margin of the thalli, or extruding out of the perithecia and pycnidia of the foliicolous Strigula buxi, S. nemathora and S. nitidula. It is so far known from the western Caucasus (Georgia and Russia), southern Italy, Tenerife (Canary Islands), St-Lucia (West Indies), and Burundi and Rwanda in Africa. The new combination Lambinonia strigulae (Elenkin & Woron.) Sérus. & Diederich is introduced and a neotype collection is designated.

A new species of Cryptothecia (Arthoniales, lichenized ascomycetes) is described from Northern Thailand. The species has been collected from planted mango trees at a single site in a rural area and is characterized by the punctiform soralia, soredia containing gyrophoric acid and 8-spored asci.

Melanohalea nilgirica Divakar & Upreti is described as new to science. Melanelixia glabroides (Essl.) O. Blanco et al., Melanohalea poeltii (Essl.) O. Blanco et al., M. septentrionalis (Lynge) O. Blanco et al., Parmelia isidioclada Vain., P. masonii Essl. & Poelt, Parmelinopsis afrorevoluta (Krog & Swinscow) Elix & Hale and Parmeliopsis ambigua (Wulfen) Nyl., are new records for the Indian lichen flora.

A corticolous species, Anisomeridium flavovulcanus, is described. It has so far been found in the Carribean and Pacific lowland rainforests of Costa Rica, where it is a frequent lichen in the understorey. This conspicuous lichen is characterized by large conical conidiomata, which release a yellow conidial mass at the apex. Dimorphic conidia occur in the same conidiomata: 1-septate microconidia and thick walled globose macroconidia. Ascomata were found only twice; the inconspicuous perithecia are hemispherical, semi-emergent with an apical ostiole, the asci are cylindrical with a cruciform ocular chamber and the ascospores are uniseriately arranged.

Schaereria dolodes (Nyl. ex Hasse) Schmull & T. Sprib. comb. nov., an epiphytic lichen species known from western North America was originally described as a member of the genus Lecidea sensu lato. However, its morphology is very characteristic of the genus Schaereria Körb. Here, we lectotypify the species and propose its placement in the latter genus. It is also reported as new to Canada from British Columbia.

The growth of the alpine lichen Cetraria nivalis was followed in a chronosequence of 240 years of primary colonization in a glacier foreland in the Jotunheimen mountain range and National Park in Norway. The largest thallus of C. nivalis was 96 mm in diameter. It was found in the area that had been exposed for a maximum of 240 years. If this individual thallus became established at about the time the habitat was exposed, its average annual diameter increase has been 0·4 mm per year. The growth curve of C. nivalis does however exhibit a pattern of fast growth in the first years followed by a decrease in growth rate. In contrast the population density of C. nivalis increases through time in a linear manner, from 0·4 thalli/m2 in the areas recently exposed to 10·5 thalli/m2 in the sites exposed for maximum of 240 years. This suggests a fairly stable flow of propagules over the landscape through the years. The size distribution (population structure) of thalli within the foreland is skewed, with many small individuals and few big ones.

The effects of two logging strategies and edge effects on cover and abundance of the epiphytic chlorolichens Cavernularia hultenii, Platismatia glauca and P. norvegica were studied in an experimentally logged boreal spruce forest. Whether lichen size distribution within the three species was affected by logging regimes was also tested. One hundred and ten branches were sampled at random within: (1) fine-grained clearcuts consisting of 23 cutblocks 0·25 ha each; (2) coarse-grained clearcuts consisting of 3 clearcuts 2·25 ha each; and (3) a control area.

Of the three species studied, C. hultenii was the most vulnerable to logging, with an abundance much lower in logged areas than in the control area. By contrast, P. glauca was equally abundant in the fine-grained area and in the control area, but significantly less abundant in the coarse-grained area where it seems to have been adversely affected by a pronounced edge effect. No such edge effect, however, was noted in the fine-grained area. Juvenile thalli of C. hultenii and P. glauca were less frequent in the coarse-grained area than in the fine-grained and control areas, suggesting that the juvenile stage might be more sensitive to logging than mature thalli. These results indicate that creation of large clearcuts (2·25 ha) may not be in accordance with the goal of maintaining population size in either C. hultenii or P. glauca. However, P. glauca does not seem to be negatively influenced by a fine-grained logging pattern. No effect of logging strategy or distance from the forest edge was observed on P. norvegica. It follows from the above that any management plans aimed at maintaining population size should be based on an understanding of ecology and life history gleaned from the area in question.

Changes in habitat affect the distribution of species at different spatial and temporal scales. Our aim was to assess the use of several retrospective methods when determining habitat history and its influence on species distribution, using the pendent lichen Usnea longissima Ach. as a model organism. The study was carried out in a Norway spruce dominated forest, located in the middle boreal zone of northern Sweden. Historical sources (including forest inventories and maps) and dendrochronology were combined with field surveys to determine past stand characteristics with a high spatial precision. Also, present stand characteristics were thoroughly surveyed and the relationship between distribution of U. longissima and past and present habitat characteristics were evaluated. Our results showed that, despite the fact that historical logging was unevenly distributed within the study area, similarities in stand structure exist today. Several essential factors affecting the distribution of U. longissima could be related to changes in past stand structure, especially the extent and intensity of previous logging operations and the subsequent stand development during the last c. 150 years. Our results also showed that U. longissima was favoured by a continuous old age structure with canopy openness preserved. The importance of detailed reconstructions of specific habitat components is highlighted when relating species presence to habitat change. It is suggested that the use of retrospective methods presented in this study can be helpful in clarifying possible causes for the complex distribution of certain organisms.