A description is given for Cetraria obtusata (Schaerer) v. d. Boom & Sipman, comb, et stat. nov., known so far only from the central Alps, and characterized by a pale yellow, C+ yellowish orange medulla and raised pseudocyphellae often surrounded by projections. It contains the rare lichen substance secalonic acid C and two unidentified substances.

A description is given of the corticolous, sciaphilous lichen associations Ramonio-Stiguletum mediterraneae Bricaud & Roux ass. nov. and Striguletum affinis Bricaud & Roux ass. nov. These associations occur mainly in mesomediterranean Quercus ilex forests and less usually in mesomediterranean or supramediterranean Quercus pubescens forests. The former usually grow on the more or less decayed rhytidome of Quercus ilex, the latter exclusively on Hedera helix trunks.

Changes in foliicolous lichen populations of the shrub Wilkiea macrophylla in rainforest at Mt Glorious (south-east Queensland) were observed in the field for 3 years. Leaves successively distal from the twig apices were treated as a chronosequence for lichen successional studies. Five species of lichen each colonized more than 50° 0 of the leaves, and leaves successively distal from the apex showed increasing mean species number. Lichen cover rose until the seventh most distal leaf from the first colonized leaf along a twig, reaching 52%. More distal (older) leaves had apparently lower cover. Different lichen species show different instantaneous colonization rates that vary with time. The sequence of lichen colonization and subsequent community composition is best described by a ‘Tolerance’ model of succession if a single leaf is selected as the unit or with a ‘Chronic Disturbance’ model if a leaf population is considered.

The distribution of epiphytic lichens on branches of a stand of Picea abies has been mapped, and patterns of succession and community structure are described. Many crustose species are of particular interest since little is known about their ecological requirements (e.g. Fuscidea pusilla Tønsb., Japewia subaurifera Muhr & Tønsb. and Gyalideopsis alnicola Noble & Vězda). Numerical treatment (correspondence analysis and canonical correspondence analysis) of the species data was used to study the lichen distribution in relation to measured environmental variables. Tree age, tree height and branch height above ground are shown to be the most important variables to explain the species distribution. No significant relationship was found between branch compass point and the distribution of lichens. The species composition and cover changed from young to old trees. The largest variation in the lichen vegetation was found on the branches of young trees. A more homogeneous and stable lichen community appears on branches of mature trees. A clear zonation of the epiphytic vegetation develops as the branches grow, resulting in the occurrence of typical ‘branch-tip’ and ‘branch-base’ species. The highest number of species was recorded on the outermost part of branches before lichen cover reached the maximum. Hyperepiphytic thalli were mainly located in specific areas with high lichen cover on the branches. Lichens with reduced vitality were most common at the base of branches.

This bibliographic review includes 316 works specifically devoted to lichens and biodeterioration of stonework and covers the time-span from 1825 to 1992. The list is accompanied by an analytical index in which the number of the articles is referred to under the appropriate topic category.