Eighteen species of foliicolous lichens have been mentioned earlier from the Fiji Islands in various literature sources and based on collections since 1860. Current records originate from the collections of Göran Thor from 1985 and Sarolta and Tamás Pócs from 2003. G. Thor visited lowland rainforests of Island Viti Levu, S. and T. Pócs collected also in higher elevations (up to ca 1,000 m) in submontane, montane and montane mossy (cloud) forests on Kadavu, Taveuni and Viti Levu Islands. These relatively small collections (of ca 300 and 150 leaves, respectively) resulted in 78 species of the 85 lichen species known today, among them 67 species are new for the foliicolous lichen flora of the area in this publication. New taxa described are Phylloblastia taveuniensis Farkas, Porina kadavuensis Farkas, furthermore the genus Tamasia Farkas (Ramalinaceae) and species Tamasia fijiensis Farkas containing cyanobacterial photobiont. Eighteen species of foliicolous lichens have been mentioned earlier from the Fiji Islands in various literature sources and based on collections since 1860. Current records originate from the collections of Göran Thor from 1985 and Sarolta and Tamás Pócs from 2003. G. Thor visited lowland rainforests of Island Viti Levu, S. and T. Pócs collected also in higher elevations (up to ca 1,000 m) in submontane, montane and montane mossy (cloud) forests on Kadavu, Taveuni and Viti Levu Islands. These relatively small collections (of ca 300 and 150 leaves, respectively) resulted in 78 species of the 85 lichen species known today, among them 67 species are new for the foliicolous lichen flora of the area in this publication. New taxa described are Phylloblastia taveuniensis Farkas, Porina kadavuensis Farkas, furthermore the genus Tamasia Farkas (Ramalinaceae) and species Tamasia fijiensis Farkas containing cyanobacterial photobiont.

Terricolous lichens are relevant associates of biological soil crusts in arid and semiarid environments. Dunes are ecosystems of high conservation interest, because of their unique, vulnerable and threatened features. The function of lichens is affected by the changing seasons and different microhabitat conditions. At the same time, inland dunes are less investigated areas from the terricolous lichens point of view. We explored the effect of seasonal variation and different micro-environmental conditions (aspect) on the metabolic activity of five terricolous lichen species, representing various growth forms, in temperate semiarid grasslands. Populations of Cladonia foliacea, C. furcata, C. pyxidata group, Diploschistes muscorum and Thalloidima physaroides were investigated. Thalli sampled from the south-west and north-east facing microhabitats were studied by chlorophyll fluorescence analysis for 2 years. The present study aims to understand how changing climate (during the year) and aspect affect photosynthetic activity and photoprotection. Microclimatic data were also continuously recorded to reveal the background of the difference between microhabitat types. As a result, the air temperature, photosynthetically active radiation, soil temperature and vapour pressure deficit were significantly higher on south-west than on north-east facing microsites, where relative humidity and water content of soil proved to be considerably higher. Higher photosynthetic activity, as well as a higher level of photoprotection, was detected in lichens from north-east-oriented microsites compared with south-west populations. In addition, the difference between sun and shade populations varied seasonally. Since a species-specific response to both aspect and season was detected, we propose to investigate more than one species of different growth forms, to reveal the response of lichens to the changing environment in space and time.

The terricolous species Cladonia foliacea (Cladoniaceae, lichenised Ascomycota) widely distributed in open, dry lowland steppe and rocky mountain grassland vegetation in Europe was chosen as a potential test organism for ecological experiments, since their thalli are producing cortical solar radiation-protective and UV screening pigment dibenzofuran usnic acid and medullary secondary substance depsidone fumarprotocetraric acid. Significant seasonal differences were found in the amounts of lichen secondary metabolites analysed by HPTLC and HPLC-PDA between summer and winter collected thalli in sandy grassland area in Hungary. The concentrations of usnic acid varied between 7.34 and 15.52 mg/g in summer collected samples and 13.90 and 21.61 mg/g in winter collected ones. A comparable amount (11.61±0.29 mg/g) was measured in pulverised samples. The concentrations of fumarprotocetraric acid varied between 0.60 and 3.01 mg/g in summer collected samples and 2.26 and 5.81 mg/g in winter collected thalli. A comparable amount (2.45±0.21 mg/g) was found in pulverised samples. The range of concentration values is comparable with data known from lichens. A higher amount of usnic acid is produced in winter probably to ensure sufficient protection also for summer. The fumarprotocetraric acid content of the medulla might contribute to the solar irradiation reflecting role of the pale lower surface lobes turning upwards in dry condition.

In lichens, each symbiotic partner cooperates for the survival of the symbiotic association. The protection of the susceptible photosynthetic apparatus is essential for both participants. The mycobiont and photobiont contribute to the protection against the damaging effect of excess light by various mechanisms. The present study investigated the effect of seasonality and microhabitat exposure on photoprotection and photoacclimation in the photo- and the mycobiont of six lichen species with different thallus morphology in inland dune system in the Kiskunság region (Hungary) with shaded, more humid and exposed, drier dune sides. High-Performance Liquid Chromatography, spectrophotometry, chlorophyll a fluorescence kinetic technique were used, and micrometeorological data were collected. The four years data series revealed that the north-east-facing side was characterized by higher relative humidity and lower light intensities compared to the south-west-facing drier and more exposed sides. The south-west facing side was exposed to direct illumination 3–4 hours longer in winter and 1–2 hours shorter in summer than the north-east facing side of the dune, influencing the metabolism of sun and shade populations of various species. Because rapid desiccation caused short active periods of lichens during bright and drier seasons and on exposed microhabitats, the rapid, non-regulated non-photochemical quenching mechanisms in the photobiont had a significant role in protecting the photosynthetic system in the hydrated state. In dehydrated conditions, thalli were mainly defended by the solar screening metabolites produced by the mycobiont and curling during desiccation (also caused by the mycobiont). Furthermore, the efficacy of light use (higher chlorophyll and carotenoid concentration) increased because of short hydrated periods. Still, a lower level of received irradiation was appropriate for photosynthesis in dry seasons and on sun exposed habitats. In humid seasons and microhabitats, more extended active periods lead to increased photosynthesis and production of solar radiation protectant fungal metabolites, allowing a lower level of photoprotection in the form of regulated non-photochemical quenching by the photobiont. Interspecific differences were more pronounced than the intraspecific ones among seasons and microhabitat types.

The distribution patterns of lichen secondary metabolites are often taxon specific. They represent cryptic chemical diversity additional to morphological-anatomical biodiversity. Cetrelia W.L. Culb. & C.F. Culb. species (c. 200 specimens) were checked and revised by thin-layer chromatography. Soredia, pseudocyphellae, rhizines, features of lower surface are the main morphological characters analysed against the presence of cortical pigment, atranorin and medullary α-alectoronic acid, anziaic acid, α-collatolic acid, β-alectoronic acid, β-collatolic acid, imbricaric acid, 4-O-demethylimbricaric acid, olivetoric acid, perlatolic acid, physodic acid and 4-O-methylphysodic acid. The European occurrence of C. chicitae (W.L. Culb.) W.L. Culb. & C.F. Culb. – described from America – is confirmed on the basis of identical secondary metabolite composition by seven lichen substances. Four species were revealed and mapped in Hungary. Cetrelia chicitae and C. monachorum (Zahlbr.) W.L. Culb. & C.F. Culb. are new for the Hungarian lichen flora. From the originally known two taxa C. cetrarioides (Delise) W.L. Culb. & C.F. Culb. proved to be rare, C. olivetorum (Nyl.) W.L. Culb. & C.F. Culb. is less frequent than regarded earlier. Currently C. monachorum is the most frequent Cetrelia species in Hungary. Cetrelia chicitae and C. cetrarioides may need protection measures. Parmelia cetrarioides f. pseudofallax (Gyeln.) Gyeln. is lectotypified here.