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Lichenostigma radicans Calat. & Barreno, a lichenicolous fungus growing on vagrant Aspicilia species, is described as new to science from Spain. It is superficially similar to L. maureri, with cushion-like ascomata, but differing mainly by its ascomata connected at their base to immersed, brown, vegetative hyphae. Comments on the variability of iodine reactions of asci and ascospore walls, and on an associated conidial fungus with small bacilliform conidia, are given for L. maureri.

A rapid method to isolate intact functional algae from the lichens Evemia prunastri and Ramalina farinacea has been developed. This method is based on the use of Percoll® gradients after mechanical disruption of lichen thalli. Results obtained show that the algal preparations were virtually free of contamination by fungal hyphae. The purified algal cells were photosynthetically active and without symptoms of photoinhibition, which indicates their functional integrity. This method may be used for the isolation of intact algae from a broad range of lichen species.

Lecanora herteliana is described from several collections from hard siliceous sandstone, in typically Mediterranean habitats in eastern Spain. The new species has a whitish thallus containing atranorin and norstictic acid. Its apothecia are mostly black, with a thalline exciple, which is finally excluded, and with a well developed true exciple.Lecanora herteliana is most closely related to L. subcoarctata, and it is discussed in relation to this species and other members of the L. marginata group.

Thelopsis foveolata Renob. & Barreno sp. nov., is described from Northern Spain. It appears to be very rare and easily overlooked, but has a well-defined ecology. It grows on limestone within sciaphilous and humidity-loving communities, such as Gyalectetum leucaspidis and Petractinetum hypoleucae. The pycnidia and conidiogenous cells are described and illustrated, this being the first detailed account of these structures in the genus Thelopsis.

Measurements of modulated chlorophyll a fluorescence emission and chlorophyll content were made in thalli of Parmelia quercina collected from northern Castellon(Spain). Althoug high air pollution concentrations have been measured in this area, the ratio of variable to maximal fluorescence is unaffected. Following dark-adaptation, the response to irradiance of chlorophyll fluorescence was examined. With respect to control samples, thalli collected in northern Castellon consistently showed differences in fluorescence quenching, the efficiency of excitation energy capture and quenching of basal fluorescence. However, the quantum ield of photochemistry and non-cyclic electron flow were not affected. The changes in chlorophyll fluorescence parameters were observed in the absence of both visual injuries and decrease in chlorophyll content. The results are discussed with regard to the possible role of environmental stress in chlorophyll fluorescence yield.

The influence on uptake and water loss of the structural changes experienced by Parmelia acetabulum during thallus development were investigated. Small specimens were characterized by flat lobes and a thin thallus and cortex. Large specimens appeared strongly rugose, imbricate and irregularly folded, and had a significantly thicker cortex and medulla than small thalli. Maximum water storage capacity did not differ between large and small thalli, although water retention was much higher in large thalli, presumably due to the interaction of structural characteristics and a higher boundary layer resistance. This translated into a longer duration of the period of thallus hydration in large thalli compared to small thalli. Incubation of thalli in water-vapour-saturated atmospheres induced full recovery of photosynthetic electron transport to the values before desiccation in small thalli but only induced a partial recovery in large thalli. The close correlation between photosynthetic electron transport and net photosynthesis during desiccation found in this species suggested that carbon-fixation activity could be regained to a larger extent by incubation of thalli in water vapour in small compared to large thalli. The higher ability for water vapour uptake of small thalli might allow them to efficiently use small amounts of intermittently available water or periods of high relative humidity. The significance of this differential ability to utilize water is discussed with regard to the known ecological preferences of the species.