A new sorediate species of Rinodina (R. algarvensis sp. nov.) is describedfrom SouthPortugal, where it grows on siliceous rocks. It is mainly characterized by its distinctivechemistry, being the only saxicolous Rinodina species hitherto known to contain stictic, cryptostictic, norstictic and menegazziaic acids in addition to atranorin and zeorin. It is compared with R. aspersa, a morphologically similar saxicolous species, which also occurs in south-west Europe, and with R. stictica, a corticolous, sorediate, North American species that also contains the stictic acid chemosyndrome.

Lecania pusilla Tretiach sp. nov. is described from the Trieste Karst, where it was collected twice on epilithic mosses in protected overhangs. The new species is characterized by simple or uniseptate spores, pruinose apothecia, and Bacidia-type asci; it has a reduced, granular thallus with no lichen substances.

We present a survey of the six known species of Anhothelium occurring in the western Mediterranean. The oceanic A. lirellans, which may occur in the study area, is included for comparison; A. taediosoides is described as new and a key to all species is given. Anhothelium as understood today is composed of more-or-less distinct natural groups of species, some of them being compared here. Representatives of the A. sardoum group are related to species of the Arthonia radiata or A. galactites group on the basis o anatomical characters of the ascomata.

The genus Lecidea in the lichen flora of the gypsum soils of Spainis represented b two species: L. gypsicola Llimona and L. circinarioides Casares & Hafellner sp. nov., which are described in this article. Chemical, anatomical and ecological differences are also described, as is the taxonomic value of the morphological characteristics of the mature ascoma.

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 cyanobiont (Nostoc) of the lichen Peltigera horizontalis was isolated using a procedure of repeated grinding, differential centrifugation and partitioning in an aqueous two-phase system of dextran/polyethylene glycol. A yield of 22% was calculated on the basis of chlorophyll recovery from the thallus. Freshly isolated Nostoc differed little from that kept in prolonged culture with respect to the relative activities of a number of enzymes of carbohydrate metabolism in the soluble fraction. However, much higher specific activities of the disproportionating transglycosylase and starch phosphorylase, higher intracellular concentrations of glucose, maltooligosaccharides and glycogen and a lower rate of glucose uptake were evidentin freshly isolated Nostoc. These activities and pool sizes, as well as CO2-fixation capability, stayed roughly constant for at least 5 h after isolation; glucose release, which is characteristic for the symbiotic Nostoc, dropped sharply within 1 h. These observations suggest the transport of glucose out of the cell, rather than that theactivities of cytoplasmic enzymes may bea point of early regulation during transition of Nostoc from the lichenized to the free-livingstate.

Surface alkanes were extracted from thalli of populations of Xanthoria parietina growing in two different Piedmont (Italy) valleys: Susa and Vermenagna. The main n-alkanes detected in the Susa Valley were C27, C28, C29 and C31, whereas C25, C27 and C29 were the most abundant in Vermenagna Valley. The results indicate that the n-alkane qualitative composition of X. parietina was affected both by elevation and climatic characteristics typical of the two valleys considered.