The terricolous species Verrucaria xyloxena Norm, and V. bryoctona (Th. Fr.) A. Orange comb. nov. are described and figured. Verrucaria sibirica Zahlbr. is described briefly and the interpretation of the name V. velutina (Bernh.) Ach. is discussed.

A sterile, sorediate, corticolous, crustose lichen from Central Sweden is tentatively assigned to the genus Buellia as B. violaceofusca sp. nov. It grows on the bark of old trunks of Quercus robur in moist, dense woods dominated by that tree.

Macentina dictyospora sp. nov. is described from wood of Betula in northern Sweden; it is distinguished from the other members of the genus by the submuriform ascospores.

The sorediate species Hyperphyscia variabilis Scutari from South America is described as new. Its apparent affinities with H. crocata Kashiw.are briefly discussed. The correlation between the type of ascospores (number and disposition of septa) and the geographical distribution of species throughout the genus is stressed, and three species groups are distinguishedon this basis. Two new combination, Hyperphyscia coralloidea (Lynge) Scutari and Hyperphyscia viridissima (Mull. Arg.) Scutari, are proposed.

The status of the lichen genus Endocarpon Hedwig (Verrucariaceae) in Australia is reviewed. Ten taxa are recognized including the following newlydescribed entities: E. aridum McCarthy, E. crassisporum McCarthy & R. Filson, E. macrosporum McCarthy, E. robustum McCarthy, E. rogersii McCarthy and E.simplicatum var. bisporum McCarthy. Endocarpon victoriae Müll. Arg. is a synonym of E. simplicatum (Nyl.) Nyl. Endocarpon pallidum Ach. is reported for the first time from Australia. A problematical corticolous specimen from Victoria is discussed.

Usnea elixii sp. nov. is a restricted endemic of north Queensland. It is usually fertile, but produces a continuum of morphs, with the other extreme being a sterile isidiate morph with large pseudocyphellae. All morphs produce protocetraric acid.

The first lichen records from the Maldives archipelago, based on fieldwork of the author in 1989, are presented. The flora is poor, due to lack of habitat variation; in total 20 species were found. The pantropical element is well represented. The lichen flora shows most resemblance to that of other coastal areas in the palaeotropics.

Epiphytic lichen communities on trunks of Pinus sylvestris and Picea abieswere studied on a west–to–east gradient through the central pan of Finland with special reference to macrolichens. Comparisons were made between the two conifer species, the coast of the Gulf of Bothnia and the more continental inland area, open commercial and denser natural forests differing in their local climate, and tree bases (0·0–0·7m) and upper trunks (0·7–2·0m). Differences were found not in species composition but in relative species abundance, the main distinction being between the two tree species. There were also noticeable geographical, vertical and habitatdependent differences. In addition to climatic factors, the importance of bark properties for the epiphytes is briefly discussed.

A technique for transplanting epiphytic lichens is described by reference to a rescue operation involving Lobaria amplissima at Lowther Park, Cumbria. Fourteen transplantswere monitored for 10 years after which period 70% survived. All failures occurred during the first 12 months.

The indirect determination of water content in lichen thalli by means of impedance measurement is described. This technique applies an alternating current between small clips placed at the margins of lichen thalli. Two zones of sensitivity were apparent in measurements with the foliose lichen Xanthoparmelia chlorochroa. Ready discrimination was provided between fully saturated thalli and thalli with standing surface water films. Similarly, this technique proved highly accurate as a measurement of thallus moisture content at water potentials of –2·5 MPa and less (between 0 and 40% water content by weight in X. chlorochroa). Resolution was lower at intermediate water contents (c. 60–100Δ water content by weight), although general trends were still clearly evident. This technique is ideally suited for unattended measurements of water potential in lichens using currently available data–logger technology and provides high resolution within the range of water potentials crucial to the control of physiological activity in lichens