A description of the polysporous Buellia dives (Th. Fr.) Th. Fr. is provided. It is distinct from Buellia polysporella (Nyl.) Arnold, with which it has been placed in synonomy, by the lecideine (versus lecanorine) apothecia, the dark brown (versus colourless) hypothecium and the Buellia-type (versus Physcia-type) ascospores. Further, B. polysporella is shown to be conspecific with Rinodina polyspora Th. Fr. and is reduced to synonomy with that species. Buellia dives is reported as new to Norway and Spain and notes on its ecology and distribution are given.

The new combination Stereocaulon cumulatum (Sommerf.) Timdal is made for the northern Eurasian and Greenlandic, arctic-alpine, terricolous lichen presently known as Toninia cumulate (Sommerf.) Th. Fr.

Apothecia from Usnea longissima thalli collected in the Oregon Coast Range are described. Fertile U. longissima specimens have seldom been observed and rarely documented in the literature. A brief history of accounts in the literature is given, and possible reasons for the infrequent occurrence of apothecia are discussed. This is the first published account of fertile U. longissima specimens in the U.S. Pacific Northwest.

A taxonomic revision of the lichen genus Gymnoderma Nyl. sensu Yoshimura & Sharp (Cladoniaceae) based on an integrative analysis of polyphasic characters supports the segregation of a new genus Cetradonia J.-C.Wei & Ahti in a new family Cetradoniaceae J.-C.Wei & Ahti. The monotypic genus and family are based on Cladonia linearis Evans. In addition, two species are recognized in genus Neophyllis F. Wilson and two species are retained in the genus Gymnoderma Nyl. of the Cladoniaceae.

Fuscoderma papuanorum is described as the first species of this genus to occur so close to the Equator, being part of the austral element of the New Guinea flora. The genus appears to be of considerable age.

A key is provided to all genera currently included in the cyanobacterial lichen family Lichinaceae as well as some close relatives. Characteristic features of the family are described and illustrated.

The lichen genus Calycidium Stirt. (Calycidiaceae, Lecanorales, ‘Caliciales’ s. lat.) contains two species: C. cuneatum Stirt., distributed in Australia (Tasmania) and New Zealand, and C. polycarpum (Colenso) Wedin, comb, nov., distributed in Argentina, Australia (Tasmania), Chile and New Zealand. The morphology, chemistry, ecology and distribution of the two species is discussed, as is the taxonomic position of the genus. Calycidium is reported as new to Argentina.

Two patterns of lichen zonation on cobbles were observed in the Negev Desert, Israel: growth on the top of the cobble and growth on the cobble margins. The causes of the different patterns are examined. Microscopic examinations did not reveal any textural or structural differences between the top and the margins of each cobble, excluding the possibility that mineralogical differences are responsible for the patterns observed. Field measurements have, however, shown a significant difference in the quantities of average daily dew, with the top of the cobbles receiving approximately double the quantity received at the margins. These results were consistent on all cobbles examined, loose as well as partially embedded cobbles. In addition, field observations following rain noted a greater moistness at the margins of partially embedded cobbles. This phenomenon, also observed following sprinkling experiments, was explained by water capillary rise. Whilst the top dwelling pattern may be explained by the significantly larger quantities of dew on the top of the cobble, the margin-dwelling pattern may be explained by greater moistness at the cobble-soil interface due to water capillary rise. Providing that the threshold moisture duration is met, lichen colonization may be expected. An estimated annual daylight moisture duration of approximately 260-320 h is thought to be necessary for lichen growth in the Negev. The findings may assist in evaluating weathering rates and paleoclimate reconstruction.