Lecanora zosterae (Ach.) Nyl. is a distinct species belonging to the Lecanora dispersa group. In the British Isles it is confined to the coast where it grows mostly on the exposed turf above sea cliffs. Some 76% of the population occurs on decayed thrift Armeria maritima. The related Lecanora umbrina (Ach.) A. Massal. is lectotypified; it is the correct name for Lecanora hagenii auct.

Stigmidium cartilagineae Calatayud &Triebel (on the apothecial discs of Squamarina cartilaginea), a lichenicolous fungus belonging to Stigmidium s. str., is described as new. Two other species of Stigmidium s. 1. with a net of branched and anastomosing, rudimentary interascal filaments are also described as new to science: Stigmidium rouxianum Calatayud & Triebel (on Acarospora cervina) and S. squamarinicola Calatayud & Triebel (on the thallus of Squamarina spp.). They are related to Stigmidium psorae and treated here as ‘Stigmidium’ psorae group. To facilitate discussion of the distinguishing features of this group, a table comparing the terms referring to hamathecial hyphae in pyrenocarpous ascomycetes is presented.

The morphology, anatomy, ecology and distribution of Buellia tesserata and Dimelaena radiata are discussed. New data on their chemistry are given. The present study reveals a very close relationship between both taxa and consequently their different generic position is questioned. Buellia fimbriata is reduced to synonymy with Buellia tesserata.

Comments on and a key to the 13 Polycoccum species known in Spain are presented, including synopses of their world distributions. Amongst these is P. rubellianae sp. nov., a lichenicolous fungus growing on thalli of Caloplaca rubelliana in eastern Spain (Valencia). It has relatively small ascomata, the lower part pale brown, and also small ascospores which are coarsely verrucose and have a thick gelatinous sheath when young. The new species is associated with a Phoma-like anamorph. The identity and systematic position of P. opulentum requires further study as the name has been applied to different species, and the occurrence of P. marmoratum in Spain is in need of confirmation. The Spanish record of P. arnoldii on Lecania cyrtella probably refers to another yet undescribed species.

The diversity of species of Ramalina occurring on the outlying islands of the New Zealand geographic area is linked to their methods of dispersal and the origin and principal climatic features of the islands themselves. It appears that species of Ramalina have reached these islands by transoceanic, wind-borne dispersal of ascospores and soredia, not necessarily in the direction of the prevailing winds. Species have become established on the islands only if both climatic and habitat requirements have been met.

A new species Opegrapha cladoniicola, lichenicolous on the podetia of Cladonia ochrochlora, is described from Hawaii. It is the first known Opegrapha species found growing on Cladonia.

The systematic position of the lichen genus Heppia in the order Lichinales was investigated. 18S rDNA sequence data were analyzed using a Bayesian approach to infer phylogeny using Markov chain Monte Carlo methods. The Lichinales are divided at family level into the sister groups Lichinaceae and Peltulaceae. The genus Heppia forms a highly supported clade in the family Lichinaceae. It is shown that the genus Heppia is morphologically well circumscribed within the Lichinaceae. As a nomenclatural consequence, the family name Heppiaceae is placed into synonymy under the older name Lichinaceae.

The distribution of alectorioid lichens in subalpine spruce-fir forests of north-central British Columbia is strongly influenced by vertical position within the canopy; Bryoria dominates upper canopy exposures, while Alectoria dominates lower canopy positions. The hypothesis that this height-related niche partitioning reflects differential growth responses to gradients in canopy microclimate is examined. Field measurements of canopy microclimate, taken over a 2-year period, were used in conjunction with laboratory-based measurements of net photosynthesis (NP) and dark respiration to model net assimilation (NA) response of Alectoria sarmentosa and Bryoria spp. (mixed collections of Bryoria fremontii and B. pseudofuscescens) at two different heights (15 and 4 m) within the canopy. Microclimate measurements indicate that lichen thalli are regularly hydrated from snowmelt events during the winter period (October-April), totalling 26 and 29% of the time, respectively, for Alectoria and Bryoria, though most winter hydration exposure (c. 75%) occurred in the dark. In the summer (May-September), rainfall was the major hydration source, with Alectoria and Bryoria each hydrated c. 16% of the time (45% of this in the dark). The NP temperature optimum (Topt) in light saturated thalli of Alectoria was 18.1 and 22.9°C, for winter and summer measurements, respectively. In Bryoria the corresponding seasonal rise in Topt was smaller, from 15.9 to 16.3°C. Both species showed an increase in maximum rates of NP during the summer period, from 1.52 to 1.92 mg CO2 g−1h−1 for Alectoria, and from 1.79 to 2.33 mg CO2g−1 h−1 for Bryoria. Although lichen hydration events peaked in early winter (October and November), NA modeling predicts that maximum growth should occur during the summer period. In Alectoria, higher rates of NA were predicted for thalli in lower canopy positions, especially during the summer months. In Bryoria, no clear trends of NA uptake with canopy position were observed. Thus, while NP response to gradients of canopy microclimate may provide a basis for niche partitioning in Alectoria, other factors (perhaps exclusionary) may be more important for Bryoria. One such factor is documented, namely the greater sensitivity of Bryoria to extended hydration exposure and we speculate that greater rates of fragmentation in upper canopy exposures may limit upper canopy biomass accumulation in Alectoria. Niche partitioning in these alectorioid lichens may therefore reflect both positive (growth responses) and negative (physical and physiological limitations) responses to gradients in canopy microclimate.

Polysaccharides from thalli of Lasallia pustulata were extracted and characterized. The major fractions were characterized as pustulan, a β-glucan-chitin complex and a β-(1→3)-glucan. Other polysaccharides, which are minor components (less than 5%) solubilized with water from the alkali extracts of thalli, were shown to be galactomannans with a backbone of α-(l→6)- mannose partially substituted at positions 2 by galactofuranose and/or mannopyranose side chains of variable length. The relationship between these polysaccharides and those obtained by the same method from free-living fungi is discussed. The proportion or composition of the different polysaccharides studied was not affected by seasonal environmental conditions over a 2-year period.