The first lichen-forming species of Psammina, P. palmata sp. nov., is described from decorticate oak in West Suffolk (UK). It is distinguished from other species by the palmate and 2–3-order branched non-septate conidia flattened in a single plane. The conidia recall those of the lichen-forming hyphomycete genus Cheiromycina in some respects, but do not originate from the swollen subglobose cells characteristic of that genus. The generic concepts in this complex of algicolous, lichen-forming, lichenicolous, and saprobic fungi are discussed, and it is concluded that Pycnopsammina should be treated as a synonym of Psammina as the conidiogenesis resembles that of the type species of Psammina, which also has rather similar conidiomata; the combination Psammina lobariae comb. nov. (syn. Pycnopsammina lobariae) is therefore made. A key to the eight species now accepted in the genus is provided, which now includes algicolous, lichen-forming, lichenicolous, and plant saprobic species.

Lichen material from the Iberian Peninsula of Melanelia commixta, M. hepatizon and M. sorediella has been studied and compared on the basis of morphology, chemistry, habitat and distribution. The new combination Melanelia sorediella is proposed and Cetraria commixta f. sorediella is lectotypified. Chemotypes I and III have been detected in M. commixta. Melanelia sorediella is characterized mainly by the formation of pycnoisidia and soralia-like structures in the lamina and margins of the thallus and by the absence of pseudocyphellae and apothecia. The pycnoisidium is here described as a combination of isidia-like proliferations of the thallus surface containing pycnidia, carrying algae and acting as vegetative symbiotic propagules. Non detached pycnoisidia grow into lobuli in central parts of the thallus, regenerating it. Pycnoisidia, soralia-like areas and lobuli are formed as a consequence of pycnidia development. Melanelia sorediella is morphologically and chemically close to M. commixta and is currently known from mountains of central and south-west Europe where it grows on acid rocks. In south-western Europe, the meridional limit of the distribution of the three species studied seems to be located in the mountains of the central part of the Iberian Peninsula (Sistema Central Ibérico). Relevant data on the three species are provided and a key is also included.

The new lichenicolous hyphomycete, Monodictys epilepraria, is described from thalli of several Lepraria species. It is known from the Czech Republic, Great Britain, Lithuania, Poland, Spain and Sweden, and appears to be widespread, but probably much overlooked. The new species is characterized by relatively small, brown, muriform, smooth-walled conidia developing on decolourized patches of the host.

Fuscopannaria atlantica P. M. Jørg. & P. James, a new species from consolidated soil near the sea is described from the Azores. It is also present in SW Ireland, S W England, Wales and SW Scotland and appears to be part of the Macaronesian element in the lichen flora of the British Isles, as well as an addition to the oceanic flora of Liguria, Italy. An updated key to the European species of Fuscopannaria is also presented.

Heppia arenacea M. Schultz and Lempholemma polycarpum M. Schultz are described as new and placed in the Lichinaceae. Heppia arenacea occurs in soil-crust communities in southern Yemen and on Socotra. It colonizes both calcareous soil-crusts over limestone as well as soils originating from basaltic rocks. The sand-coloured, squamulose thallus, the erumpent, dark red apothecia and the incorporation of soil material into the thallus are diagnostic characters. Lempholemma polycarpum occurs on inclined limestone boulders in south-eastern Yemen. It is characterized by an umbilicate-lobate thallus with radiating, tongue-shaped, furcate lobes which bear numerous, small, immersed apothecia with punctiform discs.

Two species of Halecania from Asia, H. lobulata van den Boom & Elix and H. pakistanica van den Boom & Elix are described as new to science. In addition, the new combination Halecania pepegospora (H. Magn.) van den Boom is made. The ecology, distribution and chemistry of some selected species are discussed and a key to the fifteen species known worldwide is given.

Lepraria aurescens and Lepraria pulchra are described as new from bark in Thailand; both contain thamnolic acid, but differ in thallus form and colour.

Two new species of Mycobilimbia are described and compared with other members of the genus: Mycobilimbia australis Kantvilas & Messuti from austral, cool to cold temperate regions, and Mycobilimbia meridionalis Kantvilas from Tasmania. Two additional, superficially similar species that are widespread in the Northern Hemisphere, M. hypnorum (Lib.) Kalb & Hafellner and Bilimbia lobulata (Sommerf.) Hafellner & Coppins, are recorded from Tasmania for the first time.

Lecidea kelica Stirt., formerly accepted as a corticolous species of Catillaria is shown to belong to a new, monospecific genus here described as Stirtoniella in the family Ramalinaceae. Details of Stirtoniellia kelica, its synonymy, chemistry, ecology and distribution are presented. It is known from New Zealand and Tasmania.