The term ‘cladoniiform lichens’ is applied to a group of lichen-forming discomycetes which either produce a ‘dimorphous’ thallus (differentiated into vertical and horizontal structures) or which resemble such lichens in having somewhat similar fruticose thalli and related phenolic chemistry. Seventeen genera comprising the families Cladoniaceae, Heterodeaceae, Cladiaceae, Baeomycetaceae and Siphulaceae are included in the group. A podetium is defined as a lichenized, stem-like portion (stipe) bearing the hymenial discs, and sometimes conidiomata, in a fruticose, simple or compound apothecium. The terminal structures commonly called apothecia on podetia or other ascomatal stipes in lichens are not whole apothecia but separate hymenial discs of a polydiscoid ascoma. In spite of superficial similarity in gross morphology and phenolic composition, the cladoniiform lichens are a life-form group rather than a taxonomic entity.

Eight corticolous species of Haematomma are recognized in Australia, including four new species (H. eremaeum, H. pruinosum, H. sorediatum and H. stevensiae spp. nov.) and one new combination (H. infuscum). The characters found useful in differentiation of the species included apothecium form, apothecial pigmentation, spore septation, and thallus chemistry. Taxonomic and distributional data are provided for all species. Two taxa are reduced to synonymy for the first time, and a key is provided.

The nomenclatural status of the 21 specific names in the British checklist affected by the abolition of later starting point dates for all fungi is discussed. Two are completely unchanged and the author citations of 15 are simplified by the deletion of previously ‘revalidating’ authors. Six alterations in name prove to be necessary: Microcalicium disseminatum (Ach.) Vainio for M. subpedicellatum (Schaerer) Tibell, Mycocalicium subtile (Pers.) Szat. for M. parietinum (Ach. ex Schaerer) D. Hawksw., Mycomicrothelia melanospora (Hepp) comb. nov. for M. atomaria (DC. ex Merat) Keissler, Opegrapha parasilica (Massal.) Vězda for O. persoonii (Ach. ex Gray) Chev., Orphniospora moriopsis (Massal.) comb. nov. for O. atrata (Sm.) Poelt, and Stenocybe pullatula (Ach.) B. Stein for S. byssacea (Fr.) Körber.

Twenty-five mainly crustose and saxicolous lichens are reported from the subalpine and alpine belts of Mt Changbai (n.-e. China, near the Korean border). All are new records to the lichen flora of the north-eastern provinces of China, 12 of them to the flora of all China, and four to the flora of all Asia. There is some floristic similarity to some other areas with cool humid climates in the Northern Hemisphere, e.g. Iceland.

The cryptogamic vegetation, dominated by lichens, in a secondary coastal dune area is described. The Coelocaulon aculeatum community colonizes large exposed sand patches. The Cladonia glauca–C. mitts community colonizes where litter has accumulated. The Cladonia mitis and C. portentosa communities occupy more sheltered sites than the Coelocaulon aculeatum community. The scattered Cladonia zopfii community colonizes both exposed and slightly more sheltered sand patches. The common Cladonia uncialis–C. mitis community usually colonizes smaller sand patches with some humus accumulation than those colonized by the Coelocaulon aculeatum community. The Cladonia mitis, the C. portentosa and the Cladonia uncialis–C. mitis communities and probably the Cladonia zopfii community are suggested to be final stages in the lichen succession.

The lichen flora of a very small, but outstandingly rich, outcrop of limestone and epidiorite at 1030 m in the Ben Alder range is described. One hundred and six calcicolous species were encountered, many of which are rare nationally; eight are not known elsewhere in Britain. The site is compared with other calcareous mountains in Scotland and possible reasons for its distinctive lichen flora are suggested.

Nematodes were found to be abundant in a collection of Cladonia glauca from Ireland. Irregular tuberculate galls on the podetia were probably due to a species tentatively referred to Nothanguina. Aphelenchoides lichenicola sp. nov. and Ottolenchus cabi sp. nov. are described; the former may feed on the fungal component, while the latter probably parasitizes the algal partner. The separation of Ottolenchus from Tylenchus is discussed and six new combinations into Ottolenchus are proposed. Further nematodes found in the sample included species of the genera Belondira, Chilwoodius and Discotnyctus (all Dorylaimida), and a juvenile Rotylenchulus (Hoplolaimidae); this last probably a contaminant. These observations on a single collection suggest that lichens may have a rich and specialized nematode fauna.