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.

Leprocaulon calcicola is described as new from walls in SE England; it is leprose, pale to mid blue-grey, and contains zeorin and usnic acid. It differs from L. knudsenii from North America in its habitat on mortared walls rather than non-calcareous rock and in its ITS sequence. ‘Lecanora’ ecorticata differs in the yellower colour, and the presence of unidentified fatty acids and traces of unknown terpenoids (but not zeorin) by thin-layer chromatography. Leprose lichens with usnic acid are still poorly known and sequencing must be used to support morphological and chemical studies.

Psammina inflata Earland-Bennett & D. Hawksw. and P. simplex Earland-Bennett & D. Hawksw. are described as new species from coccoid green algae and crustose or leprose lichens in lowland Britain. Additional records and hosts for P. stipitata are reported, and a key to the four species now known in the British Isles is presented. Psammina simplex is the more strongly pathogenic of the species, eventually destroying its hosts. The discovery of these new species adds weight to the view that the genus is more appropriately regarded as a hyphomycete rather than an acervular coelomycete. The size, shape and septation dimensions of the conidial arms were found to be the most reliable characters for species separations in the genus. Pycnopsammina lobariae Diederich & Etayo is also cited from the British Isles for the first time.

SUMMARY Though the grassland associated with the sugar limestone outcrops in Upper Teesdale supports the richest terricolous lichen assemblage of any calcareous site so far discovered in England or Wales it may not have acted as a significant refugium for late‐glacial lichens. A possible reason for this is suppression by open canopy forest during the boreal and atlantic periods. The current high density of terricolous lichens may, to some extent, be a result of intensive grazing over the last few centuries which has favoured the development of an extremely short, open sward offering a wide range of microhabitats.

Psammina inflate Earland-Bennett & D. Hawksw. and P. simplex Earland-Bennett & D. Hawksw. are described as new species from coccoid green algae and crustose or leprose lichens in lowland Britain. Additional records and hosts for P. stipitata are reported, and a key to the four species now known in the British Isles is presented. Psammina simplex is the more strongly pathogenic of the species, eventually destroying its hosts. The discovery of these new sp cies adds weight to the view that the genus is more appropriately regarded as a hyphomycete rather than an acervular coelomycete. The size, shape and septation dimensions of the conidial arms were found to be the most reliable characters for specie separations in the genus. Pycnopsammina lobariae Diederich & Etayo is also cited from the British Isles for the first time.