Superficially similar to Poeltidea perusta, which is frequent in similar habitats on the Falkland Islands, but readily separated from that species by the powdery hypothallus and microscopically by the smaller, hyaline ascospores.
Known from only two collections made in 1968 from the summits of the two highest mountains on West Falkland (Falkland Islands).
Known only from the summits of Mts Adam and Maria on West Falkland.
Last collected in 1968. Not seen during recent surveys (2015)
Siliceous rocks on the summits of Mts Adam and Maria on West Falkland
The lichen biota of the summits of the Falklands three mountain groups (Mts Usborne, Maria and Adam) have not been comprehensively inventoried. The most recent survey in 2015 only made a superficial inspection of this habitat and I. fuliginosa was not rediscovered.
Immersaria fuliginosa has not been discovered elsewhere among the c 5,000 collections from the Falkland Islands nor in the c. 10,000 lichen collections from southern South America held in the herbarium of Michigan State University herbarium (MSC) so is evidently extremely rare. It is probably confined to the rocky fellfields on the summits of the highest mountains of the archipelago.
Fryday, A. M. & Hertel, H. (2014) A contribution to the family Lecideaceae s. lat. (Lecanoromycetidae inc. sed., lichenized Ascomycota) in the southern subpolar region; including eight new species and some revised generic circumscriptions. Lichenologist 46: 389–412.
Fryday, A.M., Orange, A., Ahti, T., Øvstedal, D.O. & Crabtree, D.E. (2019) Checklist of lichenized and lichenicolous fungi reported from the Falkland Islands. Glalia 8(1): 1–100.