Acarospora fusca is a usually low elevation species that occurs in full sun on siliceous rocks, on granite and on schist, including pebbles, and even on old wood. It is so far known from several European countries. It was collected only several times in warmer areas in central and northern Bohemia. Other Czech records require revisions.
The species was considered a synonym of Myriospora rufescens but the neotype and a recent collection from Czech Republic was recovered in the large Acarospora clade (Knudsen et al. 2021). The species based on molecular analyses is a match for recent specimens from Sweden identified as A. anomala, a species described from the wood of outhouses and barns in Fennoscandia. The areoles of species are often small, 0.5 mm or less in diameter, and can be overlooked or misidentified as A. veronensis. In one Czech collection it is growing with A. veronensis. Old Czech collections identified as A. rufescens (Ach.) Kremp. need to be revised but apparently this name was used for some specimens of A. fuscata (Schrad.) Arnold.
Literature: Knudsen K., Kocourková J., Hodková E. & Wang Y. (2021): Lichenological Notes 8: Acarospora fusca. – Opuscula Philolichenum, 20: 19–24.taxonomic classification:
All records: 6, confirmed 6. One click on a selected square displays particular record(s), including their source(s).