Acarospora muddii grows on sunny rocks at elevations below about 500 m. In the Czech Republic, it is known mainly from natural outcrops of basic volcanic rocks. So far, the species has been confirmed at several localities in Central and Western Bohemia. It has been reported from Great Britain and from central Europe in Germany by Magnusson (1929).
The species is poorly known. It forms a dark contiguous thallus of irregular shaped areoles, dull brown, with a verrucose upper surface, replicating by division with rare apothecia toward center of thallus. The upper surface when wetted it distinctly nodulose. The apothecia are immersed, punctiform, best seen when wet, and without an elevated margin. The parathecium is very narrow or indistinct and the hymenium high, often 120–130 µm, with hemiamyloid hymenial gel. It is similar to A. inaequalis, known only from Germany but expected in Czech Republic. That species differs from A. muddii in having many fertile apothecia in elevated margin formed from a parathecium expanded around the disc.
Literature: Magnusson A.H. (1929): A monograph of the genus Acarospora. – Kungliga Svenska Vetenskaps-Akademiens Handlingar 7: 1–400.taxonomic classification:
All records: 4, confirmed 4. One click on a selected square displays particular record(s), including their source(s).