The perithecia of this lichen are characterized by the presence of two pigments: Sagedia-red (K+ bluish grey) in the involucrellum and Porina-yellow in the inner involucrellum and the exciple. As a result, they may sometimes appear strikingly bicoloured, but more often they are uniformly black. The thallus is usually grey, and the ascospores are 3-septate.
Porina mammillosa is an arctic-alpine species that typically grows on bryophytes and plant debris over siliceous substrates. In the Czech Republic, it has so far been documented from Červená hora and Velká kotlina in the Hrubý Jeseník Mountains (Vězda 1960, Halda 2017) and from the Bílé Labe Valley in the Krkonoše Mountains, where it grew epiphytically on the bark of Sorbus aucuparia in a spruce forest (Malíček & Steinová 2025). However, additional epiphytic records (e.g., from the Beskydy Mountains) exist and may also belong to this taxon.
A morphologically similar and potentially conspecific taxon is the little-known P. arnoldii, which occurs on branches of Rhododendron at high elevations (e.g., in the Alps). It differs mainly in having slightly smaller perithecia (0.15–0.3 mm versus 0.3–0.5 mm in P. mammillosa) and in the predominance of Porina-yellow pigment throughout the involucrellum (Hinteregger 1994). A similar species is also P. sudetica, which occurs in the same habitats; it differs in having more septa in ascospores.
Literature: Vězda A. (1960): K lišejníkové flóře Hrubého Jeseníku (Sudeti orient.). – Přírodovědný časopis slezský 21: 255–270. /// Hinteregger E. (1994): Krustenflechten auf den Rhododendron-Arten (Rh. ferrugineum und Rh. hirsutum) der Ostalpen unter besonderer Berücksichtigung einiger Arten der Gattung Biatora. – Bibliotheca Lichenologica 55: 1–346. /// Halda J. (2017): Lichens of the Velká kotlina glacial cirque in the Hrubý Jeseník Mts (Grossen Kessel, Hohe Gesenke). – Acta Musei Richnoviensis, Sect. Natur. 24: 7–52. /// Malíček J. & Steinová J. (2025): Contribution to lichen biota of the Krkonoše Mountains, the highest Czech mountain range. – Herzogia 38: 308–335.
taxonomic classification:Ascomycota → Lecanoromycetes → Ostropales → Porinaceae → Porina
Red List (Liška & Palice 2010):RE – extinct
Red List (Malíček 2023):DD – data deficient
Occurrence in the Czech Republic
All records: 4, confirmed 1. One click on a selected square displays particular record(s), including their source(s).