Rhizoplaca subdiscrepans (Nyl.) R. Sant.

A rather conspicuous lichen with a placodioid thallus and abundant apothecia, which may resemble representatives of the genus Protoparmelia. Molecularly, these are two cryptic species (Szczepańska et al. 2020). The ecology of the lichen is somewhat schizophrenic. Firstly, it is reported from high mountains, where it is usually found on calcareous silicates, most often on the tops of cliffs where birds often defecate (e.g. Nimis et al. 2018). The second optimum occurrence is in steppe and rock habitats at lower elevations, where it grows most often on volcanic rocks. A common feature is the occurrence on natural relict sunlit outcrops.

Rhizoplaca subdiscrepans is a very rare lichen in the Czech Republic. In the past it has been reported from less than a dozen localities (mostly from spilite or shale rocks) north of Prague under the name Lecanora rubina (Malíček et al. 2014). However, it is currently a very rare species known from only three localities (Zákolany, Košt'álov, Milá). Some of its historical localities might still exist, but in some the lichen has already been extinct. This is probably due to overgrowing and subsequent shading of the rock outcrops.

Literature: Liška J. & Pišút I. (1995): Lišajníky. − In: Kotlaba F. [ed.], Červená kniha ohrozených a vzácnych druhov rastlín a živočíchov SR a ČR 4. – Príroda, Bratislava, p. 120−156. Malíček J., Palice Z. & Vondrák J. (2014): New lichen records and rediscoveries from the Czech Republic and Slovakia. – Herzogia 27: 257–284. Nimis P. L., Hafellner J., Roux C., Clerc P., Mayrhofer H., Martellos S. & Bilovitz P. O. (2018): The lichens of the Alps – an annotated checklist. – Mycokeys 31: 1–634. Szczepańska K., Urbaniak J. & Śliwa L. (2020): Taxonomic recognition of some species-level lineages circumscribed in nominal Rhizoplaca subdiscrepans s. lat. (Lecanoraceae, Ascomycota). – PeerJ 8: e9555 [27 p.].

Ascomycota → Lecanoromycetes → Lecanorales → Lecanoraceae → Rhizoplaca