A lichen characterized by light grey to white thallus with grey soralia, which often have a purple tinge (this is where the Latin name comes from). In fact, it is not a Buellia species, but a sterile sorediate variant and at the same time a „photomorph“ with a trebouxioid alga belonging to the lichen Lecanographa amylacea, which is otherwise fertile, non-sorediate, and contains a trentepohlioid alga (Ertz et al. 2018). The two forms are functionally distinct, have slightly different ecology and a very different distribution. While the fertile L. amylacea occurs in oceanic and Mediterranean regions, the sterile type (for which we here retain the name Buellia violaceofusca) is widely distributed in Europe, and is currently known also from the Czech Republic (L. amylacea has not been recorded recently).
The species typically grows on rough bark of old oaks, in parts protected from rain, often in the company of Chrysothrix candelaris or Caloplaca lucifuga. It can be found, for example, in open oak stands in deep stream valleys or in light scree forests. The lichen is rare in Europe but has a relatively wide range. In the Czech Republic, Buellia violaceofusca was first recorded in 2014 (Šoun et al. 2015), but since then it has been found in several localities in lowlands as well as in mountains. Its centre of distribution is in areas rich in old trees (lower elevations), such as the Třeboň and České Budějovice regions. The most elevated occurrence is known from the Boubínský prales in the Šumava Mts (1100 m asl), where it grows on Ulmus glabra together with the very rare lichen Acolium karelicum.
Literature: Ertz D., Guzow-Krzemińska B., Thor G., Łubek A. & Kukwa M. (2018): Photobiont switching causes changes in the reproduction strategy and phenotypic dimorphism in the Arthoniomycetes. – Scientific Reports 8:4952 [14 p.]. Šoun J., Vondrák J. & Bouda F. (2015): Vzácné a málo známé druhy lišejníků Třebíčska a okolí. ‒ Bryonora 56: 1‒23.
taxonomic classification:Ascomycota → Lecanoromycetes → Caliciales → Caliciaceae → Buellia
Red List (Malíček 2023):C2 – strongly endangered
Occurrence in the Czech Republic
All records: 9, confirmed 9. One click on a selected square displays particular record(s), including their source(s).