Příspěvek k poznání lišejníků holubovských hadců (jižní Čechy)

Serpentinites in the surroundings of the villages of Holubov and Křemže in South Bohemia only rarely rise to the surface as rock outcrops. This rare habitat is protected here in two nature reserves: Holubovské hadce (15.5 ha) and Bořinka (8.9 ha). The former locality harbours a higher species richness (126 vs 101 species) and more red-listed lichens than the latter. Nevertheless, both reserves are very valuable localities with a specific lichen biota. A total of 180 lichen species, one lichenicolous fungus, and two non-lichenised fungi were recorded during floristic surveys in 2022 and 2023. The saxicolous communities on serpentinite were the most species-rich, but several rare species occur on other substrata, such as other siliceous rocks, and bark and wood of pines. The presence of a number of primarily epiphytic lichens on the serpentine rocks is very remarkable. Verrucaria rosula is reported here for the first time from Central Europe. The most valuable records on the serpentinites include Aquacidia viridifarinosa, Bacidia arceutina, Caloplaca xantholyta, Ionapsis ceracea, Lecania cuprea, L. suavis, Mycobilimbia epixanthoides, Normandina acroglypta, N. pulchella, Parmotrema perlatum, Porina byssophila, P. rosei, Psoroglaena stigonemoides, Reichlingia leopoldii, Thelopsis rubella, and Vahliella leucophaea. Rare epiphytic/epixylic species are represented by Arthonia dispersa, Calicium pinastri, Lecanora mughosphagneti, Micarea microareolata, and Psoroglaena neglecta. Aquatic communities on stones in the Křemžský stream are well-developed and are represented by e.g. Hydropunctaria rheitrophila and Stigmidium rivulorum. Several lichens were identified only tentatively. A part of them are potentially undescribed taxa of the genera Rinodina, Trapelia, and Verrucaria. Twenty-one specimens are supported by molecular ITS and/or mtSSU data. The identity of the poorly known taxon Pseudarthopyrenia rivularis is briefly discussed and assigned to the genus Collemopsidium.