Lathagrium dichotomum (With.) Otálora, P.M. Jørg. & Wedin

Conspicuous Lathagrium species with greenish thallus and branched, strap-like lobes. It is a very sensitive aquatic lichen of smaller river downstreams, occurring on permanently inundated siliceous stones in slow-flowing foothill watercourses. It requires moderately acidic, mineral-rich, and at the same time not polluted, clear water. Lathagrium dichotomum is widespread across Europe, but due to the water eutrophication getting less common and, in many areas, even extinct. There are historical reports on its occurrence in eastern Bohemia, namely from the river of Divoká Orlice near Litice (1925) and the river of Doubrava near Chotěboř (1889, 1891; all Pišút 1997). Literary reports from Úpa headwaters in the Krkonoše Mountains in fact refer to the rare Scytinium (Leptogium) rivale (Guttová 2000). In 2022, the species was found in a few localities on stones in the Dyje river in the areas of Podyjí and Thayatal national parks.

Literature: Pišút I. (1997): Lišajník Collema dichotomum (With.) Coppins et J. R. Laundon v Čechách. – Bryonora 20: 16–17. Guttová A. (2000): Three Leptogium species new to central Europe. – Lichenologist 32: 291–293.

Ascomycota → Lecanoromycetes → Peltigerales → Collemataceae → Lathagrium