Cladonia straminea (Sommerf.) Flörke

Cladonia straminea is the rarest species of the morphologically defined C. coccifera group, however, according to molecular data it is more closely related to the group of C. macilenta (Stenroos et al. 2019). It is characterized by blackening older thallus parts (dying parts of other red-fruited species may be melanized too but to a lesser extend) and the surface of podetia which is covered with microsquamules oriented downwards. In the Czech Republic, it is reliably identified by TLC, based on the content of usnic, squamatic and didymic acids. The latter two substances cause a conspicuous UV+ white-blue reaction. The rarer chemotype containing thamnolic acid (UV-), sometimes named var. reagens, is not known from the Czech Republic.

In the Czech Republic, C. straminea is only distributed in mountain areas. Most commonly, it grows on humus and among bryophytes on screes, siliceous boulders, humid vertical rock walls or directly on mineral soil. Most of localities are known from peaks of highest mountains, glacial cirques and humid screes. It often grows in microhabitats with the shorter period of snow cover, such as vertical and upper sides of rocks and boulders. It is known from the Šumava, Krkonoše, Brdy, Jizerské hory, Lužické hory and Novohradské hory Mts. The richest Czech populations are found in the highest parts of the Krkonoše Mts. The species is rare in central Europe. It is often parasitized by Cladonia luteoalba.

Literature: Steinová J., Bouda F., Malíček J., Palice Z., Peksa O., Svoboda D. & Vondrák J. (2015): Poznámky k rozšíření a ekologickým preferencím zástupců skupiny Cladonia coccifera v České republice. – Bryonora 55: 4–19.

Ascomycota → Lecanoromycetes → Lecanorales → Cladoniaceae → Cladonia