Cladonia crispata (Ach.) Flot.

A highly variable Cladonia species in which two varieties are recognised. Cladonia crispata var. crispata is characterised by well-developed, clearly perforated cups with relatively short proliferations. The variety cetrariiformis has a very narrow cup-like structure consisting of a single perforation surrounded by short spines and typically a brown thallus with dichotomous branching, so that at first glance it may resemble Cetraria aculeata. According to Pino-Bodas et al. (2021), these two varieties likely represent separate species, although the necessary formal combination has not yet been made.

Perforated cups, or the axils of the upper branches in small, slender specimens, can help distinguish this species from some habitually similar forms of C. gracilis (Sandstede 1931). In doubtful cases, taste may help (a mild taste in C. crispata due to the absence of fumarprotocetraric acid), as can negative spot tests or examination under UV light (UV+ white, squamatic acid). However, chemotypes containing barbatic or thamnolic acids are also known from abroad (Ahti & Stenroos 2013). Owing to its great variability, numerous forms have been described within C. crispata, including squamulose morphotypes reminiscent of the common C. squamosa.

Cladonia crispata occurs on acidic soil and peat, more rarely on wood and mossy rocks, in montane and boreal regions. From the Czech Republic, a relatively large number of historical records are available, especially from the western half of the country (see the catalogue by Vězda & Liška 1999). Recently the lichen was published from the Krkonoše Mountains, but unpublished records also exist from the Šumava Mountains and Bohemian Switzerland, mainly from near-natural habitats such as peat bogs, glacial cirques, boulder screes, relict pine forests, and similar sites (Palice, unpubl.). For reasons that remain unclear, this species has declined in the Czech Republic. On the other hand, it may also be regionally overlooked and confused with similar common species. Typical, well-developed morphotypes known for example from northern Europe seem to occur only rarely in this country.

Literature: Sandstede H. (1931): Die Gattung Cladonia. – In: Rabenhorst L., Kryptogamenflora von Deutschland, Österreich und der Schweiz, Leipzig, Band IX, Abt. 4 (2): 1–531. /// Ahti T. & Stenroos S. (2013): Cladoniaceae. – In: Ahti T., Stenroos S. & Moberg R. [eds], Nordic Lichen Flora 5: 87–89. /// Pino-Bodas R., Sanderson N., Cannon P., Aptroot A., Coppins B., Orange A. & Simkin J. (2021): Lecanorales: Cladoniaceae, including the genera Cladonia, Pilophorus and Pycnothelia. – Revisions of British and Irish Lichens 19: 1–45.

Ascomycota → Lecanoromycetes → Lecanorales → Cladoniaceae → Cladonia