Geoglossum littorale is a 1-3 cm high, robust built earthtongue is a strange fungus arange fungus confined to at bare-laid, flat, graveled lakeshores.
A distinct, very rare earth-tonque confined to oligotrophic lakes with Littorella uniflora - highly threatened from pollution.
The basidionyme Basionym: Leptoglossum littorale Rostr. Recently a revised generic classification has been proposed:
Hemileucoglossum littorale (Rostr.) (Arauzo (Arauzo & Iglesias, 2014). This classification is based on one sequenced Spanish specimen with a different ecology and apparently also with different morphological features.
Geoglossum littorale is endemic to Europe, known from 14 lakes in Denmark and Sweden. The species was described from Denmark in 1892 from a small oligotrophic lake where it occurred in association with Littorella (Plantago) uniflora. It was then not seen before 1996 (Læssøe 1997), and again in 2013 from another lake in the same region somewhat more northern than the type locality. In the meantime it was discovered at five lakes localities in southern Sweden - always in association with Littorella (Kers & Carlsson 1996). It has thereafter been recorded at 6 additional lakes in Sweden (Nilsson & Fritz per com 2019). It has been recorded but is now considered regionally extinct in Schleswig-Holstein, Germany (Lüderitz 2001) (WHEN WAS THAT RECORD MADE?). Currently the published occurrence on the Iberian peninsula (Arauzo & Iglesias, 2014) is not accepted.
The number of suitable lakes has declined dramatically within the known area of distribution due to pollution/enrichment of the oligotrophic lakes partly caused by nitrogen deposition from intensive farming.
Population Trend: Decreasing
The lifeform of G.littorale is not known but it is considered to have have either a parasitic or a symbiotic association with the vascular plant Littorella uniflora (Plantaginaceae). (. It occasionally co-occurs with species of Hygrocybe, eg. H. phaeococcinea. It produces ascomata when the water level is low following dry summers.
Polution and drainage of oligotrophic lakes. Intensive farming, drainage etc has reduced the number of suitable lakes dramatically.
Oligotrophic lakes should be protected rigorously.
Material from Scandinavian Littorella-lakes should be sequenced and compared to the material from Portugal that is not associated with Littorella.
Geoglossum litorale is not used.
Arouzo, S. & Iglesias, P. 2014. La familia Geoglossaceae ss.str. en la peninsula Ibérica y la Macaronesia. Errotari 11: 177
Johansson N. 2005. Åtgärdsprogram för strandjordtunga (Species Action program for Geoglossum littorale. In Swedish with English summary). Naturvårdsverket. Can be downloaded from https://www.naturvardsverket.se/Documents/publikationer/620-5529-1.pdf
Kers, L.E. & Carlsson, R. 1996. Jordtungan Geoglossum littorale återfunnen - i Sverige. Svensk Bot. Tidskr. 90: 65–81.
Læssøe, T. 1997. Genfund af Geoglossum littorale (Rostr.)Nannf. Svampe 35: 50–51.