Recently a revised generic classification has been proposed:
Hemileucoglossum littorale (Rostr.) Arauzo
Basionym: Leptoglossum littorale Rostr.
This classification is based on one sequenced Spanish specimen with a different ecology and apparently also with different morphological features.
It should also be noted that the Geoglossaceae do not belong to the Helotiales. Geoglossaceae is a family of fungi in the order Geoglossales, class Geoglossomycetes.
A distinct, very rare earth-tonque confined to oligotrophic lakes with Littorella uniflora - highly threatened from pollution.
It is considered regionally extinct in Schleswig-Holstein, Germany. (Lüderitz 2001). Currently the published occurrence on the Iberian peninsula is not accepted. The species was described from Denmark in 1892 from a small oligotrophic lake where it occurred in association with Littorella (Plantago) uniflora. Then it was 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 rediscovered in a number of localities in southern Sweden - always in association with Littorella (Kers & Carlsson 1996).
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: Deteriorating
Would appear to have a biotrophic relation with 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.
Swedish species fact sheets 2015.: http://www.artfakta.se/SpeciesFact.aspx?TaxonId=2011
Danish fungus atlas 2015: http://svampe.dk/soeg/rapportside.php?DKIndex=14213
Arouzo, S. & Iglesias, P. 2014. La familia Geoglossaceae ss.str. en la peninsula Ibérica y la Macaronesia.
Bohlin, K. : http://www.artfakta.se/artfaktablad/Geoglossum_Littorale_2011.pdf
Johansson N. 2005. Åtgärdsprogram för strandjordtunga. Naturvårdsverket
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.