Notes on two lichenicolous Epigloea species from Central Europe

The genus Epigloea Zukal containing 12 species [1] belongs to the family Epigloeaceae (Zahlbr.) of uncertain taxonomic position within Ascomycota [2]. All of known Epigloea species are probably under-collected due to their inconspicuousness, ephemeral ascomata and specific niche requirements. Most of these microfungi live as a fine mycelium immersed in the gelatinous algal film. These algal films cover bare damp soils, rocks, rotten wood as well as plant debris (especially moribund bryophytes) and various terricolous and epibryophytic lichens. The biological nature of the algicolous lifestyle of Epigloea spp. remains poorly understood. They were described as lichens, “semi-lichens” or non-lichenized parasites of algae or their commensals [3–7]. Lichenicolus records (without the algal film) were very rare. Almost all of them referred to the lichen parasite – E. urosperma [6–8]. E. soleiformis has been reported as a lichenicolous, weakly parasitic fungus only from two localities in Asia [9] and from N Poland [10]. From the Carpathians only several reports on Epigloea are known, one of Epigloea medioincrassata (Grummann) Döbbeler from Polish part of the Tatra Mts [11], one of E. pleiospora Döbbeler from the Bieszczady Mts [12] and one of E. soleiformis Döbbeler from the Ukrainian Eastern Carpathians [13]. The aim of this paper is to present some additional data that would contribute to the knowledge of the genus Epigloea and the distribution of its two representatives in Central Europe with special remarks on the intraspecific variability within E. soleiformis.


Introduction
The genus Epigloea Zukal containing 12 species [1] belongs to the family Epigloeaceae (Zahlbr.) of uncertain taxonomic position within Ascomycota [2].All of known Epigloea species are probably under-collected due to their inconspicuousness, ephemeral ascomata and specific niche requirements.Most of these microfungi live as a fine mycelium immersed in the gelatinous algal film.These algal films cover bare damp soils, rocks, rotten wood as well as plant debris (especially moribund bryophytes) and various terricolous and epibryophytic lichens.The biological nature of the algicolous lifestyle of Epigloea spp.remains poorly understood.They were described as lichens, "semi-lichens" or non-lichenized parasites of algae or their commensals [3][4][5][6][7].Lichenicolus records (without the algal film) were very rare.Almost all of them referred to the lichen parasite -E.urosperma [6][7][8].E. soleiformis has been reported as a lichenicolous, weakly parasitic fungus only from two localities in Asia [9] and from N Poland [10].
From the Carpathians only several reports on Epigloea are known, one of Epigloea medioincrassata (Grummann) Döbbeler from Polish part of the Tatra Mts [11], one of E. pleiospora Döbbeler from the Bieszczady Mts [12] and one of E. soleiformis Döbbeler from the Ukrainian Eastern Carpathians [13].
The aim of this paper is to present some additional data that would contribute to the knowledge of the genus Epigloea and the distribution of its two representatives in Central Europe with special remarks on the intraspecific variability within E. soleiformis.

Material and methods
Material was collected occasionally by the first author during several recent field trips in different regions of Poland and the Harz Mts in Germany.Results of field explorations of lichenicolous microlichens, mainly on terricolous Placynthiella spp.and Peltigera spp.carried out in 2005 and 2012 by the second author in the Wyżyna Śląsko-Krakowska upland geographical macroregion [14] have been included as well.
Fungi were identified by standard microscopy.Apothecial hand-made sections were mounted in water and sometimes in KOH or HNO 3 for better view of the size of investigated internal structures, especially ascospores.Details of anatomy were measured in water.Nomenclature of taxa follows MycoBank fungal databases [1].
Distributional, ecological and taxonomic notes have been included.
Specimens collected by P. Czarnota are deposited in the herbarium of the Gorce National Park (GPN) and by E. Hernik in the herbarium of Rzeszów University (RES) and his private herbarium.
NOTES.The new findings presented below characterize rather ellipsoid or only slightly ovoid ascospores almost exclusively lacking median constriction (Fig. 1c).They are usually slightly wider than described as typical in the protologue [3].Kukwa et al. [10] gave similar description of two specimens from N Poland.Döbbeler [3] mentioned in his comment to the protologue of E. soleiformis that some revised Grummann's specimens from Bavaria had no median constriction usually observed in other specimens.He suggested that such specimens may represent some separate kind of a phenetic variability within this species and could be regarded under some intraspecific taxonomic level.The variability of the shape of ascospores of E. soleiformis found in different regions of Europe is presented by the following authors: Döbbeler [3] (plate 11,1-3), Ceynowa-Giełdon [4] (Fig. 8c), Pérez-Ortega and Barreno [6] (Fig. 1d).Moreover, Zhurbenko [9] in Russian specimens of E. soleiformis found ascospores which were not exclusively 1-septate but also occasionally simple.
Epigloea renitens (Grumm.)Döbbeler has a closest phenetic affinity to E. soleiformis.Döbbeler [3] showed that both species differ in the size of ascocarps, asci and ascospores; E. soleiformis forms smaller perithecioid ascomata (70-150 µm vs. 105-220 µm in E. renitens) and its ellipsoid spores are also smaller and usually with median constriction while ascospores of E. renitens are mainly ovoid, slightly aciculate [6] and usually have distinctly larger one cell.In the description and pictures included by Döbbeler [3] we can find, however, some ascospores of both species completely similar to each other in their size and shape (distinctly ellipsoid and not constricted).Thus, the basic question -how is the real delimitation of both taxa?-seems to be unresolved, more so as an examination of the types of both species was not available by authors in recent time.Due to the lack of molecular evidences supporting the delimitation of different lineages confined to some phenetic characters of both taxa we propose to keep separately E. renitens and E. soleiformis, the later being the variable species characterized both constricted and not constricted ascospores, reaching 5.5 µm width.It is not excluded, however, that collections presented here represent some new species within the genus Epigloea.DISTRIBUTION AND ECOLOGY.Epigloea soleiformis is usually reported as a non-lichenized algicolous fungus on bryophytes, humus, soil, rotten wood, plant debris or rocks [3,4,6,15].It was also found several times on terricolous or epibryophytic lichens including: Trapeliopsis pseudogranulosa Coppins & P. James, T. granulosa (Hoffm.)Lumbsch, Placynthiella uliginosa (Schrad.)Coppins & P. James [6], Cladonia spp.[3,4,16], Peltigera aphthosa (L.) Willd.[17] or accompanying Absconditella sphagnorum Vězda & Poelt [4].To date this species was not widely regarded, however, as a lichenicolous fungus.Only Zurbenko [9] based on his own collections of Epigloea soleiformis suggested that the species could not be only algicolous.In those cases E. soleiformis inhabited two representatives of Stereocaulon slightly discoloring phyllocladia and stems of their hosts.The usually present algal films were not observed.Recently also Kukwa et al. [10] included this species into the group of lichenicolous fungi inhabiting Placynthiella dasaea (Stirton) Tønsberg and P. icmalea (Ach.)Coppins & P. James.Some of the new collections of Epigloea soleiformis mentioned below are also made directly on the thalli of terricolous or lignicolous Placynthiella dasaea without characteristic algal film overgrowing lichens.The inhabited hosts thalli are either normally colored or only sometimes slightly discolored, thus E. soleiformis could be regarded as the facultative commensal or slightly parasitic lichenicolous fungus.In two groups of cases, with or without algal film, dimensions of ascocarps and all internal ascomatal features not differ markedly.
Chambers and David [7] based on findings from abandoned lead-zinc mining sites in Great Britain concluded that E. soleiformis is a metal-tolerant species.New reports from metalenriched areas of S Poland (Wyżyna Częstochowska upland) can support that hypothesis.Considering other reports made in different environmental circumstances, this fungus has a wide ecological tolerance in general.
DISTRIBUTION AND ECOLOGY.Contrary to other representatives of the genus Epigloea, this species is not regarded algicolous but lichenicolous.It is known only from scattered localities in Europe: Germany, Sweden, Great Britain, Switzerland, Austria, N Poland [6,8,10,18,22], and recently it has been also found in South America, at one locality in Bolivia [23].Older European collections of E. urosperma were usually made together with Placynthiella uliginosa.Döbbeler [8], however, in his comment for the protologue of E. urosperma mentioned Saccomorpha uliginosa-complex as the host for this species.It is possible that within this complex was also Placynthiella dasaea not well recognized at that time elsewhere (or overgrowing the true P. uliginosa), since the recent data from Bolivia [23], N Poland [10,22] and the new records presented here, show that E. urosperma is confined to P. dasaea. The

Conclusion
Epigloea soleiformis is regarded here as more variable species than was originally described, but the real status and the phylogenetic affinity of all intraspecific groups which differ in the size and shape of ascospores can be confirmed by molecular evidences.The species seems to be at least occasionally lichenicolous, not algicolous as usually.It was found mainly on representatives of the genus Placynthiella (especially P. dasaea) and terricolous Peltigera.Its parasitic character manifests sometimes by a local disscolouration of the host thallus.Similarly E. urosperma has been confirmed here as another lichenicolous member of the genus.Both species of Epigloea were rarely reported from Central Europe to date but they are probably more widespread and frequent elsewhere.In this work E. soleiformis is presented as a new species to the Western Carpathians and the Harz Mts in Germany, and E. urosperma is reported as new to whole Carpathians.