Our knowledge of the lichens and allied fungi in Latvia (northern Europe) has been considerably advanced in recent years. Currently ca 640 taxa of lichenized fungi are recorded for Latvia (Āboliņa et al 2015, Moisejevs 2015, 2017, Motiejūnaitė et al. 2016, Moisejevs and Degtjarenko 2017), which is comparable to the 620 taxa known from the geographically similar territory of Lithuania (Motiejūnaitė 2017).

Lichenicolous fungi, on the other hand, have been understudied in Latvia. The first mention of lichenicolous species can be found in the paper by Mereschkowski (1913), who reported Acolium sessile from Jaunugulbene (Vidzeme). Later, Diploschistes muscorum was reported from the Gauja river valley and Riga city environs (Malta 1926, Vimba 1971). During the 13th International Symposium of Lichenologists and Mycologists of the Baltic States, two more species of lichenicolous fungi were reported (Motiejūnaitė and Piterāns 1998); a further four species were reported in the first annotated Latvian checklist of lichens (Piterāns 2001) and 16 more were added by Motiejūnaitė et al. (2006), Czarnota and Kukwa (2010) and Motiejūnaitė and Grochowski (2014). The second annotated checklist of lichens listed 15 lichenicolous taxa as supplementary data (Āboliņa et al. 2015). Further contribution was made by Motiejūnaitė et al. (2016), with 33 lichenicolous fungi reported for the first time from Latvia, complemented by the paper of Moisejevs (2017). Since a full and up-to-date list of lichenicolous fungi for Latvia is still lacking, a comprehensive list is provided here.

The current paper reports four new species of lichen-forming and two lichenicolous fungi new to Latvia, together with a list of lichenicolous fungi (61 taxa) known for Latvia, including their hosts and distribution data in the country (Table 1).

Material and methods

The material was determined by means of routine lichenological methods (Smith et al. 2009). Spot-tests were determined with 10% KOH (K), sodium hypochlorite (C), paraphenylenediamine in ethanol (Pd) and Lugol's solution (I), and secondary chemistry by thin layer chromatography (TLC) using solvent C (Orange et al. 2001). Specimens of the newly recorded species, according to the nomenclature of Wirth et al. (2010), are kept in the lichenological herbarium of University of Daugavpils (DAU).

The list of lichenicolous fungi presented below is a combination of published literature data and herbarium collections from DAU and the University of Latvia (RIG), together with those species reported in the current paper. Data on species distribution are derived from literature sources and herbarium collections (DAU and RIG). Regions of Latvia (Fig. 1) are abbreviated in the list as follows: K – Kurzeme (Kurland), V – Vidzeme, L – Latgale, R – Pieriga, Z – Zemgale, LV – all regions of Latvia; # = lichenicolous fungus.

Table 1.

The list of lichenicolous fungi known from Latvia, their distribution and hosts known in the country and the references that mention the species. For the abbreviations see Fig. 1.

Continued

Results

New records for Latvia

#Arthrorhaphis aeruginosa R.Sant. & Tønsberg

Distribution

Arthrorhaphis aeruginosa is known from Europe (Wirth et al. 2010, Motiejūnaitė 2017, Tsurykau 2017), including Fennoscandia (Santesson and Tønsberg 1994, Nordin et al. 2011), and also from Greenland (Alstrup et al. 2009), North America (Esslinger 2007), South America (Flakus et al. 2008) and Asia (Sohrabi and Alstrup 2007).

Material examined

Krāslavas Co., Ūdrīšu Dist., Nature Park ‘Daugavas loki’, Tartaka Forest, ca 350 m W of Tartaks village, 55°53′6.9″N, 26°59′18.1″E, 150 m a.s.l., on side of old forest road in boreal forest with Pinus sylvestris and Picea abies, on primary thallus of Cladonia sp., 25 May 2018, leg. & det.: R.Moisejevs (DAU600000910).

Notes

The collected specimen was sterile, but it was recognized by the characteristic colour of the infected host thallus. Only A. aeruginosa is known to turn the infected lichen an aeruginose colour and, as stated in the protologue of the species ‘... is therefore easily recognized even when sterile’ (Santesson and Tønsberg 1994).

Figure 1.

Regions of Latvia: K – Kurzeme (Curland), V – Vidzeme, L – Latgale, R – Pieriga, Z – Zemgale.

Calicium pinastriTibell

Distribution

Calicium pinastri is known from Europe (Tibell 1999, Śliwa and Kukwa 2008, Istomina and Likhacheva 2010, Wirth et al. 2010, Nordin et al. 2011) and North America (Hardman et al. 2017).

Material examined

Krāslava Co., Ūdrīšu Dist., Nature Park ‘Daugavas loki’, Tartaka forest, ca 500 m SW of Tartaks village, 55°53′7.6″N, 26°59′30.8″E, 130 m a.s.l., old-growth dry boreal forest, on bark of P. sylvestris, 20 June 2018, leg. & det.: R.Moisejevs (DAU600000911).

Notes

The lichen was found growing close to Calicium parvum, a species that resembles C. pinastri, but has clavate asci, while C. pinastri has cylindrical asci when mature.

Chaenotheca laevigata Nádv.

Distribution

Chaenotheca laevigata is a rare lichen with a wide distribution in Northern Hemisphere, being known from Europe (Wirth et al. 2010, Nordin et al. 2011), Asia (Titov 2000) and North America (Hardman et al. 2017).

Material examined

Ventspils Co., Usmas Dist., Nature Reserve ‘Moricsala’, ca 400m NE of guest house, 57°11′28.6″N, 22°8′12.0″E, 25m a.s.l., in a humid old-growth deciduous forest with Picea abies, on the bark of P. abies, 9 July 2018, leg. & det.: R.Moisejevs (DAU600000917).

Notes

Chaenotheca laevigata can be confused with Chaenotheca chlorella, from which it differs by its immersed thallus, ellipsoid to short cylindrical ascospores and longer ascomata.

#Chaenothecopsis epithallina Tibell

Distribution

Chaenothecopsis epithallina is distributed in central Europe, Fennoscandia (Tibell 1975, Wirth et al. 2010, Nordin et al. 2011, Tsurykau 2017) and North America (Hardman et al. 2017).

Material examined

(1) Ventspils Co., Usmas Dist., Nature Reserve ‘Moricsala’, ca 400 m NE of guesthouse, 57°11′33.5″N, 22°8′12.3″E, 25 m a.s.l., in an old-growth deciduous forest, on thallus of Chaenotheca trichialis growing on the bark of Quercus robur, 9 July 2018, leg. & det.: R.Moisejevs; (2) Kocēnu Co., Dīkļu Dist., ca 200 m S of Rāķis Lake, 57°35′34.1″N, 24°55′6.2″E, 120 m a.s.l., in a deciduous forest, on thallus of C. trichialis growing on the bark of old Q. robur, 23 March 2018, leg.: M. Kalniņš, det.: R.Moisejevs (DAU600000912).

Notes

Chaenothecopsis epithallina differs from the similar species Chaenothecopsis nigra by its association with C. trichialis, darker ascospores with less contrasting septum and dark green hypothecium.

Lecania croatica (Zahlbr.) Kotlov

Distribution

Lecania croatica is known from Europe (Printzen 1995, Mrak et al. 2004, Hafellner et al. 2005, Eichler et al. 2010, Vondrák et al. 2010, Kukwa et al. 2012, Motiejūnaitė 2017, Tsurykau 2017) and North America (Tønsberg 2004, Harris and Lendemer 2010).

Material examined

Daugavpils Co., Skrudalienas Dist., Nature Park ‘Silene’, ca 500 m N of Ilgas manor house, 55°41′54.5″N, 26°47′34.5″E, m a.s.l., in a deciduous forest with Tilia cordata, Populus tremula and P. abies, on the bark of T. cordata, 27 May 2018, leg. & det.: R.Moisejevs (DAU600000913).

Notes

The collected sterile specimen was checked using TLC, but no secondary compounds were found. The species was distinguished from species with a similar morphology and chemistry following the same characters as employed by Motiejūnaitė et al. (2012) and Tsurykau (2017).

Pycnora praestabilis (Nyl.) Hafellner

Distribution

Pycnora praestabilis is known in North America (Hodkinson 2009), Europe (Śliwa and Kukwa 2012, Randlane et al. 2016, Motiejūnaitė 2017), including Fennoscandia (Bendiksby and Timdal 2013).

Material examined

Daugavpils Co., Skrudalienas Dist., ca 3.5km E of Silene town, 55°45′41.60″N, 26°52′58.08″E, 130m a.s.l., in periphery of raised bog, on dry wood (snag) of P. sylvestris, 20 July 2017, leg. & det.: R.Moisejevs (DAU600000918).

Notes

From similar species of Pycnora and several morphologically similar species from Xylopsora genus, P. praestabilis differs in its lack of soredia, normally abundant pycnidia up to 0.3 mm diam., typical spot test reactions and presence of alectorialic acid.

Discussion

According to our data, 61 species of lichenicolous fungi have been recorded from Latvia. Acolium inquinans mentioned by Āboliņa and Vimba (1959), who described it as ‘a parasitic lichen, growing on thalli of other lichens’, has been excluded since it is a lichenized species that lacks a lichenicolous habit (Tibell 1999). Specimen on which the record was based is lacking, therefore it is impossible to check its identity. Furthermore, Piterāns (1982) did not mention A. inquinans in his list of Latvian lichens and Āboliņa et al. (2015) described the species as an epiphytic lichen; therefore, it can be assumed that the aforementioned report was based on misidentification. Specimens of Biatoropsis usnearum reported by Motiejūnaitė et al. (2006) (both on Usnea subfloridana) are housed in the herbaria of the Institute of Botany, Nature Research Centre (BILAS) and University of Tartu (TU); the BILAS specimen and DAU specimens were checked in accordance with the description of B. usnearum (s. str.) given by Millanes et al. (2016), so it is assumed that only one species of Biatoropsis is known from Latvia.