The complete genome of Hosta Virus X (HVX), which is thought to be a distinct species of Potexvirus, was sequenced. Nucleotide sequences of HVX were compared with those of other members of the genus Potexvirus and phylogenetic tree was constructed. The range of identities of viral replicase open reading frame 1 (ORF1) between HVX and other potexviruses were 43.1%–55.1% and 35.9%–46.6% at the nucleotide and amino acid levels, respectively. Phylogenetic analysis was performed according to the amino acid sequence of the replicase to determine the position of HVX in the genus Potexvirus. Results from the phylogenetic analysis demonstrated that HVX was in the same group as Cassava common mosaic virus (CsCMV), Plantago asiatica mosaic virus (PlAMV), Tulip virus X (TVX), and Hydrangea ring spot virus (HdRSV). In particular, coat protein (CP) sequences among viruses from different Hosta cultivars were revealed to be less variable than those from different isolates of Potato virus X (PVX), a Potexvirus type species. In the present study, HVX was transmissible by seeds of the Hosta “Blue Cadet” cultivar. Moreover, HVX was detected in the embryo but not in the seed coat or endosperm of the seed.

Seventeen robust monophyletic branches newly discovered in the phylogenetic tree of the Teloschistaceae after separate nrITS, nrLSU and mtSSU, as well as combined phylogenetic analysis are proposed to consider as the following separate genera: Dijigiella S. Y. Kondr. et L. Lőkös gen. nov. for the D. kaernefeltiana group, Elixjohnia S. Y. Kondr. et J.-S. Hur gen. nov. for the Sirenophila jackelixii group, Fominiella S. Y. Kondr., D. Upreti et J.-S. Hur gen. nov. for the F. tenerifensis group; Gintarasiella S. Y. Kondr. et J.-S. Hur gen. nov. for Caloplaca aggregata, Hanstrassia S. Y. Kondr. gen. nov. for the Elenkiniana lenae group, Harusavskia S. Y. Kondr. gen. nov. for H. elenkinianoides sp. n., Huriella S. Y. Kondr. et D. Upreti gen. nov. for H. loekoesiana sp. n., Ikaeria S. Y. Kondr., D. Upreti et J.-S. Hur gen. nov. for Caloplaca aurantiellina, Klauderuiella S. Y. Kondr. et J.-S. Hur gen. nov. for the Variospora thallincola group, Laundonia S. Y. Kondr., L. Lőkös et J.-S. Hur gen. nov. for the Gyalolechia flavovirescens group, Lazarenkoiopsis S. Y. Kondr., L. Lőkös et J.-S. Hur gen. nov. for Caloplaca ussuriensis, Nevilleiella S. Y. Kondr. et J.-S. Hur gen. nov. for the Caloplaca marchantii group, Opeltia S. Y. Kondr. et L. Lőkös gen. nov. for the Caloplaca neobaltistanica group, Oxneriopsis S. Y. Kondr., D. Upreti et J.-S. Hur gen. nov. for the Caloplaca oxneri group, Teuvoahtiana S. Y. Kondr. et J.-S. Hur gen. nov. for the Caloplaca rugulosa group, Tomnashia S. Y. Kondr. et J.-S. Hur gen. nov. for the Polycauliona rosei group, and Xanthaptychia S. Y. Kondr. et S. Ravera gen. nov. for the Seirophora orientalis group.

Hitherto missing molecular data on three gene sequences of the type species of the genera Seirophora and Sirenophila are completed within this study.

Six new to science species (Dijigiella kaernefeltiana S. Y. Kondr. sp. n., D. subaggregata S. Y. Kondr. et Kärnefelt sp. n., Fominiella tenerifensis S. Y. Kondr., Kärnefelt, A. Thell et T. Feuerer sp. n., Hanstrassia jaeseounhurii S. Y. Kondr., Ch.-H. Park et L. Lőkös sp. n., Harusavskia elenkinianoides S. Y. Kondr., X. Y. Wang, S.-O. Oh et J.-S. Hur sp. n., Huriella loekoesiana S. Y. Kondr. et D. Upreti sp. n.) are described, compared with closely related taxa.

A total of 34 new combinations for genera mentioned above are proposed.

Eighteen new to science species, i.e.: 13 taxa from South Korea (Astroplaca loekoesiana S. Y. Kondr., E. Farkas, J.-J. Woo et J.-S. Hur, Buellia ulleungdoensis S. Y. Kondr., L. Lőkös et J.-S. Hur, Candelariella hakulinenii S. Y. Kondr., L. Lőkös et J.-S. Hur, Flavoplaca laszloana S. Y. Kondr. et J.-S. Hur, Lichenostigma epiporpidiae S. Y. Kondr., L. Lőkös et J.-S. Hur, Mikhtomia geumohdoensis S. Y. Kondr., Liu D. et J.-S. Hur, Orientophila dodongensis S. Y. Kondr., L. Lőkös et J.-S. Hur, Physcia orientostellaris S. Y. Kondr., L. Lőkös et J.-S. Hur, Placynthiella hurii S. Y. Kondr. et L. Lőkös, Protoparmeliopsis kopachevskae S. Y. Kondr., L. Lőkös et J.-S. Hur, Psoroglaena sunchonensis S. Y. Kondr., L. Lőkös et J.-S. Hur, Rufoplaca kaernefeltiana S. Y. Kondr., L. Lőkös et J.-S. Hur, Vezdaea poeltiana S. Y. Kondr., L. Lőkös, J. Halda et J.-S. Hur), two species from India (Rusavskia indica S. Y. Kondr. et D. K. Upreti, and R. upretii S. Y. Kondr., G. K. Mishra et S. Nayaka), and two species from Atlantic Europe, i.e.: Spain and Portugal (Xanthoria schummii S. Y. Kondr. and X. lapalmaensis F. Schumm et S. Y. Kondr.), as well as a lichenicolous fungus Leptosphaeria Oxneriae Cl. Roux et S. Y. Kondr. from Asia (Russia and India) are described, illustrated and compared with closely related taxa. Forty species of lichen forming and lichenicolous fungi (i.e.: Acarospora cf. rufescens, Agonimia allobata, A. aff. blumii, Anema decipiens, Anisomeridium aff. albisedum, Bacidia laurocerasi, Cercidospora aff. epipolytropa, C. aff. lobothallia, Dictyocatenulata alba, Fuscopannaria dissecta, Lecanora ussuriensis, Lecidella aff. carpatica, Lemmopsis arnoldiana, Leptosphaeria crozalsii, Lichenostigma cf. bolacinae, L. aff. rupicolae, Lichinella stipatula, L. cribellifera, L. iodopulchra, L. aff. myriospora, Melaspilea proximella, Micarea alabastrites, Opegrapha aff. thelotrematis, Orientophila leucerythrella, Pectenia plumbea, Placynthium tantaleum, Porpidia flavicunda, Psorula rufonigra, Pyrenocarpon aff. thelostomum, Pyrenodesmia duplicata, Pyrenopsis aff. haematina, Ramboldia haematites, Rhizoplaca subdiscrepans, Rimularia gibbosa, Rinodina oxydata, Staurothele frustulenta, Stigmidium cf. clauzadei, Strigula australiensis, Thelenella luridella, Vezdaea leprosa) are for the first time recorded for Korea. Additional locality records for South Korea (74 species) and China (3 species) are also given.

Four new combinations, i.e.: Orientophila chejuensis (for Caloplaca chejuensis S. Y. Kondr. et Hur), Orientophila diffluens (for Lecanora diffluens Hue), Orientophila leucerythrella (for Lecanora leucerythrella Nyl.), and Pyrenodesmia duplicata (for Lecanora duplicata Vain.) are also proposed.

Data on 54 new for China, India, Korea and Russia species of lichen-forming and lichenicolous fungi, including 22 new for science taxa of lichen-forming and lichenicolous fungi, i.e.: Acarospora ulleungdoensis, Amandinea trassii, Aspicilia geumodoensis, Biatora ivanpisutii, Caloplaca patwolseleyae, Catillaria ulleungdoensis, Coenogonium agonimieoides, Gyalidea austrocoreana, G. ropalosporoides, Opegrapha briancoppinsii, O. ulleungdoensis, Phyllopsora loekoesii, Psoroglaena coreana, Psorotichia gyelnikii, Rinodina oxneriana, Scoliciosporum jasonhurii, Staurothele oxneri, Stigmidium coarctatae, Thelocarpon ulleungdoense, Thelopsis loekoesii, Toninia poeltiana, Unguiculariopsis helmutii, and and 7 new species to China (Caloplaca ussuriensis, Megaspora rimisorediata, Rinodina xanthophaea, Rusavskia dasanensis, Xanthoria splendens, Zeroviella coreana, Z. esfahanensis), and 1 new species to India (Zeroviella esfahanensis), and 24 new species to Korea (Agonimia blumii, Arthonia rinodinicola, Buelliella minimula, Dactylospora australis, Endococcus propinguus, Halecania santessonii, Laeviomyces aff. fallaciosus, Lecanora albescens, L. layana, Lecidella scabra, Micarea farinosa, Minutoexcipula aff. mariana, Opegrapha anomaea, O. aff. xerica, Phoma aff. lecanorina, Polycoccum rubellianae, Porina nucula, Pyrenidium actinellum, Rhexophiale rhexoblephara, Rimularia badioatra, Rinodina confragosa, R. milvina, R. occulta, Tremella phaeophysciae), as well as 1 new species to Russia (Verseghya klarae) are provided. Furthermore new for science species of lichenicolous fungus Polycoccum clauderouxii from China is described. Four new combinations, i.e.: Biatora pseudosambuci (Basionym: Lecanora pseudosambuci S. Y. Kondr., L. Lőkös et J.-S. Hur), Buellia pseudosubnexa (Basionym: Hafellia pseudosubnexa S. Y. Kondr., L. Lőkös et J.-S. Hur), Buellia extremoorientalis (Basionym: Hafellia extremorientalis S. Y. Kondr., L. Lőkös et J.-S. Hur), and Sagedia nunatakkorum (Basionym: Lecanora nunatakkorum Poelt) are proposed. Data on conidiomata and conidia for lichenicolous fungus Opegrapha anomea Nyl are for the first time provided.