The “Fourth checklist of lichen-forming and lichenicolous fungi of Ukraine”, including 2150 accepted scientific names based on published records as well as analysis of current additions are provided. Current additions include 439 taxa newly recorded for Ukraine after the third checklist of lichens of Ukraine by Kondratyuk et al. (2010) and 262 nomenclatural novelties. Annotations to each taxon of 318 newly recorded to Ukraine are provided in the style of the second checklist by Kondratyuk et al. (1998), i.e. data on phytogeographical regions and administrative districts (oblasts) of Ukraine as well as references to published papers are provided. Among current additions 99 taxa were annotated in the Checklist of lichenicolous fungi of Ukraine by Darmostuk and Khodosovtsev (2017) and consequent references to the latter are provided.The conclusion confirms the earlier recommendation that national checklists of lichens are to be re-published more often than once a decade.

The results of phytosociological studies of pioneer lichen communities of siliceous outcrops carried out in 2014-2016 in Teteriv River basin (Ukraine) are provided. The dataset of 302 relevés was analysed, 6 associations and 1 subassociation from 3 classes were distinguished as a result of the phytosociological survey in the Teteriv River basin. Four associations, i.e.: Aspicilietum contortae Kaiser ex Klement 1955, Cladonietum mitis Krieger 1937, Parmelietum conspersae Hilitzer 1925, Parmelietum somloensis Wirth 1995 and the alliance Aspicilion calcareae Albertson ex Roux 1978 are new for Ukraine, and one new association Aspicilio cinerei-Ramalinetum pollinariae Kapets et Khomyak, ass. nova is described here.

new to the Teteriv River Basin are provided. Further five species (Cercidospora crozalsiana, Lichenostigma epipolina, Lichenothelia tenuissima, Polysporina subfuscescens and Taeniolella beschiana) are new to Ukraine. Additional localities for all newly reported species are listed.

First data on lichens of the Teteriv River Basin appeared in the second part of 19th century. First records of lichenicolous fungi in this area were published at the end of the 20th century. An annotated list of lichens and lichenophilous fungi is based on literature data and materials of own researche of lichenobiota of the upper and middle course of the Teteriv river basin. Llist of lichens and lichenicolous fungi of the area includes 300 species. The distribution of 117 species (80 lichens, 37 lichenicolous fungi) are for the first time recorded for area studied. Five species (Cercidospora macrospora, Lichenostigma epipolina, Lichenothelia tenuissima, Polysporina subfuscescens і Taeniolella beschiana) are new to Ukraine, 7 species (Anisomeridium polypori, Coenogonium pineti, Lichenoconium usneae, Monodictys epilepraria, Rinodina efflorescens, Sphaerellothecium propinquellum, Taeniolella punctata) are new for the Ukrainian Plains, while 11 species (Cornutispora lichenicola, Erythricium aurantiacum, Heterocephalacria physciacearum, Intralichen christiansenii, Laetisaria lichenicola, Lichenothelia convexa, Marchandiomyces corallinus, Psoroglaena dictyospora, Pyrenochaeta xanthoriae, Sarcogyne lapponica, Scoliciosporum gallurae, Stigmidium xanthoparmeliarum) are new for the Polissia subprovince of mixed coniferous and broad-leaved forests, and one species is new for the territory of the Ukrainian forest-steppe subprovince. In addition, new information on the distribution of a number of rare to Ukraine lichen and lichenicolous fungal species (Absconditella lignicola, Cornutispora lichenicola, Clypeococcum hypocenomycis, Lichenochora obscuroides, Lichenodiplis lecanorae, Marchandiomyces corallinus, Psoroglaena dictyospora, Sclerococcum sphaerale, Strangospora deplanata, Thelocarpon epibolum ect.) is obtained.

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