Terrestrial algae and cyanobacteria of the Holosiiv National Nature Park (Kyiv, Ukraine), with the description of Leptochlorella arboricola sp. nov. (Trebouxiophyceae, Chlorophyta)

The article provides the results of a study on terrestrial algae inhabiting various substrates in the Holosiiv National Nature Park, which was established to protect the remnants of natural ecosystems in the Kyiv metropolitan area, Ukraine. Totally, 75 species were identified: Cyanobacteria (10 species), Chlorophyta (52), Charophyta (7), and Heterokontophyta (6). The largest number of species was recorded on concrete (44 species) and dead wood (41); both substrates exhibited the most diverse composition of dominant species of algae. Less species were found on tree trunks (34), soil crusts (25), and fruiting bodies of the polypore fungus (18). The genera Klebsormidium (5 species) and Stichococcus (4 species) were the most diversely represented on different substrates. Representatives of green algae, Stichococcus bacillaris, Coccomyxa subellipsoidea, Interfilum terricola, Desmococcus olivaceus, Elliptochloris subsphaerica, and Trentepohlia cf. umbrina, were most frequent in the studied habitats. Some new and noteworthy taxa have been revealed using molecular phylogenetic methods. Among them, three genera (Wilmottia, Chromochloris, and Leptochlorella) and five species (Wilmottia murrayi, Drouetiella epilithica, Chromochloris zofingiensis, Neocystis mucosa, and Coccomyxa arvernensis) were for the first time recorded for the algal flora of Ukraine. In addition, five rare species of the genera Coelastrella, Pseudochlorella, Coenochloris, Dictyochloropsis, and Coccomyxa are also reported. Finally, a new species of the genus Leptochlorella, L. arboricola Mikhailyuk, is described.