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Vaucheria aversa (Xanthophyta) was recorded for the first time in Ukraine in Sula River, Hydrological Reserve «Artopolot», Poltava Region. It was found in benthos in spring (May 2020) in silty-sandy soil in shallow water. The material was collected and processed according to a common methodology. Sterile samples before the appearance of the gametengians were kept in natural water in petri dishes in well-lit places. This method of «coarse culture», in most cases, allowed to get gametangia within two weeks. The species identification was done with fertile filaments only. 4% formaldehyde solution was used for material fixation. Taxonomic identification of samples was done using a comparative and morphological methods, which includes analysis of morphological variability and verification of the consistency of the studied material with the diagnosis. Thalli of V. aversa are direct, branched, bisexual, 80–90 μm wide. Antheridia are cylindrical, tubular shape, pressed to the filament or slightly raised above it, 119–130 × 41–43 μm. Oogonia erect, sessile, ovoid to subspherical, sometimes placed in pairs, with a curved beak at the front, 190–230 × 140–163 μm. According to morphological characteristics this species is similar to another one from section Tubligerae Walz – V. fontinalis (Linnaeus) T.A. Christensen. Their distinctive and common features are as follows. Filaments of V. fontinalis are narrower (up to 75 μm) than V. aversa (up to 131 μm). Both species are characterized by oogonia grouped together in a row. Antheridia present in quantity 1 or 2 on both sides of oogonia. But the species are very different in size and shape of oogonia: in V. aversa they are sessile, located one at a time or less often two, extended near the base, sharply narrowed at the apex. The beak is directed straight or obliquely up, bent to the side of the oogonia body. In V. fontinalis oogonia are placed in one row, most often in the amount of 1-6, the beak tapers gradually. Anteridia are cylindrical, on short pedicel. V. aversa grew as a part of polyspecies complex of green algae together with representatives of such genera as Cladophora Kützing, Spirogyra Link and Mougeotia C. Agardh. V. aversa is widely distributed in continental water bodies of Europe, Asia and North America, Australia and New Zealand, but is firstly recorded in Ukraine.

he article presents information about new finds of desmid Bambusina borreri (= B. brebissonii Kütz. ex Kütz.) in Ukraine and analysis of its distribution in the country. Peculiar features of the genus are cylindrical or barrel-shaped cells arranged in slightly twisted non-mucous filaments. Bambusina borreri is cosmopolitan with a disjunctive rangeж its distribution is limited by pH and trophic level of water bodies. Environmental selectivity determines its low frequency of occurrence. The species was included in the third edition of the Red Data Book of Ukraine. The authors first discovered B. borreri in the swamp protected by the Chornolisky Landscape Reserve of National Importance (Kirovohrad Region, Ukraine).In the Maliovanka Regional Landscape Park (Khmelnytsky Region, Ukraine) this species was confirmed to inhabit Rusalchyne Lake and first found in three more lakes. In all cases B. borreri occurred in typical habitats: oligotrophic reservoirs with low pH. A list of locations and a map of the distribution of B. borreri in Ukraine has been compiled. Among 22 localities cited for this species five sites are currently dissappeared. Most of the B. borreri localities are situated in the Pripyat-Desna Algofloristic Subprovince and only two belong to the Middle Dnieper and Carpathian-Danube algofloristic subprovinces; this is due to ecological preferences of the species. It is important to note that 10 of the 17 still existing habitats of B. borreri are located within the objects of the Nature Preservation Fund of Ukraine, which is an important aspect of its conservation.