of a paper given at the Third lAP Workshop, Seeon 1980 Further observations on chlorococcal algae in natural material and in laboratory cultures are given. The vast majority of the investigated material was collected from aquatic biotopes in the region of the city of Bratislava and in Western Slovakia. Special attention has been paid to small gravel pit lakes and sand pit lakes at the feet of the Small Carpathian Mountains, characteristic of that region. These were mainly small water bodies, fish-ponds, the rivers Danube and Moravia, their inundation lakes and dead arms. Algae collected outside the territory of Slovakia (Moravia, Poland, Switzerland, Bulgaria, India) have been studied occasionally. The investigated taxa pertain to the families Radiococcaceae, Micractiniaceae, Dictyosphaeriaceae, Chlorellaceae (subfamilies Chlorelloideae, Oocystoideae, Ankistrodesmoideae), Scenedesmaceae (subfamilies Coronastroideae, Crucigenioideae, Scenedesmoideae) and Hydrodictyaceae. The ontogenetic cycle, the mode of reproduction, the variability of diagnostical morphological features were studied using a light microscope.A proposal was made for the establishment of 12 new species: Coenochloris asymmetrica, C. helvetica, C.sphagnicola, Dictyosphaerium sphagnale, Chlorella oocystoides, Choricystis guttula, Siderocelis irregularis, Granulocystis chlamydomonadoides, Quadrigula sabulosa, Kirchneriella danubiana, Monoraphidium fontinale and Tetraedron mediocris. Apart from these, one new combination has been made: Monoraphidium nanum (Ettl) Hind. Some species have been found in Czechoslovakia for the first time following their original description by the author.

The genus Synechococcus represents an enigmatic group of cyanobacteria with very simple unicellular morphology and polyphyletic evolutionary origin. Here, we describe a new genus based on strain of Synechococcus-like cyanobacterium. The strain was isolated from the peat bog Klin (Slovakia), where it occupies different niches such as hyaline cells of Sphagnum, sheaths of cyanobacteria, dead cells of desmids, carapaces of dead crustaceans, and solitary in detritus. We describe this new genus using a combination of molecular, morphological and ecological features. A phylogeny of the 16S rRNA gene, 16S-23S ITS and rbcL loci showed a separate position of the investigated strain and its close proximity to filamentous cyanobacteria. Therefore, it is a novel lineage of Synechococcus-like cyanobacteria illustrating the polyphyletic nature of the genus Synechococcus. Moreover, the strain exhibits unique morphological and ecological features, which allow us to erect the new monospecific genus Neosynechococcus.

No abstract