RT Journal Article SR Electronic A1 Uher, Bohuslav T1 Cyanobacterium Petalonema alatum BERK. ex KIRCHN. - species variability and diversity. JF Fottea YR 2010 VO 10 IS 1 SP 83 OP 92 DO 10.5507/fot.2010.003 UL https://fottea.czechphycology.cz/artkey/fot-201001-0003.php AB Petalonema alatum is an interesting cyanobacterial species of subaerial calcareous habitats in gorges of the National Park Slovenský raj, Slovakia. Observation of different morphological forms in natural and culture materials is demonstrated and discussed. Cultures of P. alatum differed from natural populations mainly in the width of the filament apex, massiveness of mucilage sheaths, and degree of heteropolarity. This means that these features are more likely controlled by environmental variables. Other characteristics (heteropolarity, false branching, sheath structure) were found to be stable and consequently can have taxonomical importance.