Geitlerinema, a new genus of oscillatorialean cyanophytes

Certain related oscillatorialean species, originally attributed to the genusOscillatoria and recently assigned to subg.Geitlerinema of the genusPhormidium (Phormidiaceae-Phormidioideae), are revised and reclassified. Based on a reevaluation of the diacritical features, subg.Geitlerinema is raised to generic rank and assigned to the familyPseudanabaenaceae (tentatively to subfam.Pseudanabaenoideae). The individual species are reviewed and the necessary new combinations are made.