The work presents the morphology of cells and trichomes of Glaucospira laxissima (G.S. West) comb. nova analyzed by light microscopy, confocal laser microscopy (CLM) and transmission electron microscopy (TEM). Cyanobacterial characteristics are confirmed for the first time. It also contains the data on the ecology of this species, found for the first time in Serbia, in a small alkaline lake in a planktic community with the species Cylindrospermopsis raciborskii (Woloszynska) Seenayya & Subba Raju, Anabaenopsis elenkinii V.V. Miller and Chrysosporum bergii (Ostenfeld) Zapomelová et al.