The occurrence of unattached spherical (aegagropilous) populations of the green alga Cladophora prolifera in the marine lagoon of Strunjan (Gulf of Trieste) is reported. Species identification was based on molecular and morphological data, and the distribution, ecology and morphological features of the aegagropilous populations are described. The ball-shaped form of this species differs from the typical upright, attached form found on open shores by the radial arrangement of the branches and the absence of cells and rhizoids with clear annular constrictions. The formation of the aegagropilous ...