In subtidal cultures, fixed to the bottom, as well as suspended twines, the vegetative and tetrasporic phases predominated in most of the populations investigated. In both of these cultures, cystocarpic thalli were present sporadically and in the suspended cultures, masculine too. In the natural intertidal population, each phase of the life cycle was present. Furthermore mixed phases were observed, where cystocarps were found along with tetrasporangia. Under laboratory conditions, initially vegetative thalli formed either male gametangia, cystocarps or tetrasporangia. In tetrasporic thalli branches were found developing male gametangia and/or cystocarps. The life cycle was obtained in six month approximately, from tetraspore liberation to the formation of young tetrasporic individuals.