The carpospores of Scinaia complanata grow into a filamentous tetrasporophytic phase, which is capable of self-reproduction. The tetraspores grow into a morphologically recognizable filamentous gametophytic stage, which is also capable of self-reproduction, and which can give rise to adult Scinaia thalli. Growth and reproduction of the tetrasporophyte and the gametophytic filamentous stage, as well as the development of adult Scinaia thalli, are furthered by 17°C long day conditions, which roughly correspond to summer conditions in the Mediterranean.