Diploid zygote may be adapted to surviving winter conditions, as in freshwater green algae.
Sexual reproduction is triggered when the cells reach a certain minimal size.
Dinobryon Brown algae Phaeophyta Multicellular Reproductive cells, both asexual zoospores and sexual gametes, are usually flagellated. Most have life cycles with an alternation of generations . Many species show alternation of generations. These reproduce by spores in sporangia. Water molds Oomycota Coenocytic mycelium Biflagellate zoospores.