The sexual life history of Ulva is isomorphic and isogamous.  The sporophyte (h) produces quadriflagelllate  zoospores (j and j' ), which germinate to produce the gametophytes (a and a' ), which produce biflagellate cells (c and c' ) that may function as gametes (sexual reproduction) or zoospores (asexual reproduction).  There is no vegetative reproduction in this genus.