In some species, such as the alga Ulva lactuca, the diploid and haploid forms are indeed both free-living independent organisms, essentially identical in appearance and therefore said to be isomorphic.
Nalgunhas especies, como a alga Ulva lactuca, as formas diploide e haploide son ambas organismos de vida libre independentes, esencialmente idénticos en aparencia e por tanto denominados isomórficos.