Isogamy

Isogamy is a form of sexual reproduction that involves gametes of the same morphology (indistinguishable in shape and size), and is found in most unicellular eukaryotes.

[5][6] Isogamous species often have two mating types (heterothallism), but sometimes can occur between two haploid individuals that are mitotic descendents (homothallism).

[7] Under the strict definition of isogamy, fertilization occurs when two gametes fuse to form a zygote.

Isogamous reproduction evolved independently in several lineages of plants and animals into anisogamy (species with gametes of male and female types) and subsequently into oogamy (species in which the female gamete is much larger than the male and has no ability to move).

[1][14] In some multicellular fungi, such as basidiomycetes, sexual reproduction takes place between two mycelia, but there is no exchange of gametes.