Species in the genus have a polycentric thallus and reproduce sexually or asexually by zoospores that have a whiplash-like flagella.

They are mostly isolated from soils in tropical countries, commonly in ponds, rice fields, and slow-moving rivers.

[2] Allomyces thalli consist of a cylindrical trunk-like basal cell that gives rise to well-developed, highly branched rhizoids that anchor the thallus to the substrate.

[3] In Cystogenes life cycle the resting sporangia (from the sporophyte) give rise to biflagellated, bi-nucleated zoospores that will encyst, undergo meiosis, and germinate to yield motile gametes.

[4] Allomyces species seem to have a global distribution and are readily isolated from soils and waters by baiting with a sterile seed.

Based on type of life cycle, Emerson delineated three subgenera: Euallomyces, Cystogenes, and Brachyallomyces.

Based on a molecular phylogeny using portions of the nuclear ribosome, it appears Euallomyces and Brachyallomyces are polyphyletic, but Cystogenes is monophyletic.