Blastocladiomycota is one of the currently recognized phyla within the kingdom Fungi.[1] Blastocladiomycota was originally the order Blastocladiales within the phylum Chytridiomycota until molecular and zoospore ultrastructural characters were used to demonstrate it was not monophyletic with Chytridiomycota.[2] The order was first erected by Petersen for a single genus, Blastocladia, which was originally considered a member of the oomycetes.[3] Accordingly, members of Blastocladiomycota are often referred to colloquially as "chytrids." However, some feel "chytrid" should refer only to members of Chytridiomycota.[4] Thus, members of Blastocladiomyota are commonly called "blastoclads" by mycologists. Alternatively, members of Blastocladiomycota, Chytridiomycota, and Neocallimastigomycota lumped together as the zoosporic true fungi. Blastocaldiomycota contains 5 families and approximately 12 genera.[5] This early diverging branch of kingdom Fungi is the first to exhibit alternation of generations.[6] As well, two (once) popular model organisms—Allomyces macrogynous and Blastocladiella emersonii—belong to this phylum.[4]