They are distinguished by an anterior tinsel flagellum[7] on their zoospores. Also they have a rhizoidal or hypha-like vegetative system (hence the prefix "Hypho-").
This group may be put alternatively at the phylum, class, subclass or order level, being referred to as Hyphochytriomycota, Hyphochytriomycetes (or Hyphochytrea), Hyphochytriomycetidae (or Hyphochytridae) and Hyphochytriales, respectively. The variants Hyphochytridiomycota and Hyphochytridiomycetes are also sometimes used, presumably by analogy to the Chytridiomycetes, or due to the perpetuation of a typographical error. However, the stem is Hyphochytri- (from Hyphochytrium) and not Hyphochytridi- (from Chytridium).[8]
In the past the classes Hyphochytridiomycetes, Oomycetes and Chytridiomycetes were grouped together in the now obsolete taxon Mastigomycotina as fungi with flagellate spores or gametes. Now the Chytridiomycetes are still considered true fungi, but the other two sub-groups are classified in the kingdom Protista, or in the group Stramenopiles.
Hyphochytriomycetes are closely related to Oomycetes.[9]
^Dick, M.W. 1983. Validation of the class name Hyphochytriomycetes. In: Buczacki (ed.), Zoosporic Plant Pathogens, A Modern Perspective. London & New York: Academic Press.
^Van der Auwera G, De Baere R, Van de Peer Y, De Rijk P, Van den Broeck I, De Wachter R (July 1995). "The phylogeny of the Hyphochytriomycota as deduced from ribosomal RNA sequences of Hyphochytrium catenoides". Mol. Biol. Evol. 12 (4): 671–8. doi:10.1093/oxfordjournals.molbev.a040245. PMID7659021.
