A category not used in all systems

• A large and probably unnatural group of fungi and funguslike organisms comprising the Mastigomycota (including the Oomycetes) and Zygomycota subdivisions of the division Eumycota

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Phycomycetes \Phy`co*my*ce"tes\, n. pl. [NL.; Gr. ? seaweed + mycetes.] (Bot.) A large, important class of parasitic or saprophytic fungi, the algal or algalike fungi. The plant body ranges from an undifferentiated mass of protoplasm to a well-developed ...

Wikipedia Word definitions in Wikipedia
Phycomycetes is an obsolete polyphyletic taxon for certain fungi with nonseptate hyphae . It is used in Engler system . The class Phycomycetes has been abolished and in its place exists Zygomycetes , Chytridiomycetes , Plasmodiophoromycetes , Hyphochytridiomycetes ...