Archaeorhizomycetes is an class of fungi in the subdivision Taphrinomycotina of the Ascomycota. So far, the class has only one described order, Archaeorhizomycetales, family, Archaeorhizomycetaceae, and genus, Archaeorhizomyces. The class was first described by a team led by Anna Rosling in 2011. Species in the class are globally distributed, and grow in soil and around roots. Specific known host trees of various Archaeorhizomyces species include hemlock, spruce, pine and heather, but other species colonise hardwoods generally.