The originally monotypic genus Rhacophyllus was conceived for an agaric-lik
e fungus that bore sheets of miniature sclerotium-like bodies (lysomeres) i
n place of lamellae. Subsequently it was demonstrated that a "normal" Copri
nus-like teleomorph exists as an alternative state (morph). Following this
discovery, most authors have treated Rhacophyllus as an anamorph. Ontogenet
ic studies indicate that the Rhacophyllus state is a variation on basidiome
production. Rhacophyllus apparently was rediscovered and redescribed as a
new genus Zerovaemyces, for which a new family, Zerovaemycetaceae, and a ne
w order, Loculomycetes, were also described, all as teleomorphs. Nomenclatu
ral application of these names are analysed, and it is concluded that Rhaco
phyllus (and Zerovaemyces, Zerovaemycetaceae) are best considered to be nom
ina anamorphosium. These decisions affect the naming of other taxa newly re
solved molecularly. An analogous second case of modified basidiomes involve
s the anamorph Decapitatus gen. nov., described here for the well-known gem
miferous state of Mycena citricolor, Decapitatus flavidus comb, nov. (= Sti
lbum flavidum).