If there is a difference of opinion between taxonomists, perhaps the most recent is not always the classification accepted by everyone.
I use the BMS database (
British Fungi - checklist ) for checking taxonomy. If you search for Hygrocybe it has the following entry:
Genus, Family, Order, Subclass, Class, Phylum
Hygrocybe, Hygrophoraceae, Agaricales, Agaricomycetidae, Agaricomycetes, Basidiomycota
It also has a list of accepted species names (in blue type) and comprehensive list of synonyms cross reference to the currently accepted (by the BMS) name.
The checklist (
Basidiomycota Checklist-Online - Name Search Page ) does a similar job at species level but does not include families or higher classification.
p.s.
I do not want to get into a discussion on the merits of the two available databases. The other one is probably just as good, but I have not yet found the need to give it a try.
Peter