[3] Until recently a large number of other white-spored species, some very common, were assigned to this genus, but now the majority have been separated into other genera: Gymnopus, Rhodocollybia and Dendrocollybia.

[4] Collybia sensu lato is one of the groups of fungi of the order Agaricales that has created taxonomic differences of opinion in the scientific community.

[6] Later in his systematic work of 1838,[7] Fries characterized Collybia as those species with The last criterion divided these mushrooms from those of Marasmius, which had the property of being able to revive after having dried out (called "marcescent").

[10] At that point, the very varied genus encompassed the modern genera Oudemansiella (including Xerula), Crinipellis, Flammulina, Calocybe, Lyophyllum, Tephrocybe, Strobilurus, and others.

The type species for Collybia is C. tuberosa, a small white parasitic mushroom (with caps up to 1.5 cm (0.6 in)) which develops from a reddish-brown apple seed-shaped sclerotium in and on putrescent fungi or remaining in soil after complete decay of the host tissue.