This is a remarkably diverse collection containing roughly 20,000 specimens, mostly from the Catalan-speaking territories (Països Catalans). It also includes the herbarium of the Catalan Society of Mycology.In terms of taxa, the collection has a notable representation of Gasteromycetes, Russulaceae and Myxomycetes. One of the highlights is the herbarium of Myxomycetes (parasitic fungi) of T. M.Losa.
For most of the fungi, the collection only has the sporocarps and other reproductive structures that permit their identification. Materials collected in the field are dehydrated and stored in plastic or paper envelopes in cardboard boxes. The samples are organized by major group (Ascomycetes, Basidiomycetes, Myxomycetes, etc.) and then, within each of these groups, put in alphabetical order by species.