2007: mycologists agree on one tree of fungi

For two decades after molecular methods arrived, fungal systematics was a field in which every team had its own version of the tree. Rank names disagreed, phylum boundaries shifted from paper to paper, and a textbook author had to choose which version to copy. In 2007 Mycological Research published "A higher-level phylogenetic classification of the Fungi", signed by David Hibbett and a large group of co-authors.

The text came out of the Assembling the Fungal Tree of Life project, funded precisely in order to gather scattered analyses into one coherent picture. The result is a classification covering ranks from kingdom down to orders, agreed between specialists on different groups, with the uncertain places marked as uncertain. The paper itself runs to nearly forty journal pages.

The value of such a document is that it stops being somebody's proposal and becomes a reference. Databases — GBIF, Index Fungorum, later UNITE — need a single skeleton on which to hang names. The author of a new species needs to know which family to assign it to. Without an agreed classification each of those acts would require a separate decision.

The 2007 classification is not the last word and was never meant to be. The years since have brought corrections, new phyla and rearrangements based on genomes rather than a handful of genes. What changed is the practice itself: revisions are now proposed against a shared skeleton rather than built as competing wholes.

A consensus with uncertainty left visible

The 2007 classification was not a single tree imposed by one author. A first draft was presented at the 2005 Deep Hypha meeting, circulated to about 100 fungal systematists, revised after their comments, and modified again following the 2006 meeting. The published structure accepted one kingdom, one subkingdom, seven phyla, ten subphyla, 35 classes, 12 subclasses and 129 orders—195 taxa down to ordinal rank in all; 16 names were described or validated in the paper.

Its scope was deliberately restricted to the monophyletic kingdom Fungi. Oomycetes and slime moulds, although traditionally studied by mycologists, were explicitly left outside. The authors also warned that taxa assigned the same Linnaean rank need not be equivalent in age, species number or morphological divergence. The result was therefore a shared, revisable framework that databases and textbooks could use consistently, rather than a claim that every deep branch had been resolved for good.