Fungal diversity, evolution, and classification.

Fungi include mushrooms, molds, lichens, yeasts, and zoosporic forms that occur as free-living or symbiotic organisms in every ecosystem on Earth. About 155,000 species of Fungi have been described, and possibly millions more remain to be named. Recent focus on aquatic habitats has illuminated major groups near the boundary between Fungi and protists. Fungal systematists have made remarkable progress toward resolving the major branches of the phylogeny, although some deep nodes have proven recalcitrant. Fungal taxonomists steadily describe about 3,000 new species per year, and fungal molecular ecologists routinely detect many thousands of unidentifiable 'dark fungi' through metagenomic analyses. To assemble the complete fungal tree of life, it will be necessary to connect the main branches of the phylogeny to information on all described species and integrate the vast and rapidly growing corpus of dark fungi.