Ergot alkaloidsErgot alkaloids are specialized metabolites of agricultural and medical importance produced by at least two different lineages of fungi. Fungi from different lineages share early steps of the biosynthetic pathway, and functional genetic studies and genomic analyses indicate a common set of clustered genes encodes these early pathway steps. Different taxa follow different terminal branches of the pathway to produce profiles of ergotergot alkaloidsergot alkaloid that vary by lineage. In addition to the pathway end-product, the profile of ergot alkaloidsergot alkaloid observed in a given fungus often includes pathway intermediates that accumulate to high levels and sometimes products of pathway spurs. Ergot alkaloid-producing fungi fill a range of environmental niches and studies with mutants containing altered ergot alkaloidergot alkaloid pathways indicate these specialized metabolites contribute to resource acquisition and resource preservation in the fungi that produce them.