[2] Molecular phylogenetic analysis of multigene DNA sequence data indicates the taxon Clavicipitaceae is paraphyletic, and consists of three well-defined clades, at least one of which is shared with members of another fungal family (Hypocreaceae).

[3] The evolution within the Clavicipitaceae is marked by interkingdom host jumping, and the range of this large and heterogeneous fungal group spans mutualistic plant symbionts, as well as parasites of plants, insects, and other fungi.

One of its most infamous species is Claviceps purpurea, which has historical significance as the cause of St. Anthony's fire, also known as ergotism.

Metarhizium species are widely used in the biological control of insect pests.

[5] Several genera, especially those previously described as "anamorphic" (having no known sexual cycle) are now re-classified into other families, in light of current molecular and other evidence.