The genus was, for a time, considered synonymous with Endothia, but the two are now recognised as distinct.

Taxonomic studies in 2006 limited the genus to four species, but a fifth, Cryphonectria naterciae, was described in 2011 from Portugal.

By the 1940s it had killed most wild American chestnut trees, which were formerly one of the most abundant species in the eastern U.S.

In the early stage, clear yellow-brown spots appear on the young twigs; the bark then splits open, sinks in and dies out.

In the next stage the cambium layer is infected, the tree trunk becomes disformed, the split bark parts start to swell as parasitic fungus produces more peridermia and yellow colored pycnidia start to appear on the bark.