Morphologically more or less indistinguishable from Epichloë festucae var. festucae. The two taxa are clearly related phylogenetically, but var. lolii is consistently vertically transmitted and is therefore likely to be biologically separate from the populations on Festuca.
Not formally assessed. Apparently rare in Britain with only three known records (two of which were identified as the aggregate species E. typhina).
On or in living parts of Lolium perenne. Developing as an endophyte and also a parasite in its assumed teleomorphic phase.
In GB&I, known from VC14 E Sussex, VC36 Herefordshire and VC37 Worcestershire.