Anamorph: conidiomata absent. Conidiophores unbranched, sometimes verticillate, becoming loosely to moderately densely branched. Conidiogenous cells 10-35 µm long and 1.5-3 µm broad at the base, cylindrical and slightly tapering towards the tip or narrowly flask-shaped with the widest point in the middle, proliferating percurrently. Conidia formed abundantly on slimy heads, variable in size but usually (30-) 50-80 x 5.5-7 µm, cylindric-ellipsoidal to cylindrical, straight or slightly curved with rounded ends, 1- to 5-septate, thin-walled, hyaline, smooth, without a gelatinous sheath or appendages.
Teleomorph: stromata to 0.3 mm high and 8 mm diam., erumpent through the epidermis, pinkish to orange-brown. Ascomata perithecia, superficial on the stroma, in compact clusters of up to ca 30, 200-250 (-350) µm diam. and 220-300 µm tall, subglobose to pyriform, dark pinkish red, sometimes cupulate upon drying or collapsing by lateral pinching, papillate, the region immediately around the ostiole sometimes slightly darker, KOH+ purple, LA+ yellow, surface smooth or minutely roughened. Peridium 20-40 µm thick, with an outer layer of thick-walled pigmented globose to angular cells and an inner layer of ± hyaline thin-walled angular cells. Interascal tissue well-developed, composed of chains of very thin-walled ellipsoidal cells, evanescent at maturity. Asci 70-95 × 9-13 μm, cylindrical to narrowly clavate, short-stalked, the apex obtuse to rounded, thin-walled, not fissitunicate, with a very inconspicuous hardly refractive thickened ring at the apex, not blueing in iodine, 8-spored. Ascospores uniseriate or obliquely biseriate near the ascus apex, 12-14.5 x 4-6.5 µm, ellipsoidal to broadly fusiform with narrowly rounded ends, straight or slightly curved, 1-septate, hardly constricted at the ± median septum, hyaline to pale yellow, thin-walled, finely roughened, without an epispore or gelatinous sheath.
Not formally assessed, but the species is widespread and unlikely to be threatened.
Ascomata produced from stromata erumpent through the bark of Fagus sylvatica, usually only forming after the tree is dead. Presumably endophytic within living bark tissues. Records from other host trees need re-evaluation.
Throughout England and Wales, with scattered records in Scotland north to Skye, also known from N Ireland.