Anamorph: colonies effuse, dark blackish brown to black, hairy. Mycelium partly superficial, composed of branched septate pale to dark brown smooth·walled hyphae. Conidiophores 70-300 µm long, 5-6 µm diam. towards the base, 3-4 µm diam. at the apex, arising singly or in groups, terminally and laterally on the hyphae, erect or ascending, unbranched, straight or flexuous, cylindrical to subulate, sometimes swollen or lobed at the base, brown to dark blackish brown, often paler towards the apex, smooth-walled. Conidia 16-26 x 8-13 µm, arising singly through pores in the wall of the upper half of the conidiophore, obovoid or clavate, conico-truncate at the base, brown to dark brown, smooth-walled, 3-septate, the septa usually appearing as dark blackish brown to black bands.
Teleomorph: ascomata perithecia, 350–550 μm diam. and 400–550 μm high, ± globose, non-stromatic, immersed with protruding necks or becoming superficial, solitary or in small groups, dark brown to black, the surface sometimes covered by an orange to orange-red waxy to granular layer that dissolves in KOH. Neck central, 80-100 μm diam. and 500–700 μm long, cylindrical, tapering, sulcate at the apex, lined with periphyses. Ascomatal wall fragile to leathery, composed of an outer layer of dark brown thick-walled polyhedral cells and an inner layer of compressed hyaline thin-walled cells. Interascal tissue of evanescent paraphyses 4.5–6 μm diam. near the base, tapering towards the apex, constricted at the septa. Asci 110-130 x 8-9 µm [(75–) 80–100 (–110) × 9.5–11 μm fide Réblová et al. 2018], cylindrical to cylindric-clavate with a short stalk, broadly rounded or truncate at the apex, with an apical ring to 3.5 µm diam. and 2.5 µm thick that does not blue in iodine, 8-spored. Ascospores 16.5-19 (-20) x 5.2-6.5 µm [(13–) 14–16 (–17) × (5–) 5.5–6 (–7) μm fide Réblová et al. 2018], ellipsoidal to ovoid, sometimes inequilateral, aseptate or rarely with a middle septum, hyaline, smooth-walled.
Description adapted in part from Ellis (1963) and Réblová et al. (2018).
Not formally assessed due to lack of data, but the species does not appear to be threatened.
On rotten wood from various species, seemingly most common on Fagus sylvatica and Quercus spp.
Scattered throughout Britain, from Cornwall north to Skye.