Anamorph: Cylindrocarpon sp. (Samuels 1978).
Teleomorph: ascomata perithecia, 160-250 µm diam. when dry, solitary or in small clusters, seated on a small, erumpent stromatic base, ± globose when fully hydrated, not papillate, becoming cupulate when dry; orange (fresh material) but becoming brownish when dry, not changing colour in KOH, smooth or slightly roughened. Peridium composed of an outer layer of thin-walled yellowish brown globose cells 9-17 µm diam. and an inner layer of flattened thin-walled hyaline cells, without hairs or other ornamentation. Interascal tissue absent, but with slightly tapering thin-walled apical paraphyses to ca 20 µm in length and 1.5-2 µm diam. and periphyses lining the ostiole. Asci (51-) 58-67 x 9-11 µm, clavate, the basal part tapering, sometimes slightly attenuated towards the apex, thin-walled and not fissitunicate, not blueing in iodine, with a distinct refractive apical ring 2.5-3 µm diam. and ca 1 µm thick, 8-spored. Ascospores arranged biseriately, (10.5-) 12.5-15.5 x 3.5-4.5 (-5) µm, fusiform to fusiform-ellipsoidal, slightly constricted at the ± median septum, hyaline to pale straw-yellow, thin-walled, smooth or very faintly striate, without an epispore, gelatinous sheath or appendages.
Not formally evaluated, but the species is widely distributed and unlikely to be significantly threatened.
On dead stems of plants in damp places, most frequently recorded on Urtica dioica but not host-specific. Sometimes associated with other fungi (e.g. Diaporthe spp.) and possibly a hyperparasite.
Throughout the British Isles.