Anamorph: not known.
Teleomorph: ascostromata perithecia, 300-400 (-500) µm diam., immersed with only the ostiole visible, or occasionally erumpent and almost superficial; solitary to loosely clustered, globose to pyriform, mostly smooth, rarely surrounded by brown mycelium, with gradual elongation into a terete beak 50-100 µm diam. and 100-150 µm high, lined with periphyses 1.0-1.5 µm diam. Peridium 35-50 µm thick, with an outer layer of dark brown ± globose thick-walled cells 7-10 µm diam. and an inner layer of hyaline angular thin-walled cells 7-15 x 3-5 µm. Interascal tissue of cellular pseudoparaphyses 1.5-2 µm diam. Asci in a broad basal hymenium, 150-170 x 11-14 µm, narrowly cylindrical with a somewhat tapered base, the apex rounded, thick-walled and fissitunicate, 8-spored. Ascospores fasciculate, straight or slightly intertwined, 125-155 x 2-3 µm, ± cylindrical with slight narrowing towards the lower end, golden brown, (17-) 23- to 30-septate, often separating at the mid septum into two subequal part spores each with the second (rarely third) cell from the point of disarticulation enlarged near a septum, the ends obtuse, cells biguttulate, of nearly equal length, when fully mature only slightly longer than wide, without an epispore, gelatinous sheath or appendages.
Not formally assessed, but the species is common and unlikely to be threatened.
On dead stems of Arctium and Cirsium, more rarely on other herbaceous material.
Throughout the British Isles.