Perithecia superficial, solitary to somewhat crowded, setose, scattered among conidiophores, globose to subglobose, 160-120 µm broad, 190-275 µm high, with a shortly papillate apical ostiole lined on the inside by hyaline, filiform periphyses, sometimes bearing conidiophores amongst its numerous setae. Setae straight or flexuous, erect, brown, cylindrical, septate, simple, up to 300 µm long, 3-4.5 µm wide. The perithecial wall 20-23 µm thick is composed of 7-10 layers, with the outer layer of brown, thick-walled, polygonal cells and an inner layer of more or less compressed, brown to very pale brown, less thick-walled cells. Asci arising from a hymenium at the base, thin-walled cylindrical short-stalked, 8 spored, unitunicate, 40-50 x 3.5-5 µm, evanescent, with a non amyloid apical structure. Ascospores uniseriate to overlapping biseriate, aseptate, ovoid, subhyaline to pale brown, finely echinulate, 8-9 x 3.5-5.5 µm. Paraphyses filiform, hyaline.

Anamorph: Endophragmiella hymenochaeticola S. Hughes, N.Z. J. Bot. 16: 329 (1978).

The conidial state has been fully described and illustrated by Hughes (1978). Conidia mostly 2 septate, sometimes 1 septate, 21-36 µm long or may sometimes become up to 7 septate and measure 38-45 x 5.4-7.3 µm.

The presence of the teleomorph in three collections from New Zealand was first reported by Hughes (1978) who indicated the association of a unitunicatepyrenomycete with E. hymenochaeticola. He illustrated the asci and ascospores and briefly mentioned the ascospore characters.