Muellerella hospitans  

Anamorph: not known.
Teleomorph: ascomata perithecia, immersed in the apothecia of the host lichen, scattered, 70-90 µm diam., globose to subglobose, ostiolate, minutely papillate, black, thin-walled. Interascal tissue not clearly present. Asci 42-51 x 23-29 µm, clavate to saccate, ± sessile, thick-walled and fissitunicate with rostrate dehiscence, apical structures not clearly present, not blueing in iodine, multispored (probably >100-spored). Ascospores arranged irregularly, 2.1-2.9 x 1.7-2.1 µm, ellipsoidal, aseptate, pale brown, fairly thick-walled, smooth, without a gelatinous sheath or appendages.