Teleomorph: ascomata perithecia, developing in clusters of 4-10 in black necrotic patches to 1.5 mm diam. on the host thallus; 80-120 (-150) µm diam., ± globose, with a minutely papillate neck, the ostiole not extending above the host surface. Peridium composed of several layers of broad flattened dark brown hyphae to 3.5 µm diam. Interascal tissue composed of irregular, frequently anastomosing pseudoparaphyses 1.5-3 µm diam. Asci 70-85 x 16-19 µm, elongate-clavate to cylindric-clavate, the apex rounded to obtuse, the base tapered but without a distinct stalk, thick-walled and fissitunicate with a distinct ocular chamber, 8-spored. Ascospores arranged biseriately, (18-) 22-25 x 7-8.5 µm, clavate, the apex rounded and the base obtuse, dark olivaceous brown, 1-septate, the upper cell somewhat broader than the lower cell, thick-walled and strongly verruculose, without an epispore or gelatinous sheath.
Not evaluated by Woods & Coppins (2012) but listed as Nationally Rare.
On thalli of Squamarina cartilaginea, within black necrotic patches.
In GBI, only known from a single site in VC1 W Cornwall.