Anamorph: not known.
Teleomorph: ascostromata perithecial, 300-400 µm diam. and 180-280 µm high, oblate to oblate-spherical, scattered or in small clusters of 2-5, initially immersed within the blackened host epidermis but becoming almost entirely erumpent, the ostiole central, not papillate. Ascostromatal wall 50-80 µm thick laterally, 20-25 µm thick above and around the ostiolar region, and 10-15 µm thick at the base of the ascostroma, composed of layers of elongate to angular dark brown cells. Interascal tissue of narrow pseudoparaphyses, 1.5-2 µm diam., septate, branched and anastomosed, developing within a gelatinous matrix. Asci 170-190 x 38-46 µm, clavate, very thick-walled, fissitunicate, with a short tapering base and a rounded apex with a conspicuous ocular chamber, not staining blue in iodine, 8-spored. Ascospores arranged biseriately, 39-46 x 14.5-17 µm, broadly fusiform to fusiform-ellipsoidal, the ends obtuse to rounded, often slightly curved, with a strongly constricted median to slightly submedian primary septum, rarely developing further septa towards the apices of the spore, very thick-walled, hyaline and smooth-walled, surrounded by a very conspicuous gelatinous sheath 2-5 µm thick within the ascus, expanding greatly after discharge. Senescent ascospores are usually 1-septate, golden to mid brown, irregularly shrunken, often with longitudinal folds and with a minutely echinulate surface.
Not formally assessed but only known (on a global scale) from two collections and therefore potentially endangered. Further survey and monitoring would be advisable.
Differs from Asteromassaria pulchra by its smaller asci and ascospores, and ascostromata that are oblate rather than oblate-conical.
Known from dead twigs of Hedera helix.
Only known from a single site in VC1 W Cornwall and VC2 E Cornwall.
Probably a saprotroph, but no research is available on this subject.