Anthostoma gastrinum

Species affecting hardwoods, with immersed perithecia, subglobose to pyriform, black, 0.3 to 1.1 mm in diameter, with short ostiolar necks and white interperithecial tissue.

Asci cylindrical, 8-spored, unitunicate, with a thin apical ring, 75 to 120 µm long, 5 to 8 µm wide, uniseriate spore arrangement in the ascus, and a discoid apical ring amyloid in Melzer's reagent.

Interascal matter resembling paraphyses or pseudoparaphyses, filamentous, very thin, 2 to 5 µm wide, with granular content inside, protruding well above the level of the asci.

Ascospores oblong or narrowly ellipsoid, laterally compressed, 9.5 to 14 µm long, 3.5 to 5.3 µm wide, containing two guttules inside when located in the ascus, which tend to disappear with maturity.