Ostropa barbara

An uncommon saprophytic species on decaying wood (probably Crataegus monogyna in this study), with erumpent, grain-like ascomata 0.5–0.7 mm in diameter (up to 1 mm in literature), blackish, opening by a whitish longitudinal slit through which the ascospores are released.

Asci cylindrical, 8-spored, thick-walled, measuring 260–350 µm long by 11–14 µm wide, with parallel spore arrangement extending nearly the entire length of the ascus, inamyloid in Melzer's reagent.

Abundant interascal paraphysoid filaments, filiform, hyaline, 1–1.5 µm wide, richly branched, projecting considerably above the asci.

Ascospores filiform, smooth, hyaline, thin-walled, multiseptate at maturity with 20 to 30 septa, fragile and difficult to measure intact, 190–260 µm long according to literature by 1.5–2.5 µm wide.