Rosellinia britannica

Stromata generally uniperitheciate, rarely fused, globose with a flattened base, 0.7 to 1.2 mm in diameter, dark brown to black, carbonaceous in appearance, with a conical papillate ostiole; subiculum generally absent in mature stromata.

Asci cylindrical, eight-spored, uniseriate, with spores in a row to slightly overlapping, 190 to 270 µm long, 9 to 15 µm wide, the spores occupying the upper two-thirds of the ascus, with an amyloid, cylindrical apical apparatus 6.5 to 7.5 µm high and 4 to 5 µm wide.

Interascal tissue consisting of paraphyses, filamentous, hyaline, unbranched, projecting considerably above the asci.

Ascospores cylindrical-ellipsoidal to slightly fusiform, inequilateral with one flattened side, dark brown under the microscope, 18 to 25 µm long, 7 to 8.5 µm wide, with a straight to slightly sinuous germ slit extending the entire length of the spore, often with a slimy sheath at both ends.