Rosellinia thelena (Fr.: Fr.) Rabh.var. microspora
L. E. Petrini.
Stromata usually densely gregarious, uniperitheciate, rarely fused
together in a 2-3- peritheciate stroma, dark brown to black with a thin coating
of pale subicular hyphae, subglobose with a broadly attached base, 0.5-0.75 mm diam,
with conspicuous folds and ridges in the lower part when dry; ectostroma rather
thin, brittle; subiculum densely felted, purplish brown, of finely
interwoven hyphae, persistent, widely spreading.
Ostioles stout, broadly conical, darker than the stromatal wall.
Asci cylindrical, with apical apparatus urn-shaped with
attenuated base, amyloid, 4-4.8 µm high x 3.5 µm broad.
Ascospores 13.5-17 x 4.8-5.5 µm, ellipsoid-inequilateral to
slightly oblong with broadly rounded ends, dark brown, with a straight germ slit nearly spore-length
to 3/4 spore-length on the less convex side; both ends with a spiny cellular appendage up
to 6.5 µm long.
Anamorph in nature: not seen.
Specimen examined: FRANCE: Ariège (09): Castelnau Durban,
ruisseau de l'Artillac, in a Picea abies plantation, 05 Oct. 1997,
JF-97211, on twigs of Picea abies.
Notes: Petrini (1993) erected this variety for material fully in agreement
with R. thelena, but differing in smaller perithecia and significantly
smaller ascospores and apical apparati. Like her material, our collection
was made on twigs of Picea abies.
Rosellinia thelena var. microspora is known from two collections,
one from Italy and one from Switzerland. Our record is probably the first published
one from France.