Rosellinia desmazieresii

              

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JF01197

JF01197

JF01197

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JF01197

Rosellinia desmazieresii (Ber.& Br.) Sacc.

Stromata usually densely gregarious, uniperitheciate, rarely fused together in a 2-3- peritheciate stroma, dark brown to black, subglobose, 1-1.4 mm diam, with conspicuous folds and ridges in the lower part when dry; ectostroma rather thin, brittle; subiculum densely felted, light brown, of finely interwoven hyphae, persistent, widely spreading.

Ostioles stout, broadly conical to nearly cylindrical, darker than the stromatal wall.

Asci cylindrical, with apical apparatus slightly urn-shaped, amyloid, 8-10 m high x 4.5-6 m broad.

Ascospores 24-33 x 6-7.5 m, narrowly ellipsoid-inequilateral to fusiform with usually pinched ends, dark brown, with a straight germ slit 2/3 of spore length on the less convex side; both ends with a short, spiny cellular appendage up to 2.5 m long, not seen on old ascospores.

Anamorph in nature: not seen.

Specimen examined: FRANCE: Arige (09): Rimont, Las Muros, 18 Sept. 2001, JF-01197, on bark of logs of Quercus robur lying on the ground.

Notes: Rosellinia desmazieresii is well-characterized by large stromata with stout ostioles and ridges in the lower part, seated on a light brown persistent subiculum. Microscopically, its large, fusiform ascospores with short pointed cellular appendages and a germ slit less than spore-length are diagnostic. Rosellinia thelena is macroscopically much alike, but its ascospores are somewhat shorter, less fusiform and have much longer appendages at both ends and a nearly spore-length germ slit. It should be noted that ascospores in our collection are shorter than measurements given by Francis (1985) (29-35 x 6-8 m) and more in agreement with those of Petrini (1993). Apical apparati likewise average longer than reported by these authors.

Rosellinia desmazieresii is a rarely reported species, known from Europe (France, Germany, Great Britain, Italy Switzerland) (Francis, 1985; Petrini, 1993). Its ability to grow on herbaceous and woody substrates as well, often spreading over leef litter on large areas (Francis, 1985) is noteworthy. Rosellinia desmazieresii is also known to be a severe root pathogen (Francis, 1985; Petrini, 1993).