Biscogniauxia mediterranea

              

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JF96075

JF96075

JFM9533

JF96075

JF01225

JF99046

JF96075

JF99046

JF99046

Biscogniauxia mediterranea (De Not.) Kuntze.

Stromata applanate to slightly convex, broadly ellipsoid to elongate, 13-80 mm long x 5-18 mm broad x 1-1.2 mm thick; surface dull black to shiny black, carbonaceous, with a dark brown to blackish outer layer long persisting at margin; margin effused to infrequently conspicuously raised, black and carbonaceous; tissue beneath perithecia 0.2-0.5 mm thick, of whitened host tisue; a dark brown pulverulent layer 1-2 mm thick present between the base of the stromata and the surface of underlying wood.

Perithecia obovoid to tubular, 0.2-0.3 mm diam x 0.6-0.8 mm high.

Ostioles coarsely papillate, black.

Asci short-stipitate, with apical ring discoid, amyloid.

Ascospores dark brown, ellipsoid with narrowly rounded ends, 14-19 x 7-9 µm, with straight germ slit spore-length.

Specimens examined: FRANCE, Ariège (09): La Bastide de Sérou, Rhodes, chemin d'Antuzan, 19 Oct. 2001, JF-01225, on Carpinus betula; Rimont, Saurine, 13 Jun. 1996, JF-96075, on Corylus avellana; Rimont, Grand bois, 22 Mar. 1999, JF-99046, on Fagus sylvatica. Pyrénées Atlantiques (64): Oloron Ste. Marie, Forêt de Bugangue, 23 Apr. 1995, FC-5326, on Fagus sylvatica.

Notes: Biscogniauxia mediterranea is characterized by applanate black stromata with coarsely papillate ostioles and large ellipsoid ascospores with a straight germ slit on one side. Other taxa featuring applanate stromata and papillate ostioles are B. cinereolilacina and B. nummularia. The former differs in surface colour which is purplish to grey and in ascospore germ slit which is circular, the latter in less strongly papillate ostioles and smaller ascospores.

In several collections of B. mediterranea ( JF-96075, JF-01225, FC-5326 ), the stromatal margin is conspicuously raised and thick, recalling what is the distinctive feature of the section Scleraster erected by Pouzar (1986). This stromatal character of B. mediterranea is rare but not exceptional, therefore we kept it in both parts of our dichotomous key which follows Pouzar's sections.

Biscogniauxia mediterranea is reported from Africa, Central America, Europe, U. S. A. and Russia (San Martin Gonzáles and Rogers, 1993; Ju et al., 1998) and is not host-specific.