Nemania serpens var. colliculosa

              

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Nemania serpens (Pers. Fr.) S. F. Gray var. colliculosa (Schwein.: Fr.) Y.-M. Ju & J. D. Rogers.

Stromata superficial, irregularly effused to elongate, 3-42 mm long x 2-15 mm broad x 0.5-0.9 mm thick, weakly carbonaceous; surface dull black, more rarely copper brown to dark brown, plane or with inconspicuous perithecial mounds, when immature coated with a fugacious greyish brown hyphal layer; interperithecial tissue whitish to black, basal tissue whitish, inconspicuous or up to 0.4 mm thick; margin abrupt.

Perithecia subglobose to depressed-spherical, 0.4-0.5 (-0.6) mm diam.

Ostioles minutely papillate, black.

Asci cylindrical, long-stipitate, the spore-bearing parts 60-80 m long x 6-8 m broad, the stipes 50-70 m long, with apical apparatus amyloid, cylindrical to slightly urn-shaped, 2.7-3.5 m high x 2-2.5 m broad.

Ascospores 10-12 (13.5) x 4.7-5.5 m, pale to medium brown, ellipsoid-inequilateral with broadly rounded ends, at times suballantoid, with a short inconspicuous germ slit on the less convex side.

Specimens examined: FRANCE: Arige (09): La Bastide de Srou, Antuzan, 19 Oct. 2001, JF-01224, on Quercus robur; Rimont, Las Muros, ruisseau de Peyrau, 17 Oct. 2001, JF-01223, on Quercus robur; Rimont, Las Muros, 22 Oct. 2001, JF-01231, on Quercus robur; Salau, banks of Salat, 850 m. elev., 09 Jul. 2000, JF-00116, on Robinia pseudoacacia; Vernajoul, Pont Fag, ruisseau de Vernajoul, 31 Aug. 2002, JF-02149, on Sambucus nigra. Haute Garonne (31): Lestelle de St. Martory, Mauris, 11 Aug. 2002, JF-02142, on Ulmus sp. Loir et Cher (41): Molineuf, Fort Domaniale de Blois, 09 Feb. 2001, L 01367 A, leg. P. Leroy, on Carpinus betulus.

Notes: Nemania serpens var. colliculosa differs from the typical variety in less carbonaceous stromata with inconspicuous perithecial mounds and smaller perithecia. Microscopically, its asci differ in that apical apparatus is amyloid. Its field identification remains very difficult and needs a confirmation relying on observation of asci in Melzer's reagent. Granmo et al. (1999) consider it as a distinct species, as N. colliculosa (Schwein.: Fr.) Granmo. They also describe N. prava Granmo, differing from N colliculosa in perithecial size and colour of ascospore masses, but this distinction was refuted by Ju & Rogers (2002).

Nemania serpens var. colliculosa is reported from France for the first time. In our experience, N. serpens var. colliculosa is not uncommon but probably confused in the field with N. serpens. It is mostly found on Quercus wood, but also occasionally recorded on Carpinus betulus, Corylus avellana, Robinia pseudoacacia, Sambucus nigra, Tilia platyphyllos and Ulmus sp.