Nemania aenea var. aureolutea











Nemania aenea (Nitschke) Pouzar var. aureolutea ( Petrini & Rogers) Ju & Rogers.

Stromata superficial, at times erumpent from bark, irregularly ellipsoid to elongate, small-sized, 1.5-10 mm long x 1-4 mm broad x 0.5-0.6 mm thick, weakly carbonaceous; stromatal surface blackish brown to dull black, with usually inconspicuous perithecial mounds, when immature coated with a fugacious greenish to greenish yellow hyphal layer; margin abrupt, shortly extendind as a black line into the substrate which is occasionally stained yellow.

Perithecia subglobose to broadly ovoid, 0.4-0.5 mm diam.

Ostioles minutely papillate, black.

Asci cylindrical, short-stipitate, the spore-bearing parts averaging 80 m long, the stipes 40-65 m long, with apical apparatus inamyloid to weakly amyloid in basal part (Melzer's reagent), but bluing in Lugol's solution (or in Melzer's reagent after a 5-10% KOH-pretreament), cylindrical, 3.5-4 m high x 2-3 m broad.

Ascospores 14-18 x 6-7.5 m, ellipsoid-inequilateral frequently with one end slightly pinched, uniseriate, finally 2-3-seriate in the ascus, pale to medium brown, with a short inconspicuous germ slit 3.5-5 m long on the less convex side.

Specimens examined: FRANCE: Arige(09): Prat Communal, ruisseau de Loumet, 980 m elev., 16 Jul. 2002, JF-02127, on Tilia platyphyllos; Rimont, Las Muros, 27 Oct. 1996, JF-96143, on Acer campestre; Rimont, ruisseau de la Maille, 25 Mar. 1999, JF-99049, on Salix caprea; Rimont, Las Muros, ruisseau de Peyrau, 05 Apr. 2001, JF-01060, on Juglans regia (identified by Prof. J. D. Rogers); Rimont, Grillou, 09 Aug. 2002, JF-02136, on Hedera helix. Aude (11): Bareigne, Garde Bois, lac de la Ganguise, 15 Feb. 2003, JF-03031, on wood and bark of Quercus pubescens. Hautes Pyrnes (65): Bagnres de Bigorre, l'Arbizon, 04 Sept. 2002, JF-02156, leg. FC, on Cotoneaster sp.

Notes: Segregation of N. aenea var. aureolutea from related taxa was primarily based on the orange colour of cultures (Petrini and Rogers, 1986). Microscopically, Nemania aenea var. aureolutea is distinctive in its ascal apical apparatus not blueing or blueing very weakly in Melzer's reagent, but blueing in Lugol's solution. Besides this difference, it is distinguished from N. aenea by its short-stipitate asci and ascospores with an inconspicuous germ slit.

Stromata of N. aenea var. aureolutea are distinctive in being small-sized, in lacking perithecial elevations and in frequently bearing a typical yellowish green hyphal coating when young. This last feature, previously unreported, as the yellow colour observed in the wood underlying some stromata ( photograph of a section), might be related to the ability of this fungus to produce orange pigments in culture.

Nemania aenea var. aureolutea was previously reported from Europe (Italy, France, Switzerland) by Petrini and Rogers (1986) and from Denmark, Norway and U. K. by Granmo et al. (1999) [as N. aureolutea (Petrini and Rogers) Granmo]. It is a fairly common species, but easily overlooked owing to its small size.

Reported on Quercus by Petrini and Rogers (1986), N. aenea var. aureolutea was found during this study on Acer campestre, Cornus sanguinea, Corylus avellana, Cotoneaster sp., Fagus sylvatica, Fraxinus excelsior, Hedera helix, Juglans regia, Populus tremula, Quercus pubescens, Quercus robur, Sambucus nigra, Tilia platyphyllos and Ulmus minor.