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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 µm long, the stipes 40-65 µm 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 µm high x 2-3
µm broad.
Ascospores 14-18 x 6-7.5 µm, 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 µm long
on the less
convex side.
Specimens examined: FRANCE: Ariège(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 Pyrénées
(65): Bagnères 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.
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