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Nemania serpens (Pers.: Fr.) S. F. Gray.
Stromata superficial, effused, irregularly ellipsoid to elongate,
at times confluent, 4-50 mm long x 2-10 mm broad x 0.5-0.8 mm thick, carbonaceous;
surface dark brown to black, with conspicuous to less frequently inconspicuous
perithecial mounds, when immature coated with a grey to beige hyphal layer bearing
the anamorph at first stages; interperithecial tissue whitish to grey when young,
disappearing, basal tissue inconspicuous; margin abrupt.
Perithecia
subglobose, 0.5-0.7 mm diam.
Ostioles papillate, usually broadly conical, black.
Asci cylindrical, long-stipitate, the spore-bearing parts 75-90 µm
long x 6-8 µm broad, the stipes 60-80 µm long, with apical apparatus inamyloid
(not blueing in Melzer's reagent, even after a 3% KOH-pretreatment, but blueing
after a 5-10% KOH-pretreatment) but dextrinoid
(pale red brown) in Lugol's solution, inverted hat -shaped, 2.7-3.4 µm high x 2-2.7
µm broad.
Ascospores 10.5-14 x 4-5.5 µm, pale olivaceous brown, ellipsoid-inequilateral
with broadly rounded ends, at times suballantoid, 1-2-seriate in the ascus,
with a short, inconspicuous germ slit on the less convex side.
Specimens examined: FRANCE: Ariège (09): Rimont, Grillou,
05 Mar. 1996, JF-96003, on Quercus robur; Rimont, Las Muros, 04
Oct. 1997, JF-97209, on Ulmus minor; Rimont, Paletès, ruisseau de Peyrau,
13 Feb. 2002, JF-02033, on Corylus avellana; Vernajoul, Pont Fagé, ruisseau
de Vernajoul, 31 Aug. 2002, JF-02151, on Fraxinus excelsior. Aude
(11): Bassan, Parc du Château de Ribaute, 27 Dec. 2002, JF-02263, on Platanus
sp. Haute Garonne (31): Couladère, ruiseau de Tounis, 18 Jan.
2003, JF-03015, on Hedera helix. Hautes Pyrénées (64):
Auterrive, Ile du Gave d'Oloron, 17 Nov. 2002, JF-02223, on Populus sp.
Notes: Nemania serpens is the type species of the genus Nemania
and is undoubtedly the commonest species of this genus encountered in Europe.
It is reported from Europe, North America and Chile by Petrini and Rogers
(1986), and from Papua-New Guinea by Van der Gucht (1995).
Nemania serpens usually has stromata with conspicuous perithecial
mounds and conical ostioles but these characters remain variable, even within
a same collection. The distinctive feature of N. serpens, combined with
pale olive brown ascospores with broadly rounded ends and with a short inconspicuous
germ slit, is the dextrinoid reaction of apical apparatus in Lugol's solution,
while it does not react in Melzer's reagent. Routine observation of Nemania
specimens relies on the observation of perithecial contents in one of these
reagents so that the very common N. serpens is readily identified. Nemania
aenea var. aureolutea resembles N. serpens in having a
negative to very weak reaction of apical apparatus in Melzer's reagent, but
unlike N. serpens, the apical apparatus turns blue in Lugol's solution,
and ascospores average longer.
Nemania serpens var. colliculosa and N. serpens var.
hydnicola differ primarily from the typical variety in that their apical
apparatus is blueing in Melzer's reagent.
Nemania serpens is plurivorous, growing on rotten wood of most of
Angiospermous trees, and interestingly was once reported from wood of Picea
by Granmo et al. (1999), and from bamboo by Candoussau et al.
(1996, as H. serpens). During our study, it has been recorded
on Acer campestre, Coriaria myrtifolia, Corylus avellana, Fagus sylvatica,
Fraxinus excelsior, Hedera helix, Malus sylvestris, Platanus sp., Populus tremula, Quercus
ilex, Quercus pubescens, Quercus robur, Robinia pseudoacacia, Salix caprea and
Ulmus minor.
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