Stromata are usually
multiperitheciate and superficial,
and then more or less
It is not rare to observe some uniperitheciate stromata at margins
of multiperitheciate stromata, while uniperitheciate stromata often show
a tendency to fuse in small groups.
Stromata vary in degree of carbonization of the surface layer, interperithecial
tissue and perithecial wall. In the following keys and descriptions,
they are considered to be weakly carbonaceous
when they can be properly sectionned with a razor blade; when carbonaceous,
they are rather broken by the razor blade, with a characteristic noise.
Stromatal surface may have
conspicuous perithecial mounds
inconspicuous perithecial mounds
Whitish interperithecial tissue
is usually present in young stromata, becomes grey to grey brown with age and
finally disappears. It is absent from carbonaceous stromata, or very inconspicuous. The tissue beneath
the perithecial layer
is distinctive when white, massive and persisting in mature stromata
Ostioles of Nemania taxa are always papillate, opening higher
than the stromatal surface. They may be
character may vary within a same taxon.
Asci may be
with the stipe much shorter than the spore-bearing part, rarely more than
half the spore-bearing part length, to
, with the stipe nearly as
long as the spore-bearing part.
Apical apparatus may be
(blueing in Melzer's reagent)
It is considered to be
turns pale red brown (in Lugol's solution). It is usually higher than
broad but sometimes as broad as high
Its shape may vary from
when its diameter is constant to
when it is broader and flattened at apex, or
when rounded in lower part.
in most species,
in a few cases
Their colour varies with the mounting medium used for their observation, therefore
it must be evaluated in water. A
enclosing each ascospore is more conspicuous when observed in Indian ink . In
the ascospore wall is
while it is smooth in
all other European species. Ascospores may have
but these features are usually not diagnostic, and likewise are observed in
other genera (Rosellinia, Xylaria). Immature ascospores bear at their lower
end a very inconspicuous and fugacious hyaline cellular appendage,and this end is frequently
slightly truncate at maturity.
The shape, length and location of the ascospore germ slit are often diagnostic
in Nemania. The germ slit is considered
when easily seen in water, Melzer's reagent or 3% KOH at a magnification
x 1000 in all ascospores observed in front view, fairly conspicuous when
seen in only a few percentage of ascospores, and inconspicuous when apparently
absent when observed in these media. The germ slit becomes much more conspicuous
when permanent mounts of ascospores are made in Polyvinyl alcohol (Rhodoviol®)
dissolved in Lactophenol * (PVAL) (Van Brummelen, 1967),
but in that medium, ascospores are paler and occasionally
become somewhat bulged. In Nemania, the germ slit is usually on the
less convex side
but may be on the
more convex side
in some species.
In "Hypoxylon terricola",
a species presented herein with
Nemania, ascospores are enclosed in a gelatinous sheath that needs
to be observed in diluted Indian ink (Indian ink: 1, water: 1).
Photographs of ascospores were taken from permanent mounts in PVAL,
photographs of asci and their apical apparatus were taken from permanent mounts
in 50% Glycerol-50% Lugol's solution.
*Rhodoviol® 50 g, water 150 g, lactic acid 80 g, phenol 40g.