This page illustrates the characters considered in the
dichotomous and synoptic keys to xylariaceous genera. They are ordered following
the synoptic key organization. Links to illustrative photographs are in blue.
It is also possible to open illustrative plates by clicking
"illustration" (just above) or by clicking the subtitles below.
Stromata and ascomata
Stromata may be
bipartite. In this case the upper
layer that hides the stromatal surface disappears at maturity. This character
can be guessed from remnants at margins, even at maturity. It is encountered
in Biscogniauxia and Obolarina.
Stromata may be more or less
immersed in substrate (some Anthostomella, Euepixylon)
superficial broadly attached (most cases),
superficial loosely attached (Kretzschmaria),
constricted at base (Daldinia) or
In most genera, the stromatal tissue is homogenous. It is hollow and
filled with liquid
in Entonaema and presents
concentric zones in Daldinia.
Stromata are most often
and perithecia arranged in one layer. In Lopadostoma subgenus Lopadostoma,
perithecia are in
stromata occur in Anthostomella,Creosphaeria, Hypocopra,
Lopadostoma subgenus Anthostomopsis, Nemania
and Rosellinia, frequently with a tendency to become coalescent.
Acsi and ascospores
At the generic level, the most distinctive feature of asci lies in the apical
apparatus. It may be
broader than high
(ring-like or discoid) or
higher than broad
to urn-shaped), easily seen when bluing in Melzer's reagent (amyloid). Amyloidity
is not constant within a genus and is helpful at the specific level.
Ascospores are typically one-celled, ellipsoid, provided with a germination
site and pigmented. Biscogniauxia anceps is noteworthy in having
that frequently remains
hyaline, even when mature. In most Anthostomella taxa, young ascospores
are conspicuously two-celled and keep a dwarf hyaline cell when mature. This
also occurs in Nemania, Rosellinia and Xylaria,
but much less conspicuously.
The germination site is
except in Euepixylon where it is
The shape, the relative length of the germ slit and its position on the ascospore's wall is
often diagnostic at the specific level.
In Daldinia and Hypoxylon the perispore may be
in 10% KOH. Unfortunately this character is not constant in all taxa
and does not allow a reliable distinction of these two genera.