Pleosporales - CBS - KNAW

Fungal Diversity
long furcate pedicels. Ascospores fusoid to narrowly fusoid,
light to dark brown, 1-septate, constricted at the septum.
Anamorphs reported for genus: none.
Literature: Chesters and Bell 1970; Huhndorf 1993;
Mugambi and Huhndorf 2009b; Müller and von Arx
1962; Stevens 1925.
Type species
Xenolophium leve Syd., Bulletin of the Bernice P. Bishop
Museum, Honolulu, Hawaii 19: 97 (1925) (Fig. 97)
Current name: Xenolophium applanatum (Petch)
Huhndorf, Mycologia 85: 493 (1993).
≡ Schizostoma applanatum Petch, Ann. Roy. Bot. Gard.
(Peradeniya) 6: 231 (1916).
Ascomata 1–1.5 mm diam., scattered to clustered, erumpent
to superficial, globose with base immersed in host tissue, wall
black, carbonaceous, roughened with ridges, papillate. Apex
with a conspicuous hysteriform papilla extending on the sides,
1–1.4 mm long, 0.4–0.5 mm wide, 0.2–0.3 mm high, smooth,
ostiole slit-like, nearly as long as papilla length (Fig. 97a).
Peridium 140–160 μm thick, pseudoparenchymatous, composed
of two distinct layers: outer crust 16–45 μm thick,
blackish, of heavily melanized, nearly opaque thick-walled
angular cells, of uneven thickness forming irregular strands
extending into the inner layer; inner layer subhyaline,
composed of thick-walled prismatic to angular cells, with
columns or patches of darker thick-walled cells extending
inwardly from the outer layer; papilla wall 200–220 μm thick,
of heavily melanized angular thick-walled cells (Fig. 97b and
c). Hamathecium of dense, very long trabeculate pseudoparaphyses
0.8–1.5 μm broad, embedded in mucilage, anastomosing
and branching between and above the asci. Asci 104–152×
9–12 μm (excluding pedicel) (x ¼ 149 10:2mm, n=10), 8-
spored, bitunicate, fissitunicate dehiscence not observed,
clavate, with a long, narrowed, furcate pedicel which is 50–
75 μm long (Fig. 97d). Ascospores 17–26×4–5.5 μm
(x ¼ 22:5 4:8mm, n=10), upper biseriate and lower uniseriate,
fusoid, straight to slightly curved, equally 1-septate, constricted
at the septum, the upper cell slightly wider, with one or rarely
two additional septa appearing on a small number of senescent
ascospores, pale brown, median septum darker, constricted,
smooth, without sheath or appendages (Fig. 97e, f and g).
Anamorph: none reported.
Material examined: MARTINIQUE, Morne Rouge, on
rotten wood, leg C. Lécuru, det Jacques Fournier, 29 Aug.
2007, IFRD 2038.
Notes
Morphology
Xenolophium was formally established by Sydow (in
Stevens 1925) to accommodate two species, i.e. X. leve and
X. verrucosum, ofwhichX. leve is selected as the generic type
(Huhndorf 1993). Because of its morphological similarity with
some genera, such as Ostropella and Schizostoma, Xenolophium
has been treated as a synonym of Ostropella (Müller
and von Arx 1962)orevenofLophiostoma (Chesters and Bell
1970). Huhndorf (1993) clarified the circumscription of
Xenolophium and treated X. leve as a synonym of Schizostoma
applanata. Xenolophium mainly differs from Ostropella in
lack of “organized cell composition and triangular pattern of
melanization” in the peridium (Huhndorf 1993).
Phylogenetic study
The polyphyletic nature of Xenolophium has been
demonstrated (Mugambi and Huhndorf 2009b). The generic
type of Xenolophium (X. leve, current name X. applanatum)
clustered together with Ostropella albocincta (generic type
of Ostropella), and both locate in Platystomaceae
(Mugambi and Huhndorf 2009b).
Concluding remarks
The large ascomata with slit-like ostioles, hamathecium of
numerous and trabeculate pseudoparaphyses, clavate asci with
long pedicels, and the pale brown, 1-septate ascospores of
Xenolophium leve are all comparable with those of Ostropella
albocincta. However, the phylogenetic results do not support
them being congeneric (Mugambi and Huhndorf 2009b).
Synonyms
Javaria Boise, J.R., Acta Amazonica 14(Supl.): 50 (1984).
(Melanommataceae)
Current name: Astrosphaeriella Syd. & P. Syd., Annls
mycol. 11: 260 (1913).
Generic description
Habitat terrestrial, saprobic. Ascomata medium-sized, scattered,
erumpent to nearly superficial, reflexed pieces of the
ruptured host tissue usually persisting around the surface of
the ascomata; ascomata broadly conical, with a flattened
base not easily removed from the substrate, wall black,
papillate. Peridium carbonaceous. Hamathecium of trabeculate
pseudoparaphyses. Asci 8-spored, bitunicate, fissitunicate,
cylindro-clavate to narrowly fusoid, with a short,
narrowed, furcate pedicel. Ascospores elongate-fusoid,
hyaline, 1-septate, constricted at the septum.
Anamorphs reported for genus: none.
Literature: Barr 1990a; Boise 1984.
Type species
Javaria samuelsii Boise, J.R., Acta Amazonica 14(Supl.):
50 (1984) (Fig. 98)