Pleosporales - CBS - KNAW

Fungal Diversity
as a synonym of A. stellata (Hawksworth 1981). More taxa
were subsequently added (Barr 1990a; Hawksworth and
Boise 1985; Hyde and Fröhlich 1998), and the generic
concept extended to include three elements: 1. typical semiimmersed
to superficial ascomata with flattened base,
cylindro-clavate asci with fusoid ascospores and trabeculate
pseudoparaphyses, i.e. Astrosphaeriella sensu stricto (e.g.
A. fusispora and A. vesuvius (Berk. & Broome) D. Hawksw.
& Boise); 2. Trematosphaeria-like with rounded ascomata (e.
g. A. africana D. Hawksw.); and 3. Massarina-like species
with immersed ascomata (e.g. A. bakeriana (Sacc.) K.D.
Hyde & J. Fröhl.) (Chen and Hsieh 2004; Tanaka and Harada
2005a; b). Currently, a broad generic concept of Astrosphaeriella
is accepted, and 47 taxa are included in Astrosphaeriella.
Phylogenetic study
Phylogenetic analysis based on LSU and SSU nurDNA
sequence data indicates that Astrosphaeriella is polyphyletic,
and located in the basal region of the Pleosporales between
Testudinaceae and Zopfiaceae/Delitschiaceae (Tanaka et al.
2009), or basal to Aigialaceae (Schoch et al. 2009). The
genus is, however, clearly not related to Trematosphaeria as
previously understood (Boise 1985).
Concluding remarks
Astrosphaeriella is currently polyphyletic and new
collections of the different elements listed above are needed
in order to understand the placement of various species. We
suggest that some immersed bambusicolous species may
belong in Tetraplospheariaceae.
Asymmetricospora J. Fröhl. & K.D. Hyde, Sydowia 50:
183 (1998). (?Melanommataceae)
Generic description
Habitat terrestrial, saprobic. Ascomata solitary or in small
groups, immersed, black, lenticular in section, uni- or often
multi-locular, with a central ostiole without tissue differentiation.
Upper peridium carbonaceous, thicker at sides and apex.
Lower peridium composed of irregular-shaped, hyaline cells.
Hamathecium of trabeculate pseudoparaphyses, branching and
anastomosing between and above asci, embedded in mucilage.
Asci 8-spored, bitunicate, fissitunicate unknown, clavate, short
pedicellate. Ascospores 1-septate, hyaline, constricted at the
septum, with a broad, spreading mucilaginous sheath.
Anamorphs reported for genus: none.
Literature: Fröhlich and Hyde 1998.
Type species
Asymmetricospora calamicola J. Fröhl. & K.D. Hyde,
Sydowia 50: 184 (1998). (Fig. 9)
Ascomata 675–950 μm high×875–1500 μm diam.,
solitary or in small groups of 2–10, immersed and forming
slightly protruding domes on the substrate surface, with nearwhite
rim around the central ostiole; in vertical view lenticular,
multi- or rarely unilocular, individual locules 175–270 μm
high×320–400 μm diam., with a flattened base, ostiole a
central opening without tissue differentiation (Fig. 9a). Upper
peridium 32–70 μm wide, carbonaceous, composed of a few
layers of black walled cells of textura angularis. Lower
peridium thinner, composed of hyaline cells of textura
globulosa or textura prismatica (Fig. 9b). Hamathecium of
long trabeculate pseudoparaphyses, 1.2–1.6(−2) μm wide,
branching and anastomosing between and above asci,
embedded in mucilage. Asci 137.5–207.5×26–35 μm
(x ¼ 172:8 31:5mm, n=20), 8-spored, bitunicate, fissitunicate
dehiscence not observed, clavate, with short pedicel (to
25 μm), with ocular chambers (ca. 3μm wide×4 μm high)
(Fig. 9c and d). Ascospores 35–55×10.5–15 μm
(x ¼ 44:7 12:4mm, n=50), biseriate, navicular to obovoid,
hyaline, becoming pale brown when senescent, straight or
usually curved, smooth, asymmetric, 1-septate, the upper cell
larger with a rounded end, basal cell with a tapering end,
constricted at the septum, with spreading mucilaginous sheath
(Fig. 9e, f and g) (data from Fröhlich and Hyde 1998).
Anamorph: none reported.
Material examined: AUSTRALIA, North Queensland,
Palmerston, Palmerston National Park, on dead rattan of
Calamus caryotoides A.Cunn. ex Mart., Mar. 1994, J.
Fröhlich (HKU(M) 7794, holotype).
Notes
Morphology
Asymmetricospora was introduced as a monotypic genus
represented by A. calamicola based on its “absence of a
subiculum, the absence of short dark setae around the papilla
and its asymmetric ascospores” (Fröhlich and Hyde 1998).
Because of the immersed ascomata, ostiole and peridium
morphology, fissitunicate asci and trabeculate pseudoparaphyses,
Asymmetricospora was assigned to Melanommataceae
(sensu Barr 1990a; Fröhlich and Hyde 1998).
Morphologically Asymmetricospora can be distinguished
from its most comparable genus, Astrosphaeriella, by its
ostiole, which is a simple opening without tissue differentiation,
asymmetric ascospores, and the usually multiloculate
fruiting body (Fröhlich and Hyde 1998).
Phylogenetic study
None.
Concluding remarks
The placement of Asymmetricospora under Melanommataceae
remains to be confirmed.