Pleosporales - CBS - KNAW

Fungal Diversity
Ascorhombispora L. Cai & K.D. Hyde, Cryptog. Mycol.
28: 294 (2007). (Pleosporales, genera incertae sedis)
Generic description
Habitat freshwater, saprobic. Ascomata solitary or gregarious,
superficial, globose to subglobose, dark brown to black, short
papillate, ostiolate, coriaceous. Peridium relatively thin,
textura angularis in longitudinal section, 2-layered. Hamathecium
not observed. Asci 8-spored, obpyriform, broadly clavate
to saccate, pedicellate, bitunicate, apex rounded, persistent.
Ascospores overlapping 2-3-seriate, broadly fusoid to rhomboid,
thick-walled, surrounded by mucilaginous sheath, 3-
euseptate, not constricted at septa, median septum wide,
forming a darker band, central cells large, trapezoid, dark
brown to black, verruculose, polar end cells small and paler.
Anamorphs reported for genus: none.
Literature: Cai and Hyde 2007.
Type species
Ascorhombispora aquatica L. Cai & K.D. Hyde, Cryptog.
Mycol. 28: 295 (2007). (Fig. 6)
Ascomata 140–170 μm high×150–185 μm diam., solitary
or gregarious, superficial, globose to subglobose, dark brown
to black, short papillate, ostiolate, ostioles rounded, small,
coriaceous. Peridium relatively thin, 10–18 μm wide, textura
angularis in longitudinal section, composed of two layers of
angular cells, outer later dark brown to black, relatively thickwalled,
inner layer hyaline, relatively thin-walled (Fig. 6a and
b). Hamathecium not observed. Asci 100–198×72–102 μm
(x ¼ 186 88mm, n=15), 8-spored, obpyriform, broadly
clavate to saccate, pedicellate, bitunicate, apex rounded,
deliquescent (Fig. 6c, d and e). Ascospores 30.5–45×16–
26.5 μm (x ¼ 38:5 21mm, n=25), overlapping 2-3-seriate,
broadly fusoid to rhomboid, thick-walled, surrounded by
mucilaginous sheath, 3-euseptate, not constricted at septa,
median septum wide, forming a darker band, central cells
large, trapezoid, 11–18 μm long, dark brown to black,
verruculose, polar end cells small, hemispherical, 3.5–4 μm
long, subhyaline to pale brown, smooth (Fig. 6f).
Anamorph: none reported.
Material examined: CHINA, Yunnan, Jinghong, on
submerged bamboo in a small forest stream, 26 Jan. 2003,
leg. det. L. Cai, CAI-1H31 (HKU(M) 10859, holotype).
Notes
Morphology
Ascorhombispora was introduced as a monotypic
genus from freshwater by Cai and Hyde (2007), and is
characterized by superficial, coriaceous, non-stromatic
ascomata, large, saccate asci; lack of interascal filaments
and trapezoid (rhombic), 3-septate, dark brown to black
ascospores with smaller end cells which are subhyaline to
pale brown. Ascorhombispora is most comparable with
Caryospora and Zopfia. But the globose to subglobose
ascomata and thin peridium, saccate asci lacking interascal
pseudoparaphyses, and the 3-septate, rhomboid ascospores
with the paler end cells of Ascorhombispora differs from
those of Caryospora (Cai and Hyde 2007).
Phylogenetic study
Phylogenetic analysis based on either SSU or LSU
rDNA sequences indicated that Ascorhombispora aquatica
belongs to Pleosporales, but its familial placement was left
undetermined (Cai and Hyde 2007).
Concluding remarks
The sac-shaped asci and absence of pseudoparaphyses
are uncommon in Pleosporales, especially among those
from freshwater.
Asteromassaria Höhn., Sber. Akad. Wiss. Wien, Math.-
naturw. Kl., Abt. I 126: 368 (1917). (?Morosphaeriaceae)
Generic description
Habitat terrestrial, saprobic. Ascomata medium-sized,
clustered, at first immersed and then breaking through
the host surface and becoming superficial, globose,
subglobose, coriaceous. Peridium 2-layered, thicker near
the base. Hamathecium of dense, septate, cellular pseudoparaphyses
which branch and anastomosing frequently
between and above asci. Asci (4-)8-spored, bitunicate,
cylindro-clavate to clavate, with a short truncated pedicel
and a small ocular chamber. Ascospores obliquely uniseriate
and partially overlapping to biseriate, fusoid to
fusoid-ellipsoidal, pale brown when mature, 1-septate,
some becoming 3-septate when old, constricted at the
median septum.
Anamorphs reported for genus: Scolicosporium (Sivanesan
1984).
Literature: Barr 1982a; b; 1993a; Boise 1985; Shoemaker
and LeClair 1975; Sivanesan 1987; Tanaka et al. 2005.
Type species
Asteromassaria macrospora (Desm.) Höhn., F. von, Sber.
Akad. Wiss. Wien, Math.-naturw. Kl., Abt. I 126: 368
(1917). (Fig. 7)
≡ Sphaeria macrospora Desm., Ann. Sci. Nat. Bot. 10:
351 (1849).
Ascomata 400–600 μm high×450–650 μm diam., 4–20
clustered together, at first immersed and then breaking
through the host surface and becoming superficial, globose,