Pleosporales - CBS - KNAW

Fungal Diversity
paraphyses, 1.5–2 μm broad, septate, branching. Asci
275–290×25–35 μm, 8-spored, bitunicate, cylindrical,
with a short pedicel (Fig. 34b, c and d). Ascospores 37–
60.5×16.5–26 μm, uniseriate, ellipsoidal, subcylindrical
or obtuse-fusoid, dark brown, 1-septate, constricted at the
septum (Fig. 34e, f, g and h) (adapted from Kohlmeyer
and Kohlmeyer 1979).
Anamorph: none reported.
Material examined: ITALY, in rhizomes of Posidonia
oceanica (Posidoniaceae), 1861, Caldesi (S, isotype of
Sphaeria posidoniae)
Notes
Morphology
Halotthia was introduced to accommodate the marine
fungus, H. posidoniae (as Sphaeria posidoniae), which is
characterized by immersed to erumpent, large, carbonaceous
ascomata, thick peridium, bitunicate, 8-spored,
cylindrical asci, ellipsoidal, 1-septate, and dark brown
ascospores (Kohlmeyer 1963). Morphologically, Halotthia
is most comparable with Bicrouania maritima, but the
conical ascomata with flattened base of H. posidoniae can
be readily distinguished from B. maritima.
Phylogenetic study
Phylogenetically, Halotthia posidoniae, Pontoporeia
biturbinata and Mauritiana rhizophorae form a robust
clade, which may represent a potential family (Suetrong et
al. 2009).
Concluding remarks
Currently the familial status of Halotthia is unresolved
(Suetrong et al. 2009).
Helicascus Kohlm., Can. J. Bot. 47: 1471 (1969).
(Morosphaeriaceae)
Generic description
Habitat marine, saprobic. Ascostromata lenticular, immersed,
black, carbonaceous, enclosing several loculi,
pseudoclypeus composed of host cells enclosed in black
stromatic fungus material. Ascomata depressed ampulliform,
horizontally arranged under a black pseudoclypeus,
ostiolate, torsellioid ostioles, papillate. Peridium absent,
partitions between loculi formed of brown, isodiametric or
elongated cells of the stroma. Hamathecium of dense, long
pseudoparaphyses. Asci 8-spored, bitunicate, subcylindrical
to oblong clavate, with a short pedicel and conspicuous
apical ring. Ascospores uniseriate, obovoid, brown, 1-
septate, at each end with a germ pore, surrounded with
dissolving sheath.
Anamorphs reported for genus: none.
Literature: Kohlmeyer1969; Kohlmeyer and Kohlmeyer
1979; Suetrongetal.2009.
Type species
Helicascus kanaloanus Kohlm., Can. J. Bot. 47: 1471
(1969). (Fig. 35)
Ascostromata 0.6–0.78 mm high×1.25–2.75 mm diam.,
lenticular, immersed, black, carbonaceous, enclosing 3–4(−5)
loculi, pseudoclypeus composed of host cells enclosed in
black stromatic fungus material (Fig. 35a). Ascomata 235–
370 μm high×440–800 μm diam., depressed ampulliform,
horizontally arranged under a black pseudoclypeus, ostioles
70–170 μm diam., torsellioid ostiole (Adams et al. 2005),
papilla slightly rising over the surface of the pseudoclypeus,
subconical,canal filled with thick, bright orange to yellowish
periphyses, 270–435 μm high, 255–300 μm diam. Peridium
absent, partitions between loculi formed of brown, isodiametric
or elongated cells of the stroma. Hamathecium of
dense, very long pseudoparaphyses. Asci 250–335×25–
30 μm, 8-spored, subcylindrical, finally oblong-clavate
(400–480 μm long), with a short pedicel, bitunicate,
thick-walled, physoclastic, apically multi-layered and
annulate, ectoascus forming a third, thin permeable outer
layer around the base, endoascus swelling in water and
becoming coiled at maturity, finally stretching and
pushing the ascus into the ostiolar canal (Fig. 35b).
Ascospores 36.5–48.5×18–22.5 μm, uniseriate, obovoid,
brown, 1-septate, at each end with a germ pore,
surrounded with dissolving sheath, 2.7–5.4 μm thick,
with funnel-shaped, apical indentations (Fig. 35c and d)
(adapted from Kohlmeyer and Kohlmeyer 1979).
Anamorph: none reported.
Material examined: USA, Hawaii, Oahu, Kaneohe Bay,
Heeia Swamp, on Rhizophora mangle, 4 Jun. 1968 (Herb. J.
Kohlmeyer No. 2566, holotype; No. 2565, 2567, paratype).
Notes
Morphology
Helicascus is another marine genus, which is characterized
by its thin additional sheath around the base of the asci,
the coiling and stretching mechanism of the basal part of the
endoascus and its conspicuous apical apparatus which is not
that common in bitunicate asci (Kohlmeyer 1969). The
immersed stroma comprising several loculi sharing one
common ostiole is another striking character of Helicascus.
Phylogenetic study
Multigene phylogenetic analysis indicated that both
Helicascus kanaloanus and H. nypae K.D. Hyde nested
within Morosphaeriaceae (Suetrong et al. 2009).