Pleosporales - CBS - KNAW

Fungal Diversity
some effused Hypoxylon), 30 Dec. 1885, A.B. Langlois, No. 138
(NY, holotype of Amphisphaeria hypoxylon Ellis & Everh.).
Notes
Morphology
Immotthia was introduced to accommodate a species of
Amphisphaeria (A. hypoxylon), which has bitunicate asci,
and is characterized by superficial, ostiolate, periphysate,
papillate ascomata, cellular pseudoparaphyses, bitunicate, 8-
spored, cylindrical asci, ellipsoid, smooth, brown to reddish
brown, 1-septate ascospores (Barr 1987a; Wangetal.2004).
Phylogenetic study
None.
Concluding remarks
It seems that those Amphisphaeria species with bitunicate
asci should be assigned to Pleosporales. Morphologically,
Immotthia is somewhat comparable with Herpotrichia.
Isthmosporella Shearer & J.L. Crane, Mycologia 91: 141
(1999). (Pleosporales, genera incertae sedis)
Generic description
Habitat freshwater, saprobic. Ascomata small- to mediumsized,
scattered, immersed, erumpent to superficial, globose,
papillate, ostiolate, periphysate, membranous. Peridium 2-
layered, outer layer composed of brown, pseudoparenchymatic,
fusoid-cylindric cells, inner layer composed of fusoid,
subhyaline to pale brown, compressed cells. Hamathecium of
rare, broad, septate, interascal pseudoparaphyses. Asci 8-
spored, bitunicate, fissitunicate, oblong to clavate, with a
short pedicel, ocular chamber not observed. Ascospores 3–4
seriate, cylindrical to fusoid, isthmoid at centre, constricted at
septa, isthmus 1-septate, surrounded by a gelatinous sheath.
Anamorphs reported for genus: none.
Literature: Shearer and Crane 1999.
Type species
Isthmosporella pulchra Shearer & J.L. Crane, Mycologia
91: 142 (1999). (Fig. 38)
Ascomata 240–330 μm diam., scattered on decorticated
wood, immersed, erumpent to superficial, globose, black,
papillate, papilla short, cylindrical, 60 μm long×55 μm
wide, ostiolate, periphysate, membranous (Fig. 38a). Peridium
2-layered, outer 3–4 cell layers composed of brown,
pseudoparenchymatic, fusoid-cylindric cells, 2–6.5 μm
long; inner layer composed of 5–7 rows of fusoid, subhyaline
to pale brown compressed cells, 11–20×2–3.5 μm
diam. (Fig. 38a and b). Hamathecium of rare, broad,
septate, interascal pseudoparaphyses (Fig. 38f). Asci (95-)
135–160(−175)×(25-)30–45(−60) μm, 8-spored, bitunicate,
fissitunicate, oblong to clavate, with a short pedicel, ocular
chamber not observed (Fig. 38c, d and e). Ascospores 80–
105(−110)×(7-)8–10 μm, 3–4-seriate, cylindrical to fusoid,
isthmoid at centre, sometimes bent at isthmus and becoming
u- or v- shaped, end cells tapering, 12–17-phragmoseptate,
constricted at septa, isthmus 1-septate, 2–5.5×2–
4.5 μm diam., hyaline, frequently fragmenting to form
partspores; filled with lipid droplets that merge to form
large guttules; surrounded by a gelatinous sheath with a
dense region near the isthmus, sheath greatly enlarging in
water (Fig. 38g, h, i and j).
Anamorph: none reported.
Colonies on yeast soluble starch agar containing balsa
wood sticks effuse, white. Hyphae hyaline, septate.
Material examined: USA, New York, Adirondack Park.
Piercefield. Tupper Lake at public boat launch from Rt. 30,
UTM Zone 18, 539840 mE, 4892100mN; 44°10″59″N, 80°
31′6″W, on submerged, decorticated wood, 7 Jul. 1994, J.L.
Crane & C.A. Shearer A-254-1 (ILLS 53086, holotype).
Notes
Morphology
Isthmosporella was described as a freshwater genus
typified by I. pulchra, and is characterized by globose,
pseudoparenchymatous ascomata, sparse, septate pseudoparaphyses,
fissitunicate asci and hyaline, cylindrical to
fusoid, phragmoseptate, isthmoid ascospores surrounded
with a gelatinous sheath (Shearer and Crane 1999). Based
on the morphological characters, i.e. small, globose
ascomata, peridium with small pseudoparenchymatous cells
and sparse pseudoparaphyses, Isthmosporella was assigned
to the Phaeosphaeriaceae (Shearer and Crane 1999). The
aquatic habitat of Isthmosporella, however, disagree with
the Phaeosphaeriaceae. Isthmosporella seems less likely to
belong to Pleosporineae.
Phylogenetic study
None.
Concluding remarks
Molecular phylogenetic studies should be conducted to
explore its familial placement within Pleosporales.
Kalmusia Niessl, Verh. nat. Ver. Brünn 10: 204 (1872).
(Montagnulaceae)
Generic description
Habitat terrestrial, saprobic. Ascomata small- to mediumsized,
solitary, scattered or in small groups, immersed to