Pleosporales - CBS - KNAW

Fungal Diversity
Generic description
Habitat terrestrial, saprobic. Ascomata medium-sized, clustered,
immersed in host tissue, forming under darkened,
slightly raised, somewhat liner or dome-shaped stroma on the
host, with a flush intra-epidermal papilla; immersed under
clypeus, papillate, ostiolate. Peridium thin, comprising
several layers of compressed cells. Hamathecium of dense,
long trabeculate pseudoparaphyses, embedded in mucilage,
hyaline, anastomosing and septate. Asci 8-spored, bitunicate,
cylindrical, with furcate pedicel, and a conspicuous ocular
chamber. Ascospores uniseriate to partially overlapping, fusoid
or ellipsoidal, brown, 1-septate, constricted at the septum.
Anamorphs reported for genus: Cytoplea (Hyde et al.
1996a).
Literature: Hyde et al. 1996a; Hyde 1997; Ju et al. 1996;
Tanaka et al. 2009.
Type species
Roussoëlla nitidula Sacc. & Paol., Atti Ist. Veneto Sci., Ser.
6, 6:410. (1888). (Fig. 83)
Ascomata 160–200 μm high×400–500 μm diam., clustered,
immersed in host tissue, forming under darkened,
slightly raised, somewhat liner or dome-shaped stroma on the
host, with a flush intra-epidermal papilla; in vertical section
subglobose with a flattened base, immersed under clypeus,
subglobose with a flattened base, papillate, ostiolate (Fig. 83a).
Peridium up to 20 μm thick, comprising several layers of
compressed cells. Hamathecium of dense, long trabeculate
pseudoparaphyses, 1–1.5 μm broad, embedded in mucilage,
anastomosing and septate. Asci 123–220×7–11 μm,8-spored,
bitunicate, cylindrical, with furcate pedicels, and a conspicuous
ocular chamber (Fig. 83b, c and d). Ascospores 17.5–
22×5.5–8 μm, uniseriate to partially overlapping, fusoid or
ellipsoidal, brown, 1-septate, constricted at the septum,
ornamented with longitudinal wall striations and surrounded
by a wide mucilaginous sheath (Fig. 83e, f, g and h).
Anamorph: Cytoplea hysterioides K.D. Hyde (Hyde et
al. 1996a).
Material examined: MALAYSIA, Malacca, on culms of
Bambusa Bar & Grill, 1885, B. Scortechini 15 (PAD,
Roussoëlla nitidula Sacc. Paol. 2484, holotype, on a loose
label Roussoëlla nitidula S. & P. Est Phyllachora phaeodidym./15
prob. original material from Malacca Peninsula).
Notes
Morphology
Roussoëlla was introduced by Saccardo for the single
species R. nitidula Sacc. & Paol. (Saccardo and Paoletti
1888). It was redescribed by Hyde et al. (1996a) and the
anamorph of Roussoëlla hysterioides (Ces.) Höhn., Cytoplea
hysterioides K.D. Hyde was determined and described.
Roussoëlla was then reviewed by Hyde (1997) and a
modified key for Roussoëlla species was provided based on
the one proposed by Ju et al. (1996). Roussoëlla is
characterized as having immersed ascomata containing
long cylindrical asci and brown 1-septate ornamented
ascospores. In this study, we have checked the type species
and it matches Hyde et al. (1996a). The asci are bitunicate,
but we could not observe the fissitunicate dehiscence.
Phylogenetic study
Species of Roussoëlla, Roussoellopsis as well as Arthopyrenia
salicis form a robust phylogenetic clade, which form
a sister group with pleosporalean families, but the generic
type of Roussoëlla (R. nitidula) was not included in the
phylogenetic study (Tanaka et al. 2009).
Concluding remarks
The bambusicolous habitat of Roussoëlla is a striking
character at generic rank classification but its relationship to
the lichenized Arthopyrenia is unexpected and will require
more analysis.
Saccharicola D. Hawksw. & O.E. Erikss., in Eriksson &
Hawksworth, Mycologia 95: 431 (2003). (Massarinaceae)
Generic description
Habitat terrestrial, parasitic. Ascomata medium-sized, solitary,
scattered, immersed, globose to subglobose, carbonaceous,
papillate, ostiolate. Peridium relatively thin, composed of one
cell type of pale brown to hyaline pseudoparenchymatous cells.
Hamathecium of trabeculate pseudoparaphyses. Asci bitunicate,
8-spored, cylindro-clavate to clavate. Ascospores biseriate and
sometimes laterally uniseriate, fusoid with narrowly rounded
ends, septate, constricted at the septa, the upper second cell
becoming pigmented when mature, smooth or verruculose.
Anamorphs reported for genus: Stagonospora (Eriksson
and Hawksworth 2003; Kaiser et al. 1979; Leuchtmann
1984).
Literature: Eriksson and Hawksworth 2003.
Type species
Saccharicola bicolor (D.Hawksw.,W.J.Kaiser&Ndimande)
D. Hawksw. & O.E. Erikss., Mycologia 95: 431 (2003).
(Fig. 84)
≡ Leptosphaeria bicolor D. Hawksw., W.J. Kaiser &
Ndimande, Mycologia 71: 483 (1979).
Ascomata 125–175 μm high×175–220 μm diam.,
solitary, scattered, immersed, globose to subglobose, wall
black, carbonaceous, with a protruding papilla, with a
central ostiole (Fig. 84a). Peridium 15–20 μm thick