Pleosporales - CBS - KNAW

Fungal Diversity
Table 1 Major circumscription changes of Pleosporales from 1955 to 2011
References
Luttrell 1955
Müller and von Arx 1962
Luttrell 1973
Barr 1979a
Barr 1987b
Kirk et al. 2001, 2008
Boehm et al. 2009a, b; Mugambi
and Huhndorf 2009b; Schoch et
al. 2009; Shearer et al. 2009;
Suetrong et al. 2009; Tanaka et
al. 2009; Zhang et al. 2009a
Circumscriptions distinguishing Pleosporales from other orders of Dothideomycetes
Pleospora-type centrum development.
Ascomata perithecoid, with rounded or slit-like ostiole; asci produced within a locule, arranged regularly
in a single layer or irregularly scattered, surrounded with filiform pseudoparaphyses, cylindrical,
ellipsoidal or sac-like.
Ascocarps perithecioid, immersed, erumpent to superficial on various substrates, asci ovoid to mostly
clavate or cylindrical, interspersed with pseudoparaphyses (sometimes form an epithecium) in mostly
medium- to large-sized locules.
Saprobic, parasitic, lichenized or hypersaprobic. Ascomata perithecioid, rarely cleistothecioid or
hysterothecioid, peridium pseudoparenchymatous, pseudoparaphyses cellular, narrow or broad,
deliquescing early at times, not forming an epithecium, asci oblong, clavate or cylindrical, interspersed
with pseudoparaphyses, ascospores mostly asymmetric.
Saprobic, biotrophic or hemibiotrophic. Ascomata globose, subglobose or conical, asci bitunicate, oblong,
clavate or cylindrical, cellular pseudoparaphyses, ascospores hyaline or pigmented, asymmetric or
symmetric, with or without septa.
Ascomata perithecioid or rarely cleistothecioid, sometimes clypeate, mostly globose, thick-walled,
immersed or erumpent, black, sometimes setose, peridium composed of pseudoparenchymatous cells,
pseudoparaphyses trabeculate or cellular, asci cylindrical, fissitunicate, with a well-developed ocular
chamber, rarely with a poorly defined ring (J-), ascospores hyaline to brown, septate, thin or thickwalled,
sometimes muriform, usually with sheath, anamorphs hyphomycetous or coelomycetous.
Hemibiotrophic, saprobic, hypersaprobic, or lichenized. Habitats in freshwater, marine or terrestrial
environment. Ascomata perithecioid, rarely cleistothecioid, immersed, erumpent to superficial, globose
to subglobose, or lenticular to irregular, with or without conspicuous papilla or ostioles. Ostioles with or
without periphyses. Peridium usually composed of a few layers of cells with various shapes and
structures. Hamathecium persistent, filamentous, very rarely decomposing. Asci bitunicate, fissitunicate,
cylindrical, clavate to obclavate, with or without pedicel. Ascospores hyaline or pigmented, ellipsoidal,
broadly to narrowly fusoid or filiform, mostly septate.
Morpho-characters used in taxonomy of Pleosporales
Sexual characters
According to the Linnean classification system, reproductive
structures are the most important criteria in plant
taxonomy, and this proposal is widely applied in fungal
taxonomy (Gäumann 1952). In the classification of Dothideomycetes,
reproductive characters such as the uni- or
multilocular nature and shape of ascomata, presence and
shape of ostioles/papillae, shape and apical structures of
asci and shape, pigmentation and septation of ascospores
play important roles at different ranks (Clements and Shear
1931; Luttrell 1951, 1955, 1973). Besides the common
morphological characters possessed by Dothideomycetes
(bitunicate and fissitunicate asci as well as the perithecioidlike
ascostromata), most pleosporalean fungi also have
pseudoparaphyses among their well-arranged asci (Zhang et
al. 2009a). Currently, classification of Pleosporales at the
family level focuses mostly on morphological characters of
ascomata (such as size, shape of ostiole or papilla), presence
or absence of periphyses, characters of centrum (such as asci,
pseudoparaphyses and ascospores) as well as on lifestyle or
habitat (Barr 1990a; Shearer et al. 2009; Suetrong et al.
2009; Tanaka et al. 2009; Zhang et al. 2009a), whilst relying
extensively on DNA sequence comparisons.
Ascomata
Most species of Pleosporales have uniloculate ascomata.
The presence (or absence) and forms of papilla and ostiole
are the pitoval character of ascomata, which serve as
important characteristics in generic or higher rank classification
(Clements and Shear 1931). The vertically flattened papilla has
recently been shown as an effective criterion for familial level
classification, e.g. in the Amniculicolaceae and the Lophiostomataceae
(Zhang et al. 2009a). Papillae and ostioles are
present in most species of Pleosporales, except in the
Diademaceae and Sporormiaceae. Members of Diademaceae
have apothecial ascomata, and some genera of Sporormiaceae
have cleistothecioid ascomata. Another coprophilous pleosporalean
family, Delitschiaceae, can be distinguished from
Sporormiaceae by the presence of periphysate ostioles.
Pseudoparaphyses
Presence of pseudoparaphyses is a characteristic of
Pleosporales (Kirk et al. 2008; Liew et al. 2000). Although
pseudoparaphyses may be deliquescing in some families
when the ascomata mature (e.g. in Didymellaceae), they are
persistent in most of other pleosporalean members. According
to the thickness, with or without branching and density
of septa, pseudoparaphyses were roughly divided into two
types: trabeculate and cellular, and their taxonomic significance
need to be re-evaluated (Liew et al. 2000).