Pleosporales - CBS - KNAW

Fungal Diversity
papillate, ostiolate. Peridium thin. Hamathecium of dense,
cellular pseudoparaphyses. Asci 8-spored, bitunicate,
fissitunicate, cylindrical to clavate, with furcate pedicel
and small inconspicuous ocular chamber. Ascospores
muriform, brown or pale brown, with or without
sheath.
Anamorphs reported for genus: Stemphylium (Simmons
1985).
Literature: Barr 1981; Frisullo and Braun 1996; Kodsueb
et al. 2006a; Luttrell1951; Wehmeyer1946, 1961, 1975;
Zhang et al. 2009a.
Type species
Pleospora herbarum (Pers.) Rabenh., Klotzschii Herb. Viv.
Mycol. 2: no. 547 (1854). (Fig. 80)
≡ Sphaeria herbarum Pers., Syn. meth. fung. (Göttingen)
1: 78 (1801).
Ascomata 130–220 μm high×250–420 μm diam.,
scattered, or in small groups of 2–3, immersed, semiimmersed
to erumpent, broadly to narrowly oblong and
flattened, with flattened base not easily removed from the
substrate, wall black, papillate, ostiolate (Fig. 80a and b).
Peridium 30–50 μm thick on sides, thinner at the base,
coriaceous, 2-layered, outer layer composed of one or two
layers of heavily pigmented thick-walled cells of textura
angularis, cells 5–10 μm diam., cell wall 2–4 μm thick,
apex cells smaller and walls thicker, inner layer composed
of hyaline thin-walled cells of textura angularis, 8–12 μm
diam., wall hyaline, 0.5–1.5 μm thick (Fig. 80c). Hamathecium
of dense, cellular pseudoparaphyses, 2–3 μm
broad, filling the gaps between the asci. Asci 100–210×
27.5–30 μm (x ¼ 142:2 28:3mm, n=10), 8-spored, bitunicate,
fissitunicate, broadly cylindrical to clavate, with a
short, thick, furcate pedicel, 8-12(−20) μm long, with
small inconspicuous ocular chamber (ca. 3 μm wide×
1 μm high) (Fig. 80d and e). Ascospores 28–38×12.5–
15 μm (x ¼ 33 14:5mm, n=10), ellipsoidal, straight or
sometimes curved, with broadly rounded ends and upper
hemispore slightly shorter and broader; spores usually
divided by 3 A-transsepta, all 4 segments by longisepta
andthenbyonestratumofB-transsepta(maturesporesas
a rule with 7 transsepta, 3A+4B), yellowish brown,
smooth; each hemispore with thick gelatinous sheath, the
lower one with umbilicus (sheaths fused in mature spores)
(Fig. 80f, g, h, i, j and k).
Anamorph: Stemphyllium herbarum E. Simmons
(Simmons 1985).
Material examined: GERMANY, on stalks of Melilotusalla?
at the bank of the Elbe in Konigstein, 1882 (E,
Krieger 683); as Sphaeria herbarum Persoon Syn. fung. p.
78 (E, 81); as Sphaeria herbarum Fries, Scleromyceti
Sueciae 38 (E, lectotype).
Notes
Morphology
Pleospora was originally assigned within Sphaeriales.
Subsequently, it was assigned within Pseudosphaeriales and
Pleosporales (Wehmeyer 1961). Pleospora is a large group,
which is widely distributed and associated with a wide range
of species of monocotyledons as well as dicotyledons
(Wehmeyer 1975). All species of Pleospora have muriform
ascospores (Wehmeyer 1961, 1975). Pleospora has downward
growing pseudoparaphyses within the ascomata of
“Pleospora-type” development (Luttrell Univ. Mo. Stud.
1951), which subsequently served as a diagnostic character.
However, only a limited number of species had detailed
studies on this character (Wehmeyer 1961). The heterogeneous
nature of Pleospora has been noted, and several
subgenera have been erected, such as Scleroplea to include
all “sclerotioid” species of Pleospora, Teichosporoides to
accommodate species of Pleospora with immersed ascomata,
Pleosphaeria for those having superficial and setose ascomata
(Wehmeyer 1961). Similarly, Cucurbitaria, Fenestella and
Montagnula are also separated as a section from Pleospora.
Most of these subgenera are currently at genus rank.
Phylogenetic study
The polyphyletic nature of Pleospora is clear (Kodsueb et
al. 2006a), and those that stain the woody substrate purple
should be assigned to Amniculicolaceae (Zhang et al. 2009a).
Concluding remarks
As some Pleospora species have a wide range of host
spectrum, especially on both monocotyledons and dicotyledons,
it is highly possible they are cryptic species.
Preussia Fuckel, Hedwigia 6: 175 (1867) [1869–70].
(Sporormiaceae)
Generic description
Habitat terrestrial, saprobic (on decaying fibers or coprophilous).
Ascomata small- to medium-sized, cleistothecial or
perithecial, solitary or scattered on substrate surface,
globose, membraneous, black. Peridium thin, composed
of thick-walled, poly-angular cells from the surface view.
Pseudoparaphyses not observed. Asci (4-) 8-spored, bitunicate,
clavate to broadly clavate, with a long and thin and
furcate pedicel. Ascospores 3–6 seriate to uniseriate near
the base, cylindrical with rounded ends, brown, septate,
easily breaking into partspores, with germ slits in each cell.
Anamorphs reported for genus: Phoma (von Arx 1973;
Cain 1961; Malloch and Cain 1972).
Literature: Ahmed and Cain 1972; Arenaletal.2005; von
Arx 1973; von Arx and van der Aa 1987; Auerswald1866;