Pleosporales - CBS - KNAW

Fungal Diversity
Material examined: USA, Kansas, Kansas State College,
on Poa pratensis L. Grass plots, 2 Jul. 1953, leg. T.
Rogerson, det. L.E. Wehmeyer (NY, C.T. Rogerson 3836).
Notes
Morphology
Leptosphaerulina, introduced by McAlpine (1902), is
characterized by small immersed ascomata, obpyriform asci
with a large ocular chamber and apical ring as well as
muriformly septate ascospores which may be hyaline or
pigmented. Species of Leptosphaerulina may occur on
monocotyledons or dicotyledons. Leptosphaerulina is most
comparable with Pleospora, and the only difference between
them is that Leptosphaerulina has smaller ascomata and
hyaline ascospores that only become pigmented after
discharge, whereas the ascospores of Pleospora become
brown within the asci. Currently, about 60 names are
accepted in this genus, and some even reported from marine
environments, e.g. L. mangrovei (Inderbitzin et al. 2000).
Phylogenetic study
Based on multigene phylogenetic analysis, two putative
strains of Leptosphaerulina australis, the generic type of
Leptosphaerulina, from Switzerland (CBS 311.51) and
Indonesia (CBS 317.83) resided within Didymellaceae (de
Gruyter et al. 2009; Zhang et al. 2009a).
Concluding remarks
Because of its morphological confusion with Pleospora
and the diversity of habitats within the genus, Leptosphaerulina
sensu lato is likely to be polyphyletic. Fresh
collections of this species are needed from Australia to
epitypify this taxon and define the genus in a strict sense.
The specimen described here is a collection from USA and
therefore may not represent the type.
Lewia M.E. Barr & E.G. Simmons, Mycotaxon 25: 289
(1986). (Pleosporaceae)
Generic description
Habitat terrestrial, parasitic or saprobic? Ascomata
small, scattered, erumpent to nearly superficial at maturity,
subglobose to globose, black, smooth, papillate,
ostiolate. Papilla short, blunt. Peridium thin. Hamathecium
of pseudoparaphyses. Asci (4–6-)8-spored, bitunicate,
fissitunicate, cylindrical to cylindro-clavate, with a
short, furcate pedicel. Ascospores muriform, ellipsoid to
fusoid.
Anamorphs reported for genus: Alternaria (Simmons 1986).
Literature: Kwasna and Kosiak 2003; Kwasnaetal.2006;
Simmons 1986, 2007; Vieira and Barreto 2006.
Type species
Lewia scrophulariae (Desm.) M.E. Barr & E.G. Simmons,
Mycotaxon 25: 294 (1986). (Fig. 46)
≡ Sphaeria scrophulariae Desm., Plantes cryptogames
du Nord de la France, ed. 1 fasc. 15:no. 718
(1834).
Ascomata ca. 150–200 μm diam., scattered, erumpent to
nearly superficial at maturity, subglobose to globose, black,
smooth, papillate. Papilla short, blunt. Peridium thin.
Hamathecium of septate pseudoparaphyses, ca. 2–2.5 μm
broad, anastomosing or branching not observed. Asci 100–
140×13–17 μm, (4–6-)8-spored, bitunicate, fissitunicate,
cylindrical to cylindro-clavate, with a short, furcate pedicel,
ocular chamber unknown (Fig. 46a). Ascospores ellipsoid,
5 (rarely 6 or 7) transversal septa and one longitudinal
septum mostly through the central cells, yellowish brown to
gold-brown, 20–24×8–10 μm (x ¼ 21:5 9:1mm, n=10),
constricted at median septum, smooth or verruculose
(Fig. 46b, e and f).
Anamorph: Alternaria conjuncta (Simmons 1986).
Primary conidiophore simple with a single conidiogenous
locus; conidia produced in chains, the first conidia
in chain is larger, 30–45×10–12 μm, 7 transverse septa,
1–2 longitudinal or oblique septa in lower cells.
Secondary conidiophore with 5–7 conidiogenous loci,
sometimes branched; sporulation in chains, rarely
branched.
Material examined: (FH, slide from lectotype).
Note: The specimen contains only a slide, so limited
structures could be observed e.g. ascospores. The information
about ascomata, peridium and whole asci is referred to
Simmons (1986).
Notes
Morphology
Lewia has “Pleospora-like” teleomorphs, while it has
Alternaria anamorphs, which are characterized by the
beakless conidia connected together with secondary
conidiophore (Simmons 1986). Based on these characters,
more species under this genus were subsequently reported,
i.e. Lewia avenicola Kosiak & Kwaśna (Kwasna and
Kosiak 2003); L. chlamidosporiformans B.S. Vieira & R.
W. Barreto (Vieira and Barreto 2006); L. alternarina (M.
D. Whitehead & J.G. Dicks.) E.G. Simmons and L.
daucicaulis E.G. Simmons (Simmons 2007). Currently
Lewia comprises 15 species (http://www.mycobank.org,
24-02-2009).
Phylogenetic study
Phylogenetic analysis based either on SSU rDNA
sequences or on multigenes indicated that Lewia species