Pleosporales » Leptosphaeriaceae » Paraleptosphaeria

Paraleptosphaeria nitschkei

Paraleptosphaeria nitschkei (Rehm ex G. Winter) Gruyter, Aveskamp & Verkley, in Gruyter, Woudenberg, Aveskamp, Verkley, Groenewald & Crous, Stud. Mycol. 75: 20 (2012) [2013]

Index Fungorum number: IF 564723; Facesofungi number: FoF 00442

Saprobic on dead stems of Petasites sp. Sexual morph: Ascomata (296–)328–362 × (406–)420–423 μm (x̄ = 329 × 416 μm, n = 5), superficial, solitary or scattered, subglobose to obpyriform, dark brown, without subiculum covering host. Ostiolar neck protruding. Peridium (38–)45–56(–64) μm wide, brown to dark brown, comprising dark brown cells of textura angularis. Hamathecium comprising 0.5–1 μm wide, cylindrical to filiform, pseudoparaphyses. Asci (80–)97–102(–107) × 9–10 μm (x̄ = 98 × 9 μm, n = 10), 8-spored, bitunicate, cylindric-clavate, slightly curved, smooth-walled, apically rounded, short pedicellate, with an ocular chamber (ca. 1–1.5 μm wide). Ascospores 27–29(–34) × 4.5–6 μm (x̄ = 29 × 5μm, n = 10), 1–2-seriate, overlapping in the ascus, fusiform to inequilateral, hyaline, 3-euseptate, constricted at medium septum, widest at the middle and tapering towards narrow ends, straight or slightly curved, thick and smooth-walled. Asexual morph: Coelomycete. Conidiomata 435–455(–475) × (276–)300–330 μm (x̄ = 455 × 305 μm, n = 5), pycnidial, globose to subglobose, solitary, peridium 30–35(–38) μ m , thick-walled, scleroplectenchymatous. Conidiogenous cells 3–4×5–6 μm, phialidic. Conidia 1.5–2 × (–12)15–20 μm, hyaline, aseptate, cylindrical to filiform.

Culture characters: Ascospores germinating on MEA within 48 hours at 18 °C and germ tubes produced from both ends. Colonies growing on MEA, reaching 20 mm diam. after 7 days at room temperature, flat, margin crenated, olivaceous brown.

Material examined: ITALY, Province of Forlì-Cesena [FC], Passo la Calla, Santa Sofia, on stems of Petasites sp. (Asteraceae), 14 July 2012, E. Camporesi IT563 (MFLU 14-0021, reference specimen designated here), living culture, MFLUCC 13-0688; GenBank ITS: KR025860; LSU, KR025864.

ITALY, Province of Forlì-Cesena (FC), Monte Falco, on decaying grass stems of Petasites sp., 21 May 2013, E. Camporesi IT648 (MFLU 13-0644), DNA was extracted from the fruiting body), GenBank ITS: KP729446, LSU: KP729447.

Notes: Paraleptosphaeria is typified by Paraleptosphaeria nitschkei (Rehm ex G. Winter) De-Gruyter et al. Munk (1957) recognized Leptosphaeria section Para-Leptosphaeria, an invalid taxon, as a heterogeneous group. The section was differentiated from Eu-Leptosphaeria, which included the generic type species Leptosphaeria doliolum. Leptosphaeria nitschkei was considered a typical representative of section Eu-Leptosphaeria (Müller and von Arx 1950). de Gruyter et al. (2013) introduced Paraleptosphaeria to accommodate Leptosphaeria nitschkei and its relatives. The putative strain of Paraleptosphaeria nitschkei (holotype) clustered with our newly collected strains from Italy. Paraleptosphaeria nitschkei was originally described from Austria, whereas our specimen is from grass stems of Petasites sp. in Italy. Even though the morphology and the molecular data of our Italy collection show 100 % identity to the putatively named Paraleptosphaeria nitschkei, it would be unwise to epitypify this species with the Italy collection as they are from different continents. We therefore designate our collection as a reference specimen of P. nitschkei so that further work on these taxa can be carried out.