Premilcurensis senecionis Tibpromma, Camporesi & K.D. Hyde, sp. nov.
Index Fungorum number: IF551294, Facesoffungi number: FoF: 00700
Etymology: refers to the host genus from which the fungus was isolated.
Holotype: MFLU 14-0678
Saprobic on decaying stem of Senecio sp. (Asteraceae). Sexual morph: Ascostromata 160–215 µm high, 230–265 µm diam. ( x = 195 × 242 μm, n = 5), superficial, semi-immersed at the base, globose to subglobose, solitary or in small groups, glabrous, dark brown to black, scattered on the host surface, base not easily removed from the substrate, ostiole central, papilla minute, thin-walled, shiny, like charcoal. Peridium 20–28 μm wide, thick, externally multi-layered, heavily pigmented at the surface, composed of thick-walled light brown cells of textura angularis, inwardly cells thinwalled. Hamathecium comprising numerous, 1.1–1.5 µm wide, filiform, cellular, branched, hyaline pseudoparaphyses. Asci 58–65 × 7–10 μm ( x = 60 × 10 μm, n = 30), 8-spored, bitunicate, fissitunicate, cylindrical to cylindric-clavate, short pedicellate, rounded at the apex, with well-developed ocular chamber. Ascospores 18–27 × 4–5 μm ( x = 22 × 4 μm, n = 50), overlapping uni- to bi-seriate, initially hyaline, becoming yellow-green to yellow-brown at maturity, fusiform-cylindrical to elongate fusiform, with rounded ends, usually 3–5-septate, straight to slightly curved, constricted at the central septum, with wing-like appendages, smooth-walled, with small guttules in each cell. Asexual morph: Undetermined. Culture characteristics: on PDA reaching 2 cm diam. after 2 weeks at 16°C, later with dense mycelium, with circular, rough margin, flattened; upper surface white at first, pale yellow after 4 weeks; reverse cinnamon; hyphae septate, branched, hyaline, thin-walled.
Material examined: ITALY, Province of Forlì-Cesena
Notes: Barr (1979) introduced the family Phaeosphaeriaceae typified by Phaeosphaeria with P. oryzae (Miyake 1909) as the type species. Fifteen genera were included in this family, although Kirk et al. (2008) later accepted 35 genera. Its characteristics are similar to taxa in the family Leptosphaeriaceae and the two are often confused (Hyde et al. 2013, Phookamsak et al. 2014, Ariyawansa et al. 2015). The taxa within Phaeosphaeriaceae are often associated with monocotyledons, have a peridium of pseudoparenchymatous cells and asexual morph of pycnidial coelomycetes, mostly identified as phoma-like or stagonospora-like (Hyde et al. 2013). Premilcurensis is similar to some species of Nodulosphaeria and Leptosphaeria , but based on phylogeny Nodulosphaeria and Leptosphaeria are not congeneric with our taxon
Fig 1. Premilcurensis senecionis (MFLU 14-0678, holotype). a, b, c Ascostromata on host substrate. d Section of ascoma. e Section through peridium. f Relatively wide cellular pseudoparaphyses. g–i Asci. j Ocular chamber of ascus. k–m Ascospores with wing-like equatorial appendage. Scale bars: a = 200 μm, b–d = 100 μm, e, g, h, i = 20 μm, f = 1 μm, j = 5 μm, k–m = 10 μm.
