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Amphisphaeria sorbi Senanayake & K.D. Hyde
Index Fungorum number: IF550904, Facesoffungi number: FoF00414; Figs. 1 and 2
Etymology: Named after the host genus on which the fungus occurs.
Holotypus: MFLU 14–0797
Saprobic on branch of Sorbus aucuparia L. Sexual morph  Ascomata 350–380μm high×450–505μm diam. (x=370×482μm, n=10), immersed to erumpent, visible as black spots opening through the cracks of host surface, solitary, scattered, globose to subglobose, short papillate, ostiole periphysate, dark brown. Peridium 30–35μm (x=31μm, n=15) at the base, 65–70μm (x=68μm, n=15) at the neck, comprising 8–10 layers, inner layer of hyaline cells of textura angularis, outer layer of brown cells of textura angularis. Paraphyses 2–5μm wide (x=3μm, n=10), longer than asci, filamentous, septate, embedded in gelatinous matrix. Asci 125–170×9–13μm (x=145×11μm, n=20), 8- spored, unitunicate, cylindrical, short pedicellate, apically rounded, with a J-, apical apparatus. Ascospores 16–24×6–8μm (x=19×6.5μm, n=20), uniseriate, rarely overlapping uniseriate, ellipsoidal, light brown, one median septate, slightly constricted at the septum, smoothwalled, surrounded by a thick mucilaginous sheath. Asexual morph Coelomycete, Conidiomata 500–900μm diam. (x=800μm, n=10), superficial on MEA, solitary or aggregated, globose, dark brown. Peridium consisting of thick walled, septate, brown mycelium. Conidiophores 17–20μm long, 1.5–2.5μm (x=18×2μm, n=20), arising from peridium, septate, branched, thick walled, hyaline. Conidiogeneous cell elongated conical,0.7–1μm wide at the apex, 2–2.5μm wide at the base (x=1×2μm, n=20), thin-walled, septate, hyaline, annelidic. Conidia 10–12×1–1.5μm (x=10×1μm, n=20), elongate-fusiform, hyaline, smooth-walled.

Culture characters: Colonies onMEA reaching 4 cmdiam. after 14 days at 18 °C, white, cottony, flat, low, dense, with slightly wavy margin and few ariell mycelia.
Material examined: ITALY, Trento [TN], Dimaro, Folgarida, on branch of Sorbus aucuparia L. (Rosaceae), 2 August 2013, E. Camporesi IT 1400 (MFLU 14–0797, holotype); ex-type living cultures, MFLUCC 13–0721.

GenBank LSU: KP744475.

Notes: Amphisphaeria was introduced by Cesati and De Notaris (1863) without designating a generic type (Wang et al 2004). Petrak (1923) proposed A. umbrina as the lectotype of the genus. Different studies have listed more than 250 species in Amphisphaeria and Wang et al. (2004) accepted 12 species in the genus after examining more than 170 type specimens. Amphisphaeria sorbi shows more similarities to A. vibratilis. Amphisphaeria sorbi however, differs from A. vibratilis in having small perithecia, a peridium with a cell arrangement of textura angularis, and wide, non-flexuose paraphyses. The ascus apical apparatus is discoid in Amphisphaeria sorbi and has shorter, smooth walled ascospores without deeply pigmented septa. Molecular analysis of the LSU gene region (Fig. 1) confirms that Amphisphaeria sorbi clusters with A. umbrina in Amphisphaeriaceae with 52 % bootstrap support.

Fig. 1 Amphisphaeria sorbi (holotype) a Ascomata on substrate b Cross section of ascoma c Peridium d–g Asci in water h. Asci inMelzer’s reagent i Paraphyses j–l Ascospores m Sheath around spore n Germinating ascospore. Scale bars: a=1000μm, b=100μm, c=50μm, d-h=20μm, i–n=10μm.

Fig. 2 Amphisphaeria sorbi (ex-type culture) Asexual morph in culture a, b Conidiomata on MEA c Peridium d–g Conidiophore and conidiogenous cells with attached conidia h Conidia. Scale bars: a=500μm, b=1000μm, c=100μm, d–h= 10μm.