Comoclathris sedi Wanasinghe, Ariyawansa, E. Camporesi & K.D. Hyde, sp. nov.,

Holotype: MFLU 14 0758

Index Fungorum number: IF 550955,

Etymology: The specific epithet sedi is based on the host genus from which the fungus was isolated.

Saprobic on dead stem. Sexual morph: Ascomata 200–250 × 290–350 µm ( =230 × 320 µm, n = 10), scattered or aggregated on the host stem, subglobose or nearly globose, superficial, coriaceous, brown to blackish brown with a blunt ostiole. Peridium 20–38 µm ( =25 µm, n = 10) wide, comprising 3–4 layers of brown, relatively thick-walled cells of textura angularis, inner cells flattened, thin-walled and lighter. Hamathecium composed of dense 1.5–2.5 µm ( =2 µm, n = 10) wide, septate, hyaline, filiform, pseudoparaphyses longer than the asci. Asci 80–110 × 16–18 µm ( =98 × 18 µm, n= 20), 8-spored, bitunicate, fissitunicate, cylindrical to cylindro-clavate, with a short knob-like pedicel, and indistinct shallow ocular chamber. Ascospores 19–20 × 8–10 µm ( = 20 × 19 µm, n = 40 ), 1–2 overlapping seriate, fusiform, with 4–5-transverse septa and 1–2-longitudinal septa, not constricted at the septa, brown to reddish brown, muriform, surrounded by a distinct, hyaline, mucilaginous 5–9 µm wide sheath. Asexual morph: not observed in culture

Material examined: ITALY, Stavel, Ortignano-Raggiolo, on stem of Sedum sp. (Crassulaceae), 6 June 2012, E. Camporesi IT 416, (MFLU 14 0759, holotype) – extype living culture (MFLUCC 13 0817, BRIP); ITALY, Monte Cervarola, Sestola, on dead branch of Clematis vitalba (Ranunculaceae), 21 July 2012, E. Camporesi IT 589, (KIB, paratype) – extype living culture (ICMP); ITALY, Almazzago, on dead stem of Rosa sp. (Rosaceae), 8 August 2013, N. Camporesi IT 1408 (MFLU14-0760) – living culture (MFLUCC 13 0763).

Notes: The novel taxon, Comoclathris sedi was initially isolated on dead stem of Sedum sp. But later the same species was isolated from Clematis vitalba, Rosa sp. and Digitalis sp. and they are morphologically and phylogenetically identical. Comoclathris sedum shows similarities with Comoclathris, in having globose, black, ascomata with setae and cylindrical to cylindro-clavate asci having knob-like pedicel with muriform, yellowish to dark brown applanate ascospores but differs from other species of genus in having superficial ascomata (200–250 × 290–350 µm) with distinct ostiole, 20–38 µm wide, comprising one layer of brown, relatively thick-walled cells of textura angularis, 1–2 overlapping seriate, fusiform to ellipsoidal, muriform, with 2–5-transverse septa and 1–4-longitudinal septa, not constricted at the septa, brown to reddish brown ascospores. The phylogenetic analysis of combined ITS, LSU, SSU nrDNA and RPB2 sequences provides strong evidence that Comoclathris sedi belongs in Pleosporaceae and forms a robust clade within the genus Comoclathris sister to Comoclathris compressa (CBS 157.53 and CBS 156.53) with relatively high bootstrap support (Fig 1), thus a new species is proposed.

Fig 1. Comoclathris sedi (holotype). a. Habit of the fungus on host stem. b. Superficial ascomata. c. Thick section through ascoma. d. Dark brown setae. e. Hyaline pseudoparaphyses. f-h. Asci with shallow ocular chamber. i-k. Muriform ascospores with thick sheath. Scale Bars: b = 200µm, c = 40 µm, f-h = 10 µm, i-k = 20 µm.