Phacidium italicum W.J. Li, Camporesi & K.D. Hyde
Etymology: Named after country from where it was collected.
Saprobic on dead stems of Rubus sp. (Rosaceae). Sexual morph: undetermined. Asexual morph: Conidiomata 1500–3570 µm long, 730–1120 µm wide, black, pseudostromatic, solitary or gregarious, oval to irregular in outline, semi-immersed to superficial, ostiolate, thick-walled, glabrous, multi-locular, with less than 10 locules embedded in the pseudostroma, individual locules 80–430 µm diam., 120–460 µm wide, with irregular or globose to subglobose, each with an ostiole. Ostioles 140–240 µm long, 20–70 µm wide, centrally located, circular, rounded, with relatively long necks, opening into a mutual area of dehiscence marked by white furfuraceous border. Conidiomatal wall 20–120 µm wide, composed of outer layers of thick-walled, dark brown to black cells of textura angularis, inner layers of thick-walled, pale brown to hyaline cells of textura epidermoidea to textura porrecta. Conidiophores arising from the innermost layer of the locular walls, hyaline, branched, septate, smooth-walled. Conidiogenous cells 8–20 × 2–3 µm, hyaline, enteroblastic, phailidic, cylindrical to subcylindrical with marked periclinal thickenings in the collarette zone, smooth-walled. Conidia 10–16 × 2–3.6 µm (= 13.5 × 3 µm; n = 30), hyaline, cylindrical to subcylindrical, with a broad and occasionally protuberant base, and a rounded apex, unicellular, smooth, thick-walled, bearing a cone-shaped or irregular, subapical, mucoid appendage.
Culture characters: Colonies on PDA, reaching 3–4 cm after 7 d at 25–30 °C, white to brown with age, circular, flattened, dense, felty, with aerial mycelium on the surface, rounded and smooth at margins, reverse brown. Mycelium composed of hyaline to pale brown, cylindrical, branched, septate hyphae. Sporulation appearing after 4 weeks. Conidiomata formed from mycelium, brown, pycnidial, solitary or gregarious, globose or irregular, unilocular to multilocular, thick-walled. Conidiophores hyaline.
Material examined: Italy, Province of Arezzo, on dead aerial branches of Rubus sp. (Rosaceae), 13 July 2016, Erio Camporesi, IT3034 (MFLU 16-2155, holotype), ex-type living culture MFLUCC 16-1314 = ICMP 21553 = KUMCC 16-0108, (KUN, HKAS 101655, isotype).
Notes: The dimensions of Phacidium italicum (10–16 × 2–3.6 µm) fall into the variation of asexual morph of P. lauri (7–17 × 2–3 µm, Nag Raj 1993), but the latter has up to 10 individual locules, while P. italicum has less than 10 locules, mostly 5–6-locules. Phylogenetic analyses of multi-locus show that P. italicum is closer to P. distylii than to P. lauri. Therefore, P. italicum is introduced as a new species.
Phacidium italicum (MFLU 16-2155, holotype) a Herbarium specimen. b–g Appearance of black conidiomata on the host. h, i Vertical sections of conidioma. j locules. k, n Sections of peridium. l, m Ostiole. o, p Conidiophores, conidiogenous cells and developing conidia. q–t Conidia. Scale bars: b = 1000 µm, c–d = 200 µm, e–i = 500 µm, j = 100 µm, k–o = 50 µm, p = 20 µm, q–t = 10 µm.