Nectria dematiosa (Schwein.) Berk., N. Amer. Fung.: no. 154 (1873)
Faces of fungi number: FoF 07461
Saprobic on the host plant in terrestrial habit. Sexual morph: see Hirooka et al. (2011, 2012). Asexual morph: Conidiomata 120–300 µm diam., 100–250 µm high, sporodochial, sessile, orange to yellowish or red, mostly solitary, occasionally gregarious or confluent, semi-immersed to erumpent, pulvinate, subepidermal, cup-shaped, subglobose, thick-walled. Conidiomatal wall 20–40 µm wide, middle wall composed of thick-walled, hyaline cells of textura angularis to tight textura prismatica towards upper part; basal wall composed of thick-walled, pale brown cells of textura angularis; lateral wall adjacent to host tissue composed of thick-walled, hyaline to light brown cells of textura epidermodea to textura intricata. Conidiophores up to 150 µm long, 2–3 µm wide, formed from the upper cells of conidiomata, hyaline, cylindrical to subcylindrical, densely branched and swollen at base, septate, straight or flexuous, flared towards the apices, smooth-walled, with acropleurogenous conidiogenous cells. Conidiogenous cells 3–10 × 2–5 µm, hyaline, enteroblastic, phialidic, short cylindrical or subcylindrical, determinate, integrated or discrete, arising from apical or on short lateral branches which form immediately below septa. Conidia 13–17 × 2–5.5 µm ( = 15 × 4 µm; n = 30), hyaline, cylindrical to subcylindrical or fusiform, with a rounded apex and a narrow truncate base, straight or slightly curved, unicellular, thick- and smooth-walled, accumulating in a slimy orange mass above the conidioma.
Culture characteristiers: Colony on PDA, reaching 50–60 mm diam. after 14d at 25–30°C, white to whitish saffron with age, flattened, dense, radial, slightly cottony with aerial mycelium on the surface, with rounded margins, sporulating at 4 weeks, reverse white.
Material examined: Iatly, Province of Forlì-Cesena, Santa Sofia, near Corniolo, on dead aerial branches of Populus tremula (Salicaceae), 23 February 2016, Camporesi Erio, IT2848 (MFLU 16-0921), living culture MFLUCC 16-1141 = KUMCC 16-0078, (KUN, HKAS 97474); ibid., Santa Sofia, Campigna, on dead aerial branches of Acer pseudoplatanus (Sapindaceae), 2 April 2016, IT2917 (MFLU 16-1131), living culture MFLUCC 16-1143 = ICMP 21543 = KUMCC 16-0092, (KUN, HKAS 97460); ibid., Monte Fumaiolo, on dead aerial branches of Rhamnus alpinus (Rhamnaceae), 3 July 2016, IT3017 (MFLU 16-2053), living culture MFLUCC 16-1309 = ICMP 21552 = KUMCC 16-0104; ibid., Province of Arezzo, near Casuccia di Micheli, on dead aerial branches of Crataegus sp. (Rosaceae), 30 May 2016, Erio Camporesi, IT2986 (MFLU 16-1951), living culture MFLUCC 16-1307 = ICMP 21550 = KUMCC 16-0101, (KUN, HKAS 97501).
Notes: Nectria dematiosa was epitypified by Hirooka et al. (2011) based on the collection on Morus sp. (Moraceae) from the USA with a detailed description and illustration. This species has wide distribution (Canada, China, Finland, Japan, New Zealand, Poland, USA) and is associated with a broad range of host plants (Acer macrophyllum, A. pseudoplatanus, Acer sp., Morus sp., Prunus tenella, Ribes sp., Rosa sp., Sambucus nigra ssp. canadensis, and Weigela coraeensis). In this study, four additional strains collected on A. pseudoplatanus, Crataegus sp., P. tremula, and R. alpinus from Italy are added.
Nectria dematiosa (asexual morph, MFLU 16-1131) a Herbarium specimen. b, c Appearance of orange to red conidiomata on the host. d, e Vertical sections of conidiomata. f–h Section of peridium. i–p Conidiophores, conidiogenous cells and developing conidia. q Germinating conidia. r–t Conidia. Scale bars d–e = 500 µm, f = 25 µm, g–i, k = 50 µm, j, l, m, q = 20 µm, n–p, s–t = 5 µm, r = 10 µm.