Apiognomonia pseudohystrix W.J. Li, Camporesi & K.D. Hyde, sp. nov.

Index Fungorum number: IF 557136, Facesofungi number: FoF 07117, Fig. 1

Etymology: Phylogeny closely related to A. hystrix, but morphology distinct.

Saprobic on dead branch of Ostrya carpinifolia. Sexual morph: undetermined. Asexual morph: Conidiomata 800–950 µm diam., 300–350 µm high, pale brown to brown, stromatic, acervular, solitary, deeply immersed when young, becoming erumpent at maturity, subglobose, multilocular, thick-walled, glabrous. Ostiole absent, dehiscing by irregular breakdown of the overlapping host tissue. Conidiomatal wall 20–150 µm wide, composed of relatively thick-walled, pale brown to hyaline cells of textura intricata in the middle wall (Fig. 25g), gradually merging with thick-walled, pale brown cells of textura angularis in the basal part and inner part of the locular wall. Conidiophores arising from the inner layer cells of the conidiomata, reduced to conidiogenous cells or present, hyaline, short cylindrical, branched at the base, smooth-walled. Conidiogenous cells 7–15×2–4 µm, hyaline, enteroblastic, annellidic, cylindrical to lageniform, mostly discrete, occasionally integrated, indeterminate, smooth-walled, with 1–2 distinct percurrent proliferations towards apex (Fig. 25k, m). Conidia 14–22×3–5 µm (x̄ =17×4 µm; n=50), hyaline, fusiform, obtuse at the apex, slightly truncate at the base, 1-septate, slightly constricted at the septum, smooth-walled, guttulate.

Culture characters – colonies on PDA, reaching 30–50 mm diam. after 14 d at 25 °C, whitish to pale brown in the middle region, whitish in the margin region, becoming olivaceous brown with age, plane, velutinous to felty, with entire margin; reverse whitish to olivaceous brown with age.

Material examined – Italy, Province of Forlì-Cesena, Santa Sofa, Camposonaldo, on dead branch of Ostrya carpinifolia (Betulaceae), 8 May 2016, Erio Camporesi, IT2962 (MFLU 16-1333, holotype), living culture MFLUCC 16-1140=ICMP 21546=KUMCC 16-0096, (KUN, HKAS 101650, isotype); ibid., Predappio, Rocca Delle Caminate, on dead aerial branches of Torilis arvensis (Apiaceae), 2 March 2016, IT2862 (MFLU 16-0936), living culture MFLUCC 16-1311=ICMP 21535.

Notes – Phylogenetically, Apiognomonia pseudohystrix is related to the sexual morph of A. hystrix (CBS 911.79), but it formed a separated branch (Fig. 23). The asexual morph of A. hystrix is undetermined. Apiognomonia pseudohystrix is distinguished from other taxa of Apiognomonia by its 1-sepate, fusiform conidia.

Fig. 1. Apiognomonia pseudohystrix (MFLU 16-1333, holotype). a Herbarium specimen. b, c Appearance of brown conidiomata on the host. d–e Vertical section of conidiomata. f–h Section of peridium. i–m Conidiogenous cells and developing conidia (arrows show two annellides). n Conidia. o–p Culture on PDA. Scale bars b–c=200 µm, d–e=500 µm, f, h=20 µm, g=50 µm, i–l=10 µm, m=5 µm, n=20 µm, o–p=20 mm.