Seimatosporium pseudocornii Wijayaw., Camporesi & K.D. Hyde, sp. nov.
Index Fungorum number: IF 551754, Facesoffungi number: FoF 01653, Figs. 1 and 2
Etymology – Named as its morphological similarity to Seimatosporium rosae
Holotype – MFLU 15–3558

Saprobic on dead branches and stems of Cornus sp. Sexual morph Undetermined. Asexual morph Conidiomata 320 – 350 μm diam., 50 – 120 μm high, acervular, unilocular, subglobose, superficial to subepidermal, solitary to gregarious, dark brown to black, non papillate ostiole. Conidiomata wall multi-layered, outer wall thick, composed of brown cells of textura angularis, inner wall thin, hyaline. Conidiophores 5 – 30 × 2 – 4 μm, long, cylindrical, branched, hyaline, smoothwalled. Conidiogenous cells holoblastic, annellidic, simple, integrated, determinate, hyaline. Conidia 31 – 42 × 5 – 7 μm (x̄ = 38.1 × 6.1 μm, n = 20), obovoid to fusiform, occasionally truncate base, obtuse apex, straight to slightly curved, 3-transverse septate, brown to dark brown septa, constricted at the septa, often guttulate at immaturity, medium brown, hyaline to subhyaline basal cell, smooth-walled, appendage absent.

Culture characteristics – On PDA slow growing, attaining a diam. of 2 cm in 7 days at 18 °C, white to pale brown from top, greyish white from below, with sparse mycelium, flat, uneven margin.

Material examined – ITALY, Forlì-Cesena [FC] Province, near Monte Riccio – Bagno di Romagna, on dead branch of Cornus sp. (Cornaceae), 5 January 2013, Erio Camporesi, IT 1000 (MFLU 15–3558, holotype); (HKAS isotype), ex-type living cultures MFLUCC 13–0529, GUCC IT 1000, KIB.

Notes – Farr and Rossman (2015) reported Seimatosporium lichenicola (Corda) Shoemaker & E. Müll. (conidial dimensions 13 – 15 × 5.5 – 6.5 μm fide Sutton 1980) and S. salicinum (Corda) Nag Raj (11 – 17 × 4 – 6 μm fide Nag Raj 1993) from Cornus spp. Senanayake et al. (2015) reported Seimatosporium corni Wijayawardene et al. (conidial dimensions 21 – 29 × 9 – 11 μm). In morphology our new collection is distinct from these species, thus we introduce a new species based on morphology, host association and phylogenetic analyses.

Fig. 1 Phylogram generated from maximum likelihood analysis (ML) based on combined LSU and ITS sequence data of Seimatosporium. Maximum likelihood bootstrap support values greater than 50% are near the nodes. New taxa are in blue and ex-type strains are in bold. The tree was rooted to Pseudopestalotiopsis theae (MFLUCC 12–0055)

Fig. 2 Seimatosporium pseudocornii (holotype) a Appearance of conidiomata on dead branch of Cornus sp. b, c Cross sections of conidiomata d – h Different stages of conidiogenesis i – o Conidia p Germinating conidium. Scale bars: b = 50 μm, c – o = 25 μm, p = 30 μm.