Phacidium chinense G.C. Ren & K.D. Hyde sp. nov.

Index Fungorum number: IF 559693; MycoBank number: MB 559693; Facesoffungi number: FoF 10836, Fig. 1

Etymology – The species epithet reflects the country where the species was collected.

Holotype – KUN-HKAS 112899

Saprobic on dead wood of Rosa sp. Sexual morph: Not observed. Asexual morph: Conidiomata 170–200 μm high, 150–240 μm diam. (x̄ =180×200 μm, n=5), black, pseudostromatic, solitary or gregarious, semi-immersed to superficial, multi-locular, with 3–10 locules embedded in the pseudostroma. Ostioles 60–85×45–70 (x̄ =73.5×58.5, n=5) μm, centrally located, circular. Conidiomata wall 15–35 µm thick, 3–5 layered, comprising brown cells of textura angularis, thick-walled at basal, thin-walled at side. Conidiophores reduced to conidiogenous cells. Conidiogenous cells 3.5–5.5×1.2–2.0 µm (x̄ =4.8×1.5, n=10), hyaline, enteroblastic, phialidic, discrete, cylindrical, smoothwalled, arising from stratum. Conidia 4.5–6×2.0–2.4 µm (x̄ =5.2×2.1 µm, n=30), hyaline, oblong, unicellular, thick and smooth-walled.

Culture Characters – Colonies on PDA, reaching 80–90 mm diam., after four weeks at 20–25 °C, medium dense, circular, rough, fluffy, cotton, gray, with white papillate on the surface, reverse dark-gray.

Material examined – China, Yunnan Province, Diqing Autonomous Prefecture, Xianggelila (27.28′ 8° N, 99.50′ 45° E), 2958 m, on dead wood of Rosa sp. (Rosaceae), 30 August 2020, Guang-Cong Ren, W06 (KUN-HKAS 112899, holotype), ex-type living culture KUMCC 20-0168.

GenBank numbers – ON490924 (LSU), ON490925(ITS), ON506923(tef1), ON506922 (rpb2)

Notes – Phacidium chinense is introduced as a new species based on its distinct morphology, which is supported by phylogenetic analyses. In the phylogenetic analyses, P. chinense is distinct from extant species in Phacidium and formed a sister clade to Phacidium calderae, however, there is no bootstrap support (Fig. 2). Phacidium chinense is different to P. calderae in having oblong conidia and phialidic, cylindrical conidiogenous cells, while P. calderae in having subcylindrical conidia with apical mucoid appendage and proliferating with periclinal thickening conidiogenous cells (Crous et al. 2014).

Figure 1 – Phacidium chinense (KUN-HKAS 112899, holotype). a Herbarium. b Conidiomata on the host. c Vertical sections of conidioma. d Sections of peridium. e Conidiogenous cells and developing conidia. f–k Conidia. l Germinating conidium. m, n Culture on PDA. Scale bars: c=100 µm, d=50 µm, e, k=10 µm, f–j=5 µm, l=20 µm

Figure 2 –  Phylogram generated from maximum likelihood analysis based on combined LSU, ITS, tef1, and rpb2 sequence data. Forty-eight strains are included in the combined a nalyses which comprised 3378 characters (8200 characters for LSU, 546 characters for ITS, 879 characters for tef1, 1133 characters for rpb2) after alignment. The tree topology of the maximum likelihood analysis is similar to the Bayesian analysis. The evolutionary model SYM+G applied to ITS sequence data, while SYM+I+G applied to LSU, GTR+G tef1 and rpb2 gene regions. Bootstrap support values for ML≥80% and BYPP≥0.95 are given near nodes respectively. The tree is rooted in Phlyctema vincetoxici (CBS 123,726). Ex-type strains are in bold. The newly generated sequences are indicated in bold red