Melanomma populicola Crous & R. K. Schumach, Fungal Systematics and Evolution 6: 201 (2020)

Fig. 8

Basionym.

Aposphaeria populina Died., Krypt. - Fl. Brandenburg (Leipzig) 9: 206 (1912).

Synonym.

Melanomma populinum (Died.) Phukhams. & K. D. Hyde [as ‘ populina ’], Fungal Diversity 83: 49. 2017.

Description.

Saprobic on dead stem of Fagus sylvatica L. ( Fagaceae). Sexual morph: Ascomata 130–200 × 200–300 µm (x ̄ = 150 × 255 μm, n = 15), solitary or scattered, immersed, erumpent through host surface, black, multi-loculate, globose to subglobose, ostiolate. Peridium 10–15 μm wide, thick-walled, carbonaceous, composed of several layers of light brown to dark brown pseudoparenchymatous cells, cells towards the inside hyaline, arranged in a textura angularis, fusing at the outside indistinguishable from the host tissues. Hamathecium comprising numerous, 1–2 µm wide, hyaline, septate, filiform pseudoparaphyses. Asci 80–110 × 6–8 μm (x ̄ = 96 × 7 μm, n = 20), 8 - spored, bitunicate, fissitunicate, cylindrical, apically rounded, short pedicellate with furcate end, with an indistinct ocular chamber. Ascospores 13–17 × 4–5.2 μm (x ̄ = 15 × 4.8 μm, n = 35), overlapping, 1–2 - seriate, ellipsoid, initially hyaline, becoming light brown at maturity, 3 - septate, straight to slightly curved, slightly constricted at the septa, guttulate, smooth-walled. Asexual morph: See Crous et al. (2020).

Material examined.

China, Kunming, on a dead stem of Fagus sylvatica ( Fagaceae), 25 July 2016, D. S. Tennakoon, KDS 25 (HFJAU 10335) .

Known hosts.

Populus canadensis, Picea abies, Quercus sp., Sorbus aucuparia (Crous et al. 2020; this study).

Known distribution.

China, Germany, The Netherlands (Crous et al. 2020; this study).

Notes.

Melanomma populicola was introduced by Diedicke (1912) as Aposphaeria populina, which was a phoma-like species collected from Populus canadensis . An epitype for A. populina was established by De Gruyter et al. (2013). Tibpromma et al. (2017) synonymised A. populina under Melanomma and erected as M. populina . Subsequently, this was validated by Crous et al. (2020) and erected as M. populicola . Morphological characteristics of our collection (HFJAU 10335) fit well with the M. populicola in having black, globose to subglobose ascomata, cylindrical, apically rounded asci and ellipsoid, 3 - septate, light brown ascospores. In addition, there are overlapping size ranges of asci (80–110 × 6–8 μm vs. 91–106 × 6.5–7.5 μm) and ascospores (13–17 × 4–5.2 μm vs. 15.1 × 5 μm) (Crous et al. 2020). Multi-gene phylogeny also shows that our collection groups with M. populicola isolates in a 99 % ML and 0.99 BYPP supported clade. Therefore, we introduce our collections as a new host record of M. populicola from Fagus sylvatica .