Hypoxylon rubiginosum (Pers.) Fr., Summa Veg. Scand. II, p. 384. (1849).

Pourmoghaddam, Mohammad Javad, Lambert, Christopher, Surup, Frank, Khodaparast, Seyed Akbar, Krisai-Greilhuber, Irmgard, Voglmayr, Hermann & Stadler, Marc, 2020, Discovery of a new species of the Hypoxylon rubiginosum complex from Iran and antagonistic activities of Hypoxylon spp. against the Ash Dieback pathogen, Hymenoscyphus fraxineus, in dual culture, MycoKeys 66, pp. 105-133 : 105

Hypoxylon rubiginosum (Pers.) Fr., Summa Veg. Scand. II, p. 384. (1849). Fig. 3

Teleomorph.

Stromata superficial, effused-pulvinate, up to 8 cm long × 0.3-0.2 cm wide; with inconspicuous to conspicuous perithecial mounds, surface Red (2) to Brick (59); Scarlet (5) to Orange (7) granules beneath the surface and between the perithecia, with Orange (7) to Scarlet (5) KOH-extractable pigments. Perithecia spherical to obovoid, 0.2-0.5 high × 0.15-0.45 mm wide. Ostioles umbilicate, inconspicuous. Asci 8-spored, cylindrical, with amyloid, discoid apical apparatus, 0.5-1 µm high × 1.5-2.5 µm wide, stipe up to 180 µm long and spore-bearing portion 40-80 × 6.5-10 µm. Ascospores smooth, unicellular, brown to dark brown, ellipsoid, inequilateral with narrowly rounded ends, 9-12 (-13) × 4-6 µm, with straight germ slit spore-length on convex side; perispore dehiscent in 10% KOH; epispore smooth.

Cultures and anamorph.

Colonies on OA covering a 9 cm Petri dish in 3 wk, at first white, becoming Smoke Grey (105), felty, azonate with diffuse margins; finally becoming Pale Luteous (11) to Straw (46). Asexual morph not produced in culture.

Secondary metabolites.

Rubiginosin A and an unknown compound of the mitorubrin / rubiginosin azaphilone family prevalent; cultures produce phomopsidin and unidentified compounds on barley-malt agar.

Specimens examined.

Iran, Guilan Province, Siahkal County, Deilaman forest, 36°57'25"N, 49°51'54"E, 1100 m elev., on fallen branch of Quercus castaneifolia , 6 Oct 2017 (GUM 1586; culture MUCL 57727); Guilan Province, Shaft County, 36°59'08"N, 49°18'43"E, 594 m elev., on fallen trunk of Pterocarya fraxinifolia , 15 Sep 2015 (GUM 1583); Guilan Province, Langaroud County, Liseroud forest, 37°7'44"N, 50°8'41"E, 28 m elev., on fallen branch of Quercus castaneifolia , 10 Sep 2016 (GUM 1584); Guilan Province, Talesh County, Gisoum forest, 37°37'30"N, 48°58'15"E, 477 m elev., on fallen branch of Populus sp., 20 Oct 2016 (GUM 1585). All specimens collected by M.J. Pourmoghaddam.

Notes.

H. rubiginosum sensu stricto is a very common fungus in the temperate Northern hemisphere ( Stadler et al. 2008) and may occur in subtropical areas, such as Florida, USA ( Ju and Rogers 1996). Most of the characters of the Iranian specimens are in accordance with previous descriptions ( Stadler et al. 2004), aside from insignificant variations in the size of ascospores.

Figures

Figure 3. Hypoxylon rubiginosum (GUM 1586) A, B stromatal habit C close-up view of stromatal surface D close-up view of stromatal surface, with stromatal pigments in 10 % KOH E ascospores in 10 % KOH with dehiscent perispore F mature and immature asci in water G immature ascus in water H mature ascus in water I ascus in Melzer's reagent J ascospores in water K ascus tip in Melzer's reagent. Scale bars: 2 cm (A); 1 cm (B); 4 mm (C); 2 mm (D); 10 µm (E); 20 µm (F-I), 10 µm (J, K).