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 Author Pourmoghaddam, Mohammad Javad Department of Plant Protection, Faculty of Agricultural Sciences, University of Guilan, Rasht, Iran & Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, 1030, Wien, Austria & Helmholtz-Zentrum fuer Infektionsforschung GmbH, Dept. Microbial Drugs, Inhoffenstrasse 7, 38124, Braunschweig, Germany Author Lambert, Christopher Helmholtz-Zentrum fuer Infektionsforschung GmbH, Dept. Microbial Drugs, Inhoffenstrasse 7, 38124, Braunschweig, Germany Author Surup, Frank Helmholtz-Zentrum fuer Infektionsforschung GmbH, Dept. Microbial Drugs, Inhoffenstrasse 7, 38124, Braunschweig, Germany Author Khodaparast, Seyed Akbar Department of Plant Protection, Faculty of Agricultural Sciences, University of Guilan, Rasht, Iran Author Krisai-Greilhuber, Irmgard Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, 1030, Wien, Austria Author Voglmayr, Hermann Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, 1030, Wien, Austria & Institute of Forest Entomology, Forest Pathology and Forest Protection, Department of Forest and Soil Sciences, BOKU-University of Natural Resources and Life Sciences, Franz-Schwackhoefer-Haus, Peter-Jordan-Strasse 82 / I, 1190, Vienna, Austria https://orcid.org/0000-0001-7666-993X Author Stadler, Marc Helmholtz-Zentrum fuer Infektionsforschung GmbH, Dept. Microbial Drugs, Inhoffenstrasse 7, 38124, Braunschweig, Germany https://orcid.org/0000-0002-7284-8671 marc.stadler@t-online.de text MycoKeys 2020 66 105 133 http://dx.doi.org/10.3897/mycokeys.66.50946 journal article http://dx.doi.org/10.3897/mycokeys.66.50946 1314-4049-66-105 C5A0C9E410E354A8A1FF1A8FE8F4EA98 Hypoxylon guilanense Pourmoghaddam & C. Lambert sp. nov. Fig. 2 Holotype. Iran, Guilan Province, Rasht County, Saravan forest, 37°04'26"N , 49°38'13"E , 183 m elev., on fallen branch of Quercus castaneifolia , 9 Apr 2015, M.J. Pourmoghaddam. (GUM 989; ex-holotype culture MUCL 57726). Etymology. Guilanense, refers to its origin in Guilan province, Iran. Teleomorph. Stromata superficial, hemispherical to pulvinate, up to 2 cm long x 0.1-0.7 cm wide, with conspicuous perithecial mounds, surface Sienna (8), Umber (9) to Buff (45); Scarlet (5) to Orange (7) granules beneath the surface and between the perithecia, with Orange (7) KOH-extractable pigments. Perithecia spherical to obovoid, 0.33-0.66 high x 0.3-0.55 mm wide. Ostioles umbilicate, inconspicuous. Asci not seen. Ascospores smooth, unicellular, brown to dark brown, ellipsoid, inequilateral with narrowly rounded ends, 12-15 x 5-6 µm , with straight germ slit spore-length on convex side; perispore dehiscent in 10% KOH, conspicuous coil-like ornamentation in SEM; epispore smooth. Cultures and anamorph. Colonies on OA covering a 9 cm Petri dish in 4 wk, at first white, becoming Buff (45), cottony, slightly zonate with diffuse margins; finally, becoming Honey (64). Anamorph not produced in culture. Secondary metabolites. Orsellinic acid, rubiginosin A and an unknown isomer thereof, as well as mitorubrinol acetate as prevailing stromatal components; cultures produce yet unidentified compounds on barley-malt agar. Notes. The description of this taxon is based on a single specimen, which shows the salient features of the teleomorph and can be discriminated easily from all previously described species of the H. rubiginosum complex. The stromata of the holotype specimen differ from H. texense (i.e. the closest relative in the phylogeny), in having stromata with hemispherical to pulvinate shape, Orange (7) KOH-extractable pigments and larger ascospores [12-15 x 5-6 vs. 9.1-10.8 (-11.5) x (4.0-) 4.5-5.4 (-5.7) μm with straight germ slit. Hypoxylon guilanense can also be easily differentiated from H. rubiginosum sensu stricto and H. petriniae in the peculiar stromatal shape and it also has larger ascospores. H. cercidicola differs from H. guilanense in having erumpent stromata with discoid shape and smaller ascospores [(9-) 9.5-12 x 5-6 μm )] with straight to slightly sigmoid germ slit. Table 2 compares morphological characters of some other taxa that may be confused with H. guilanense . Figure 2. Hypoxylon guilanense (Holotype GUM 989) A stromatal habit B close-up view of stromatal surface, with stromatal pigments in 10% KOH C, H, I ascospores in water, with germ-slits D, E ascospores in 10% KOH with dehiscent perispore F, G ascospore under SEM J, K culture on 9 cm OA plates after 1 and 3 wk of incubation (left to right). Scale bars: 2.5 mm ( A ), 1 mm ( B ); 10 µm ( C-E ); 2 µm ( F, G ); 10 µm ( H, I ). Table 2. Diagnostic characters of Hypoxylon rubiginosum sensu stricto and closely related species.

Taxon	Stromatal shape	Stromatal surface	KOH-extractable pigments	Ascospores (µm)	Germ slit	Host	Known distribution	Anamorph	Secondary metabolites*
Hypoxylon canariense	effused to effused-pulvinate	Fulvous, Dark Brick, Dark Vinaceous	Orange to Sienna	9.5-11.5 x 4.5-5	straight	Erica , Ocotea , Laurus , Persea	Spain (Canary Islands)	virgariella-like	Rubiginosins A-C, mitorubrinol acetate
Hypoxylon carneum	Effused-pulvinate	Dark purple, Dark vinaceous	Livid violet, absent in old stromata	(7.5-)8-11.5 x 4.5-5	straight	Various angiosperm hosts including Fraxinus	probably cosmopolitan but rare	sporothrix-like	Carneic acids A and B, BNT
Hypoxylon cercidicola	discoid	Dark brick to Sepia	Orange	(9-)9.5-12 x 5-6	straight to slightly sigmoid	Fraxinus	Europe and North America	unknown	Mitorubrin, rubiginosin A and C
Hypoxylon guilanense	hemispherical to pulvinate	Sienna, Umber to Buff	Orange	12-15 x 5-6	straight	Quercus	Iran	unknown	Rubiginosin A, mitorubrinol acetate
Hypoxylon lusitanicum	effused	Brown Vinaceous	Sienna	11-13.5 x 5-7	straight	Rhamnus	Portugal	unknown	Rubiginosins A and C, rutilin A
Hypoxylon petriniae	irregularly effused	Lilac, Vinaceous to Brown Vinaceous	Orange to Rust	8-11.5(-13) x 4.8-6	straight	Fraxinus (mostly); Acer , Salicaceae	Western and Central Europe	virgariella-like	Rubiginosin A, BNT
Hypoxylon retpela	effused-pulvinate	Livid Vinaceous, Brown Vinaceous,	Orange or Scarlet	(9-)9.5-12 x 4.5-5	straight or slightly sigmoid	unknown	Southeast and East Asia, New Guinea	nodulisporium-like	Mitorubrinol acetate, unknown rubiginosins
Hypoxylon rubiginosum	effused-pulvinate	Dark Brick, Brown Vinaceous	Orange	9-13 x 4-5.5	straight	Various angiosperm hosts including Fraxinus	Europe, North America	nodulisporium-like	Mitorubrin, rubiginosin A-C, rubiginosic acid, daldinin C
Hypoxylon aff. rubiginosum (GUM 1587)	pulvinate to effused-pulvinate	Luteous, Orange to Ochraceous	Orange	8-10 (-11) x (3-) 4-4.5 (-5)	straight to slightly sigmoid	Quercus	Iran	virgariella-like	like H. rubiginosum
Hypoxylon aff. rubiginosum (GUM 1588)	pulvinate	Orange to Apricot	Orange	10-15 x 5-6.5	straight to slightly sigmoid	unknown	Iran	not observed-	like H. rubiginosum
Hypoxylon salicicola	effused	Dark rust to Sepia, Brown Vinaceous	Fulvous to Rust	7.2-9.6 x 3-4.2	straight	Salix , rarely on Fraxinus and Prunus	Northern Europe, USA	nodulisporium-like	Mitorubrinol acetate
Hypoxylon texense	effused to effused-pulvinate	Livid Vinaceous to Brown Vinaceous	Rust to Dark Brick	9.1-10.8(-11.5) x (4.0-)4.5-5.4(-5.7)	straight or slightly sigmoid	unknown	USA	nodulisporium to virgariella-like	Rubiginosin A, mitorubrinol acetate, unknown rubiginosins
Hypoxylon urriesii	effused	Dark Brick	Orange	11-14.5 x 5-6	straight or slightly sigmoid	unknown	Spain (Canary Islands)	unknown	Mitorubrinol acetate, rubiginosin A