Biscogniauxia marginata (Fr.) Pouzar, Česká Mykol. 33: 216 (1979
Saprobic on wood. Sexual morph: Stromata 3.3–7.5 × 2.5–3 mm, superﬁcial, raised-discoid, globose, surface black, with concave surface, distinct raised margins, outer dehiscing layer, woody layer immediately beneath the stromal surface and between ascomata with carbonaceous tissue encasing each ostiole, tissue beneath ascomata comprising with host tissue, carbonaceous. Ascomata 0.2–0.4 × 0.5–1 mm, immersed, obovoid, thick-walled light brown inner cell layers, outer cell layers carbonaceous. Ostioles slightly umbilicate with punctuate openings,with white residues. Paraphyses 3–5 μm wide, numerous, between asci, ﬁlamentous, septate. Asci 160–200 × 9–12 μm, 8-spored, unitunicate, cylindrical, pedicellate, with J+ apical ring bluing in Melzer’s reagent, discoid, 0.5–0.7 × 1.5–2 μm. Ascospores 13–17 × 10–13 μm, uniseriate, unicellular, globose-subglobose, with broadly rounded ends, dark brown to black, with sigmoid germ slit up to spore-length, smooth. Asexual morph: Sporulating regions scattered over entire middle part of the colony,brown vinaceous(84) after 4 weeks. Conidiogenous structure nodulisporium-like, arising from roughened masses of hyphae, hyaline. Conidiogenous cells 50–60 × 4–5 μm, hyaline, ﬁnely roughened. Conidia 6–8 × 3.5–4 μm, hyaline, smooth to ﬁnely roughened, ellipsoid, unicellular.
Culture characteristics: Colonies on OA (Oat Agar medium) at 25–28 ºC reaching the edge of 6 cm dish in 14 days, whitish, velvety to felty, azonate, with diffuse margins, reverse at ﬁrst straw (46), becoming dark brown colonies after 3–4 weeks.
Material examined: FRANCE, on wood, 16 Apr. 2012, A. Gardiennet, AXL 001 (MFLU 13–0099, living culture, MFLUCC 12–0740, ICMP).
Notes: Biscogniauxia marginata and B. baileyi (Berk. & Broome ex Cooke) Kuntze are similar as they both have subglobose ascospores, which is not common to many other Biscogniauxia species. However, B. marginata has globose-subglobose ascospores with a sigmoidal germ slit while the latter has a straight germ slit. We observed a nodulosporium-like asexual morph for B. marginata. Callan and Rogers (1986), Petrini and Mu ¨ller (1986) and Ju and Rogers (1996) also identiﬁed the asexual morph as nodulisporium-like.
Fig. 1 Biscogniauxia marginata (MFLU 13–0099). a Habitat. b, c Concave stromal surface in with carbonaceous tissue. d Cross section of stromata showing the ascoma and ostiole. e J+ apical ring in Melzer’s reagent. f Mature ascus in Cotton Blue Lactophenol. g Ascus in Cotton Blue Lactophenol showing sigmoid germ slit. h Paraphyses in water. i Ascospores in water. j Germinating spore from MEA. Scale bars b, c = 5 mm, d = 02 mm, e–h = 20 μm, i, j = 15 μm.
Fig. 2 Biscogniauxia marginata in MEA after 2 weeks. a From above. b From below. c Conidiogenous structure. d Conidiogenous cells. e, f Conidia. Scale bars c, d = 30 μm, e, f =5 μm.