Anthostomella formosa Kirschst., Verh. bot. Ver. Prov. Brandenb. 66: 29 (1924)

Index Fungorum number: IF 265208; Facesoffungi number: FoF 00317

Isotype – W 19885

Saprobic on twigs, Sexual morph: Ascomata: immersed, solitary or clustered, visible as blackened, slightly raised, conical areas, ostiolar canal central, with periphyses, in cross-section 250–340 µm diam. and 260–300 µm high ( = 325 × 275 µm, n = 10), globose. Peridium 15–20 µm diam. ( = 16.5 µm, n = 10), with several cell layers, outwardly comprising thick-walled, yellowish-brown cells of textura irregularis and inwardly comprising thin-walled, hyaline cells of textura prismatica. Paraphyses 2.5–4 µm diam. ( = 3.5 µm), slightly longer than asci, filamentous, septate, numerous, embedded in a gelatinous matrix. Asci 105–145 × 7–10.5 µm ( = 125 × 8.8 µm, n = 30), 8-spored, unitunicate, cylindrical, short-pedicellate, apically rounded, apical apparatus not observed. Ascospores 11–15 × 5.2–6 µm ( = 14.5 × 5.5 µm, n = 40), uniseriate, arranged within compartments in asci, inequilaterally oblong-ellipsoidal, dark brown, smooth-walled, unicellular with hyaline dwarf cell at base, larger cell bark brown, 1.5–2 µm ( = 1.7 µm, n = 40) long, germ slit, full length, straight. Asexual morph: Undetermined.

Cultural characteristics – Colonies on Difco OA at 25–27 oC reaching the edge of 4 cm Petri-dish in 8 weeks, at first whitish, felty, azonate, with diffuse margins, reverse turning citrine (13).

Specimen examined – ITALY, Province of Forlì-Cesena, Porcentico-Predappio, on needle of Pinus sylvestris L. (Pinaceae), 23 November 2013, E. Camporesi IT1535 (MFLU 14-0232, PDD, reference specimen designated here), living cultures, MFLUCC 14-0170 .

Notes – We designate our collection of Anthostomella formosa as a reference specimen (sensu Ariyawansa et al. 2014) in order to stabilize the classification of Anthostomella sensu stricto and also the name. Anthostomella formosa is phylogenetically close to A. obesa and differs from the new taxon in having a hyaline dwarf cell in ascospores and lacking an apical apparatus. Anthostomella obesa has more broader asci than A. formosa.

Fig. 1 Anthostomella formosa (MFLU 14-0232). a Habitat on wood. b Ascoma in wood. c Cross section of an ascoma. d Paraphyses e Peridium. f Asci in Melzer’s reagent. g Immature asci in water with six ascospores. h Mature asci in water with eight ascospores. i Asci in water showing the straight germ slit. j, k Mature ascospores in water with a hyaline basal dwarf cell. Scale bars: a, b = 500 μm, c = 100 μm, d, e = 50 μm, f–j = 10 μm.

Fig 1 Anthostomella formosa