Nemania diffusa (Sowerby) S.F. Gray, Nat. Arr. Brit. Pl.: 517 (1821)

Pi, Yin Hui, Long, Si Han, Wu, You Peng, Liu, Li Li, Lin, Yan, Long, Qing De, Kang, Ji Chuan, Kang, Ying Qian, Chang, Chu Rui, Shen, Xiang Chun, Wijayawardene, Nalin N., Zhang, Xu & Li, Qi Rui, 2021, A taxonomic study of Nemania from China, with six new species, MycoKeys 83, pp. 39-67 : 39

Nemania diffusa (Sowerby) S.F. Gray, Nat. Arr. Brit. Pl.: 517 (1821)

Fig. 6

Nemania diffusa Synonyms. Sphaeria diffusa Sowerby, Col. fig. Engl. Fung. Mushr. (London) 3(no. 25): tab. 373, fig. 10 (1802)

Sphaeria unita Fr., Elench. fung. (Greifswald) 2: 67 (1828)

Sphaeria exarata Schwein., Trans. Am. phil. Soc., New Series 4(2): 192 (1832)

Hypoxylon exaratum (Schwein.) Sacc., Syll. fung. (Abellini) 1: 392 (1882)

Ustulina linearis Rehm, Hedwigia 31(6): 310 (1892)

Hypoxylon lilacinofuscum Bres., Fl. Trident. Nov. 2: 43 (1892)

Hypoxylon cohaerens var. brasiliense Starbäck, Bih. K. svenska VetenskAkad. Handl., Afd. 3 27(no. 9): 8 (1901)

Hypoxylon vestitum Petch, Ann. R. bot. Gdns Peradeniya 8: 156 (1924)

Nemania unita (Fr.) Krieglst. & Enderle, Mitteilungsblatt der Arbeitsgemeinschaft Pilzkunde Niederrhein 1: 64 (1989)

Description.

Saprobic on the surface of rotten wood. Sexual morph: Stromata effused-pulvinate, clear outline, ellipsoid or irregularly lobed, occasionally confluent into a larger compound stromata, 2-20 mm long × 2-9 mm wide × 0.5-1 mm thick, with conspicuous perithecial mounds, carbonaceous between the perithecia, surface dark brown or brown; the inter-perithecial tissue blackish, carbonaceous; does not release a coloured pigment in 10% KOH. Perithecia 0.3-0.55 diam. × 0.4-0.7 mm high, subglobose to obovoid. Ostioles finely conic-papillate, black, shiny. Asci 130-250 × 6-10 μm (av. = 170 × 8 μm, n = 30), 8-spored, unitunicate, cylindrical, long-stipitate, the spore-bearing parts 70-90 µm, apically rounded with a J+ apical apparatus, 1.5-2.5 × 2-3.5 µm (av. = 2 × 2.6 µm, n = 30), tubular with a faint upper rim, bluing in Melzer’s Reagent. Ascospores 9.5-13 × 4.5-7 μm (av. = 11 × 5.5 μm, n = 30), unicellular, ellipsoid-inequilateral, with narrowly-rounded ends, smooth, brown to dark brown, with a conspicuous, straight germ slit spore-length to slightly less than spore-length on the ventral side; lacking a sheath and appendage; perispore indehiscent in 10% KOH. Asexual morph: Undetermined.

Culture characteristics.

Colonies grow on PDA at 25 °C for a week reaching a diameter of 5 cm. Colonies are cotton white in colour, flocculent or velvety, dense, circular, radial. On the reverse, white edge, light yellow in the middle. Not sporulating on OA nor on PDA.

Material examined.

China, Guizhou Province, Tongren City, Fanjingshan Nature Reserve (27°53'46.59"N, 108°431'16.29"E, altitude: 1058 m), on dead wood, 14 October 2020, Y.H. Pi, 2020FJS1 (GMB0072, KUN-HKAS 112686), living culture, GMBC0072; CHINA, Yunnan Province, Changning County: Lancang River Nature Reserve (21°54'17.44"N, 107°54'10.05"E, altitude: 1382 m), on dead wood, 1 October 2019, Y.H. Pi, 2019LC008 (GMB0071, KUN-HKAS 112658), living culture, GMBC0071 .

Notes.

The new collection morphologically resembles N. diffusa ( Gray 1821), having effused-pulvinate carbonaceous stromata with inconspicuous perithecial mounds, brown to dark brown ellipsoid-inequilateral ascospores (9.5-13.5 × 5-6 µm), with narrowly-rounded ends and a long germ slit on the ventral side ( Granmo et al. 1999; Ju and Rogers 2002). Fournier et al. (2018) predicted that N. diffusa might be a species complex as it is difficult to identify, based solely on morphology, thus, it should be evaluated after extensive sampling and using DNA-based taxonomy. In phylogenetic analyses of combined ITS, rpb2, β-tubulin and α-actin genes (Fig. 1 ), new collections clearly showed its close kinship with N. diffusa . Only a 2% difference of ITS sequences existed between our strains and N. diffusa (HAST 91020401, authoritative strain). Therefore, we regard the new collection as N. diffusa . Nemania carbonacea Pouzar. can be confused with N. diffusa by having the same dark ascospores and nearly spore-length germ slits. However, N. carbonacea has white, soft stromatal tissue between the perithecia ( Ju and Rogers 2002).

Figures

Figure 1. RAxML tree based on analysis of a combined dataset of ITS, α-actin, rpb 2 and β-tubulin sequences from taxa of Nemania and related genera. Bayesian posterior probability (PP) ≥ 0.90 is marked at the node and the maximum likelihood bootstrap support (BS) values greater than ≥ 75 %; a dash (" - ") indicates a value <0.90 (PP) or <75 % (BS). The strain number is indicated after the species name. The here-studied strains are in bold and new species are indicated in red.

Figure 6. Nemania diffusa (GMB 0072) A specimen B, C stromata on the surface of host D transverse sections of stromata E longitudinal sections of stromata F-H asci with ascospores I pigments in 10 % KOH J ascospore with indehiscent perispore in 10 % KOH K ascus apical apparatus (stained in Melzer's Reagent) L, M ascospores N, O colonies on PDA (N - upper, O - lower). Scale bars: 0.5 mm (C-E); 10 μm (F-H, J-M).