Scytinostroma beijingensis Yue Li, S.L. Liu & S.H. He, 2023

Li, Yue, Xu, Wei-Qi, Liu, Shi-Liang, Yang, Ning & He, Shuang-Hui, 2023, Species diversity and taxonomy of Scytinostroma sensu stricto (Russulales, Basidiomycota) with descriptions of four new species from China, MycoKeys 98, pp. 133-152 : 133

Scytinostroma beijingensis Yue Li, S.L. Liu & S.H. He sp. nov.

Figs 2 , 3

Type.

China, Beijing, Haidian District, Yangtaishan Forest Park, on dead Pyrus tree, 4 September 2022, He 7768 (BJFC 038905, holotype) .

Etymology.

Refers to the type locality in Beijing, China.

Fruiting body.

Basidiomes annual, resupinate, widely effused, closely adnate, inseparable from substrate, coriaceous, first as small patches, later confluent up to 12 cm long, 4.5 cm wide, up to 200 µm thick in section. Hymenophore smooth, greyish yellow (4B5) to greyish orange (5B5), unchanged in KOH, not cracked or deeply cracked with age; margin thinning out, adnate, fimbriate, white or concolorous with hymenophore surface. Context yellow.

Microscopic structures.

Hyphal system dimitic. Context thickening, compact. Generative hyphae rare, scattered, simple-septate, colorless, thin-walled, 2-3 µm in diam., IKI-, CB-. Skeletal hyphae dominant, colorless to yellow, distinctly thick-walled, moderately branched, 2.5-4 µm in diam., weakly dextriniod, CB+. Catahymenium composed of skeletal hyphae, gloeocystidia, basidia and basidioles. Skeletal hyphae abundant, similar to those in the context, but strongly dextrinoid, frequently dichotomous-branched with acute tips, 1-2 µm wide at lowest part. Gloeocystidia abundant, SA+, with two shapes (1) ventricose, colorless, thin- to slightly thick-walled, mostly embedded, usually with contents, 28-40 × 8-15 µm; (2) subcylindrical, colorless, thin- to slightly thick-walled, mostly projecting beyond the hymenium, usually with contents, 45-65 × 5-7 µm. Basidia subcylindrical, slightly curved, thin-walled, colorless, smooth, with four sterigmata and a basal simple septum, 30-36 × 4.5-6.5 µm; basidioles in shape similar to basidia, but slightly smaller. Basidiospores subglobose, with a distinct apiculus, thin-walled, colorless, smooth, occasionally with oil-drops, amyloid, CB-, 5.5-6.5 (-6.8) × (5-) 5.2-6.2 (-6.5) µm, L = 5.9 µm, W = 5.8 µm, Q = 1.01-1.02 (n = 90/3).

Additional specimens examined.

China, Beijing, Haidian District, Jiufeng Forest Park, on dead Pyrus tree, 26 August 2022, He 7759 (BJFC 038896); Xiangshan Park, on dead Pyrus tree, 16 July 2022, He 7668 (BJFC 038804); Miyun District , Yunmengshan Scenic Spot, on dead Pyrus branch, 7 August 2021, He 7201 (BJFC 036518) & He 7203 (BJFC 036520) & He 7220 (BJFC 036537) .

Notes.

Scytinostroma beijingensis is characterized by having two kinds of gloeocystidia and short branched skeletal hyphae in hymenium, and growing on Pyrus . In the phylogenetic tree (Fig. 1 ), S. beijingensis formed a distinct lineage with strong support values that is sister to the clade comprising S. renisporum Boidin, Lanq. & Gilles, S. subrenisporum , S. acystidiatum Q.Y. Zhang, L.S. Bian & Q. Chen and S. caudisporum Boidin, Lanq. & Gilles. Scytinostroma renisporum differs from S. beijingensis by having cylindrical, subclavate or fusoid gloeocystidia (20-35 × 6-10 µm), ovoid to reniform basidiospores (5.2-6.5 × 3.2-4.8 µm) and a distribution in Côte d’Ivoire, western Africa ( Boidin and Lanquetin 1987). Scytinostroma subrenisporum and S. acystidiatum can be easily distinguished from S. beijingensis by the absence of gloeocystidia ( Zhang et al. 2023). Scytinostroma caudisporum is unique in the group for its distinctly large basidiospores (15-30 × 3-3.5 µm, Boidin and Lanquetin 1987).

Figures

Figure 1. Phylogenetic tree of ML analysis from the ITS 1 - 5.8 S-ITS 2 - nrLSU sequences of Peniophoraceae taxa. Branches are labelled with likelihood bootstrap values (≥ 50 %, first) and Bayesian posterior probabilities (≥ 0.95, second). New species are set in bold and highlighted.

Figure 2. Basidiomes of Scytinostroma beijingensis a He 7768 (BJFC 038905, holotype) b He 7201 (BJFC 036518) c He 7203 (BJFC 036520) d He 7220 (BJFC 036537) e He 7668 (BJFC 038804) f He 7759 (BJFC 038896). Scale bars: 1 cm (a-f).

Figure 3. Microscopic structures of Scytinostroma beijingensis (from the holotype He 7768) a basidiospores b basidia c basidioles d, e gloeocystidia f skeletal hyphae from hymenium g skeletal hyphae from subiculum. Scale bars: 10 µm (a-g).