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

Fig. 8

Type.

China, Guizhou Province, Libo County, Maolan Nature Reserve , on dead angiosperm branch, 11 July 2017, He 4792 (BJFC 024311, holotype) .

Etymology.

Refers to the morphological similarity and close phylogenetic relationship with S. renisporum .

Fruiting body.

Basidiomes annual, resupinate, widely effused, closely adnate, inseparable from substrate, membranaceous to coriaceous, first as small patches, later confluent up to 10 cm long, 2.5 cm wide, up to 100 µm thick in section. Hymenophore smooth, pale orange (5A3), light orange (5A4) to greyish orange [5B(5-6)], unchanged in KOH, not cracked; margin thinning out, adnate, fimbriate, white or concolorous with hymenophore surface. Context pale 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, 1.5-2 µm in diam., dextriniod, CB+. Catahymenium composed of skeletal hyphae, basidia and basidioles. Skeletal hyphae abundant, similar to those in the context, but strongly dextrinoid, moderately branched with acute tips, 1.5-2 µm wide at lowest part. Gloeocystidia absent. Basidia subcylindrical, slightly curved, thin-walled, colorless, smooth, with four sterigmata and a basal simple septum, 35-45 × 4.5-6.5 µm; basidioles in shape similar to basidia, but slightly smaller. Basidiospores ellipsoid to reniform, with a distinct apiculus, thin-walled, colorless, smooth, amyloid, CB-, (5.5-) 6-6.5 (-7) × (3.8-) 4-5 (-5.5) µm, L = 6.2 µm, W = 4.4 µm, Q = 1.35-1.45 (n = 60/2).

Additional specimens examined.

China, Anhui Province, Qimen County, Guniujiang Nature Reserve , on dead angiosperm branch, 8 August 2013, He 1720 (BJFC 016187) ; Fujian Province, Wuyishan County, Wuyishan Nature Reserve , on dead angiosperm branch, 3 October 2018, He 5685 (BJFC 026747) & He 5686 (BJFC 026748) ; Guangxi Autonomous Region, Huanjiang County, Mulun National Nature Reserve , on dead angiosperm branch, 10 July 2017, He 4751 (BJFC 024270) ; Guizhou Province, Libo County, Maolan Nature Reserve , on angiosperm tree, 15 June 2016, He 3792 (BJFC 022291) ; Hunan Province, Guzhang County, Gaowangjie National Nature Reserve , on dead angiosperm branch, 3 August 2018, He 5626 (BJFC 026688) ; Jiangxi Province, Ji’an County, Jinggangshan Scenic Spot, on dead angiosperm branch, 11 August 2016, He 4303 (BJFC 023745); Lianping County , Jiulianshan Nature Reserve , on dead Liana branch, 14 August 2016, He 4384 (BJFC 023825); Yifeng County , Guanshan Nature Reserve , on dead angiosperm branch, 9 August 2016, He 4170 (BJFC 023612) & He 4199 (BJFC 023641) .

Notes.

Scytinostroma subrenisporum is characterized by the absence of gloeocystidia and ellipsoid to reniform basidiospores. In the phylogenetic tree (Fig. 1 ), S. subrenisporum is closely related to S. acystidiatum and S. renisporum . Scytinostroma acystidiatum that was recently described from China, is similar to S. subrenisporum by sharing the absence of gloeocystidia but differs in having smaller basidiospores (5.2-6 × 3.5-4.5 µm, measured from the type by the authors, Zhang et al. 2023). Scytinostroma renisporum is similar to S. subrenisporum by sharing ellipsoid to reniform basidiospores but differs by having cylindrical, subclavate or fusoid gloeocystidia and a distribution in Côte d’Ivoire, western Africa ( 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 8. Scytinostroma subrenisporum (from the holotype He 4792) a basidiomes b basidiospores c basidia d skeletal hyphae from hymenium e skeletal hyphae from subiculum. Scale bars: 1 cm (a); 10 µm (b-e).