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

Figs 4 , 5

Type.

China, Beijing, Mentougou District, Xiaolongmen Forest Park, on dead angiosperm branch, 28 August 2020, He 6911 (BJFC 033860, holotype) .

Etymology.

Named to honor Dr. Jacques Boidin (Lyon, France) who contributed much to the taxonomy of Scytinostroma .

Fruiting body.

Basidiomes annual, resupinate, widely effused, closely adnate, inseparable from substrate, membranaceous to coriaceous, first as small patches, later confluent up to 9 cm long, 3.5 cm wide, up to 300 µm thick in section. Hymenophore smooth, pale yellow (4A3), greyish yellow (4B4) to greyish orange [5B(3-4)], 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, slightly thick-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, gloeocystidia, basidia and basidioles. Skeletal hyphae abundant, similar to those in the context, but strongly dextrinoid, dichotomous-branched with acute tips, 1-1.5 µm wide at lowest part. Gloeocystidia abundant, subcylindrical to subfusiform, colorless, slightly thick-walled, with or without contents, weakly SA+, 50-80 × 5-10 µm. Basidia subclavate to subcylindrical, thin-walled, colorless, smooth, with four sterigmata and a basal simple septum, 30-50 × 4-7 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-, (4.5-) 5-5.5 (-6.5) × (4-) 4.5-5.5 (-6.2) µm, L = 5.1 µm, W = 5.0 µm, Q = 1.02-1.04 (n = 60/2).

Additional specimens examined.

China, Beijing, Mentougou District, Lingshan Scenic Spot , on dead angiosperm branch, 10 April 2022, He 7465a (BJFC 038600) & He 7465b (BJFC 038601) ; Gansu Province, Tianshui County, Dangchuan Forest Farm, on dead Quercus tree, 9 August 2015, He 2499 (BJFC 020952) ; Hebei Province, Xinglong County, Wulingshan Nature Reserve , on dead angiosperm branch, 2 September 2017, He 4985 (BJFC 024503) ; Jilin Province, Jiaohe County, forestry experimental area, on fallen angiosperm trunk, 3 September 2017, He 5138 (BJFC 024656) .

Notes.

Scytinostroma boidinii is characterized by the relatively long gloeocystidia and subglobose basidiospores. In the phylogenetic tree (Fig. 1 ), S. boidinii formed a distinct lineage sister to S. alutum Lanq., which differs in having cracked basidiomes, slightly larger basidiospores (5-7 × 5-7.5 µm) and a distribution in France, Spain and Pakistan ( Boidin and Lanquetin 1987; Bernicchia and Gorjón 2010). Scytinostroma yunnanense C.L. Zhao from Yunnan Province, southwestern China, has similar-sized basidiospores (4.5-5.5 × 4.2-5.2 µm) to S. boidinii , but differs in having white to cream hymenophore, smaller gloeocystidia (28-33 × 4-5 µm) and smaller basidia (21-28 × 4-5.5 µm, Wang et al. 2020).

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 4. Basidiomes of Scytinostroma boidinii a He 6911 (BJFC 033860, holotype) b He 4985 (BJFC 024503) c He 7465 a (BJFC 038600) d He 7465 b (BJFC 038601). Scale bars: 1 cm (a-d).

Figure 5. Microscopic structures of Scytinostroma boidinii (from the holotype He 6911) a basidiospores b basidia c basidioles d gloeocystidia e skeletal hyphae from hymenium f skeletal hyphae from subiculum. Scale bars: 10 µm (a-f).