Two new species of Scytinostroma (Russulales, Basidiomycota) in Southwest China

Abstract

Two new species of Scytinostroma viz. S. acystidiatum and S. macrospermum, are described from southwest China. Phylogeny based on ITS + nLSU dataset demonstrates that samples of the two species form two independent lineages and are different in morphology from the existing species of Scytinostroma. Scytinostroma acystidiatum is characterized by resupinate, coriaceous basidiomata with cream to pale yellow hymenophore, a dimitic hyphal structure with generative hyphae bearing simple septa, the absence of cystidia, and amyloid, broadly ellipsoid basidiospores measuring 4.7–7 × 3.5–4.7 μm. Scytinostroma macrospermum is characterized by resupinate, coriaceous basidiomata with cream to straw yellow hymenophore, a dimitic hyphal structure with generative hyphae bearing simple septa, numerous cystidia embedded or projecting from hymenium, and inamyloid, ellipsoid basidiospores measuring 9–11 × 4.5–5.5 μm. The differences between the new species and morphologically similar and phylogenetically related species are discussed.

Species diversity and taxonomy of Scytinostroma sensu stricto (Russulales, Basidiomycota) with descriptions of four new species from China

“…Based on our phylogenetic and morphological study results, we recognized 14 species of Scytinostroma s.s.worldwide. Until now, seven species have been reported from China, all of which were newly described in the present study and other recently published papers ( Liu et al 2018 ; Wang et al 2020 ; Zhang et al 2023 ). It seems that China, especially its temperate areas, is rich in species diversity of Scytinostroma s.s.…”

“…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 ).…”

“… 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 ).…”