Hyphoderma niveomarginatum Y. Yang & C.L. Zhao
MycoBank no.: 849948.
Annual, resupinate, adnate, ceraceous, odorless when fresh, and up to 4 cm long, 2 cm wide and 50–200 µm thick. Hymenial surface smooth, pale yellowish when fresh, cream on drying, cracking. Sterile margin white to cream, up to 2 mm wide. Hyphal system: Monomitic; generative hyphae with clamp connections; colorless, thin-walled, frequently branched, interwoven, 2–4 µm in diameter; IKI–, CB–, tissues unchanged in KOH. Hymenium: Cystidia moniliform, with a variable number of constrictions, colorless, thin-walled, 29–55.5 × 5–7 µm; basidia clavate, slightly constricted in the median to somewhat sinuous, often with oil droplets, with four sterigmata and a basal clamp connection, 22–24 × 7–8 µm; basidioles in shape similar to basidia, but slightly smaller. Spores: Basidiospores ellipsoid, colorless, thin-walled, smooth, with irregular oil droplets inside, IKI–, CB–, (6–)7–9(–10) × (3–)3.5–5(–5.5) µm, L = 8.01 µm, W = 4.24 µm, Q = 1.90 (n = 30/1).
Notes: Hyphoderma litschaueri (Burt) J. Erikss. & Å. Strid, H. malenconii (Manjón & G. Moreno) Manjón, G. Moreno & Hjortstam, H. membranaceum, H. moniliforme (P.H.B. Talbot) Manjón, G. Moreno & Hjortstam and H. tropicum Z.Y. Duan & C.L. Zhao are similar to H. niveomarginatum by having the moniliform cystidia. However, H. litschaueri differs in its larger moniliform cystidia (60–100 × 6–8 µm) and larger subcylindrical basidiospores (9–12 µm × 3–4 µm); H. malenconii is separated from H. niveomarginatum by having the dendrohyphidia and larger subcylindrical basidiospores (12–15 × 5.5–10 µm); H. membranaceum is distinct from H. niveomarginatum by tuberculate hymenial surface and larger basidiospores (11–13.5 × 4.5–5.5 µm); H. moniliforme differs in its membranous basidiomata and having the larger moniliform cystidia (85–100 × 6–8 µm); and H. tropicum is distinguished from H. niveomarginatum by having tuberculate hymenial surface and larger basidia (29.5–38 × 4–6 µm) .Hyphoderma floccosum C.L. Zhao & Q.X. Guan, H. mopanshanense C.L. Zhao, H. sinense and H. transiens are similar to H. niveomarginatum by having the ceraceous basidiomata. However, H. floccosum differs in H. niveomarginatum by farinaceous hymenial surface and two types of cystidia: septate cystidia and tubular cystidia; H. mopanshanense is separated from H. niveomarginatum by porulose hymenial surface and wider thick-walled generative hyphae (4–6 µm); H. sinense is distinct from H. niveomarginatum by having two types of cystidia: encrusted cystidia and moniliform cystidia, and cylindrical to allantoid basidiospores; and H. transiens is distinguished from H. niveomarginatum by having odontioid hymenophore, larger cystidia (40–95 × 7–9 µm) and cylindrical basidiospores (8.5–12 × 2.7–4.1).
Fig. 1 Maximum parsimony strict consensus tree illustrating the phylogeny of three new species and related species in within Polyporales based on ITS+nLSU+mt-SSU+RPB1+RPB2 sequences. The branch is labeled with a maximum likelihood lead value greater than 70%, a reduced lead value greater than 50% and a Bayesian posterior probability greater than 0.95. The new species are in bold/green, the holotypes superscript “T”.