Cremeoderma unicum (H.S. Jacks. & Dearden) C.C. Chen & Sheng H. Wu, comb. nov.   Figs. 10, 11

MycoBank number: MB 840749; Index Fungorum number: IF 840749; Facesoffungi number: FoF;

Basionym: Peniophora unica H.S. Jacks. & Dearden, Canadian Journal of Research 27:148. 1949.

= Phlebia cremeoalutacea (Parmasto) K.H. Larss. & Hjortstam, Mycotaxon 5:478. 1977.

Phlebia unica (H.S. Jacks. & Dearden) Ginns, Myco- taxon 21:329. 1984.

Holotype: CANADA. BRITISH COLUMBIA. Cariboo District, Prince George, on Abies lasiocarpa, 27 Aug 1945, P. J. Salisbury, OTB 21416 (V4061).

Description: Basidiocarps annual, effused, adnate, ceraceous or pruinose due to projecting lamprocystidia, thin, 60–150 μm thick in section. Hymenial surface ivory white to cream, becoming buff when old, darkening in KOH, smooth, sparsely cracked in dry; margin concolorous with hymenial surface, thinning out. Hyphal system monomitic; generative hyphae nodose-septate. Subiculum fairly uniform, with com- pact texture, very thin, up to 30 μm thick, often indistinct; hyphae horizontal, colorless, 2–5 μm diam, with 0.4–0.9 μm thick walls, rarely ramified, densely interwoven. Hymenial layer thickening, up to 120 μm thick, with compact texture, subhymenium clearly differentiated from subiculum; hyphae vertical, colorless, 1.5–3 μm diam, thin to up to 0.5 μm thick walls, moderately ramified, densely interwoven, agglutinated, indistinct. Lamprocystidia 40–70 × 10–15 μm (with encrustation), with 0.5–2 μm thick walls, numerous, usually broadly obclavate or subfusiform, sometimes subulate, apically heavily encrusted, ± flexuous, usually with one or more secondary septa at maturity, originating from subiculum or hymenial layer, immersed or projecting for approximately half their lengths. Basidia 12–20 × 3–4 μm, clavate to cylindrical, essentially thin-walled, ± slightly thick-walled at the basal parts, ± flexuous, 4-sterigmate. Basidiospores mostly 3–3.6 × 1.8–2.2 μm, [(2.9–)3–3.6(–4.3) × (1.6–)1.8–2.2(–2.5), L = 3.3 μm, W = 2 μm, Q = 1.69 (n = 35) (Wu 1707-100)], ellipsoid, adaxially flattened, colorless, thin-walled, smooth, sometimes with 1–2 oily drops, inamyloid, nondextrinoid, acyanophilous. For type illustrations, see Jackson and Dearden (1949).

Specimens examined: CHINA. LIAONING PROVINCE: Fushun City, Qingyuan Manchu Autonomous County, Qingyuan Ecological Experiment Station, 41°51ʹ N, 124°56ʹ E, 590 m, on fallen trunk of Pinus sp., 30 Jul 2017, S.H. Wu, Wu 1707-94 (TNM F31542); ibid., Wu 1707-100 (TNM F31546).

Ecology and distribution: On angiosperm (e.g., Alnus) and gymnosperm (e.g., Abies, Pinus) wood in temperate to boreal regions of North Hemisphere [Canada (British Columbia) (type locality), Europe, NE China (Liaoning) and Russia (Siberia)], Jul to Sep (Jackson and Dearden 1949; Eriksson et al. 1981; Bernicchia and Gorjón 2010; Polemis et al. 2019; Volobuev et al. 2019; this study).

Notes: Cremeoderma unicum was first described under Peniophora Cooke from Canada (British Columbia). It is recognized by the ivory white to cream basidiocarps with smooth hymenophore, thickening hymenial layer with compact texture, a monomitic hyphal system with clamped hyphae, clavate to cylindrical basidia (12–20 × 3–4 μm), small basidiospores (3–3.6 × 1.8–2.2 μm), and the pres- ence of broadly obclavate or subfusiform lamprocystidia (40–70 × 10–15 μm). In the present study, this species is transferred to the new genus Cremeoderma which differs from Peniophora by its thin-walled basidia and absence of gloeocystidia. According to Polemis et al. (2019) and Index Fungorum (2020), Phlebia cremeoalutacea is considered as a latter synonym of Cremeoderma unicum. Morphology of our specimens fit well within the protologue of this species (Jackson and Dearden 1949). This species is newly recorded in NE China.

Fig. 10 Basidiocarps of Cremeoderma unicum (Wu 1707-94) in general and detailed views. Bars = 10 mm

Fig. 11 Micromorphologi- cal features of Cremeoderma unicum (drawn from Wu 1707- 100). a Vertical section through basidiocarp. b Hyphae from hymenial layer. c Subicular hyphae. d Lamprocystidia. e Basidia. f Basidiospores