Kneiffiella pseudoalutacea Xue W. Wang & L.W. Zhou, sp. nov.

Index Fungorum number: IF 900290; Mycobank number: MB 900290; Facesoffungi number: FoF 14053; Figs. 1, 2

Etymology – pseudoalutacea (Lat.) referring to the similarity to Kneiffiella alutacea.

Holotype – LWZ 20210625-5b (HMAS).

Diagnosis – Characterized by annual, resupinate, adnate basidiomes, smooth to slightly tuberculate, lime to cream hymenophore, a monomitic hyphal system, subcylindrical cystidia, subclavate basidia and narrowly allantoid basidiospores.

Basidiomes annual, resupinate, adnate, membranous, cracked and brittle when dry, without odour. Hymenophore smooth to slightly tuberculate, lime to cream. Margin concolorous with subiculum, thinning out, indeterminate.

Hyphal system monomitic; generative hyphae in trama with clamp connections, hyaline, slightly thick-walled with a wide lumen, parallel, 3.5–4.5 μm in diam; generative hyphae in subhymenium with clamp connections, hyaline, thin-walled to slightly thick-walled with a wide lumen, usually dichotomous branching, 3–4 μm in diam. Cystidia subcylindrical, smooth, thin-walled, 35–50×5.5–6 μm, projecting up to 10 µm beyond the hymenial surface. Basidia subclavate with a median constriction, 12–15×4–4.7 μm, with a clamp connection at the base; basidioles similar in shape to basidia, but smaller. Basidiospores narrowly allantoid, hyaline, smooth, thin-walled, IKI–, CB–, (6–)6.1–6.8(–7) × 1.3–2.2(–2.3) μm, L = 6.38 μm, W=1.78 μm, Q=3.58 (30/1).

Material examined – China, Jiangxi Province, Jiujiang, Lushan Mountains, on fallen branch of gymnosperm, 25 June 2021, L.W. Zhou, LWZ 20210625-5b (HMAS, holotype).

GenBank numbers – ITS=OQ540895; LSU=OQ540853.

Note: – Kneiffiella pseudoalutacea is phylogenetically close to K. alutacea (Fig. 3). Morphologically, these two species share a monomitic hyphal system, thin-walled cylindrical to subcylindrical cystidia, subclavate basidia and allantoid basidiospores; however, K. alutacea differs in the presence of creamish white to ochraceous, odontioid to coralloid hymenophore and longer cystidia (50–75 µm in length, Eriksson and Ryvarden 1976).

Figure 1 – Basidiomes of Kneiffiella pseudoalutacea (LWZ 20210625-5b, holotype)

Figure 2 – Microscopic structures of Kneiffiella pseudoalutacea (LWZ 20210625-5b, holotype). a Basidiospores. b Basidia and basidioles. c Cystidia. d Tramal hyphae. e Section in hymenium. Scale bars: a–e=10 μm

Figure 3 – Phylogram generated by the maximum likelihood algorithm based on combined nLSU and ITS sequence data is presented along with the bootstrap values and the Bayesian posterior probabilities above 50% and 0.8, respectively, at the nodes. Type specimens are in bold and the isolates of new species characterized are in blue