Crustomyces juniperi S.L. Liu & L.W. Zhou, sp. nov.

Index Fungorum number: IF 901033; Mycobank number: MB 901033; Facesoffungi number: FoF 14803; Figs. 1, 2

Etymology– juniperi (Lat.) referring to inhabiting Juniperus przewalskii.

Holotype – LWZ 20180905–5 (HMAS).

Diagnosis – Differing from Crustomyces heteromorphus by its thin-walled gloeocystidia with an apical rounded bulb and relatively larger basidiospores (Hallenberg 1980).

Basidiomes resupinate, effused, adnate, crustaceous, up to 8 cm long, 4 cm wide, 200 µm thick. Hymenophore smooth with scattered tubercles, olivaceous buff when fresh, concolorous when dry, cracked. Margin white, thinning out as byssoid, 2 mm wide.

Hyphal system dimitic; generative hyphae with clamp connections, hyaline, thin-walled, moderately branched in subiculum, 2–3 µm in diam; skeletal hyphae hyaline, unbranched or occasionally unbranched, with a narrow to wide lumen, 1.5–2 µm in diam; tissues becoming a claybuff colour in KOH. Gloeocystidia numerous, with an empty content, thin-walled, clavate, with an apical rounded bulb, 20–30×5–7 µm. Dendrohyphidia absent. Basidia subclavate, 4-sterigmate, basal clamp present, 12–18×4.5–6 μm. Basidiospores ellipsoid to subcylindrical, hyaline, smooth, thinwalled, IKI–, CB–, (4–)4.5–5.2(–5.5) × 2.2–3(–3.3) µm, L=4.9 µm, W=2.7 µm, Q=1.8–1.9 (n=90/3).

Material examined – China, Qinghai Province, Menyuan Hui Autonomous County, Qilian Mountains National Nature Reserve, Xianmi Forest Farm, Sigou, on base of living Juniperus przewalskii, 9 September 2018, L.W. Zhou, LWZ 20180905–5 (HMAS, Holotype), LWZ 20180905–3 (HMAS), LWZ 20180905–4 (HMAS).

GenBank numbers – LWZ 20180905–5: ITS=OR557241, LSU = OR527267; LWZ 20180905–3: ITS= OR557242, LSU = OR527268; LWZ 20180905–3: ITS= OR557243, LSU=OR527269.

Notes – Crustomyces juniperi is nested within the Crustomyces clade from a phylogenetic perspective (Fig. 3). Morphologically, C. juniperi resembles C. indecorus by olivaceous buff hymenophore and similar basidiospores; however, the latter species differs in lack of apical schizopapilla on gloeocystidia and presence of dendrohyphidia (Hjortstam 1987b).

Figure 1 – Basidiomes of Crustomyces juniperi (LWZ 20180905–5, holotype). Scale bars: a=1 cm, b=1 mm

Figure 2 – Microscopic structures of Crustomyces juniperi (LWZ 20180905–5, holotype). a A vertical section of basidiomes. b Hyphae from subiculum. c Cystidia. d Basidia. e Basidiospores. Scale bars: 10 μm

Figure 3 – Phylogeny generated by the maximum likelihood algorithm based on combined ITS and nLSU regions is presented along with the bootstrap values and the Bayesian posterior probabilities above 50% and 0.8, respectively, at the nodes. Holotypes are in bold and the newly generated sequences are in blue. Coniophora olivacea FP-104386 and C. puteana FP-105438 were selected as the outgroup taxa