Umbellus sinensis

Umbellus sinensis Xue W. Wang & L.W. Zhou 2023, in Wang, & Zhou, Journal of Fungi, 10(1), 22 (2023).

Etymology: sinensis (Lat.), referring to the type locality China.

Diagnosis: Distinguished by smooth to grandinioid hymenophoral surface and not flattened, broadly ellipsoid basidiospores with a tiny apiculus. Basidiomes annual, adnate and resupinate, easily cracked when dry. Hymenophore smooth to grandinioid, white to cream; margin thinning out, arachnoid, paler than subiculum. Hyphal system monomitic; generative hyphae with clamp connections. Subicular hyphae hyaline, branched, 4–5.5 μm in diam, thin- to slightly thick-walled. Subhymenial hyphae hyaline, thin-walled, 4–4.5 μm in diam. Cystidia dimorphic: (1) arising from subhymenium and strongly projecting out for the greater part of their length, cylindrical, 45–60 × 6.5–9.5 μm, unevenly thick-walled with a lumen up to 4 μm, with a narrow or wide lumen, rooted at the base, gradually tapering, broadly rounded at the apex and covered by a large umbrella-shaped crystalline head of up to 9 μm in diam, set with 10–12 deflexed and radiating ridges terminating in acute spines; (2) originating laterally on subicular hyphae with the same shape as those arising from subhymenium but smaller in size, 15–25 × 1.5–3.5 μm, with an umbrella-shaped crystalline head of 5–6 μm in diam, stalk slightly thick-walled. Basidia subclavate to barrel-shaped, with a basal clamp connection and four sterigmata, 15–17 × 5–7 μm. Basidiospores broadly ellipsoid, hyaline, smooth, thin-walled, inamyloid, indextrinoid, acyanophilous, 4.5–5(–5.1) × (3.2–)3.3–4.2(–4.3) μm, L = 4.80 μm, W = 3.47 μm, Q = 1.37–1.38 (n = 60/2).

Index Fungorum Number: IF851429

Figure 1. Phylogenetic position of Umbellaceae (marked with a red star) within Hymenochaetales, inferred from the combined dataset of nrSSU, ITS, nrLSU, mtSSU, and RPB2 regions. The topology has been generated using the maximum likelihood algorithm. The maximum likelihood bootstrap values and the Bayesian posterior probability values above 50% and 0.8, respectively are shown at the nodes. Boletopsis leucomelaena and Thelephora ganbajun from Thelephorales have been selected as outgroup taxa.