Resupinatus porrigens J.Z. Xu & Yu Li, sp. nov.
Index Fungorum number: IF 901101; Mycobank number: MB 901101; Fig. 1
Etymology – “porrigens” refers to the macroscopic morphological features resembling a conch.
Holotype – HMJU 261.
Basidiomes small, sessile, mostly lateral or dorsal, fleshy. Pileus up to 7 mm in diam, surface beige (7F3), red-brown (8E4) toward the margin, convex, orbicular when young, becoming conchate, flabelliform, discoid when mature, smooth; margin incurved, entire to variously cracked or wavy. Hymenophore lamella-like with radiating folds, separated by 4–6 series of lamellulae interconnected, reddish brown (8E5). Basidiospores (3.8–)4.1–4.6(–4.9) × (3.0–)3.3–4.0(–4.3) μm ( x=4.3 × 3.6 μm, n=20), Q=1.04–1.40, Qm=1.19, globose to subglobose, with a small hilar appendage, faint bump, multiguttulate, thin-walled, hyaline. Basidia (17.2–)19.0–25.1(–27.4)×5 .0–6.9 μm (x=22×5.9 μm, n=20), narrowly clavate, tetrasporic, sterigmata up to 3.2 μm long, with numerous oil drops. Cheilocystidia 2.1–4.2 μm wide, clavate to subcoralloid, with 1 or 2 branches, hyaline. Divergent hymenophoral trama. Pileipellis intricately interwoven layer of hyphae 1.6–4.4 μm in diam, thin-walled, compact. Clamp connections are present in all hyphae.
Material examined – China, Qinghai Province, Halihatu National Forest Park, on the rotting coniferous trunk, 7 August 2018, Jize Xu, HMJU 261 (holotype); Qinghai Province, Halihatu National Forest Park, 22 July 2021, HMJU 3836.
GenBank numbers – HMJU 261: ITS = OP727724, LSU = OP727807; HMJU 3836: ITS = OP729420, LSU=OP727819.
Notes – The main characteristic of Resupinatus porrigens is the lateral or dorsal, beige pileus with conchate, flabelliform, discoid, entire to variously cracked or wavy form, and reddish brown hymenium, lamella-like with radiating folds, separated by 4–6 series of lamellulae interconnected. The pileus is beige similar to Resupinatus merulioides, but R. merulioides is differentiated by taupe and alveolate hymenium (Redhead and Nagasawa 1987). Resupinatus odoratus resemblance R. porrigens due to cracked edge, but R. odoratus has a sticky and striate pileus with a beige and poroid hymenium when young (Bijeesh 2020). Resupinatus vinosolividus is distinguished from R. porrigens by lamellulae, but R. vinosolividus having the livid vinaceus and floccose pileus with alveolate and livid hymenium (Cooper 2012). Resupinatus porrigens, R. applicatus and R. trichotis are lamella-like of hymenium distributed in China, but R. porrigens has thickened lamella, similar to Cantharellus, and the relationships were not closed in the phylogenetic analysis tree (Fig. 2).
Figure 1 – Resupinatus porrigens (HMJU 261, holotype). a, b Habitat and basidiomes c Basidia d Basidiospores e Cheilocystidia f–g SEM images of basidiospores. Scale bars: a, b=10 μm, c=5 μm, d=2 μm, e=5 μm, f=1 μm, g=2 μm
Figure 2 – Bayesian and ML phylogenetic trees of Resupinatus based on ITS and LSU sequences, nodes were annotated if supported by>0.95 Bayesian posterior probability (PP) (left) or>80% ML bootstrap proportions (BP) (right) values. Newly generated sequences are shown in bold black. The ex-types are in bold; the new isolates are in blue