Parasola setulosa (Berk. & Broome) Redhead, Vilgalys & Hopple, in Redhead, Vilgalys, Moncalvo, Johnson & Hopple, Taxon 50: 236 (2001).

Index Fungorum number: IF 474661; Mycobank number: MB 474661; Facesoffungi number: FoF 12911; Fig. 1

Pileus 20–30 mm in diam, very thin, conical when young, expanding to broadly conical in age; dull, dry, plicato-striate with minute, erect, brown setules; brownish orange (7C6, 6C4) at center, light brown (7D4) to greyish brown (7D3) fading to orange white (5A2), orange grey (5B2) or brownish grey (5C2) at margin. Context very thin, orange grey (5B2). Lamellae free to adnate, moderately crowded with 1–2 series of lamellulae, narrow, orange grey (5B2) finally black, not deliquescent. Stipe 65–90×1.5–2 mm, cylindrical, hollow, central, glabrous, dull, orange grey (5B2).

Basidiospores (8–)9–11 × 7–9 × (6–)7–8 μm, Q =1.13–1.43, q=1.25±0.10 (n=25), lentiform, broadly ovoid to subglobose in frontal view, ellipsoid to broadly ellipsoid in lateral view, smooth, dark brown, moderately thick-walled, germ-pore central, 1.5–2 μm wide. Basidia 17–22×9–11 μm, clavate to broadly clavate, with 4 sterigmata, thin-walled, inamyloid. Lamella-edge heteromorphous with cheilocystidia. Cheilocystidia common, 31–45×16–21 µm, clavate to broadly clavate, hyaline, inamyloid, thin-walled. Pleurocystidia numerous, 26–35×13–25 µm, pyriform to turbinate, hyaline, inamyloid, thin-walled. Pileipellis a non-stratified epithelium of hyaline elements and numerous sclerocystidia, elements 19–40×15–23 µm, clavate to pyriform, hyaline, inamyloid, thin-walled; sclerocystidia setoid 56–190×14–19 µm, lageniform, cylindrical, brown, thick-walled (up to 4 µm).

Habitat and distribution: Solitary on dead wood or the ground, and known from Sri Lanka, Pakistan and Thailand (Redhead et al. 2001; Szarkándi et al. 2017).

Material examined: Thailand, Nakhon Ratchasima Province, Khao Yai National Park, trail to Kong Kaew waterfall, 14°26′22′′ N, 101°22′19′′ E, elevation 744 m, 24 September 2018, N. Wannathes, N. Suwannarach, J. Kumla, S. Khuna, P. Lumyong and S. Lumyong, SDBR-CMUNW1161 (new record for Thailand).

GenBank number: ITS=OP503478.

Notes: Parasola setulosa was classified into Parasola section Auricomi based on morphological and phylogenetic analysis (Fig. 2). This species is characterized by a small to medium-sized coprinoid basidiomes with light brown to greyish brown, radial plicato-striate pileus, moderately crowded lamella, cylindrical, orange grey stipe, lentiform basidiospores with broadly ovoid to subglobose in frontal view with the size of 8–11×7–9×6–8 µm, and central germ pore. The pileipellis is composed of hyaline sclerocystidia with brown thick wall, and presence of cheilo- and pleurocystidia. The Thai specimen matches nicely with the description of type study reported by Nagy et al. (2010) and is in concordance with the note of Pegler (1986). Parasola setulosa is morphologically similar to P. malakandensis, but differs by forming larger basidiospores (13–18×12.5–16×10–13 µm, Hussain et al. 2016).

Figure 1 – Parasola setulosa (SDBR-CMUNW1161). a Habit and basidiome. b Basidiospores. c Basidia. d Cheilocystidia. e Pleurocystidia. f Sclerocystidia. Scale bars: a=10 mm, b–f=10 µm

Figure 2 – Phylogenetic tree derived from maximum likelihood analysis of ITS gene of 23 sequences and the aligned dataset was comprised of 667 characters including gap. The average standard deviation of the split frequencies of the BI analysis was 0.00826. A best scoring RAxML tree was established with a final ML optimization likelihood value of -2987.9897. The matrix had 268 distinct alignment patterns with 9.05% undetermined characters or gaps. Estimated base frequencies were found to be: A=0.2290, C=0.2428, G=0.2255, T=0.3024; substitution rates AC=1.3958, AG=2.6467, AT=2.2120, CG=0.2505, CT=4.1800, GT=1.0000. Coprinopsis pseudomarcescibilis AH33711 HNL501802 and Coprinopsis villosa NL1758 were used as outgroup. Numbers above branches are the bootstrap statistics percentages (left) and Bayesian posterior probabilities (right). Branches with bootstrap values≥70% and PP≥0.90 are shown at each branch. The bar represents 0.1 substitutions per nucleotide position. Type strains are in bold. The newly generated sequences are indicated in blue