Gliophorus roseus Reschke, C. W. Fisch. & Lotz-Winter 2021, sp. nov.

Gliophorus roseus Reschke, C.W. Fisch. & Lotz-Winter, sp. nov. Figs. 1–3

Mycobank MB838253

Diagnosis: —Differs from other species in the genus by basidiocarps with rose, purplish pink to pale violet colour, viscid pileus, stipe surface and lamellar edges, gelatinized subhymenium, absence of clamp connections and ellipsoid to ovoid basidiospores.

Etymology: —rosa (Latin) = rose, referring to the colour of the basidiocarps.

Type: — PANAMA. Chiriquí Province: near Alto Boquete, Sendero Culebra, N 08°50‘33.9‘‘ W 82°28‘52.1‘‘, 1680 m a.s.l., montane forest dominated by Quercus spp., 17 July 2016, H. Lotz-Winter, O. Koukol, P. Zehnalek PAN612 (holotype UCH 11755, isotype M-0312079)!

Description:—Basidiocarps mycenoid to omphalinoid. Pileus 1.0– 2.5 cm diam., broadly convex to convex umbilicate, with straight and crenate margin, central disk rose (13 A 5) to purplish pink (14 A 3–4), sometimes pale violet (15 A 3) to light lilac (15 A 4–5), paler towards margin, pileal surface viscid, translucently striate at the margin up to 2/3 the radius, hygrophanous reaction not recorded. Lamellae decurrent, arcuate, distant, relatively thick, white to greyish white, with intervenose ridges and hyaline, viscid edge. Stipe 2.8–5.5 × 0.15–0.3 cm, cylindrical, cartilaginous, hollow, greyish magenta (13 B 4–5) to purplish red (13 B 6), sometimes lilac (15 B 3–5), at the apex, pinkish white (13 A 2) and paler towards base, often yellowish white, pale yellow to light yellow (3 A 2–4) at the base, with strongly viscid surface, longitudinally striate when moist, at least at the upper third of the stipe. Basal mycelium indistinct. Odour indistinct, taste not tested.

Basidiospores 5.0–5.6–6.5(–7.5) × 3.5–3.9–4.5 µm, Q = 1.30–1.43–1.60 (n = 60 spores of 2 specimens), broadly ellipsoid to somewhat ovoid, smooth, hyaline, thin-walled. Basidia (18.5–)20–26(–29) × 4.5–6.0 µm, clavate, hyaline, 4-spored, with up to 12(–20) µm long sterigmata. Lamellar edge sterile and gelatinized, formed by cylindrical-flexuous, hyaline, thin-walled ixocheilocystidia, 15–45 × 1.5–2.0(–2.5) µm, sometimes with a few basidia in between. Lamellar trama subregular, formed by inflated cells, (25–)30–75 × (6–)10–20(–30) µm, hyaline, thin-walled. Subhymenium strongly gelatinized. Pileipellis an ixotrichoderm composed of narrow, cylindrical cells, 15–70 × 1.0–2.0 µm, hyaline, thin-walled, in gelatinous matrix. Pileitrama formed by inflated cells, 35–75 × 12.5–30 µm, hyaline, thin-walled. Stipe surface an ixotrichoderm, similar to the pileipellis. Pigment not located. Sometimes with oleiferous hyphae in lamellar trama. Clamp connections absent from all parts of the basidiocarp.

Habitat: —Basidiocarps found in small groups on soil and on rotten wood on the forest floor in Quercus -dominated montane forests between 1700 and 2300 m a.s.l. in Chiriquí, Panama.

Notes: — Gliophorus roseus belongs to the section Glutinosae (Kühner 1926: 53) Lodge & Padamsee in Lodge et al. (2013: 45). It is related to G. laetus (Persoon 1799: 48: Fries 1821: 102) Herink (1959: 84), with a p-distance of 7.9, 8.1, and 8.7% in the ITS (FM 208890, KaiR1035, and FM 208887, respectively, compared to KaiR619). This species was described by Persoon (1799) without notes on the collection localities and original material is not preserved. Persoon worked and collected in Göttingen, Central Germany. A strict concept of G. laetus is used here based on own observations in Germany and Austria, as well as the description given by Boertmann (2010). Molecularly, this concept is in agreement to the concept used by Babos et al. (2011) based on material from eastern Europe. Sequences annotated as G. laetus (‚ Hygrocybe laeta ‘) are located at different positions in our phylogenetic analysis and have p-distances of 4.7, 6.0, 6.6, and 8.3% (HQ604792, HM 020692, HM 240529, FJ 627027) compared to G. roseus (KaiR619).Apparently, this name is used for several species in North America. Lodge et al. (2013) mentioned that many of their material of Hygrophoraceae from North America identified with names of taxa described from Europe did not match material and sequences derived from such from Europe. Their sequences annotated as G. laetus formed three clades. Michal Kuo (http://www.mushroomexpert.com/gliophorus_laetus.html, accessed 14 November 2021) presents under the name G. laetus basidiocarps with umbilicate pileus, which is pale yellowish-greyish, with dark orange centre. However, a note is included that G. laetus in its current use possibly represents a species group.

Gliophorus laetus s. str. differs from G. roseus by a different habitat in moss-rich grassland, dunes and heaths, in average larger, brownish orange basidiocarps, toruloid clamp connections in the hymenium and the pileipellis, and a rubber-like smell. The yellow variety H. laeta var. flava Boertmann (1995: 86) similarly differs from G. roseus. In addition, it is mainly known from alpine and arctic habitats (Boertmann 2010). Gliophorus glutinosus K. Das, D. Chakr. & Vizzini in Chakraborty et al. (2018: 128), described from India, differs by orange basidiocarps. Clamp connections are absent from the pileipellis of this species, but present in the hymenium and subhymenium. Hygrocybe noelokelani Desjardin & Hemmes (1997: 621), not combined to Gliophorus so far, forms basidiocarps with pink pileus, never with violet tones, and a yellow stipe. Two varieties were described for this species: var. noelokelani differs from G. roseus in addition to the somewhat different colours of the basidiocarps by the presence of clamp connections and larger basidiospores. Hygrocybe noelokelani var. defibulata Desjardin & Hemmes (1997: 623) lacks clamp connections, but differs from the type variety as well as G. roseus by ellipsoid basidiospores with higher Q-values of 1.30–1.55–1.90 (Desjardin & Hemmes 1997).

Lodge et al. (2013) stressed the presence of toruloid clamp connections at basidia as one of the characters of species in the sect. Glutinosae, which distinguish them from species in sect. Gliophorus, with regular clamp connections. By the addition of the new species to sect. Glutinosae, but also with regard to Hygrocybe noelokelani var. defibulata, the concept of this section has to be changed to include also species without clamp connections. Nested within the complex of G. laetus, G. roseus and related, unresolved species is a sequence of another specimen collected in Panama (KaiR549). However, the material of this putatively further new species of Gliophorus is insufficient for description.

Additional specimen examined: — PANAMA. Chiriquí Province: near Cerro Punta, Entre Ríos, Montaña Azul, montane forest dominated by Quercus spp., 2300 m a.s.l., N 08°53’42.8’’ W 82°34’58.7’’, 21 June 2017, K. Reschke KaiR619 (UCH9222, M-0312080)!

Specimen examined of Gliophorus laetus: — GERMANY. Rheinland-Pfalz: near Tiefenbach, Landwiesen, nitrogen-poor grassland, 560 m a.s.l., 27 Oct. 2017, E. Wandelt KaiR1035 (M-0312092)!