Pluteus lauracearum Kaygusuz, Ševčíková & Justo, 2021

Kaygusuz, Oğuzhan, Justo, Alfredo, Knudsen, Henning, Ševčíková, Hana & Türkekul, Ibrahim, 2021, Pluteus lauracearum (Agaricales, Basidiomycota), a new species of Pluteus sect. Hispidoderma from thermophilic Laurus forests, Phytotaxa 523 (2), pp. 126-140 : 130-132

Pluteus lauracearum Kaygusuz, Ševčíková & Justo , sp. nov. ( Figs. 3‒6 )

MycoBank: —MB839367

Type: — TURKEY. Aydın Province: Kuşadası District, Güzelçamlı Village, around Dilek Peninsula National Park , on well-rotten branches of Laurus nobilis , at 37°42′40.5″N, 27°12′57.8″E, alt. 50 m, 03 April 2011, leg. O . Kaygusuz , OKA-TR1009 (holotype GUL!, ITS MW 600395 ) .

Diagnosis:— Pluteus lauracearum is morphologically similar to P. semibulbosus , differing in the brown pileus centre with a distinctly granulose surface, the slightly thick-walled pleurocystidia, the distinctive habitat in Laurus woods, and the ITS sequence.

Etymology: —Name refers to Laurus , the plant host genus on which this species was found.

Description:—Pileus 5–20 mm in diameter, at first hemispherical, becoming plano-convex, finally expanded, with a slightly depressed centre, without umbo; surface pruinose or distinctly granulose at centre, shiny or not; dark brown at centre and light to pale brown towards the margin, sometimes pale brownish to whitish, always becoming paler from the centre towards the margin; hygrophanous, margin translucently striate up to half of the pileus radius, persistently white to whitish. Lamellae free, moderately crowded to crowded, up to 1 mm broad, thin, ventricose, at first white, becoming pale pinkish, with flocculose, concolorous or whitish edges, with 1–2 lengths of lamellulae. Stipe 9.0‒36 × 0.6‒2.5 mm, central, cylindrical or somewhat broadened towards the base, with the basal part bulbous or discoid, innately longitudinally fibrillose, surface white to whitish cream, indistinctly pruinose, with whitish strigose mycelium at the base, sometimes very pale brownish only at the base, smooth and fragile. Context in stipe and pileus white to whitish, thin, shiny, sometimes hygrophanous. Smell and taste indistinct.

Basidiospores (6.4‒)6.7‒7.8(‒8.5) × (5.1‒)5.6‒6.5(‒6.9) μm, L m × W m = 7.3 × 6.0 μm, Q = (1.1‒)1.3(‒1.5), Q m = 1.2, broadly ellipsoid to rarely ellipsoid or subglobose, guttulate, hyaline in KOH, smooth, thick-walled, inamyloid. Basidia (17.0‒)19.5‒33(‒33.5) × 7.0‒11.5(‒12.0) μm, broadly clavate to subfusiform or subutriform, 4-spored, rarely 2- or 3-spored, hyaline in KOH, with or without granular contents, thin-walled. Pleurocystidia (35‒)56‒85(‒95) × (9.0‒)11.5‒21.5(‒25) μm, scarce to moderately abundant, predominantly narrowly fusiform to lageniform with a long narrow neck and with a subcapitate to capitate apex, narrow at base, less frequently fusiform to broadly fusiform, sometimes with a pedicel up to 18.0 μm long, slightly thick-walled up to 1.8 μm thick, sometimes thin-walled, hyaline in KOH, pigment and vacuoles absent. Lamellar margin sterile. Cheilocystidia (25‒)45‒87(‒95) × (9.8‒)12.0‒26.5(‒ 32) μm, abundant, most frequently narrowly clavate to clavate or subfusiform, a few cylindrical to narrowly utriform, narrowly to broadly lageniform or pedunculate, thin-walled, hyaline in KOH, pigment and vacuoles absent. Pileipellis a trichoderm composed of suberect to erect, narrowly clavate to clavate or narrowly fusiform, and cylindrical terminal elements, with rounded apex or subutriform, (46‒)58.5‒110(‒135) × (10.0‒)12.7‒23.5(‒28.5) μm, septate, hyaline or with very pale brown intracellular pigment especially at centre of pileus, thin-walled. Caulocystidia in the upper part of the stipe, (29‒)45‒92.5(‒106) × (8.0‒)10.0‒17.0(‒21.0) μm, numerous, often grouped in clusters, mostly narrowly clavate to narrowly fusiform, fusiform or cylindrical; in the lower part of the stipe, (28.5‒)47.5‒82(‒88.5) × (7.2‒)9.5‒ 22.5(‒26.0) μm, numerous fusiform to narrowly conical to lageniform, sometimes lecythiform or clavate in clusters, often with a short to long neck and with a mucronate to rostrate or an acuminate to acute apex, sometimes inflated at the middle part, septate, hyaline in KOH, thin-walled. Stipitipellis a cutis of 5.0–13.0(–18.0) μm wide hyphae, made up of cylindrical, colorless, hyaline in KOH, and thin-walled hyphae. Clamp connections absent in all parts examined.

Habit, habitat and distribution: —Solitary or in small scattered groups, on well-rotten branches or buried wood of Laurus nobilis , which is widely distributed along the coastal zones of the Aegean Region (Western Anatolia), and on decaying branch of deciduous wood, probably Laurus sp. , on Laurisilva ( Laurus Forest ) with scarce Quercus . So far it is only known from Turkey and Madeira Islands ( Portugal).

Additional specimens examined: — TURKEY. Aydın Province: Kuşadası District, Güzelçamlı, around Dilek Peninsula National Park , on well-decayed branches of Laurus nobilis , at 37°42′40.4″N, 27°12′47.8″E, alt. 58 m, 27 March 2013, leg. O . Kaygusuz ( OKA-TR1050 ; ITS MW 600396 ); ibid., on decayed wood of L. nobilis , at 37°42′40.8″N, 27°12′49.8″E, alt. 65 m, 15 March 2016, leg. O . Kaygusuz ( OKA-TR1515 ; ITS MW 600397 ); ibid., on L. nobilis , at 37°42′40.8″N, 27°12′55.8″E, alt. 62 m, 3 March 2020, leg. O . Kaygusuz ( OKA-TR1723 ; ITS MW 600398 ) . Muğla Province, Dalyan District , on decayed wood of L. nobilis , at 36°49’42.15”N, 28°38’15.5”E, alt. 10 m, 12 March 2015, leg. O . Kaygusuz (OKA-146; ITS MG 544922 as P. semibulbosus ) . PORTUGAL. Madeira Island: Ribeiro Frio District, around Levada do Furado , on decaying wood of Laurisilva associated with Quercus , at about 32°44’10”N, 16°51’52”W, alt., at two sites distant 20 m, 23 September 2015, leg. H . Ševčíková (HS15-9-23-4, BRNM 828877 ; ITS MW 889881 ) .

Figures

FIGURE 3. Pluteus lauracearum: fresh basidiomata growing in its natural habitat at Dilek Peninsula National Park (Kuşadası, Turkey). a, c, e. Collection OKA-TR1009 (holotype). b, d, f. Collection OKA-TR1050. g, h. Collection OKA-TR1723. Photos: O. Kaygusuz. Scale bars: 5 mm.

FIGURE 4. Pluteus lauracearum (collection HS15-9-23-4): fresh basidioma growing in its natural habitat at endemic Laurisilva forest (Portugal). a–b. Basidioma. Photos: H. Ševčíková. Scale bars: 5 mm.

FIGURE 5. Microscopic features of Pluteus lauracearum (OKA-TR1009; holotype): a. Basidiospores. b. Basidia. c. Pleurocystidia. d. Cheilocystidia. Scale bars: 10 μm.

FIGURE 6. Microscopic features of Pluteus lauracearum (OKA-TR1009; holotype): a. Pileipellis elements. b. Caulocystidia in upper part of stipe. c. Caulocystidia in base of stipe. Scale bars: 10 μm.