Leucoagaricus pseudopilatianus Migl., Rocabruna & Tabarés, Revta Catal. Micol.

Forin, Niccolò, Tatti, Alessia, Vizzini, Alfredo, Coppola, Alessandra & Migliozzi, Vincenzo, 2022, Leucoagaricus cupresseoides (Agaricaceae), a new species in sect. Piloselli and L. aurantiovergens and L. pseudopilatianus redescribed from Italy, Phytotaxa 536 (2), pp. 126-140 : 136-138

Leucoagaricus pseudopilatianus Migl., Rocabruna & Tabarés, Revta Catal. Micol. 23: 67 (2001) Fig. 7

= Leucoagaricus pseudopilatianus var. rugosoreticulatus Migl. & Resta, Micol. Veg. Medit. 15: 129 (2000)

The description is based on the Italian collections, the isotype of L. pseudopilatianus and the holotype of L. pseudopilatianus var. rugosoreticulatus ( Fig. 7 ).

Description:— Pileus large, 90–100 mm diam, at first subglobose, then convex to plane, slightly umbonate, without velar remnants; vinaceous brown, brown, reddish brown, brownish grey in the disc area, becoming bright red to brown after bruising; surface with tendency to crack radially; context creamy white; margins moderately appendiculate. Lamellae free, crowded, rarely interspersed with white lamellulae; white, creamy white, creamy vinaceous, turning orange to brownish red after bruising; edges entire and concolorous with faces. Stipe 90–120 × 10–20 mm, hollow, cylindrical, broadening towards the base, without a basal bulb, white, turning vinaceous red after bruising, fibrillose. Annulus located at the upper half of the stipe, persistent, ascending, white. Context white. Smell not distinctive, fungoid. Pileus , lamellae and stipe turn dark brown to black in dried material.

Basidiospores (6.8–) 7.7– 8.7 –9.8 (–11.8) × (4.2–) 4.7– 5.2 –5.8 (–6.9) μm, Q= (1.4–) 1.5– 1.7 –1.8 (–2.2) [200, 4, 4], hyaline, smooth, with an obvious hilar appendage, without a germ-pore, subglobose to ellipsoid, sub-amygdaliform in side-view, dextrinoid, metachromatic in Cresyl Blue. Basidia 24–29 x 6–10 μm, four-spored, clavate. Hymenophoral trama regular, made up by colorless, cylindrical, up to 18 μm wide hyphae. Cheilocystidia (20) 27–65 × 10–16 (20) μm, abundant, cylindrical, clavate-cylindrical with rounded apex, not pedicellate, with brownish intracellular pigments and necropigments in dried specimens treated with ammonia. Pleurocystidia not observed. Pileus covering trichodermal, consisting of terminal elements 80–260 (300) × 10–20 (24) μm, cylindrical with rounded apex, with pigments both parietal and intracellular, presence of brownish necropigments in dried specimens with ammonia; at the base there are similar elements of diameter but of shorter length 40–70 × 10–15 μm; preterminal elements with parietal pigments. Clamp connections absent.

Macrochemical reactions:—Lamellae and pileus surface become dark green when treated with NH 4 OH while stipe surface becomes emerald green.

Habitat and distribution:—Terrestrial, growing in small groups; it occurs in Italy and Greece under Cupressus sempervirens , and in Spain under sequoia and Abies masjoani .

Material examined:— ITALY. Rome, Macchia Grande , on sandy soil under Quercus ilex , 16 October 1996; V. Migliozzi, TR MV41/96, holotype of Leucoagaricus pseudopilatianus var. rugosoreticulatus, GenBank accession OK235671 (nrITS) ; ITALY. Sardinia, Teulada, under Quercus ilex , 16 November 2018, A. Tatti, CAG P.12-9/8.40, GenBank accession OM327668 (nrITS); ITALY. Pisa, Marina di Vecchiano, on sandy soil, under Cupressus sempervirens , 16 November 2019, V. Migliozzi, MV161119 LeuPil002 (GenBank accession MT416133 ); ITALY. Pisa, Vecchiano, under Cupressus sempervirens and Quercus ilex , 22 November 2019, M. Raumi, MVBB27, GenBank accession OM327667 (nrITS); ITALY. Rome, Castel di Guido, under Cupressus sempervirens , 03 December 2019, V. Migliozzi, MVBB26, GenBank accession OM327666 (nrITS) ITALY. Ladispoli, Palo Laziale, on sandy soil under Cupressus sempervirens , 4 January 2020, V. Migliozzi, MV LeuPil023, GenBank accession OK235669 (nrITS); SPAIN. Osona, Espinelves , on acid soil, under an old sequoia and Abies masjoani , 29 September 1999, A. Rocabruna and M. Tabarés, PAD H0061558, isotype of Leucoagaricus pseudopilatianus (holotype SCM 3904B ), GenBank accession OK235668 (nrITS) .

Discussion:—The types of L. pseudopilatianus and L. pseudopilatianus var. rugosoreticulatus group together in the highly supported L. pseudopilatianus clade (MLB = 100, BPP = 1) ( Fig 1 ). Dimensions and morphology of spores, basidia and cheilocystidia observed in the isotypes L. pseudopilatianus ((7.1–) 7.4– 8.7 –9.9 (–11.8) × (4.5–) 4.7– 5.2 –5.7 (–6.3) μm, Q= (1.4–) 1.5– 1.7 –1.8 (–2.2); 24–29 × 7–8 μm; 28–35 × 9–13 μm) and in the holotype of L. pseudopilatianus var. rugosoreticulatus ((6.8–) 7.2– 7.8 –8.5 (–9.7) × (4.2) 4.4– 4.8 –5.1 (–5.7) μm, Q= (1.4–) 1.5– 1.6 –1.8 (–2); 23–29 × 6–8 μm; 27–32 × 10–13 μm) are similar to each other and with those reported in the original descriptions ( Migliozzi & Resta 2001; Migliozzi et al. 2001). Considering the high morphological similarity between the two taxa and the high sequence identity (99% sequence identity between OK235668 and OK235671 ) we place the variety in synonymy with Leucoagaricus pseudopilatianus . The L. pseudopilatianus clade includes the nrITS sequence of a L. cf. cupresseus specimen collected in Greece ( AY243632 ) ( Fig. 1 ). This specimen was also included in the phylogenetic analysis performed by Vellinga (2010). In the phylogram reported in her work, it occupies an isolated position sister to the group consisting of the nrITS sequences of Californian L. cupresseus suggesting a misidentification of the specimen. Nevertheless, Vellinga did not discuss this specimen, as in the case of L. cf. cupresseus from France (Vellinga 2010). In Salom et al. (2021b), the nrITS sequence obtained from the holotype of L. pseudopilatianus ( MZ230525 not yet available in GenBank) clusters in a clade comprising L. cf. cupresseus from Greece and a Leucoagaricus sp. from Italy ( MT416133 ). Our phylogenetic analysis, based on an nrITS sequence obtained from an isotype collection of L. pseudopilatianus , confirms the presence of the same grouping ( Fig. 1 ). Thus, L. cf. cupresseus from Greece and the specimen already deposited in GenBank as Leucoagaricus sp. , but morphologically examined here, are two L. pseudopilatianus collections.

Figures

FIGURE 1. Maximum Likelihood phylogram obtained from nrITS sequences of Leucoagaricus taxa. Cystolepiota seminuda was selected as outgroup taxon. Maximum Likelihood Bootstrap (MLB) values ≥ 70% (left) and Bayesian Posterior Probability (BPP) values ≥ 0.95 (right) are shown on the branches. Newly obtained sequences are reported in bold.

FIGURE 7. Leucoagaricus pseudopilatianus. A. Basidiomes in the natural habitat coll. MV LeuPil023; B. Basidiospores in Congo Red coll. MV LeuPil023; C. Cheilocystidia coll. MV LeuPil023; D. Cheilocystidia coll. PAD H0061558 (isotype L. pseudopilatianus); E. Cheilocystidia coll. TR MV41/96 (holotype Leucoagaricus pseudopilatianus var. rugosoreticulatus); F. Pileus covering elements coll. MV LeuPil023. Scale bars: A = 1 cm, B = 10 μm, C = 30 μm, D = 25 μm, E = 20 μm, F = 30 μm. Photos: A–C, F by Vincenzo Migliozzi; D–E by Niccolò Forin.