Pluteus salicinus (Pers.: Fr.) Kummer (1871: 99). Fig. 27 Basionym: Agaricus salicinus Persoon (1798: 9); Agaricus salicinus Persoon: Fries (1821: 202). To the best of our knowledge, no holotype exists and no lectotype, neotype or epitype have been designated for this taxon. Pileus 25–60(–80) mm in diameter, hemispherical or campanulate when young, expanding to convex or planoconvex, with or without a low, broad umbo; surface with distinct squamules at center, radially fibrillose or smooth towards margin; usually gray or gray-brown (7.5YR 4/1–4/2, 5/1–5/2; 10YR 5/1–5/4, 6/1–6/2), in some specimens with distinct blue-green tinges especially around center (Gley1 6/1, 7/1; Gley2 7/1, 8/1); dry or slightly viscid when moist; margin smooth or translucent-striate. Lamellae crowded, free, ventricose, up to 6 mm broad, white when young, later pink, with even, or white, flocculose edges. Stipe 20–70 × 3–7 mm, cylindrical, with slightly broad base; surface white with distinct blue-green tinges (Gley1 6/1, 7/1; Gley2 7/1, 8/1) especially near the base, smooth or with longitudinal brown or gray-brown fibrils, especially near base. Context in stipe and pileus white or slightly grayish. Smell usually strong and like leaves of Pelargonium, more rarely slightly raphanoid or indistinct. Taste similar to smell or indistinct. Spore print pink to pinkish brown. 60 Phytotaxa 180 (1) © 2014 Magnolia Press JUSTO ET AL. Basidiospores [480, 20, 20] 7.0–10.0(–12.0) × (4.5–)5.0–7.5(–8.0) µm, avl × avw = 8.3–9.5 × 6.2–6.8 µm, Q = 1.17–1.55(–1.70), avQ = 1.32–1.48, ellipsoid or broadly ellipsoid, more rarely oblong, sometimes ovoid or slightly constricted in the middle. Basidia 17–35(–47) × 7–14 µm, tetrasterigmate, clavate, some with median constriction. Pleurocystidia metuloid, 60–100(–110) × 10–20(–25) µm, fusiform, narrowly fusiform or narrowly utriform, provided with 2–4(–5) apical hooks (usually entire, rarely bifid, and well-developed), with up to 4 µm thick wall, frequent all over lamellar faces. Intermediate cystidia similar to the pleurocystidia but smaller and/or with thinner walls, a few irregularly shaped, without distinct apical hooks and/or with rounded apices; without a predominant morphological type. Lamellar edge sterile. Cheilocystidia 25–70(–85) × 10–25 µm, predominantly clavate or narrowly clavate, hyaline, thin-walled, crowded, forming a well-developed strip. Pileipellis a cutis, with terminal elements 80–200(–270) × 6–18 µm, individual elements cylindrical, some strongly tapering towards apex, hyaline or filled with brown intracellular pigment, sometimes grayish or bluish in fresh specimens, with thin, smooth walls. Stipitipellis a cutis; hyphae 5–25 µm wide, cylindrical, hyaline or with brown intracellular pigment, with thin, smooth walls. Clamp-connections common and readily seen on pileipellis hyphae; also present and common in other parts of the basidiocarp. Habit, habitat and phenology:—Solitary or subgregarious. Growing on decayed wood of hardwoods (e.g. Alnus, Eucalyptus, Fagus, Populus, Quercus,). In hardwood-dominated or mixed temperate forests, also in Eucalyptus plantations in Spain. May–November. Distribution:— Eurasia: Widespread in western Europe and eastwards into Siberia. HOLARCTIC SPECIES OF PLUTEUS SECTION PLUTEUS Phytotaxa 180 (1) © 2014 Magnolia Press 61 Observations:— The collection LE 289410 (Fig. 6a), made in the Novosibirsk Region (Russia), marks the easternmost confirmed occurrence of P. salicinus in Eurasia. All other collections in this species complex from the eastern parts of Eurasia and from North America have turned out to be different species. Pluteus salicinus is relatively easy to recognize because of the combination of gray pileus with squamules at center; blue-green tinges in pileus and/or stipe; relatively large basidiospores; metuloids with well-developed hooks and presence of clamp-connections in pileipellis. Additional collections examined: — RUSSIA. Northwestern Federal District: Leningrad Region, Kingiseppsky District, Kurgalsky Peninsula, Alnus glutinosa forest, on decayed wood of Alnus, 04 July 1997, O.V. Morozova s.n. LE 202301, nrITS KJ009755, tef1 KJ010023 (LE). Siberian Federal District: Novosibirsk Region, Novosibirsk District, Akademgorodok, mixed forest (Betula pendula, Pinus sylvestris), on decayed wood, 2008, I.A. Gorbunova s.n. LE 289410, nrITS KJ009758, tef1 KJ010025 (LE). Volga Federal District: Samara Region, Zhigulevsky Nature Reserve, Betula forest, on fallen trunk of deciduous tree, 11 June 2003, E.F. Malysheva s.n. LE 213033, nrITS KJ009753, tef1 KJ010022 (LE); ibid., broadleaf forest (Tilia cordata, Acer platanoides), on fallen trunk of deciduous tree, 25 July 2003, E.F. Malysheva s.n. LE 213034, nrITS KJ009756, tef1 KJ010028 (LE); ibid., broadleaf forest (Tilia cordata, Acer platanoides), on fallen trunk of deciduous tree, 26 July 2001, E.F. Malysheva s.n. LE 213064, nrITS KJ009754, tef1 KJ010024 (LE); ibid., broadleaf forest with Tilia cordata, on fallen trunk of deciduous tree, 25 July 2003, E.F. Malysheva s.n. LE 213023, nrITS KJ009757, tef1 KJ010027 (LE). SPAIN. Barcelona: La Floresta, on unidentified wood, 5 October 2002, A.M. Tarín s.n. SCM 4598 (SCM). Rupit, Pruit, on Fagus sylvatica stump, 1 June 1999, M. Tabarés s.n. SCM 4599 (SCM). Sta. Fe del Montseny, on Fagus sylvatica stump, 24 June 1987, A. Rocabruna s.n. SCM 120 (SCM); ibid., 19 July 1987, A. Rocabruna s.n. SCM 284 (SCM); ibid., 01 June 1988, M. Tabarés & A. Rocabruna s.n. SCM 1094 (SMC); ibid., 17 June 1995, A. Rocabruna s.n. SCM 2523 (SCM); ibid., 15 August 1995, A. Rocabruna s.n. SCM 2545 (SCM). Cádiz: Los Barrios, Arroyo del Tiradero, in forest of Quercus canariensis, Q. suber, Alnus glutinosa, on wood, 03 January 2004, A. González-Cruz & F. Prieto-García s.n. JA-CUSSTA 4098 (JA); Grazalema, Las Cumbres, on Quercus suber wood, 07 October 2001, A. Castro s.n. MA-Fungi 53681 (MA). Girona: Requesens, Castell, on Populus wood, 07 October 1995, A. Prunell s.n. LOU-Fungi 8264 (LOU). Riells, on wood of unidentified deciduous tree, 28 September 1996, A. Rocabruna s.n. SCM 3140 (SCM). Gipuzkoa: Tolosa, on wood of unidentified deciduous tree (Quercus rubra or Acer), 23 June 2001, P. Pasabán ARAN s.n (ARAN). Granada: Aldeire, Río Aldeire, in Populus forest, apparently terrestrial, 27 September 2003, A. Capilla s.n. JA-CUSSTA 4305 (JA). Huelva: Ribera del Múrtiga, La Nava, on Populus nigra wood, 18 October 1992, L. Romero de la Osa s.n. MA-Fungi 33470 (MA). Navarra: Bakaiku, Fagus forest, 07 November 2004, L. Garcia Bona s.n. MA 67874, nrITS HM562051, tef1 KJ010029 (MA). Oviedo: Lugones, mixed forest, on well-decayed hardwood log (probably Quercus or Castanea), 08 May 2005, L.A. Parra s.n. AJ 349, nrITS JN603199, tef1 KJ010026 (CUW). Somiedo, Veigas, on unidentified wood, 22. August 1997, E. Rubio-Domínguez s.n. MA-Fungi 38383 (MA). Pluteus americanus (P. Banerjee & Sundb.) Justo, E.F. Malysheva & Minnis, comb. & stat. nov. Fig. 28 MycoBank 808736 Basionym: Pluteus salicinus var. americanus Banerjee & Sundberg, Mycotaxon 47: 393. 1993. Holotype:— UNITED STATES OF AMERICA. Michigan: Emmet Co., Pellston Hills, west of Pellston, 03 September 1957, on wood of Populus, A.H. Smith 57842, nrITS KJ009762, tef1 KJ010037 (MICH!). Pileus 10–60 mm in diameter, hemispherical or campanulate when young, expanding to convex or plano-convex, with or without a low, broad umbo, sometimes slightly depressed at center; surface usually with distinct squamules at center, radially fibrillose or smooth towards margin; usually with predominant brown or pale brown colors (10YR 7/3–7/8, 8/3–8/8), darker and more gray-brown at center (10YR 5/1–5/3, 4/1–4/3), in some collections with distinct blue-green tinges especially center (Gley1 6/1, 7/1; Gley2 7/1, 8/1); dry or slightly viscid when moist, strongly hygrophanous; margin smooth or translucent-striate. Lamellae crowded, free, ventricose, up to 6 mm broad, white when young, later pink, with even, or white, flocculose edges. Stipe 15–65 × 3–6 mm, cylindrical, with slightly broad base; surface white, commonly with distinct blue-green tinges (Gley1 6/1, 7/1; Gley2 7/1, 8/1) especially near the base, sometimes all over the stipe, smooth or with longitudinal brown or gray-brown fibrils, especially near the base. Context in stipe and pileus white or slightly grayish. Smell usually strong and like leaves of Pelargonium, more rarely indistinct. Taste similar to smell or indistinct. Spore print pink to pinkish brown. 62 Phytotaxa 180 (1) © 2014 Magnolia Press JUSTO ET AL. HOLARCTIC SPECIES OF PLUTEUS SECTION PLUTEUS Phytotaxa 180 (1) © 2014 Magnolia Press 63 Basidiospores [110, 5, 4] 6.5–9.5(–11.0) × 4.5–7.0(–7.5) µm, avl × avw = 7.9–8.5 × 5.6–6.1 µm, Q = 1.29–1.59, avQ = 1.35–1.44, ellipsoid, more rarely broadly ellipsoid, sometimes ovoid or slightly constricted in the middle. Basidia 16–34 × 6–12 µm, tetrasterigmate, clavate, some with median constriction. Pleurocystidia metuloid, 50–93 × 12–24(–28) µm, fusiform, narrowly fusiform or narrowly utriform with 2–4 apical hooks (usually entire and well-developed, sometimes bifid), with up to 4 µm thick wall, frequent all over lamellar faces. Intermediate cystidia similar to the pleurocystidia but smaller and/or with thinner walls, a few irregularly shaped, without distinct apical hooks and/or with rounded apices; without a predominant morphological type. Lamellar edge sterile. Cheilocystidia 34–65(–70) × 12–22 µm, clavate, narrowly clavate or spheropedunculate, hyaline, thinwalled, crowded, forming a well-developed strip. Pileipellis a cutis, with terminal elements 80–194 × 10–22 µm, individual elements cylindrical, some strongly tapering towards apex, hyaline or filled with brown intracellular pigment, sometimes grayish or bluish in fresh specimens, with thin, smooth walls. Stipitipellis a cutis; hyphae 5–25 µm wide, cylindrical, hyaline or with brown intracellular pigment, with thin, smooth walls. Clamp-connections common and readily seen on pileipellis hyphae; also present and common in other parts of the basidiocarp. Habit, habitat and phenology:—Solitary or gregarious. Growing on decayed hardwoods (Fraxinus, Populus). In hardwood-dominated or mixed, temperate or transitional forests. August–September. Distribution:— Eurasia. Known only from the Russian Far East (Primorsky Territory). North America. Known with certainty from Illinois, Michigan and New York, probably more widespread in the Eastern parts. Not recorded from western North America. Observations:— Banerjee & Sundberg (1993) described Pluteus salicinus var. americanus as different from the type variety based on the hygrophanous pileus, the translucent-striate pileus margin and pleurocystidia with “compound ornamentation” (i.e. with bifid hooks). Based on our observations, margin striation and the proportion of pleurocystidia with bifid hooks are not really different from what is found in Pluteus salicinus. P. americanus has a pileus with more predominantly brown tinges that is strongly hygrophanous while P. salicinus has a more grayish pileus that is less markedly hygrophanous but both characters intergrade to some extent. Geographical distribution is probably the best character to tell both species apart, with Pluteus salicinus confined to Eurasia and Pluteus americanus in North American and the Russian Far East. Many of the North American records of Pluteus salicinus probably correspond to Pluteus americanus, but some may correspond to other taxa in this group (e.g. P. oreibatus, P. saupei). The separation of both taxa is not supported in the nrITS phylogenies, however they appear as separate species in the tef1 and combined analyses, with statistical support in the former (Fig. 6). Additional collections examined: — RUSSIA. Far East Federal District: Primorsky Territory, Ussuriisky Nature Reserve, Peishula Reserve Field Station, valley of Suvorovka River, floodplain forest (Chosenia, Salix, Corylus), on decayed wood of deciduous tree, 15 August 2011, E.F. Malysheva s.n. LE 289369, nrITS KJ009759, tef1 KJ010034 (LE). UNITED STATES OF AMERICA. Illinois: Cook Co., Elk Grove Village, Busse Woods, mixed forest, on Fraxinus wood, 09 September 2013, A. Houghtby MO145100, nrITS KJ009785, tef1 KJ010038 (CUW). Michigan: Emmet Co., French Farm, 25 September 2009, M. Keirle SF2-BPI 882765, nrITS HM562174, tef1 KJ010035 (BPI). New York: Essex Co., Adirondack Ecological Center, Huntington Wildlife Forest, mixed forest, on decayed wood, 18 August 2012, A. Justo 591, nrITS KJ009760 (CUW); ibid., A. Justo 596, nrITS KJ009761, tef1 KJ010036 (CUW). Pluteus sepiicolor E.F. Malysheva, sp. nov. Fig. 29 MycoBank 808733 Diagnosis:—Differs from other species in the P. salicinus complex (P. salicinus, P. americanus, P. oreibatus) by the combination of deep brown pileus, metuloid pleurocystidia with predominant bifid apical hooks, the presence of clampconnections in pileipellis and growth on conifers. Holotype:— RUSSIA. Far East Federal District: Primorsky Territory, Sikhote - Alinsky Nature Biosphere Reserve, vicinities of Kabany Reserve Field Station, Picea - Abies forest with isolated Alnus and Betula, on mossy wood, 24 August 2011, A.E. Kovalenko s.n. LE 289365, nrITS KJ009765, tef1 KJ010030 (LE!). Etymology:— sepiicolor refers to color of pileus (sepia, deep brown). Pileus 40–60 mm in diameter, nearly hemispherical or obtusely campanulate when young, expanding to convex or plano-convex, with a low, broad umbo; surface smooth or innately radially fibrillose, at center squamulose with dark (almost black) slender squamules; deep brown or sepia (7.5YR 4/3–4/6, 3/3–3/4); dry or slightly viscid when moist, hygrophanous; translucent-striate at margin. Lamellae crowded, free, slightly ventricose, up to 5 mm broad, 64 Phytotaxa 180 (1) © 2014 Magnolia Press JUSTO ET AL. white-cream when young, later pink, with concolorous edges. Stipe 50–70 × 4–6 mm, cylindrical, slightly broadened towards base (up to 7–8 mm); surface white or yellowish in the upper part, grayish brown in the lower part; longitudinally fibrillose, with blackish brown fibrils. Context in stipe and pileus white or slightly grayish yellow. Smell indistinct. Taste not recorded. Spore print not recorded. HOLARCTIC SPECIES OF PLUTEUS SECTION PLUTEUS Phytotaxa 180 (1) © 2014 Magnolia Press 65 Basidiospores [60/3/2] 7.8–8.6 (–9.0) × 5.0–6.2 (6.5) µm, avl × avw = 8.0–8.3 × 5.4–5.8 µm, Q = 1.29–1.60, avQ = 1.38–1.47, ellipsoid to oblong, some ovoid, occasionally with medial constriction. Basidia 20–30 × 5.5–10 µm, tetrasterigmate, narrowly to broadly clavate. Pleurocystidia metuloid, 40–90 × 13–25 µm, fusiform, narrowly fusiform or narrowly utriform with 2–4(–5) apical hooks (commonly bifid, but entire hooks also present), hyaline, thick-walled (up to 2.7–3.0 µm). Intermediate cystidia similar to the pleurocystidia but slightly smaller and/or with thinner walls. Lamellar edge sterile. Cheilocystidia 40–70 × 8–20 µm, clavate, narrowly clavate or narrowly utriform, some with slightly elongated apices, hyaline, thin-walled, crowded, forming a well-developed strip. Pileipellis a cutis, with repent and slightly ascending hyphae; terminal elements 80–120 × 10–25 µm, individual elements narrowly fusiform, filled with yellow-brown intracellular pigment, thin-walled. Stipitipellis a cutis; hyphae 7–20 µm wide, cylindrical, hyaline or with brown intracellular pigment, with thin, smooth walls. Clamp-connections present on pileipellis hyphae but not at every septum, also present and common in other parts of the basidiocarp. Habit, habitat and phenology:—Solitary. Growing on decayed or mossy wood of conifers. In mixed or conifer forests in mountain area. August. Distribution:— Eurasia. Known only from the Russian Far East (Primorsky Territory). Observations:— Pluteus sepiicolor can be distinguished from P. salicinus and P. americanus by the growth on conifers and the dark brown colors of the pileus. P. oreibatus also grows on conifers but has differently shaped pleuro and cheilocystidia. Both nrITS and tef1 phylogenies recover P. sepiicolor as a separate species in the salicinus clade. Pluteus nigropallescens Singer (1961a: 116) can also have dark colors in the pileus but it differs from P. sepiicolor in the pleurocystidia with entire hooks and the terrestrial habitat. This species is only known from Venezuela (Singer 1961a). Pluteus velutinornatus can also present pleurocystidia with bifid hooks, but it has a more markedly fibrillose-squamulose pileus, usually wrinkled at center, and pigmented lamellar edges (Stevenson 1962; Horak 2008). This species is only known from New Zealand. Additional collection examined: — RUSSIA. Far East Federal District: Primorsky Territory, Sikhote - Alinsky Nature Biosphere Reserve, vicinities of Kabany Reserve Field Station, conifer forest, on decayed wood, 24 August 2011, N. V . Psurtseva s.n. LE 289366, nrITS KJ009766, tef1 KJ010031 (LE). Pluteus oreibatus Justo, sp. nov. Fig. 30 MycoBank 808734 Diagnosis:—Differs from other species in the P. salicinus complex (P. salicinus, P. americanus., P. sepiicolor) by the combination of pleurocystidia with poorly developed hooks, cheilocystidia cylindrical or lagenif, Published as part of Justo, Alfredo, Malysheva, Ekaterina, Bulyonkova, Tatiana, Vellinga, Else C., Cobian, Gerry, Nguyen, Nhu, Minnis, Andrew M. & Hibbett, David S., 2014, Molecular phylogeny and phylogeography of Holarctic species of Pluteus section Pluteus (Agaricales: Pluteaceae), with description of twelve new species, pp. 1-85 in Phytotaxa 180 (1) on pages 60-73, DOI: 10.11646/phytotaxa.180.1.1, {"references":["Kummer, P. (1871) Der Fuhrer in die Pilzkunde. C. Luppe, Zerbst, 146 pp.","Persoon, C. H. (1798) Icones et Descriptiones Fungorum Minus Cognitorum. Breitkopf-Haertel, Leipzig, 26 pp.","Fries, E. M. (1821) Systema Mycologicum vol. 1. Lund, 520 pp.","Banerjee, P. & Sundberg, W. J. 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