Pluteus meridionalis Menolli & Capelari, 2014

Jr, Nelson Menolli, Justo, Alfredo, Arrillaga, Pedro, Pradeep, C. K., Minnis, Andrew M. & Capelari, Marina, 2014, Taxonomy and phylogeny of Pluteus glaucotinctus sensu lato (Agaricales, Basidiomycota), a multicontinental species complex, Phytotaxa 188 (2), pp. 78-90 : 84-86

Pluteus meridionalis Menolli & Capelari , sp. nov. ( Fig. 4 )

MycoBank: MB 809615

Diagnosis: —Similar to P. izurun but differing in the tef1 sequence ( KJ010052 ), absence of distinctly blue-green tinges at stipe base, narrower basidiospores, pleurocystidial apex, and shorter pileipellis elements.

Type: — BRAZIL. São Paulo : São Paulo, Parque Estadual das Fontes do Ipiranga , 2 December 2008, M. Capelari & U.C. Peixoto MC4412 (Holotype SP!; nrITS: HM 562157 ; tef1: KJ 010052 ) .

Pileus 35–65 mm in diam., conic when young, expanding to plane, and becoming slightly depressed at center; surface apparently smooth but slightly fibrillose under lens when young, becoming entirely fibrillose to densely fibrillose, fibrils more concentrated at center, with olive green to greenish gray (N 80 A 00 M 40) shades, becoming paler outward, whitish at least one-half the radius towards margin in young specimens, sometimes developing reddish brown tones in age; dry to viscid when moist, slightly hygrophanous; margin translucent-striate mainly on insertion points of the lamellae. Lamellae crowded, free; white-cream when young, later pinkish. Stipe 30–75 × 4–10 mm, cylindrical or compressed (but probably due to development on the substrate), with slightly broad base; surface longitudinally striate, white to pale cream with light brown to slightly greenish punctations or longitudinal fibrils at base, lacking any blue-green tinges; with scanty basal mycelium. Context, odor, taste and spore print color not recorded. Basidiospores [80/4/4] (6.2–)7.5–10.0 × 5.0–6.2(–7.5) μm (Q = 1.21–1.74; Qm = 1.40; Lm = 8.1 μm; Wm = 5.9 μm), broadly ellipsoid to elongate, inamyloid, hyaline, smooth, thick-walled. Basidia 17.5–31 × 6.2–11.2 μm, four-spored, clavate or narrowly utriform. Pleurocystidia (31–)40–65(–75) × (8.7–)10.0–21(–25) μm; narrowly lageniform, narrowly utriform or fusoid, rarely clavate, with a rounded apex or some with an almost truncate apex with minor apical and lateral projections, colorless, thin-walled; scattered, rare to relatively common. Lamellar edge sterile. Cheilocystidia 37–67 × 6.2–20 μm; narrowly lageniform to narrowly utriform, sometimes clavate, fusiform or mucronate, apices usually with a short and narrow papilla, colorless, thin-walled; crowded, forming a well-developed strip. Pileipellis a cutis; individual terminal elements 98–140 × 8.0–16.0 μm; cylindrical or fusiform; mostly with evenly dissolved brownish intracellular pigment; thin-walled. Stipitipellis a cutis; hyphae 6.2–33 μm wide; cylindrical; colorless or with intracellular brown pigment; thin-walled. Clamp connections absent.

Etymology: — meridionalis , belonging to the south, in this case the southeast Brazil. Pluteus meridionalis is also the species with the most meridional distribution in this complex.

Habit, habitat and distribution: —Gregarious or in pairs. On dead wood or on standing trees with fruitbodies of polyporoid fungi. October to February. South America: Known only from southeast Brazil.

Additional specimens examined: — BRAZIL. São Paulo: Santo André, Reserva Biológica do Alto da Serra de Paranapiacaba , 21 October 1990, L.K. Okino & A.M. Gugliotta 3630 (SP! as P. atriavellaneus Murrill ) ; São Paulo, Parque Estadual da Cantareira , 19 February 2008, F. Karstedt et al. FK1084 (SP!; nrITS: KJ 009767 ; tef1: KJ 010054 ) ; ibid. Parque Estadual das Fontes do Ipiranga , 27 October 2009, L.A.S. Ramos LASR64 (SP!; nrITS: HM 562147 , tef1: KJ 010052 ) .

Notes: — Pluteus meridionalis is characterized by broadly ellipsoid to elongate basidiospores (Qm = 1.40), pleurocystidia with truncate apices and minor apical or lateral projections, and cheilocystidia usually with a short and narrow apical papilla. Besides the difference in geographical distribution, P. meridionalis can be separated from the other species in this complex by the comparatively more elongated basidiospores and the absence of distinctly blue-green tinges at the stipe base. Pluteus glaucotinctus lacks any apical or lateral projections on the pleurocystidia, their cheilocystidia do not have an apical papilla, and it has shorter pileipellis elements (up to 90 μm long). Pluteus izurun has pleurocystidia with rounded apices and longer pileipellis elements. Pluteus padanilus has incrusting parietal pigment at the apices of some pleuro- and cheilocystidia. Pluteus thoenii has predominantly subglobose basidiospores (Qm = 1.15), longer cheilocystidia (up to 94 µm long) and pleuro- and cheilocystidia with a different shaped apex.

The occurrence of one of the Brazilian specimens (LASR64) on a standing tree (apparently a living tree) also is an anomalous habit for Pluteus . However, the presence of a polyporoid fungus likely indicates that this species was responsible for the death of the plant tissue instead of P. meridionalis .

Although the presence of distinctly blue-green tinges was not observed in P. meridionalis , the occurrence of slightly greenish punctations or longitudinal fibrils at stipe base could correlate to the presence of psilocybin, which has been recorded from other taxa in this clade. Besides P. glaucotinctus , P. izurun , P. padanilus , and P. thoenii (considering the macro-morphological data described for P. glaucotinctus by Horak & Heinemann 1978) and among the species sampled in the salicinus / albostipitatus clade, the presence of blue-green tinges or psilocybin has been previously reported for P. salicinus (Pers.: Fr.) P. Kumm. ( Saupe 1981; Stijve & Bonnard 1986; Justo et al. 2014), P. americanus (P. Banerjee & Sundb.) Justo, E.F. Malysheva & Minnis ( Justo et al. 2014) and P. saupei Justo & Minnis ( Saupe 1981; Justo et al. 2011b; Justo et al. 2014). Additionally, P. nigrolineatus Murrill is also frequently reported with blue-green pigments at the stipe base ( Singer 1962; 1969; Rodríguez & Guzmán-Dávalos 2001) and recently Menolli et al. (2010) showed by molecular data that this species is also positioned with other ones of the salicinus / albostipitatus clade. Stijve & de Meijer (1993) also recorded psilocybin for materials previously identified as P. glaucus Singer , but which most likely represent P. glaucotinctus sensu lato ( Menolli et al. 2014 –see comments under P. padanilus ).

Considering these records, the presence of blue-green tinges or psilocybin within Pluteus sect. Pluteus seems to be restricted to species of the salicinus / albostipitatus clade, although blue-green tinges were not reported for P. sepiicolor E.F. Malysheva ( Justo et al. 2014), P. oreibatus Justo ( Justo et al. 2014), P. albostipitatus (Dennis) Singer ( Menolli et al. 2010), P. harrisii Murrill ( Menolli et al. 2010), and P. meridionalis . To confirm this statement, the phylogenetic position of P. nigroviridis Babos within Pluteus sect. Pluteus needs to be investigated because Stijve & Bonnard (1986) also mentioned the presence of psilocybin for this species. Furthermore, Pluteus species with blue-green tinges are also present in Pluteus sect. Celluloderma , viz. P. cyanopus Quél ( Homola 1972) and P. phaeocyanopus Minnis & Sundb. ( Minnis & Sundberg 2010), which could indicate that this character has originated at least twice during the evolution of the genus.

Figures

FIGURE 4. Pluteus meridionalis. a–c. Basidiomata. d, e. Basidiospores. f, g. Pleurocystidia. h, i. Cheilocystidia. a, b, d, f, h. MC4412 (holotype). c, e, g, i. LASR64. Scale bars: a–c = 1 cm. d–i = 10 μm. Photos a–c by M. Capelari, line drawings d–i by N. Menolli Jr. and Luiz Antonio S. Ramos.