Pluteus padanilus Justo & C.K. Pradeep, 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 : 86-88

Pluteus padanilus Justo & C.K. Pradeep , sp. nov. ( Fig. 5 )

MycoBank: MB 809616

Diagnosis: —Similar to P. izurun but differing in the tef1 sequence (KF010049), differentiation of the cystidial apices and shorter pileipellis elements.

Type: — INDIA. Kerala: Trivandrum District, Enikkara , 1 November 2011, leg. C.K. Pradeep 13844 (Holotype CUW!; nrITS: JQ801374 ; tef1: KJ 010049 ) .

Pileus 20–35 mm in diam., hemispherical when young, expanding to convex or plano-convex, with a broad obtuse umbo; surface strongly radially fibrillose around center, becoming smooth towards margin, brown (5 YR 3/4, 4/4–4/6,) or gray (10 YR 5/1–5/2, 6/1–6/2), darker at center and paler towards margin; dry; margin translucent-striate. Lamellae crowded, free, ventricose, up to 3 mm broad; white when young, later pink; with white, flocculose edges. Stipe 30–60 × 2–5 mm, cylindrical; surface white, with distinct blue or blue-green tinges at base, smooth or with longitudinal gray-brown or bluish fibrils, sometimes grouped forming squamules, especially near the base. Context in stipe and pileus white, in some places on the stipe context with slight blue-green tinges. Odor indistinct. Taste indistinct. Spore print pinkish brown (2.5 YR 7/6–7/8). Basidiospores [60/2/2] (6.0–)6.5–8.0 × (4.5–)5.0–6.0 μm (Q = 1.15–1.42; Qm = 1.28; Lm = 7.0 μm; Wm = 5.6 μm), broadly ellipsoid to ellipsoid, inamyloid, hyaline, smooth, thick-walled. Basidia 20–35 × 7.0– 14.0 μm, four-spored, rarely one-spored (only a single one was observed), clavate or narrowly utriform. Pleurocystidia 50–85 × 15.0–27 μm; predominantly narrowly utriform or lageniform, some with truncate to subcapitate apices or with 2–3 indistinct short projections at the apex, a very few with an internal septa; colorless but a few with some incrusting parietal pigment at the apices, thin-walled; common. Lamellar edge sterile. Cheilocystidia 40–65 × 10.0–20(–25) μm; predominantly (narrowly) clavate or narrowly utriform, a few with a short apical appendage, colorless but a few with some incrusting parietal pigment at apex, thin-walled; crowded, forming a well-developed strip. Pileipellis a cutis with repent and slightly ascending elements towards the center of the pileus; individual terminal elements 90–160(–190) × 8.0–15 μm; cylindrical or fusiform; mostly with brown intracellular pigment; thin-walled. Stipitipellis a cutis; hyphae 5.0–20 μm wide; cylindrical; colorless or with brown pigments; thin-walled. Clamp connections absent on pileipellis hyphae; present, but scarce, on some hyphae of the hymenophoral trama.

Etymology: — padanilus is the transliterated and Latinized form of two Sanskrit words “pada” (foot) and “neela” (blue), making reference to the blue colors on the stipe.

Habit, habitat and distribution: —Fruiting in pairs. On decayed angiospermous wood. November. Asia: Known only from Kerala state ( India)

Additional specimen examined: — INDIA. Kerala: Trivandrum District, Enikkara , 6 November 2012, leg. C.K. Pradeep 14418 ( CUW!; nrITS: KJ 009768 ; tef1: KJ 010050 ) .

Notes: — Pluteus padanilus is characterized by a stipe base with distinct blue or blue-green tinges, broadly ellipsoid to ellipsoid basidiospores (Qm = 1.28), pleurocystidia with truncate to subcapitate apices or with 2–3 indistinct short apical projections and the presence of incrusting parietal pigment at the apex in some pleuro- and cheilocystidia. All species discussed herein differ from P. padanilus in the lack of incrusting parietal pigment at apex of the cystidia. Additionally, P. glaucotinctus has few cheilocystidia with brownish pigment and a majority of pleuro- and cheilocystidia with rounded apices and with no apical projections; P. izurun has longer pileipellis elements (up to 380 μm); P. meridionalis has a stipe with no distinct blue-green tinges and narrower basidiospores (Qm = 1.40); and P. thoenii differs in having preponderantly subglobose basidiospores (Qm = 1.15) and longer cheilocystidia (up to 94 µm long).

An additional morphological character that separates P. padanilus from the other species in this complex is the presence of clamp-connections at some septa of the hymenophoral trama hyphae. The presence/absence of clampconnections in the pileipellis hyphae is a useful character for the species-level taxonomy of Pluteus sect. Pluteus , but its presence in other parts of the basidioma is not constant enough to be used as a reliable character ( Justo et al. 2014). Horak & Heinemann (1978) also reported the presence of a few clamp-connections on the pileipellis elements in the African collections named as P. glaucotinctus , but they were not observed during our re-examination. One should not disregard the fact that clamp connections are often more difficult to find in older, dried herbarium material.

Recently, Menolli et al. (2014) reported the presence of cheilocystidia with incrusting parietal pigment at the apex in one Brazilian material (coll. ANc-4214) under the name of P. glaucotinctus . According to their description it could fit also within the concept of P. padanilus , however, further molecular investigation will be necessary to elucidate the identity of the material studied by the authors and to certify the real occurrence of P. glaucotinctus or P. padanilus in Brazil.

Figures

FIGURE 5. Pluteus padanilus. a–b. Basidiomata. c. Basidiospores. d, e. Pleurocystidia. f. Cheilocystidia. g. Pileipellis elements. a, c, d, f, g. C.K. Pradeep 13844 (holotype) b, e. C.K. Pradeep 14418. Scale bars: a, b = 1 cm. c–g = 10 μm. Photos a–b by C.K. Pradeep, line drawings c–g by A. Justo.