Rhodocybe formosa Vila, Contu, F. Caball. & A. Ortega, Bol. Soc. Micol.

Vizzini, Alfredo, Picillo, Bernardo, Ercole, Enrico, Vila, Jordi & Contu, Marco, 2016, Rhodocybe formosa (Agaricales, Entolomataceae): new collections, molecular data and synonymy, and Rhodocybe griseonigrella comb. nov., Phytotaxa 255 (1), pp. 34-46 : 38-40

Rhodocybe formosa Vila, Contu, F. Caball. & A. Ortega, Bol. Soc. Micol. Madrid 31: 78 (2007) Figs. 2‒4

≡ Clitopilus formosus (Vila, Contu, F. Caball. & A. Ortega) Vila & Contu, Boll. Assoc. Micol. Ecol. Romana 25 (77‒78): 12 (2009).

= Rhodocybe minutispora Vila, Contu, A. Ortega & F. Caball., Riv. Micol. 50(4): 304 (2007).

≡ Clitopilus minutisporus (Vila, Contu, A. Ortega & F. Caball.) Vila & Contu, Boll. Assoc. Micol. Ecol. Romana 25 (77‒78): 12 (2009).

Pileus 25‒55 mm broad, convex, becoming plano-convex or plane and shallowly depressed with age, margin long inrolled, becoming decurved then plane and eventually uplifted with age, entire, undulate, not translucently striate; surface dry, not hygrophanous, at first dark grey (Deep Plumbeous, Blackish Plumbeous, Plate LII), grey (Cinereous, Plumbeous, Plate LII), fading to beige-brown, ochre with age (Avellaneous, Plate XL; Cream-Buff, Chamois, Honey Yellow, Plate XXX; Cinnamon, Cinnamon-Buff, Clay Color, Plate XXIX), minutely felty-tomentose, matt, covered by a white pruina overall (as a micaceous sheen), often becoming concentrically areolate-rimose (sometimes the concentric cracks are darker than the rest of the surface). Lamellae broadly adnate to shortly decurrent, subdecurrent, up to 4 mm deep, medium crowded, L = 20‒30, intermixed with lamellulae of variable length, l = 1‒4(5), at first grey (Pale Drab-Gray, Pale Smoke Gray, Plate XLVI), then grey-beige (Pallid Brownish Drab, Plate XLV), pinkish (Light Vinaceous-Gray, Plate L) with age, edge entire or slightly eroded, concolorous. Stipe 25‒60 × 4‒10(‒12) mm, central, sometimes slightly off-centre, cylindrical to clavate, terete (solid) then fistulose (stuffed inside), straight to flexuose, sometimes laterally compressed/flattened, concolorous with the pileus or slightly paler, white pruinose at apex, fibrillose elsewhere; with a white basal mycelial tomentum and white rhizomorphs. Context fibrous, whitish, beige in the cortex, unchanging when handled; smell slightly farinaceous, sometimes flowery and reminding of Lepista irina ; taste mild, sometimes slightly bitterish after long chewing. Spore-print pinkish.

Spores ‘96/3/3’ (5‒)5.5‒6.5(‒7.6) × (4.2‒)4.5‒5.5(‒6) μm, on average 6.0 × 4.7 μm, Q = 1.16‒1.38, Qm = 1.26,

subglobose to broadly ellipsoid and with evident suprahilar depression in side view, pyriform to subovoid in frontal view, angular in polar view (6‒9 facets), in side and face view strongly undulate-pustulate, gibbous, walls cyanophilic,

inamyloid, non-dextrinoid. Basidia 4‒spored, 24‒34 × 6‒8.5 μm, strictly clavate, 5% with thickened walls (0.8–1.5

μm) (sclerobasidia); sterigmata up to 4 μm long. Cheilo- and pleurocystidia as pseudocystidia, abundant, similar in size, shape and colour, 30‒75 × 4‒9 μm, cylindrical to clavate, subfusiform to lageniform, thin-walled, often septate at base, with refringent granular contents yellowish in H 2 O, 5% KOH and L4, soon strongly dextrinoid in Melzer’s reagent. Subhymenium filamentous, formed by short cylindrical, 3‒4 μm wide hyphae. Hymenophoral trama regular,

consisting of cylindrical to sausage-shaped hyphae mixed with short, inflated elements, 7‒24 μm wide, thin-walled,

sometimes secondarily septate and with irregular outgrowths. Thromboplerous hyphae (= oleiferous hyphae sensu

Clémençon 2004) present, but rare. Pileipellis: suprapellis as a xerocutis, made up of subparallel, thin-walled, 3‒9 μm wide, tightly packed cylindrical hyphae; subpellis not well-differentiated, consisting of interwoven cylindrical, up to 12 μm wide hyphae, sometimes arranging in chain, walls brownish in 5% KOH; pigment epiparietal, strongly incrusting the elements of the suprapellis. Stipitipellis as a dry cutis of parallel, thin- to moderately thick-walled cylindrical hyphae, 2‒11 μm wide. Caulocystidia absent. Clamp-connections absent.

Habit, habitat and distribution: — terricolous, gregarious or in small clusters consisting of 2‒ 3 specimens, under Pinus pinea L., on sandy soil. Fruiting in late Autumn (November) ‒Winter (December). Rare, so far known only from Italy and Spain.

Collections examined: — R. formosa . SPAIN, Catalonia: Parc Serralada de Marina, Santa Maria de Martorelles, under Corylus avellana L. and Alnus glutinosa (L.) Gaertn., 360 m a.s.l., 15 October 2006, F. Caballero and J. Vila, LIP JVG 1061015, holotype (LIP!). ITALY, Latium: Rome, loc. bosco di Castel Fusano, under Pinus pinea , on sandy soil, in a mixed wood, with Quercus ilex L., Pistacia lentiscus L. and Ruscus aculeatus L., 0 m a.s.l., 24 November 2012, B. Picillo and Gualberto Tiberi, Herb. B. Picillo 12/198 (Herb. B. Picillo!); ibidem, 26 November 2012, B. Picillo, Herb. B. Picillo 12/208 (Herb. B. Picillo!); ibidem, 19 December 2013, B. Picillo and L. Perrone, Herb. B. Picillo 13/339 (Herb. B. Picillo!); ibidem, 14 December 2014, B. Picillo, Herb. B. Picillo 14/459 (Herb. B. Picillo!); ibidem, 18 October 2015, B. Picillo, Herb. B. Picillo 15/268R (Herb. B. Picillo!); ibidem, 31 October 2015, B. Picillo and M. Marchionni, Herb. B. Picillo 15/271R (Herb. B. Picillo!). R. minutispora . SPAIN, Catalonia: Parc Serralada de Marina, Santa Maria de Martorelles, under Corylus avellana L., Alnus glutinosa (L.) Gaertn. and Rubus sp. , 360 m a.s.l., 01 November 2007, J. Vila and F. Caballero, LIP JVG 1071101, holotype (LIP!).

Figures

FIGURE 2. Rhodocybe formosa. Basidiomes in the field.a (Herb.B. Picillo12/198). b (Herb. B. Picillo12/208).c (Herb. B. Picillo14/459). d (Herb. B. Picillo15/271R). Scale bars: 20 mm. Pictures by B. Picillo.

FIGURE 3. Rhodocybe formosa. Microscopic features (Herb. from B. Picillo12/198). a–b Basidia and pseudocystidia (in ammoniacal Congo red). c Pseudocystidia (in L4). d Spores (in phase contrast). Scale bars: 10 μm. Pictures by B. Picillo.

FIGURE 4. Rhodocybe formosa. Microscopic features (Herb. from B. Picillo12/208). a Pileipellis. b Spores. c Basidia. d Pseudocystidia. Scale bars: a–d = 20 μm; b–c = 10 μm. Drawings by B. Picillo.