Leucoagaricus viridariorum G. Muñoz, A. Caball., Salom & Vizzini, 2015

Muñoz, Guillermo, Salom, Joan Carles, Ercole, Enrico & Vizzini, Alfredo, 2015, Leucoagaricus viridariorum (Agaricaceae, Agaricales), a new species from Spain, Phytotaxa 236 (3), pp. 226-236 : 230-233

Leucoagaricus viridariorum G. Muñoz, A. Caball., Salom & Vizzini , sp. nov. ( Figs. 2−5 )

MycoBank MB815024

Original diagnosis:—Pileus 1−3 cm diam., conico-convex, plano-convex with low umbo; surface sericeous, at first white, then cream with yellow tinges, turning ochraceous-orange, rust brown. Lamellae white, cream to straw-yellow spotted at maturity. Stipe 2−3.5 × 0.2−0.3 cm, cylindrical, often with bulbose base, white. Annulus submembranaceus, very fragile, simple, thin, whitish. Odour strong, reminding of soy sauce. Basidiospores (4.91−) 5.58−6.22−7.27 (−7.83) × (4.05−) 4.57−4.98−5.39 (−5.60) μm, Q = (1.07−) 1.13−1.25−1.40 (−1.43), subglobose to broadly ellipsoid, without germ pore, smooth, hyaline, dextrinoid. Basidia tetraspored. Cheilocystidia 20−35(−40) × 9−14(−16) μm, clavate to broadly clavate. Pileus covering an irregular xerotrichoderm made up of interwoven hyphae, terminal elements 70−160 (−180) × 8−16 (−18) μm, usually with rounded apex, some basal elements shorter and subclavate. Clamp connections absent. This species is distinguised from L. sardous (Zecchin & Migl.) Consiglio & Contu mainly by differences in the nrITS sequence.

Type:— SPAIN, ZARAGOZA: Zaragoza, Parque Grande, on the grass, under Pinus halepensis , P. pinea and palms, 240 m a.s.l., 09 October 2012, G. Muñoz & L. Ballester, AH-4652 (Holotype, AH!); GM-2602 (Isotype, GM!).

Etymology:—from Latin vĭrĭdârĭum (garden) and therefore it means Leucoagaricus of the gardens.

Detailed description —Macrocharacters ( Figs. 2 , 3 and 5a ). Pileus 1−3 cm diam., at first subcylindrical to paraboloid, conical, conico-convex, expanding to convex, plano-convex with low umbo, never applanate when old; margin not striate, usually covered with white submembranaceous remnants of the partial veil; surface sericeous, felted at centre, minutely squamulose-fibrillose, at first snow white, whitish (Mu. 2.5Y 8/1), then cream to straw-coloured with yellow tinges at maturity (Mu. 2.5Y 8/3–6), turning ochraceous-orange, yellowish-brown or rust brown (Mu. 10YR 8/4–6, 7/4–6) when handled. Lamellae free, sub-crowded, with lamellulae, L = 50−70, l = 1−2, up to 0.2−0.3 cm wide, ventricose; white, cream to straw-yellow spotted at maturity, sometimes with yellowish hues, with entire to slightly eroded concolorous edge. Stipe 2−3.5 × 0.2−0.3 cm, central, terete, cylindrical, slightly thickening downwards, often with a bulbouse base up to 0.5 cm broad, straight, slightly sinuosus or recurved; surface smooth or minutely fibrillose, white or rarely cream to straw-yellow. Annulus superior or subcentral, ascending, submembranaceous, simple, thin, whitish, very fragile, soon disappearing (evanescent) or becoming inconspicuous and leaving remnants on pileus margin. Context thin (up to 0.4 cm at pileus centre), fragile, whitish in pileus, pale cream in stipe. Odour strong and peculiar but difficult to define, somewhat reminding of soy sauce or Laetiporus sulphureus -like. Spore print white.

Microcharacters ( Figs. 4 and 5b–e ). Basidiospores [198/5/5] (4.91−) 5.58−6.22−7.27 (−7.83) × (4.05−) 4.57−4.98−5.39 (−5.60) μm, Q = (1.07−) 1.13−1.25−1.40 (−1.43), subglobose to broadly ellipsoid, rarely ellipsoid, with a distinct hilar appendix, without germ pore, smooth, hyaline, dextrinoid, distinctly metachromatic in Brilliant cresyl blue, congophilous. Basidia 18−25 × 8−10 μm, clavate, 4-spored. Lamella edge sterile. Cheilocystidia 20−35(−40) × 9−14(−16) μm, clavate to broadly clavate, sometimes subspheropedunculate. Pleurocystidia absent. Partial veil (annulus) consisting of interwoven and septate cylindrical hyphae, congophilous, thin-walled, often ramified or bifurcate, intermixed with abundant inflated to clavate elements up to 20 μm wide. Pileus covering an irregular xerotrichoderm made up of interwoven hyphae, terminal elements 70−160(−180) × 8−16(−18) μm, usually with rounded apex, some basal elements shorter and subclavate; pigment colourless, usually parietal, smooth, also intracellular in some terminal elements. Stipitipellis consisting of parallel and septate, thin-walled cylindrical hyphae, congophilus, up to 4−7 μm wide, often connected by branches, intermixed inflated elements up to 15 μm wide. Clamp-connections absent.

Habit, habitat, ecology and distribution:—Termophilic and nitrophilic species typically found in man-made environments, human-disturbed areas (parks, gardens, greenhouses, flowerbeds, etc.), forming semihypogeous densely clustered basidiomata in humid areas subjected to drip irrigation and gregarious basidiomata in those characterised by sprinkler irrigation. So far known only from Spain.

Additional collections examined of L. viridariorum :— SPAIN, MÁLAGA: Málaga, Jardín Botánico-Histórico de la Concepción, 36º 45’ 38” N – 4º 25’ 32” W, 70 m a.s.l., under Cupressus sempervivens , Phoenix dactylifera , Pittosporum tobira and Alocasia sp. , on dirt, in sandy soil, 05 September 2010, Joaquín Escalona, GM-2245 (GM!). MALLORCA: Campos, Sa Ràpita, 39º 21’ 53” N – 2º 56’ 27” W, 9 m a.s.l., in private garden, under Thuja orientalis and herbaceous nitrophilic plants, 14 August 1998, Toni Estelrich & J.C. Salom, JCS-55L (JCS!); ibidem, 10 July 1999, JCS-60L (JCS!). Andratx, Sant Elm, Can Pedro Vivern, 39º 34’ 51.42” N – 2º 21’ 2.92” W, 10 m a.s.l., in a private garden near to the sea with Pinus halepensis and Pistacia lentiscus , 26 November 2005, Josep L. Siquier & J.C. Salom, JCS-243 (JCS!). L. Palma de Mallorca, Clínica Juaneda, 39º 34’ 36.36” N – 2º 37’ 38.73” W, 38 m a.s.l., in a drip irrigated garden under Citrus aurantium and Lavandula dentata , 26 July 2007, Carles Constantino, Josep L. Siquier & J.C. Salom, JCS-271L (JCS!); ibidem, 20 August 2013, J.C. Salom, JCS-337L (JCS!). Palma de Mallorca, Secar de la Reial, 39º 36’ 29” N – 2º 38’ 11” W, 78 m a.s.l., in a garden planter of a private house, with ornamental plants, 03 November 2009, Imma Vidal, Joan Salom & J.C. Salom , JCS-296L (JCS!). Calvià, Platja des carregador, Restaurante La Piazzetta, 39º 31’ 33.75” N – 2º 32’ 18.95” W, 4 m a.s.l., in a garden with Pinus halepensis and Cycas revoluta , 13 October 2012, J.C. Salom, JCS-325L (JCS!). Palma de Mallorca, Plaça des Progrés, 39º 34’ 19.19” N – 2º 38’ 10.32” W, 15 m a.s.l., on urban parterre, with Cynodon sp. , Platanus orientalis x hispanica and Cercis siliquastrum , 05 September 2013, Imma Vidal & J.C. Salom , JCS-339L (JCS!). TENERIFE: La Orotava, Parque de Pueblo Chico, 28º 23’ 45” N – 16º 32’ 17” W, 390 m, under palms and other tropical plants, growing between the volcanic stones used as substrate, 25 September 2008, G. Muñoz, GM-1284 (GM!), dupl. AC-3890. ZARAGOZA: Zaragoza, Parque Grande, 41º 37’ 33” N – 0º 53’ 48” W, 240 m, on the grass, under Pinus halepensis , P. pinea and palms, 13 September 2012, G. Muñoz, GM-2563 (GM!); ibidem, 18 September 2012, G. Muñoz, GM-2565 (GM!); ibidem, 02 October 2012, G. Muñoz, GM-2600 (GM!); ibidem, 14 October 2012, A. Caballero & G. Muñoz, AC-4978 (AC!).

Collections examined of L. sardous :— ITALY, SARDINIA: Nuoro, Sierra Orrios-Nuoro, under Olea europaea , among nettles, 29 October 1990, G. Zecchin , MCVE 20105 (Holotype, MCVE!), MCVE 672 (Isotype, MCVE!; dupl. in JCS-336 L) .

Figures

FIGURE 2. Basidiomata of L. viridariorum and its natural habitat. a. Fasciculate and semihypogeus growth in drip irrigation conditions. b. Gregarious growth in flowerbeds. c. Gregarious growth in gardens and parks in between the grass. Scale bars: 2 cm. Photos by G. Muñoz and J.C. Salom.

FIGURE 3. Macroscopic characters of L. viridariorum. a–e Fresh basidiomata in situ. a. (AH 46526, holotype); b. (GM-1284); c. (GM- 2245); d. (AC-4978); e. (JCS-296L). Scale bars: 2 cm. Photos by G. Muñoz, A. Caballero, J.C. Salom and J. Escalona.

FIGURE 4. Microscopic characters of L. viridariorum. a–b. (AH-46526, holotype) (in ammoniacal Congo red). a. Basidiospores. b. Cheilocystidia. c–d. (JSC-296L) (in ammoniacal Congo red). c. Cheilocystidia. d. Elements of the annulus. e. Elements of the pileus covering (in H2O). Scale bars: a–c = 10 μm; d–e = 20 μm. Photos by G. Muñoz and J.C. Salom.

FIGURE 5. Microscopic characters of L. viridariorum (AH-46526, holotype). a. Basidiomata. b. Basidiospores. c. Basidia. d. Cheilocystidia. e. Pileus covering elements. Scale bars: a = 1 cm; b–d = 10 μm; e = 100 μm. Line drawings by A. Caballero.