Studies in Hygrocybe s. l. (Hygrocyboideae, Hygrophoraceae) in Brazil: New species of Humidicutis and Neohygrocybe Author Cardoso, Juli Simon 0000-0003-2795-7067 Divisão do Curso de Pós-graduação em Botânica, Instituto Nacional de Pesquisas da Amazônia (INPA), Av. André Araújo 2936, 69067 - 375, Manaus, AM, Brazil & jul 3 asc @ gmail. com; https: // orcid. org / 0000 - 0003 - 2795 - 7067 jul3asc@gmail.com Author Moncalvo, Jean-Marc 0000-0003-4011-1381 Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, ON M 5 S 3 B 2, Canada & Department of Natural History, Royal Ontario Museum, 100 Queens Park, Toronto, ON M 5 S 2 C 6, Canada & jeanmarcm @ gmail. com; https: // orcid. org / 0000 - 0003 - 4011 - 1381 jeanmarcm@gmail.com Author Lodge, D. Jean 0000-0003-4807-348X Department of Plant Pathology and Odum School of Ecology, University of Georgia, Athens, GA 30602, United States & dlodgester @ gmail. com; https: // orcid. org / 0000 - 0003 - 4807 - 348 X dlodgester@gmail.com Author Margaritescu, Simona 0000-0001-5560-8847 Department of Natural History, Royal Ontario Museum, 100 Queens Park, Toronto, ON M 5 S 2 C 6, Canada & margaritescu. simona @ gmail. com; https: // orcid. org / 0000 - 0001 - 5560 - 8847 margaritescu.simona@gmail.com Author Neves, Maria Alice 0000-0002-1810-4890 Graduate Program in Biology of Fungi, Federal University of Santa Catarina (UFSC), Campus Universitário Reitor João David Ferreira Lima, s / n, 88040 - 900, Florianopolis, Brazil & maliceneves @ gmail. com; https: // orcid. org / 0000 - 0002 - 1810 - 4890 maliceneves@gmail.com Author Oliveira, Jadson J. S. 0000-0001-6643-3421 Divisão do Curso de Pós-graduação em Botânica, Instituto Nacional de Pesquisas da Amazônia (INPA), Av. André Araújo 2936, 69067 - 375, Manaus, AM, Brazil & oliveira. j. j. s. 86 @ gmail. com; https: // orcid. org / 0000 - 0001 - 6643 - 3421 oliveira.j.j.s.86@gmail.com text Phytotaxa 2023 2023-08-03 607 1 57 71 http://dx.doi.org/10.11646/phytotaxa.607.1.5 journal article 10.11646/phytotaxa.607.1.5 1179-3163 8212211 Neohygrocybe fumosa J.S. Cardoso, M.A. Neves & J.S. Oliveira , sp. nov. ( Figs. 3f–h , 4d–f , 5 ) MycoBank # MB844323 Etymology:—From Latin “fumosus” = smoky, grey, changing to brown; refers to the greyish light brown pileus. Type :— BRAZIL . Mato Grosso : Novo Mundo , Reserva Particular do Patrimônio Natural Cristalino , Castanheira Trail , 250 m elev., 9º33’52’’S 55º54’19’’W , 9 January 2019 , Cardoso, J . S . & Furtado , A . N . M . 600 ( FLOR67460 , holotype ) . Diagnosis:—Basidiomata dull-coloured, pileus umbonate, greyish brown, lamellae pale greyish brown, stipe light silvery grey, basidiomata with a distinct nitrous smell and without colour changes when injured. Differs from Neohygrocybe subovina by having brighter colours, no colour changes upon bruising, ellipsoid basidiospores and pyriform cheilocystidia. Description:— Pileus 30–44 mm diam., plane-convex, umbonate, sometimes tearing in the centre, slightly fibrillose, moist to dry, becoming translucent-striate towards margin, hygrophanous, light grey-brown (oac730, oac729) to brown (oac748, oac749); margin translucent-striate, uplifted to revolute, undulating, eroded, pale grey (oac732). Lamellae uncinate, up to 8mm broad, subdistant, thick, white with shades of grey-brown (oac711, oac718), intervenose, with veins projecting in the lamellar faces; lamellulae of two lengths, anastomosing. Stipe 75–83 × 5–7 mm , central, flexuous, hollow, smooth, glabrous, moist to dry, silky, tapering towards the base, light silvery grey (oac774, oac690) to whitish. Odour nitrous. Basidiospores 6.8– 7.99 –9.1 × 5.2– 6.08 –7.1 µm, Q = 1.315, ellipsoid, smooth, hyaline, inamyloid, thin-walled, guttulate, hilar appendage visible. Basidia 26.8–36.4 × 6.3–9.7 (–10.8) µm, clavate, thin-walled, hyaline, 2–4-spored, sterigmata up to 7 µm, with basal regular clamp connections. Lamellar edge fertile. Cheilocystidia 32.8–35.6 × 16.6– 22.1 µm, pyriform, like a swollen basidiole, sometimes guttulate. Pleurocystidia absent. Pseudocystidia 96.7–219.3 × 15.1–23.6 µm, obclavate to ventricose-rostrate, apex sometimes with conspicuous cellular contents, emerging from the lamellar trama and projecting up to 40 µm above basidia and basidioles ( Figure 5 ). Lamellar trama regular, composed of parallel inflated elements, 40.2–233.2 × 8.6–33.8 µm, clamp connections present. Pileipellis a cutis, with parallel, undifferentiated hyphae, 3.3–7 µm diam., some with granular encrusting pigments, pale brownish in water, hyaline in KOH, clamp connections present. Stipitipellis a cutis, hyphae 2.3–15.9 µm diam., hyaline in KOH and water, with rare encrustations, clamp connections present. FIGURE 4. a, b, c. Humidicutis pindorama (JS485). a. basidiospores, b. basidia, c. lamellar trama hyphae. d, e, f. Neohygrocybe fumosa (JS600). d. basidiospores, e. basidia, f. cheilocystidia . Scale = 10 μm. Drawings by: J. S. Cardoso Specimens examined:— BRAZIL . Mato Grosso : Alta Floresta , RPPN Cristalino , Dr. Haffer’s Trail , 250 m elev., 9º3”10’ S 55 º54”53’ W , 25 January 2018 , Cardoso , J . S . 277 ( FLOR63574 ); Novo Mundo , RPPN Cristalino , Castanheira Trail , 250 m elev., 9º33’52’’S 55º54’19’’W , 9 January 2019 , Cardoso , J . S . & Furtado , A . N . M . 600 ( FLOR67460 ) . Distribution:—Known only from the type locality. Habitat:—Growing solitary on clay soils of terra-firme forest. Comments:— Neohygrocybe fumosa is the first species of the genus described from Brazil . There are two species known from the neotropical region: Neohygrocybe subovina (Hesler & A.H. Sm.) Lodge & Padamsee (2013 [2014]: 41) and Hygrocybe ovinoides Lodge, S.A. Cantrell & T.J. Baroni (2004: 1312) combined in Neohygrocybe herein. Neohygrocybe subovina , from USA , also has cheilocystidia and pseudocystidia projecting from the hymenium, but the basidiomata are much darker in colour, the lamellae bruise pink to reddish brown or darker, the basidiospores are globose to subglobose rather than ellipsoid, and the cheilocystidia are vermiform and cylindrical rather than pyriform ( Hesler & Smith 1963 ). Hygrocybe ovinoides produces very small basidiomata which are also dark in colour, but the pilei have a white margin ( Cantrell & Lodge 2004 ). In the microscopy, H. ovinoides lacks cheilocystidia and has hook-like pileocystidia ( Cantrell & Lodge 2004 ). Both N. subovina and H. ovinoides lack the nitrous odour found in N. fumosa .