Taxonomic study of Collybiopsis (Omphalotaceae, Agaricales) in the Republic of Korea with seven new species Author Kim, Ji Seon School of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul 08826, Republic of Korea Author Cho, Yoonhee School of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul 08826, Republic of Korea Author Park, Ki Hyeong School of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul 08826, Republic of Korea Author Park, Ji Hyun Water Supply and Sewerage Research Division, National Institute of Environmental Research, Incheon 22689, Republic of Korea Author Kim, Minkyeong https://orcid.org/0000-0001-6666-6639 Microorganism Resources Division, National Institute of Biological Resources, Incheon, Republic of Korea Author Kim, Chang Sun Forest Biodiversity Division, Korea National Arboretum, Pocheon-si 11186, Republic of Korea Author Lim, Young Woon https://orcid.org/0000-0003-2864-3449 School of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul 08826, Republic of Korea ywlim@snu.ac.kr text MycoKeys 2022 2022-03-30 88 79 108 http://dx.doi.org/10.3897/mycokeys.88.79266 journal article http://dx.doi.org/10.3897/mycokeys.88.79266 1314-4049-88-79 BFE1E3F5B8B2513199EFD80D2E09DEF0 Collybiopsis vellerea J.S. Kim & Y.W. Lim sp. nov. Fig. 4E-F Etymology. Epithet " Collybiopsis vellerea " refers to having a velvety stipe. Holotype. The Republic of Korea, Seoul: Gwanak-gu, Mt. Gwanak, 37°27'32"N , 126°56'49"E , alt. 90 m, 21 August 2014, Young Woon Lim, SFC20140821-29 (GenBank accession no. ITS: OL467267; nrLSU: OL462810). Diagnosis. It has a dull, greyish orange, 18-45 mm pileus with darker center, a tomentose (like velvet), insititious, orangish, 15-55 x 3-5 mm stipe, sphaeropendunculate, subovoid, 23.4-49 x 7.5-13.4 μm pleurocystidia, oblong to subcylindrical basidiospores, narrowly clavate with rostrate apex, sometimes lobed, 7.7-49.7 x 3.8-14.6 μm cheilocystidia. Description. Pileus: 18-45 mm, hemispherical, appendiculate to convex, subumbonate with an uplifted margin when old; Surface smooth, dull, hygrophanous, orange white (5A2) to greyish orange (6E8 to 7F8) on the center, gradually becoming paler to the edge (5A1 to 5B2). Lamellae: crowded to close, L = 38-52, l = 3-7, furcate, white. Stipe: 15-55 x 3-5 mm, cylindrical, finely tomentose, insititious, pale orange (5A3) to reddish grey (7B2), becoming darker to the base (6A2 to 7C2). Basidiospores: 5.2-7 x 2.5-3.8 μm (average 6.17 x 3.06 μm ), Q = 1.8-2.4 (mean = 2.03), oblong to subcylindrical, smooth, hyaline, non-dextrinoid, with drops. Basidia: 16.2-24.8 x 3.3-5.3 μm , 4-spored, (narrowly) clavate, often curved or constricted. Cheilocystidia: 7.7-49.7 x 3.8-14.6 μm , narrowly clavate with rostrate apex, sometimes lobed. Pleurocystidia: 23.4-49 x 7.5-13.4 μm , sphaeropendunculate, subovoid. Trama hyphae: cylindrical, often subinflated, thin-walled, smooth, branched, non-dextrinoid, 2-5 μm wide. Pileipellis: a cutis made up of cylindrical, thin-walled, with weak annular ornamentation, 3-10 μm wide hyphae; terminal elements adpressed to suberect, cylindrical, fusoid, clavate, 5-11 μm wide. Stipitipellis: a cutis of cylindrical, thin-walled, smooth, 2.0-6.0 μm wide hyphae. Caulocystidia: 12-38 x 2.4-6.6 μm , cylindrical, narrowly utriform, sometimes irregular, or curved. Clamp connections: present in all tissues. Other specimens examined. The Republic of Korea , Chungcheongnam-do : Seosan-si , Mt. Gaya , 36°41'0"N , 126°35'19"E , alt. 260 m , 20 August 2012 , Jae Young Park, SFC20120820-02. The Republic of Korea , Incheon : Ongjin-gun, 37°13'10"N , 126°10'4"E , alt. 6 m , 4 September 2018 , Changmu Kim, Jin Sung Lee, NIBRFG0000502858. The Republic of Korea , Jeollanam-do : Jindo-gun, Seogeocha island , 34°15'22"N , 125°55'11"E , alt. 38 m , 5 July 2018 , Jae Young Park, Tae Heon Kim, SFC20180705-90 . Habit and habitat. Scattered to gregarious on the ground covered with dead and decaying conifer needles, from summer to autumn. Distribution. The Republic of Korea. Remark. Collybiopsis vellerea is morphologically similar to Co. menehune and G. spongiosus Halling. Collybiopsis menehune has a paler stipe, a smaller pileus (8-30 mm), and fewer lamellulae (4-6 series) ( Desjardin et al. 1999 ). Gymnopus spongiosus has a smaller pileus (8-20 mm) and longer stipe (20-55 mm). Micromorphologically, Co. menehune has larger basidiospores, basidia, and caulocystidia ( Desjardin et al. 1999 ). Gymnopus spongiosus differs from Co. vellerea in that its pileipellis is a Dryophila -type cutis and its color changes in alkalies. Furthermore, its basidia (18-25 x 6-9 μm ) and trama hyphae (3.5-17 μm ) are thicker and its caulocystidia (3.5-10.5 μm broad) are smaller ( Halling 1996 ). Collybiopsis vellerea is phylogenetically close to Co. omphalodes . Collybiopsis omphalodes differs in having smaller basidiomata (20-30 mm) and its habit on logs ( Dennis 1951 ).