A new species and four new records of Bacidia (Lecanorales, Ramalinaceae) from South Korea, with a key to Korean species Author Lee, Beeyoung Gun https://orcid.org/0000-0002-5626-852X Baekdudaegan National Arboretum, Bonghwa, 36209, Republic of Korea gitanoblue@koagi.or.kr Author Hur, Jae-Seoun https://orcid.org/0000-0001-8547-7075 Korean Lichen Research Institute, Sunchon National University, Suncheon 57922, Republic of Korea text MycoKeys 2022 2022-10-19 93 107 130 http://dx.doi.org/10.3897/mycokeys.93.89283 journal article http://dx.doi.org/10.3897/mycokeys.93.89283 1314-4049-93-107 496770EB8D855C33A293322A1B32D1CA Bacidia suffusa (Fr.) A. Schneid., Guide Study Lich.: 110 (1898) Fig. 4 Description. Thallus corticolous, crustose, continuous, wrinkled, warted or subsquamulose, often granular locally, whitish pale grey. Prothallus generally not present or present as dark brown to black between different colonies. Apothecia flat, marginate, with a little or heavy white pruina, generally more pruinose at margin, 0.3-1.7 mm diam. (mean = 0.75, SD = 0.28, n = 116). Disc lecideine, without thalline exciple, brown to dark brown. Proper exciple with radiating clusters of crystals produced around hypothecium and expanding to excipular rim and finally shown as pruina on surface, hyaline downwards but brown around rim, the brown concolorous or slightly paler to epihymenium, 80-100 μm wide laterally. Epihymenium brown to dark brown, ca. 10 μm high, with pruina (ca. 10 μm high) on surface. Hymenium hyaline, 70-80 μm high. Hypothecium hyaline, 80-100 μm high. Other small crystals present a few in upper hypothecium. Oil droplets absent. Asci cylindrical, 8-spored, 65-75 x 10-16 μm (n = 7). Ascospores acicular to filiform, up to 13-septate, 45-70 x 2.5-4.5 μm (n = 10). Pycnidia not detected. Chemistry. Thallus K+ yellow, KC-, C-, Pd-, UV-. Epihymenium K-. Atranorin was detected by TLC. Notes. Bacidia suffusa is the most similar to B. russeola (Kremp.) Zahlbr. in having dark apothecia, generally colourless epihymenium without green pigment, long ascospores with the L/W ratio over 11, pale or colourless hypothecium and K+ purple reaction on epihymenium and nearby excipular rim amongst corticolous species. However, B. suffusa differs from B. russeola by the presence of pruina on the disc and in proper exciple as radiating clusters of crystals and more than 10-septate ascospores ( Ekman 1996 ). Phylogenetic analysis resulted in B. suffusa of Korea (ON352605, ON352614, ON352615 and ON352616) being nested in a sister clade of the sequences of Pakistan (MW728313 and MW788561), Russia (MH048615, MH048616 and MH048617) or U.S.A. (MH048618 and MH048619). The molecular data of Korea converged into the previous data of B. suffusa , supported by a bootstrap value of 100 and a posterior probability of 1.00 for the branch (Fig. 2 ). Bacidia suffusa was previously detected from North America, North Caucasus, Russian Far East and Pakistan, but rare or absent in Europe ( Otte 2007 ; Gerasimova et al. 2018 , 2021 ; Adrees et al. 2022 ). This is a new record to Korea. Specimens examined. South Korea , Gangwon Province , Yanggu , Nam-myeon , Dumu-ri , a forested wetland, 38°02.12'N , 128°05.14'E , 421 m alt., on bark of Salix pierotii Miq. , 28 April 2020 , B.G. Lee 2020-000158 (KBA-L-0000358); same locality, on bark of Salix pierotii , 28 April 2020 , B.G. Lee 2020-000159 (KBA-L-0000359; GenBank ON352605 for ITS); same locality, on bark of Salix pierotii , 28 April 2020 , B.G. Lee 2020-000168, with Candelaria concolor , Phaeophyscia adiastola , Phaeophyscia hirtuosa (Kremp.) Essl. (KBA-L-0000368) ; South Korea , Gangwon Province , Gangneung , Okgye-myeon , Mt. Seokbyung , 37°34.45'N , 128°55.01'E , 271 m alt., on bark of Acer pictum var. mono , 17 June 2020 , B.G. Lee & H.J. Lee 2020-000799 (KBA-L-0000999) ; South Korea , Gangwon Province , Jeongseon , Imgye-myeon , Gamok-ri , a forested wetland, 37°32.47'N , 128°57.72'E , 760 m alt., on bark of Fraxinus chiisanensis Nakai , 17 June 2021 , B.G. Lee & H.J. Lee 2021-001304, with Normandina pulchella (Borrer) Nyl. , Phaeophyscia sp. (KBA-L-0002776; GenBank ON352614 for ITS); same locality, on bark of Fraxinus chiisanensis , 17 June 2021 , B.G. Lee & H.J. Lee 2021-001305, with Anisomeridium polypori , Normandina pulchella , Phaeophyscia sp., Porina hirsuta (KBA-L-0002777); same locality, on bark of Fraxinus chiisanensis , 17 June 2021 , B.G. Lee & H.J. Lee 2021-001306, with Normandina pulchella , Opeltia flavorubescens , Phaeophyscia adiastola (Essl.) Essl. (KBA-L-0002778; GenBank ON352615 for ITS); same locality, on bark of Fraxinus chiisanensis , 17 June 2021 , B.G. Lee & H.J. Lee 2021-001308, with Phaeophyscia adiastola (KBA-L-0002780); same locality, on bark of Fraxinus chiisanensis , 17 June 2021 , B.G. Lee & H.J. Lee 2021-001320, with Opeltia flavorubescens (KBA-L-0002792); same locality, on bark of Acer tartaricum subsp. ginnala , 17 June 2021 , B.G. Lee & H.J. Lee 2021-001363 (KBA-L-0002835; GenBank ON352616 for ITS) .