Myelochroa aurulenta (Tuck.) Elix & Hale,

Mycotaxon 29: 240, 1987.

Basinonym: Parmelia aurulenta Tuck., Amer. J. Sci. Arts, Ser. 2 25: 424, 1858. Type collection: Harpers Ferry, Virginia, U.S.A., Tuckerman (lectotype in FH, Tuckerman Herb.!).

Parmelina aurulenta (Tuck.) Hale, Smiths. Contr. Bot. 33: 19, 1976.

Myelochroa coreana Y.S. Park, Bryologist 93: 132, 1990. Type collection: South Korea. Kwangwon Province: Mt. Sorak National Park, elevation 1100 m, July 10, 1986, Y.S. Park 1837 (holotype in DUKE!).

Myelochroa ibukiensis K.H. Moon, Kashiw. & Keis. Kobay., J. Jpn. Bot. 88: 140, 2013. Type collection: JAPAN. Prov. Ohmi (Shiga Pref.): Ibuki Shrine, Ibuki, Maibara City. On bark of Zelkova serrata, elevation about 180 m, November 16, 2012, H. Kashiwadani 50701 (holotype in TNS!).

For other synonyms, see Hale (1976) and Kurokawa and Arakawa (1997).

Chemistry. Race 1, atranorin, zeorin, leucotylic acid and its derivatives, and secalonic acid A. Race 2, atranorin, zeorin, leucotylin and its derivatives, and secalonic acid A.

Myelochroa aurulenta is characterized by a foliose thallus with pustules or granular soredia and a yellow medulla containing secalonic acid A, zeorin, and leucotylic acid or leucotylin.

The present species is easily distinguished from allied species of the genus by the presence of soredia. Soralia are variable in shape, varying from pustules to farinose soredia. They are formed laminally and subterminally; laminal soralia are rounded and often diffusing, and subterminal soredia often inflated, forming capitate soralia.

Hale (1976) considered that Parmelina aurulenta (= Myelochroa aurulenta) produces leucotylic acid as the major substance. According to Kurokawa and Arakawa (1997), leucotylic acid was demonstrated in 24 of 25 specimens collected in Japan, while leucotylin was detected from only one specimen. The Korean materials show a similar tendency with leucotylic acid demonstrated in 40 of the 43 specimens and leucotylin detected in only three specimens; however, no morphological differences have been found between the two chemical races, and the chemical difference seems to have no taxonomic value.

Park (1990) described Myelochroa coreana Y.S. Park based on a specimen collected at Mt. Sorak, Korea. As discussed by Moon (1999), the holotype specimen preserved in DUKE shows typical morphological characters found in M. aurulenta. In addition, specimens examined by her include the two chemical variations shown above. Therefore, M. coreana is simply reduced to a synonym of M. aurulenta.

Moon et al. (2013) described Myelochroa ibukiensis K.H. Moon, Kashiw. & K. Kobayashi based on a specimen collected at Ibuki, Maebara-city, Japan. They stressed the presence of red dots that appeared to be pigments of the medulla; however, detailed study of the holotype reveals that the red dots are derived from the juvenile colony of a parasitic fungus (Marchandiomyces corallines), which does not belong with the mycobiont of the holotype. All other morphological and chemical characters are those found in M. aurulenta. Thus, M. ibukiensis is reduced to a synonym of M. aurulenta.

In Korea, M. aurulenta has been reported as Parmelia aurulenta (Park, 1979; Lee, 1987; Ri and Hyun, 1988; Ri, 1988; 2000), Parmelina aurulenta (Hale, 1976), M. coreana (Park, 1990) and M. aurulenta (Park, 1990; Moon, 1997; 1999; Kashiwadani et al., 2002; Hur et al., 2004; Jayalal et al., 2012).

Myelochroa aurulenta is widely distributed in temperate and subtropical regions in the world excepting Europe, having been reported from Japan, eastern and southeastern Asia including Siberia, Korea, mainland China, Taiwan, Hong Kong, Pakistan, Nepal, India, Sri Lanka, Java, the Philippines, New Guinea, eastern Africa including Madagascar, Hawaii, Canada, the U. S. A., Mexico and South America (Hale, 1976) and Australia (Kurokawa and Arakawa, 1997). This species was also reported from Thailand (Moon et al., 2000), Fiji (Elix, 2001) and Turkey (Yazici et al., 2010).

Myelochroa aurulenta is apparently widely distributed throughout the Korean peninsula.

Representative specimens examined. Prov. Hamkyongnam, Pyong-yang, Forest Sung-ja, P. Chun (F. Den) (TNS). Prov. Gangwon (=Prov. Kangwon), Pyongchang-gun, Jinbu-myun, Mt. Ohdae, around Woljong temple, on Tsuga sp., elevation 670-690 m, October 8, 1995, K.H. Moon 1956 & H. Kashiwadani (TNS); Inje-gun, Puk-myon, Mt. Sorak, around Peaktam temple, on bark of Prunus jamasakura, elevation 460-550 m, October 6, 1995, K.H. Moon 405 & H. Kashiwadani (TNS). Prov. Gyongsangbuk, Yecheon-gun, Pungyang-myeon, Hyogal-ri, around Chungryoung Temple, on bark of Juniperus sp., elevation 145 m, May 3, 2009, K.H. Moon 10820 (NIBR); Gyeongju city, Jinhyeon-dong, around Bulguk temple, on bark of Zelkova serrata, elevation 230 m, September 16, 2012, K.H. Moon 13463 (NIBR). Prov. Jeonllanam, Gohung-gun, Podu-myeon, Mt. Cheoundeung, St. Gumtap-gil, around Gumtap temple, on bark of Zelkova serrata, elevation 100 m, October 18, 2013, K.H. Moon 13877 (NIBR). Prov. Jeju (=Prov. Cheju), Cheju-shi, Odung-dong, Kwanum temple, on bark of Prunus sp., elevation about 580 m, May 29, 2001, K.H. Moon 5928 (TNS).