Myelochroa irrugans (Nyl.) Elix & Hale,

Moon, Kwang Hee, Ahn, Chorong & Kashiwadani, Hiroyuki, 2015, Revision of the lichen genus Myelochroa (Ascomycotina: Parmeliaceae) in Korea, Journal of Species Research 4 (1), pp. 23-32 : 26-27

Myelochroa irrugans (Nyl.) Elix & Hale,

Mycotaxon 29: 241, 1987.

Basinonym: Parmelia irrugans Nyl., Lich. Japon.: 26, 1890. Type collection. Japan, Umagayeshi, Mt. Fuji, E. Almquist (lectotype in H; Nylander Herb. 35551!).

Parmelia subaurulenta Nyl. , Flora 68: 606, 1885- Myelochroa subaurulenta (Nyl.) Elix & Hale, Mycotaxon 29: 241, 1987. Type collection. India, N.W. Himalays, Narkanda, Skoliczka (lectotype in H; Nylander Herb. 35672).

Parmelia homogenes Nyl. , Flora 68: 607, 1885. Type collection. India, Hooker & Thomson 1942 (lectotype in H; Nylander Herb. 35664).

Myelochroa crassata (Hale) Elix & Hale, Mycotaxon 29: 240, 1987. Type collection. Japan, Prov. Kozuke, Mt. Amagi, S. Kurokawa 550466 (holotype US and isotype in TNS).

Parmelia denegans auct. non Nyl.: Cho SS and Lee YN, 1980.

Myelochroa xantholepis auct. non (Mont. & Bosch) Elix & Hale: Jayalal et al. 2012.

For other synonyms, Kurokawa and Arakawa (1997) and Hale (1976) under Parmelina irrugans and P. subaurulenta .

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 irrugans is characterized by the lobes loosely attached to the substrata, the absence of asexual propagules and the absence of galbinic acid. Morphologically this species very much resembles M. galbina , which differs by the production of galbinic and salazinic acids. In addition, it is rather loosely attached to the substrate, whereas M. galbina is always tightly attached.

In 2012, Jayalal et al. reported M. xantholepis (Mont. & Bosch) Elix & Hale from South Korea and stressed that their specimens have dimorphic lobes and a pale yellow medulla. Although the Korean specimens used by them have newly found small lobes ( Fig. 1 ), these are not the same as those found in M. xantholepis , which has dichotomously divided lobules ( Fig. 2 ) toward the lobe margins ( Hale, 1976). In addition, the yellow medulla of the Korean materials is different from the characteristic orange-yellow medulla observed in M. xantholepis ( Hale, 1976) . Therefore, these specimens should be simply identified with M. irrugans .

Cho and Lee (1980) reported the occurrence of Myelochroa denegans (Nyl.) Elix & Hale under a name of Parmelia denegans . Although the specimen examined by them has disappeared and is unable to be traced, it is highly possible that this specimen could be identified with M. irrugans as they indicated the absence of soredia and isidia, and the presence of K+ yellow medulla.

Myelochroa irrugans shows extensive variation in regard to thickness of the thallus, lobe width and size of mature apothecia. Among the specimens of this species, those with a narrow and thin thallus were once treated under Parmelia subaurulenta (= M. subaurulenta ) and those with small apothecia as P. subaurulenta var. myriocarpa ( Asahina, 1951) ; however, these morphological characters found in the present species have no taxonomic value for separating species as already discussed by Kurokawa and Arakawa (1997).

This species has two chemical races characterized by differences in terpenoides (the leucotylic acid containing race and the leucotylin containing race). Both races are commonly found throughout the Korean peninsula.

Myelochroa irrugans is one of the common species of Myelochroa in Korea. It has been reported from Korea as Parmelia irrugans ( Lee, 1987) , as Parmelia subaurulenta ( Asahina, 1951; Kim, 1965; 1979; Park, 1976; Cho and Lee, 1980; Ban, 1983; Lee, 1987; Ri, 1988), as Parmelia homogenes ( Kim, 1965; Cho and Lee, 1980; Ri, 1988), as M. crassata ( Park, 1990) , as M. subaurulenta ( Park, 1990; Huneck et al., 1994) and as M. irrugans ( Park, 1990; Moon, 1998; 1999; Kashiwadani et al., 2002; Hur et al., 2004; Jayalal et al., 2012).

This species seems to be endemic to eastern Asia, having been reported from China, India, Japan, Nepal, Sakhalin, Sri Lanka, Taiwan and Thailand ( Kurokawa and Arakawa, 1997; Jayalal et al., 2012). In Korea, it grows on tree trunks and rocks including stone works and is found from lowlands to mountainous areas.

Representative specimens examined. Prov. Hamkyongnam, Shihung-gun, Hamjiwon, August 2, 1934, F. Fujikawa (TNS). Prov. Gangwon (=Prov. Kangwon), Tongchon-gun, eastern slope of Mt. Daimond, Outer Diamond (Ohikumgang), July 28, 1934, Y. Asahina (TNS); Pyongchang-gun, Jinbu-myun, Mt. Ohdae, around Woljong temple, on bark of Tsuga sp. , elevation 670-690 m, October 8, 1995, K.H. Moon 1962 & H. Kashiwadani (TNS); Hongcheon-gun, Nae-myeon, Myeonggae-ri, Mt. Ohdae, en route from Mt. Ohdae control office at Myounggyeri to Bukdae Temple, on bark of Quercus sp. , elevation about 650 m, April 23, 2009, K.H. Moon 10961 (NIBR); Sokcho city, Mt. Sorak, en route from Mangyongdae to Mt. Daechongbong, on bark of Quercus crispula , elevation about 1000-1480 m, July 17, 1996, K.H. Moon 1076 & H. Kashiwadani (TNS); Jeongseongun, Mt. Hambaek, on bark of Quercus sp. , elevation 1401 m, June 19, 2007, J.S. Hur 070662 (KoLRI no. 007 535, as M. xantholepis ). Seoul, Chongno-gu, Mt. Pukhan-san, en route from Younhwa temple to Kumson temple, on rocks along stream, elevation about 285 m, August 24, 1997, K.H. Moon 1680 (TNS). Incheon, Ongjin-gun, Bukdo-myeon, Jangbong-ri, on bark of Quercus acutissima , elevation about 10 m, April 20, 2013, K.H. Moon 13354 (NIBR). Prov. Chungcheongbuk, Danyang-gun, Mt. Sobaek, on bark, elevation 1322 m, April 25, 2007, J.S. Hur 070344 (KoLRI no. 007489, as M. cf. xantholepis ); Danyang-gun, Mt. Sobaek, on bark of Quercus sp. , elevation 1009 m, June 10, 2007, J.S. Hur 070412 (Ko LRI no. 007274, as M. cf. xantholepis ). Prov. Gyongsangbuk, Pohang city, Nam-gu, Homigot-myeon, Gangsa-ri, on rocks, elevation about 20 m, September 15, 2012, K.H. Moon 13442 (NIBR); Ulleung-gun, Ulleungeup, Dodong-ri, Haengnam walking track along east coast, on rocks, elevation about 5 m, June 28, 2012 (NIBR). Prov. Gyongsangnam, Geoje city, Jangseungpo-dong, on rocks, elevation about 50 m, September 12, 2012, K.H. Moon 13368 (NIBR). Prov. Jeonllanam, Yeosu city, Geomun-do, on rock, elevation 61 m, March 24, 2007, J.S. Hur 070150 (KoLRI no. 007137, as M. cf. xantholepis ); Gohung-gun, Podu-myeon, Namseong-ri, around Geumtap-sa temple, on rocks, elevation about 100 m, October 18, 2013, K.H. Moon 13867 (NIBR); Sinan-gun, Heuksan-myeon, Jin-ri, Is. Heuksan en route from Ye-ri to Jin-ri, on rocks, elevation about 4 m, July 29, 2008, K.H. Moon 10560 (NIBR). Prov. Jeju (=Prov. Cheju), Mt. Halla, en route from Youngshil Rest Area to Witsae Oreum Shelter, on bark of Quercus sp. , elevation 1280-1650 m, May 24, 2001, K.H. Moon 5934 (TNS); Jeju city, Jocheon-eup, Seonheul-ri, around Seonheul pond, on bark of Prunus sp. , elevation about 180 m, May 24, 2012, K.H. Moon 13025 (NIBR).

Figures

Fig. 1. Myelochroa irrugans (Nyl.) Elix & Hale(reported as M. xantholepis (Mont. & Bosch) Elix & Hale by Jayalal et al. in 2012, J.S. Hur 070662(KoLRI no. 007535), KoLRI), showing newly developed young lobes(arrows). Scale bar=5 mm.

Fig. 2. Myelochroa xantholepis (Mont. & Bosch) Elix & Hale (collected from India and determined by S. Kurokawa, H. Hara s.n., TNS), showing dichotomously and irregularly divided lobules along the lobe margins (arrows). Scale bar=5 mm.