Identification Information: The species was described as a Letharia (Asahina 1952) and later transferred to the genus Lethariella according to morphological-anatomical and chemical characters (Krog 1976). It is the only species of the subgenus Nipponica; the latter is characterized by the solid and elastic axis, like in Usnea, but with soft, reticulately ridged cortex. The genus Letharia is morphologically separated from Lethariella mainly bythe lacerate axis. The yellow-coloured thallus due to vulpinic acid is distinct in Letharia; this substance is also present in the medulla of Lethariella togashii but due to the low concentration not always recognizable as yellow pigment (Obermayer 1997; Ohmura 2011).
Global distribution of Lethariella togashii is limited to only six localities in Japan and Russian Far East, meaning it's true area of occupancy is likely to be well below the threshold for Vulnerable (2,000 km²). In Japan, it has been recorded in Hokkaido (2 locations, extant) and in central Honshu, around Mt. Fuji,but in this area the species has not been found after 1950s, and is considered extinct at present. It is also known from Russia: Sakhalin, Kunashir Isl. and adjacent region in Habarovsk krai (Sikhote-AlinMts), all 3 locations are extant. The species is treated as a relict from the last glacial period and its distribution area in Japan has declined (Kashidawani & Inoue 2000; Y. Ohmura, pers. comm.). It is alsounder threat in Russian locations by the destruction of habitats (montane coniferous forests), possibly due to human activities – forest fires and tree cutting (Russia’s Boreal Forests 2007).
Assessor/s: Ohmura, Y., Randlane, T. & Spribille, T.; Reviewer/s: Scheidegger, C.; Contributor(s): Weerakoon, G.
Bibliography:
Asahina, Y. (1952) Lichenologische Notizen §85–87. Journal of Japanese Botany27:293–296.
IUCN (2018) The IUCN Red List of Threatened Species. Version 2018-2. Available at: www.iucnredlist.org. (Accessed: 15 November 2018).
Kashiwadani, H. & Inoue, M. (2000) Lichens. In: Environment Agency (ed.), Red Data Book 2nded, Bryophytes, Algae, Lichens, Fungi, pp. 259–312. Japan Wildlife Research Center, Tokyo.
Krog, H. (1976) Lethariella and Protousnea, two new lichen genera in Parmeliaceae. Norwegian Journal of Botany23: 83–106.
Obermayer, W. (1997) Studies on Lethariella with special emphasis on the chemistry of the subgenus Chlarea (Lichenological results of the Sino-German Joint Expedition to south-eastern and eastern Tibet1994. IV). J. Cramer in der Gebr. Borntraeger Verlagsbuchhandlung, Berlin-Stuttgart.
Ohmura, Y. (2011) Notes on eight threatened species of lichens in Japan. Bulletin of the National Museumof Nature and Science, Series B 37: 55-61.
Skirina, I. F. (2006) Lethariella togashii (Parmeliaceae), a rare new species to the lichen flora of Russia from the southern Far East. Botanicheskii Zhurnal (St. Petersburg) 91: 1114–1116.
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