Leymus komarovii (Triticeae, Poaceae) in Japan

Leymus komarovii (Roshev.) J. L. Yang & C. Yen (Triticeae, Poaceae) is a rare species in Japan, reported only twice from Hokkaido. In 2018, an additional specimen of L. komarovii was collected in Oketo-cho, Tokoro-gun, Hokkaido. Subsequent examination of specimens in Japanese herbaria revealed that its dis-tribution range in Hokkaido was wider than previously known. Asperella longearistata (Hack.) Ohwi f. glabra Ko. Ito, described from Hokkaido, is reduced to synonym under L. komarovii and a lectotype for Hystrix sachalinensis Ohwi, another synonym of L. komarovii, is designated, superseding a previous lectotypification. A detailed description of L. komarovii based on Japanese materials and a key to the Japanese taxa of Leymus is provided.