Abstract
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 distribution 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.
