Yoania japonica Maximowicz 1873
Yoania japonica is the type species of its genus and was described by Maximowicz (1873). It has been recorded from the Himalaya Mountains of South China, Assam (India), Taiwan and montane Japan (POWO 2021). There are two proposed variations of this species: Yoania japonica var. squamipes and Yoania japonica var. amagiensis. Both resulted in the proposal of a seperate species, of which Yoania squamipes was synonymized but Yoania amagiensis is accepted as distinct. Y. amagiensis differs from Y. japonica by its complicatedly branched rhizome, more numerous flowers (6-11) on the raceme, longer-stalked yellowish flowers, ovate petals, long and densely bearded labellum, and longer ovaries (Nakai & Makaewa 1931). Yoania prainii is another very similar species of which the first specimens were determined to be Y. japonica until King & Pantling (1898) described them as a distinct species (Nakai & Makaewa 1931).