Yoania amagiensis Nakai & Maekawa 1931
Yoania amagiensis was described by Nakai & Maekawa (1931) from Mount Amagi, Idzu province in Central Japan. It is very closely related to Yoania japonica, but is distinguished from this species by its complicatedly branched rhizome, more numerous flowers (6-11) on the raceme, longer-stalked yellowish-brown flowers, ovate petals, long and densely bearded labellum, and longer ovaries. The strong resemblance resulted in the proposal of Hiroe (1971) who classified the variations as variation, Yoania japonica var. amagiensis. This proposal is not accepted today (WCSP 2021). Y. flava is known to be confused with this species aswell (Inoue & Yukawa 2002).