Yoania flava Inoue & Yukawa 2002
Yoania flava was described by Inoue & Yukawa (2002) from Southern Nagano, Central Japan. The examined specimens were formerly identified as Yoania amagiensis from Honshu, Nagano about 1.400 m a.s.l.. The authors recognized differences in flower colour and flower posture. Furthermore the patent flowers stronger resemble those of Yoania japonica. Subsequent studies by the authors pointed out, that Y. flava is closer related to Y. japonica (Inoue & Yukawa 2002). Y. flava has creeping rhizomes like Y. japonica. This differs from the collaroid rhizomes in Y. amagiensis. The flower colour is creamy yellow and differs from the yellowish-brown colours in Y. amagiensis and rosy colours in Y. japonica. The lip shape is another distinctive feature from Y. japonica. While Y. japonica is distributed in the northern parts of Nagano, Y. flava grows in the southern parts of Nagano and is not known from anywhere else. Inoue & Yukawa (2002) therefore hypothesize that the speciation of Y. flava occured recently.