Cypripedium japonicum Thunb.

Distribution : Japan
Pictures 3 & 4 in Japan, Honshu, Kyoto, May 2008 (cultivated)
Pictures 5 & 6 in Japan, Honshu, Nikko, June 2010 (cultivated)
(picture 1 by Benoit Gauthier, drawing by Cédric Basset)