Syneilesis palmata Maxim.

in South Korea, Sobaeksan, September 2011 (picture 2)
in South Korea, Wolaksan, September 2011 (pictures 3, 4 & 5)
in Japan, Honshu, Aizu, June 2010 (picture 6)
in Japan, Shikoku, Omogo, May 2008 (pictures 7, 8 & 9)
in Japan, Honshu, Kawaguchi Lake, May 2008 (pictures 10 & 11)