Matteuccia orientalis (Hook.) Trevis.

Picture 1 in Japan, Honshu, Hibara Lake, June 2010
Picture 2 in Japan, Honshu, Gomi Pond, June 2010
Distribution : China, Japan, Korea, Taiwan, Bhutan, Nepal

Description in Atti Reale Ist. Veneto Sci. Lett. Arti ser. 3, 14:586 (1869)