Origin: Introduced from Japan, Sakhalin, and Kuril Islands
selected vouchers: WTU
Notes: A large perennial herb persisting and slightly spreading at a long abandoned homestead, now forested, in Skagit Co. "NoCa" = National Park Service herbarium for North Cascades National Park, in Marblemount.
» Naas, D., R. Naas, and E. Burnett. 1990. A checklist of vascular plants of the North Cascades, Washington. North Cascades National Park, Sedro Woolley, WA. 57 p.
» Ohwi, J. 1984. Flora of Japan (in English). Smithsonian Institution, Washington, D.C.
» Toman, J. 1972. A taxonomic survey of the genera Petasites and Endocellion. Folia Geobot. Phytotaxon. 7: 381-406.