I can even give better coordinates on where to possibly find them:
"Submerged basidiocarps were collected underwater in the Rogue River at 42°51′42″N, 122°30′28″W, 900 m elevatioin, approximately 45 km downstream from Boundary Springs, the predominant source of water for the upper reaches of the Rogue River in the Rogue River-Siskiyou National Forest"