North Carolina,
United States 
Two years ago, I attended a Shitake mushroom growing class. I brought the log home and left it in my stream for two years, and it is now growing hundreds of small water lily type pods. They are attractive but are now getting invasive which is not a problem. I wonder if anyone has an explanation for this weird outcome.
On plant
Shitake growth ?
24 Jul, 2013
Answers
I too thought cool and damp not a water course. It it were mine I'd remove and bin I think.
24 Jul, 2013
"Water lily type pods"? What do you mean, Cashiers? Are these mushrooms, or actual flowering plants?
24 Jul, 2013
I know little about growing mushrooms but thought you just kept them cool and damp, not in running water?
I would be very careful about introducing an unknown growth into a watercourse that could infest other watercourses.
24 Jul, 2013