a rolling moss gathers no stones

Glacier mice !!!

http://mossplants.fieldofscience.com/2012/08/moss-tumbleweeds.html

That is so neat to know. I've got places where the sphagnum moss grows like this, sometimes into towers 8 or 10 inches tall.

Edit: I was just thinking that maybe I should gather some up to grow some of my smaller phalaenopsis orchids on them. Note to Icelanders, this could be a money making proposition, orchid growers can be more rabid than permies, but usually with a lot more money. lol

or portable mushroom factories !