The hike wasn't an area that I would have expected to find aquatic
plants. There were hundreds and hundreds of these growing in a
mountain meadow, about 11,000 feet. They were usually next to tiny
mountain brooks, but some of them were in the middle of the field, no
were near the water.
Chuck Gadd
http://www.csd.net/~cgadd/aqua

It's not what you think. Grab a plant list of apline plants of CO.
You'll find it. There's not too many plants that live at 11,000ft.
So that should narrow it down and it's a big old monocot.
Regards,
Tom Barr