what is this?!!!

went on vacation to yellowstone and montana last week and found so many plants that i want namly this water plant, the leaves look like a water hawthorn but the flower isnt right any ideas?

I think it is Swamp Smartweed (Polygonum amphibium).
There are two forms, the floating and the terrestrial. Your pic is of the floating form.
http://www.ct-botanical-society.org/galleries/polygonumamph.html

wow thats it

ill have to find some now:)

thank you!

we have the terrestrial form, never knew it had a water form. Learn something new every day. :-)

I have some in my pond, we just found it in the ditch
by the raod side..
I really like the pink colour in the pond..

Wilma