Planted Tank Guru
Join Date: Mar 2009
Location: Madison, Wisconsin
Those look like some kind of Vallisneria in the link (from that very unpopular Website) that oldpunk78 posted. Vals are also good ones for hard water. I don't know Vallisneria at all really, but the plants in those pictures look like they have very short leaves, with long flower stalks. Something like that would scale nice with your tank.
I like Vallisneria. Those lake-bottom pictures resemble the hard water lakes that we have around here, in the springtime, before they fill up with stinky algae.