Plant ID?

[JBtheExplorer]

So, this plant started growing in the pot I keep my Red Stem Golden Club in. I have no idea what it is or how it got in there. It seems to take being underwater well, so I'm guessing it may be some sort of pond plant, but I have no idea what it is. Can someone ID it?

 

[bettasngoldfish]

Maybe this? http://www.liveaquaria.com/product/prod_display.cfm?c=768+1626&pcatid=1626

 

[HARO]

Some type of sagittaria or valisneria, most likely. Both sold as tape grass in the aquarium trade.
John