Help: What is this plant

[zctyy]

Got this for free from another pond owner and put in my new bog. It grows extremely well here so I would like to know what this plant is.

Thanks

Please help.

 

[BKHpondcritters]

Looks like some variety of Arrow plant to me. I have a variegated version, but the flowers look really similar -

 

[Mmathis]

Pretty flower!

 

[addy1]

I agree a type of arrowhead plant.

 

[zctyy]

Thanks for the replies. I was thinking it is some type of sword plants but I could not find it online.