Plant ID needed

I found this plant in a stream in New Hampshire, it seemed to grow in the higher current areas. (knowing my luck it'd just be millfoil as the pond the stream flowed from had signs warning about it).

looks like hornwort

looks to me to be hornwort as well.
mine often looks like that after a long cold winter,save some it may come back to good healthy state.
here is a link

http://www.lgyp.com/...50&srg=NH&biz=2

Edited by CATfishTONY, 27 April 2010 - 02:27 PM.

It can be hard to tell those apart if you aren't that familiar with them. Hornort (Ceratophyllum) will have leaflets that are whorled and the leaflets are often forked (sort of like a short family tree) They also often have tiny teeth. Myriophyllum spicatum looks similar (especially when out of water), but will have whorled leaves that are usually in groups of 4. These leaves generally will be pinnately branched, but not dichotomously, meaning that there will have filiments in pairs off the axis.

If you can, cut off a set of whorls and arrange it neatly and flat on a piece of paper for a photograph - sort of like a star. That will help nail it down for sure.

Looks pinnate to me >> milfoil. Does it have roots? Hornwort never has roots.

Does it have roots? Hornwort never has roots.

Supposedly it can grow rhizoids (or rhizoid-like structures) on occasion, but I've never seen any. And I've seen a pretty good sampling of hornwort.

Looks pinnate to me >> milfoil.

Ditto that. NOT hornwort.