Unidentified NC native plant

[nplummer at duke_edu]

Last weekend, we drove down to Emerald Isle, North Carolina.  I abandoned
my wife on the beach and spent most of the day poking around roadside
ditches in Carteret County.  Why get sandy when you can get muddy?  Found
lots of interesting things:  Sundews, pitcher plants, bladderworts,
turtles, a big black racer, and a beautiful eastern glass lizard.

Among the aquatic plants, I found some very nice red Ludwigia and what I
am pretty sure is Proserpinaca palustris.  I also found a green plant that
I initially thought was a different color of Ludwigia, because it was
growing among the red stuff and had very similar leaves.  On closer
inspection, though, I see that the leaves are alternate rather than paired
like the Ludwigia leaves.

Is there a common eastern U.S. aquatic species that fits this (admittedly
vague) description?  Since it had recently rained heavily, I suppose this
could be a terrestrial species that was temporarily submerged, but it was
definitely growing in the same locations as the Ludwigia and Proserpinaca.

Nick

--
Nicholas Plummer
nplummer at duke_edu