HeyPK

They look as though they are related to Eichornia crassipes, the water hyacinth, but they turn out to be Heteranthera species, and there are two of them. The first is, I think, H. reniformis:


This species has multiple flowers on a stalk. The other plant in the picture is Ludwigia peploides:


The other species has single white flowers. It could be H. limosa, which usually has blue flowers, but is also shown in a number of pictures with white flowers. Or, it could be H. rotundifolia, which, on the USDA plant database, is west of Mississippi but not in Mississippi.

davemonkey

Awesome! We have H. limosa here in SE Texas as well (at least in the coastal counties) and I've only seen them with blue flowers. They also seem to stay quite small (compared to other wetland plants like burheads and pickerel weed).

Noto

Nice! For what it's worth, the few H. limosa I've seen blooming in TN have had white flowers.

PeterE

Great pics! Both look like attractive species.

Tex Gal

The heart-shaped leaves are adorable. What is the size? Does the submerged growth look the same?

HeyPK

The H. reniformis can have leaves two to three inches across with petioles up to six inches long. The floating plants in the first picture were smaller with leaves an inch or so across. I suspect that the submerged growth would have strap-like leaves.
Update: They sprayed the ditch with roundup, and all the visible growth of the white-flowered species was killed. Hopefully, they didn't get all of it, and the species can make a comeback. It is a nice ditch for other aquarium plants, such as Echinodorus cordifolius. I don't know why people hate plants that grow in ditches. The ditch was so much prettier when it was all green and the plants were flowering. Now it looks all brown and dead.

HeyPK

The white-flowered Heteranthera species is coming back! They sprayed the ditches and they also used a weed eater before they sprayed. The plants that were not cut down with the weed eater were killed entirely by the roundup, but the plants that were cut down got such a small dose of the roundup that they are putting out new leaves. Yea! Nature, 1. Stupid anti-nature people, 0.

HeyPK

Update and major correction!

The white flowered species, I am now convinced, is not Heteranthera at all, but Limnobium spongia. I should have recognized it by its flower, which has too many petals to be Heteranthera.

Attached Thumbnails

 

miremonster

Hello Paul,
nice to see real Limnobium spongia! The name is often in aquarium literature, also erroneously for L. laevigatum in the trade, but it seems to me that this species is nowhere cultivated in Europe.

Cavan Allen

I saw it in Vermont one time.