mudboots

I went to a wetland site that was inundated to about an inch on average across a couple of acres (some isolated deeper areas). I found 5 sps of Ludwigia. I have to revisit the site in August and hope to get pics of a species thought to be L. pilosa. But I brought one home and had a tough time differentiating between L. repens and L. palustrus. The key I was using at the office (North Central Texas - Diggs, Lipscomb and O'Kennon) differentiated mostly based on the repro structure, noting that in L. repens it sits on a pedicel that can be as short as 0.3mm, while the structure in L. palustrus is sessile.

So, I am leaning toward L. palustrus, but wanted some help confirming. Here are the pics of the specimen I brought home. It was prostrate, making a mat in the field, but has straightened since I planted it in the picotope yesterday. You can see the petioles, but it fits in the range described for both species, as does the leaf shape...I did not cut open the capsules.

Michael

Shinner and Mahler's Illustrated Flora of North Central Texas--I know it well! Can't help with the Ludwigia though, those things confuse me to death.

Cavan Allen

It looks like L. palustris to me. L repens capsules are not as stout and have shorter sepals. The latter also has petals, though they are shed somewhat early. Also, I've just plain seen a lot of both. Could be a hybrid of the two, though I still lean to palustris.

This is available online free somewhere, though I have to dig it up. It is by far the best reference for this:
http://www.google.com/url?sa=t&rct=j...ryIVeFqJdOY_cw

mudboots

Awesome and Thanks!!! I wish L. decurrens would grow submersed in aquaria...it's one of the nicer ones I saw out there. Maybe there's room for a stem or two in the Wetland-n-a-Box at my office.

Cavan Allen

Found it!

http://www.biodiversitylibrary.org/p...8100087371.pdf

mudboots

Thanks Cavan; I'll swim through it when I get back from my wetland training travels.