Here are more pics that are probably better. I am leaning towards the slender pondweed (Potamogeton pusillus) or some variation of it, but still have doubts. I must admit that I have a hard time translating what some of the descriptions really mean when they talk about this plant stuff. The leaves look like the slender pond weed link that I included below. Yet the leaves seem to both alternate and opposite at different places on the same vine.
Here is a shot of a basic run of the weed. The plant branches out, one being a large leaf, the other turns into a small stem that then just goes a short way and has leaves again. It does this along the entire length of the vine/stem.
This is another shot of the same along the same stem, but seems a bit more advanced/longer.
And here is the end of the vine with seed pod? Looks like a total of eight seeds to me. Four on each side. This doesn't look like the slender pondweed seed photo in my link below.
Seed Pod of slender pondweed Leaves of slender pondweed
