@Bill: A few months ago, I posted about finding what appeared to be V. nana growing in a small/new urban "pond". This was the first time I've encountered this plant. Assuming the ID is correct, I'm guessing it originated from someone's aquarium.
Wonder if the plant in John's picture might be V. nana. The growth-patterns look very similar.
John - can you secure a better image of an extracted plant?
