I have a few plants in my freshwater aquarium. Recently I have noticed
a stringy substance coming off of them. It almost reminds me of a web
being stretched by the water.

I have discussed it (verbally describing the situation) with some other
hobbyists and have received to possible answers.

1) Algae growth from the plants.
2) Plants are rooting

The substance extends from all parts of the plant.

Any help greatly appreciated... Justin