Quillworts are low plants similar to Club Mosses. In contrast to the terrestrial Mediterranean Quillworts such as Isoetes histrix, the representatives of the genus native to Central Europe live under water, e.g. in the lakes Titisee and Feldsee in the Black Forest, or in lakes of the Vosges in France. Isoëtes lacustris is the more common of the two native Quillworts. Occasionally, plants that have detached from the bottom are washed onto the shore. The fine threads between the branches are Algae that do not belong to the Quillwort.