Rushes of the genus Juncus are herbaceous plants that superficially resemble grasses or sedges. They have historically received little attention from botanists; in his 1819 monograph, James Ebenezer Bicheno described the genus as "obscure and uninviting". As aquarium plants they are even less interesting. They may be used around ponds however.
Juncus has a cosmopolitan distribution, with species found throughout the world, with the exception of Antarctica. They typically grow in cold or wet habitats, and in the tropics, are most common in mountain environments.
There are a large number of species organized in a odd system of subgenera. It may be beyond the scope of an aquarists reference to include all of them, a selected few species are shown, the reader is invited to peruse the most recent (1999) monograph of the genus by Kirschner et. al. (SUPRASPEClFIC DIVISION OF THE GENUS JUNCOS
(JUNCACEAE, in Folia Geobotanica 34: 377-390, 1999) for more detailed information.