Vallisneria spiralis
Vallisneria spiralis, also known as straight vallisneria, tape grass, or eel grass is a common aquarium plant that prefers good light and a nutrient rich substrate. In the wild, it can be found in tropical and sub-tropical regions worldwide.
Overview
It has narrow, linear leaves that range in colour from a pale-green to reddish up to 3 feet long and up to 0.75 inches broad. V. spiralis is monoecious with male flowers carried on long spiral stalks that break away from the plant and float on the water's surface. In the variety V.s, gigantea the female flowers are on stalks up to six feet in length. After the female flowers have been pollinated, the pedicel curls up like a tendril, drawing the young fruit closer to the bed of the stream or pond; thus the name "spiralis". Seeds have not been observed germinating in aquaria. Instead, it most often propagates by runners which can lead to dense stands.One form of this plant has been described: V. spiralis f. tortifolia, which has also been elevated to the species level by some taxonomists under the name V. tortissima. The form has tightly twisted leaves. Along with this form, many other trade names have been developed for small variations on the species. Their taxonomic status is uncertain.