Vallisneria Spiralis (Eel or Tape Grass)
Vallisneria spiralis is also recognized by the names of eel grass, tape grass, and channel grass. This plant is a firm favourite of most aquarists, and definitely one of mine. It is a tall plant, and well suited to form a background for the smaller ones.
It's, actually, just the plant one would expect to discover in an under-water scene. The tall, grass-like leaves are a light green in colour and rise vertically from the crown to the top of the water, where they float along the surface.
One of the very best oxygenators, Vallisneria spiralis also has the virtue of being simple to grow. The technique of propagation is by runners. These runners grow out from the crown along the sand, and new plants shoot up from the ends of them. It's feasible in a well-established tank to remove a plant and discover a entire string of them connected together. It's, as a result, advisable when removing plants of this nature from the aquarium to snip the runners prior to really removing the plant.
The species are separate, either male or female. The female flowers are on lengthy stems which reach to the surface. The male flowers are attached to the base of the leaves, which, when ripe, turn out to be detached and rise to the surface, where they float among the females fertilising them. The stem of the female flower coils up spirally under water, and it's from this that the name is derived.
Don't cover the crown with sand when planting, leave about 1/8 in. totally free.
Vallisneria torta is a variation of V. spiralis. The somewhat broader translucent leaves twist in a slow twirl like a corkscrew, and this plant is most likely much better recognized as 'corkscrew val'. This species doesn't grow so tall as V. spiralis. V. spiralis var. gigantea is an very big selection growing up to 6 ft. under favourable conditions, with leaves between 1/2 in. and 2 in. in width. It thrives in tropical aquaria in which a temperature of 85°F is maintained.