Vallisneria, a genus of endogenous aquatiG plants, named in honor of Antonio Vallisnieri. It belongs to a small family, the hydrochariclacea, all water or marsh plants, and consists of but two species, one exclusively Australian, and the other, V. spiralis, found in the fresh waters of most countries, especially the warmer ones, and in nearly all parts of the United States, where it is known as tape grass and eel grass, though quite distinct from the eel grass of salt waters (zostera). The stem or rootstock lies prostrate in the mud; from this proceed the tape-like leaves, 1 to 2 ft. long, 2 to 5 lines wide, and minutely serrulate on the edges; these are dark green and entirely submerged. The flowers are dioecious; those of the staminate plant are several in a small cluster, surrounded by a three-valved spathe and borne upon a very short scape which rises at the base of the leaves. The fertile flowers are solitary, with a long ovary, at the apex of which are three small petals and three large two-lobed stigmas; each flower is borne upon a slender spirally coiled scape, which is from 2 to 4 ft. long, according to the depth of the water.
At flowering time these female or pistillate flowers rise by means of their long flexible stems to the surface of the water, where they are quite beyond the reach of the staminate or male flowers, which are confined at the bottom upon a stem only about an inch long. The male flowers, as they mature, spontaneously break away from their short stems and rise to the surface, where they expand and float about, shedding their pollen upon the stigmas of the female flowers; after fertilization takes place, the long stem to* the pistillate flower shortens its coils and carries the impregnated ovary to the bottom again, where it ripens into a many-seeded berry from half an inch to two inches long. The leaves of Vallisneria afford a most interesting object for the microscope; the tissues being very thin and transparent, they allow the contents of the cells to be distinctly seen, and these are found to be in constant motion, the contents of each cell moving independently of those of the others. The plant is very abundant in some waters; there are localities upon the Hudson where at certain seasons it is difficult to force a boat through it.
It is also abundant on the waters of Chesapeake bay, where it is called by the singular misnomer of wild celery; the rootstocks and their buds are the favorite food of the canvas-back duck, a fact recognized in its specific name, fuligula Vallisneria.
Vallisneria spiralis - Staminate and Pistillate.