Wrack Grass, Or Grass Wrack, the plant zostera marina, of the pond-weed family (naiadaceai), growing at or beyond low-water mark upon sandy or muddy sea shores in most parts of the world. Wrack is an old Norse name for sea weed thrown ashore, this being called grass wrack in distinction from the proper sea weeds or algaa. Along our coasts it is usually called eel grass (see Vallisneria for the eel grass of fresh water), and incorrectly sea weed; on the Florida coast it is known as aloa. The genus zostera (Gr. Cwcrr^p, a band, in reference to the long and narrow leaves) contains but two species; they are marine herbs with jointed creeping stems, and long grass-like leaves which grow completely under water, or are covered at high tide; the monoecious flowers have both kinds enclosed in the sheathing base of a leaf which serves as a spathe; they are arranged in two rows upon one side of a narrow leaf-like spadix; the staminate consist of single, ovate, one-celled, sessile anthers; the fertile of oblong ovaries, attached near their apex, and terminated by two long, bristle-like styles, and in Z. marina ripening into an oblong ribbed seed, or nutlet. The other species, Z. nana, found on the shores of western Europe, is seldom a foot long, and has smooth seeds.

Wrack grass is very abundant in the bays and inlets of the coast, and is often washed up in large quantities by the tide; it is collected with the true sea weeds for a fertilizer; it is also used to protect tender plants in winter, and to place around cellar walls to keep out the frost. In Holland it is utilized in the construction of dikes. When dried the leaves have considerable toughness, and they make an excellent material with which to pack glass and china ware; dried and baled, it is an article of trade, being used by upholsterers to stuff cushions, mattresses, etc.; but it is not sufficiently durable, and is only used for the cheapest kind of work. The fibre has been used to some extent in paper making.

Wrack Grass (Zostera marina).