bulrush

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. Any of various aquatic or wetland herbs of the genus Scirpus, having grasslike leaves and usually clusters of small, often brown spikelets.
2. n. Any of several wetland plants of similar aspect, such as the papyrus and the cattail.

Century Dictionary and Cyclopedia

1. n. The popular name for large rush-like plants growing in marshes. It is very indefinitely used. Thus, while Johnson says the bulrush is without knots, Dryden (“Meleager and Atalanta”) calls it “the knotty bulrush.” Some authors apply the name to Typha latifolia and T. angustifolia (cat's-tail or reed-mace); but it is more generally restricted to Scirpus lacustris, a tall rush-like plant from which the bottoms of chairs, mats, etc., are manufactured. (See Scirpus.) In the United States the name is commonly given to species of Juncus. The bulrush of Egypt (Ex. ii. 3) is the papyrus, Cyperus Papyrus.

Wiktionary

1. n. Any of several wetland herbs, of the genus Scirpus, having clusters of spikelets.
2. n. Any similar plant, such as papyrus.

GNU Webster's 1913

1. n. (Bot.) A kind of large rush, growing in wet land or in water.

WordNet 3.0

1. n. tall marsh plant with cylindrical seed heads that explode when mature shedding large quantities of down; its long flat leaves are used for making mats and chair seats; of North America, Europe, Asia and North Africa
2. n. tall rush with soft erect or arching stems found in Eurasia, Australia, New Zealand, and common in North America