cotton grass

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. Any of various perennial grasslike plants of the genus Eriophorum native chiefly to wet places in northern temperate and cold regions and bearing at maturity one or more conspicuous tufts of cottony bristles.

Century Dictionary and Cyclopedia

1. n. The popular name of plants of the genus Eriophorum, natural order Cyperaceæ. They are rush-like plants, common in swampy places, with spikes resembling tufts of cotton. The cottony substance has been used for stuffing pillows, making candle-wicks, etc. Also cotton-rush, cotton-sedge.
2. n. A panic-grass, Panicum insulare, bearing cottony or silky hairs on its spikelets. It is a tropical species appealing in the southern United States, and, where abundant, is excellent for pasture. The name is also applied locally to the feather-sedge, Andropogon saccharoides. The Arizona cotton-grass is Panicum lachnanthum, called also wiry panic and silky panic-grass.

GNU Webster's 1913

1. n. (Bot.) a genus of plants (Eriphorum) of the Sedge family, having delicate capillary bristles surrounding the fruit (seedlike achenia), which elongate at maturity and resemble tufts of cotton.

WordNet 3.0

1. n. any sedge of the genus Eriophorum; north temperate bog plants with tufted spikes