Northern Prairie Wildlife Research Center
SEDGE FAMILY (Cyperaceae)
IND. STATUS: OBL
FIELD CHARACTERISTICS: A clump-forming, perennial herb. The stems grow to a height of 2-7 dm. Leaves are thread-like and 1 mm. wide. The spikelet is solitary with several sterile, basal scales. Nutlets are 2.5-3.5 mm. long and are surrounded by long, silky, bright white bristles. In flower, and thus conspicuous, in May and June. E. vaginatum is the only cottongrass in Minnesota and Wisconsin that is both densely cespitose (clump-forming) and has a single spikelet on the stem.
ECOLOGICAL NOTES: Tussock cottongrass is generally restricted to bogs. Its name is derived from the fact that the flowering head resembles a ball of cotton. A synonym is E. spissum Fern. There are seven species of cottongrass (Eriophorum spp.) in Minnesota and Wisconsin, all of which have the cottonball flowering heads, and all are found in bogs. One species (E. angustifolium) also occurs in calcareous fens.
SOURCE: Gleason and Cronquist (1991); and Voss (1972).