This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol1", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Perennial by tuber-like corms, culm slender, smooth, erect, mostly longer than the leaves. Leaves pale green, 1 1/2"-2" wide, those of the involircre 5-10, the longer usually much exceeding the umbel; umbel simple, 6-13-rayed, the rays filiform, their sheaths short, mucronate; spikelets 2"-3' long, linear, flat, densely or lopsely capitate in globose heads; scales thin, pale green, appressed, ovate-lanceolate, acute, 9-13-nerved, with narrow scarious margins; joints of the rachis broadly winged; stamens 3; style 3-cleft; achene oblong-obovoid, obtuse, one-half as long as the scale, about twice as long as thick.