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..
Grasses with narrow, flat or involute leaf-blades and contracted or open panicles. Spike-lets shortly pedicelled, 2-6-flowered, the glabrous rachilla articulated between the flowers, the internodes very long. Scales 4-8, membranous, the lower 2 empty, keeled, the flowering scales dorsally rounded at the base, 3-nerved, the lateral nerves pilose, deeply 2-lobed at the apex, long-awned between the lobes, the callus long and subulate, pubescent on the outer surface; palet 2-keeled, the keels long-ciliate. Stamens 3. Styles short, distinct. Stigmas plumose. Grain free, enclosed in the scale. [Greek, referring to the 3 divisions of the flowering scales.]
Culms 1°-3° tall, erect, prostrate or decumbent, smooth and glabrous or the nodes pubescent. Sheaths shorter than the internodes, rough; ligule a ring of short hairs; blades 1/2'-2 1/2' long, 1" wide or less, rigid, scabrous, sometimes sparsely ciliate; panicle l' - 3' in length, the branches rigid, finally widely spreading, the lower 3/4'-1 1/2' long; spikelets 2-5-flowered, 2 1/2"-4" long, the joints of the rachilla half as long as the flowering scale; lower scales glabrous; flowering scales oblong, 2-lobed at the apex, the lobes erose-truncate, the nerves strongly ciliate, the middle one excurrent as a short point; palets long-ciliate on the upper part of the keel.