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..
Erect grasses with flat leaf-blades and racemose inflorescence. Spikelets 5-14-flowered; flowers perfect, or the upper staminate. Two lower scales empty, unequal, thin-membranous, 1-nerved, or the second imperfectly 3-nerved; flowering scales longer, membranous, 7-nerved, the middle nerve excurrent as a short point or awn. Palet scarcely shorter than the scale, 2-keeled, the keels winged or appendaged. Stamens 3. Styles short. Stigmas plumose. Grain free, enclosed in the scale and palet. [Greek, side-beard, from the appendages to the palets.]
Three known species, the following arctic, the others Californian. Type species: Pleuropogon Sabinii R. Br.
P. Sabinii R. Br. App. Parry's Voy. 289. 1824.
Smooth, culms 6' or less tall, erect, simple, glabrous. Sheaths one or two; ligule 1" long; blades 1/4'-1' long, erect, glabrous; raceme 1-2' in length; spikelets 3-6, 5-8-flowered, about 5" long, on spreading or reflexed pedicels 1" or less in length; lower scales smooth, the first acute, shorter than the obtuse second; flowering scales oblong, 2"-2 1/2" long, erose-truncate at the scarious summit, scabrous, the midnerve sometimes excurrent as a short point; palet slightly shorter than the scale, truncate and somewhat 2-toothed at the apex, bearing an awn-like appendage on each keel near the middle.
Arctic regions of both the Old World and the New. Summer.