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..
Culms 16'-2 1/2° tall, glabrous or sparingly pubescent, tufted, finally branched, the nodes densely barbed with spreading hairs, appearing like a ring; sheaths glabrous or the lower ones softly pubescent; ligule less than ¥' long; blades 2 1/2-5' long, 3"-7" wide, velvety pubescent on both surfaces; panicle 1 1/2'-4' long, open, its branches erect-ascending or ascending, rarely spreading; spikelets about 1" long and nearly 1/2 as wide, elliptic, strongly pubescent with spreading hairs.
Culms at first erect and simple, 1°-2° tall, later decumbent and somewhat branched, smooth and glabrous. Sheaths shorter than the internodes, usually smooth, ciliate; ligule short, ciliate; blades 3'-5' long, \'-Y wide, erect, truncate or rounded at the sparsely ciliate base, acuminate; panicle 2'-4' long, ovoid, its branches 1'-2' long, spreading or ascending; spikelets 1" long, about equalling the pedicels, ellipsoid, somewhat pubescent; first scale ovate, obtuse, about one-third as long as the spikelet; second and third scales oblong-ovate, 7-nerved, pubescent, equalling the fourth, which is oval, acute, and slightly more than 3/4" long; palet of third scale usually empty.
Moist soil, Newfoundland to Ontario south to New York, Indiana and Minnesota. June and July.
P. mattamuskeetense Ashe, Journ. E. Mitch. Sci. Soc.
15: 45- 1898. P. Clutei Nash, Bull. Torrey Club 26: 569. 1899.
Plant usually purplish. Culms tufted, 1 1/2°-3 1/2° tall, glabrous, the nodes sometimes puberulent or the lower ones barbed; sheaths loose, the upper ones glabrous excepting on the margins and occasionally toward the summit, the lower ones often softly pubescent; blades 2 1/2'-5 1/2' long, 3"-6" wide, firm, lanceolate, ascending or sometimes reflexed, glabrous; panicle 2 1/2'-4' long, broad and open; spikelets about \\" long, a little more than 1/2 as wide, pubescent with short hairs.
Sandy borders of swamps and bogs, Massachusetts to North Carolina. July.
Plant glabrous and usually purple. Culms erect, 2°-3 1/2° tall, finally branched; sheaths much shorter than the internodes; ligule a narrow ring usually less than i" wide; blades erect, firm, 1 1/2'-4 1/2' long, 2"-4" wide, lanceolate; panicle 3'-5' long, 3/4'- 1 1/2' wide, dense, longer than broad, its branches erect or erect-ascending; spikelets less than 3/4" long and 1/2" wide, oval, glabrous.
In wet places, New Jersey to Florida and Texas. May-Aug.