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..
Stems erect, tufted, 6'-3o' high from branching root-stocks, somewhat bulbous at the base, compressed, 2-4-leaved. Leaf-sheaths auriculate; blades 1/2"-1 1/2" broad, 2-4 conspicuous veins in addition to the midrib; inflorescence 4' high or less, the panicle composed of 2-20 turbinate to subspherical 5-10-flowered heads; perianth 1 1/4"-1 3/4" long, the outer parts ovate, acute, the inner slightly longer, obovate, obtuse, with hyaline margins; stamens 3, nearly as long as the perianth; anthers ovate, reddish brown when dry, much shorter than the filaments; capsule equalling the perianth, obo-void, truncate or retuse, almost 3-celled, the placentae deeply intruded; seed oblong, 1/5"-1/4" long, pointed at either end, 12-16-ribbed.
Grassy places, Maine to Ontario, Florida and Nebraska.
Wash. 8: 123. 1893.
Plants solitary or sparingly tufted, 10'-3° high or sometimes lower. Stems markedly bulbous-thickened at the base; leaves similar to those of j. marginatus, but sometimes 2 1/2" broad; panicle 6' high or less, composed of numerous, usually 20-100, relatively small, 2-5-flowered heads; perianth about 1 1/4" long; sepals acute or acuminate; petals oblong or obovate, obtuse, longer than the sepals; stamens as long as the perianth or longer; anthers much shorter than the filaments; capsules obovoid, about 1" long, truncate or depressed at the apex.
In moist soil or meadows, Massachusetts to Michigan, Florida, Texas and Mexico.
j. marginatus setosus Coville, Proc. Biol. Soc.
Wash. 8: 124. 1893. Juncus setosus Small, Fl. SE. U. S. 258. 1903.
Plants rather loosely tufted, 1°-2 1/2° high, bright green. Stems not much thickened at the base; leaves with auriculate sheaths, sometimes quite numerous; blades 1"-2 1/2" wide, similar to those of j. marginatus; panicle 1'-4' high, composed of 20-100 heads, or smaller in depauperate forms; perianth 1 1/2"-2" long, the outer parts lanceolate-acuminate, the inner slightly larger than the outer, lanceolate to ovate-lanceolate, setiform-acuminate; stamens 3, much shorter than the perianth; anthers and filaments about equal in length, the former reddish-brown; capsules oblong, about as long as the perianth, blunt.
In woods and wet places, Nebraska to Louisiana, Arizona and Mexico.