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..
Xyris flexuosa var. pusilla A. Gray, Man. Ed. 5, 548.
Scapes very slender, straight or slightly twisted, 2-edged above, 2'-12' tall, not bulbous-thickened at the base. Leaves narrowly linear, 1'-6' long, 1/2"-1" wide, not at all twisted or but very slightly so; head ovoid, acute during anthesis, or narrowly subacute, 1 1/2"-3" long; bracts oval or obovate, rounded and finely lacerate at the apex; lateral sepals linear, irregularly erose on the winged keel near the apex, about as long as the bracts.
In bogs, Nova Scotia to Ontario and Michigan, south to the Pocono Mountains of Pennsylvania. July-Aug.
Xyris caroliniana Walt. Fl. Car. 69. 1788. Xyris Jupacai Michx. Fl. Bor. Am. 1: 23. 1803.
Scapes mostly slender, straight or somewhat twisted, 2-edged above, 1°-2° tall, not thickened at the base. Leaves linear, flat, 4-15' long, 1"-5" wide; head broadly ovoid, blunt, 4"-8" long; scales oval or slightly obovate, entire or somewhat lacerate; lateral sepals linear, about as long as the bracts, the narrowly winged keel serrate only above the middle.
Scapes slender, slightly twisted, 2-edged above, 1-edged below, not thickened at the base, 6'-18' tall. Leaves nearly linear or linear-lanceolate, flat, 3'-10' long, 1"-6" wide; head ovoid, or subglobose, blunt or subacute, about i' long; scales ovate or oval, mostly entire; lateral sepals lanceolate, the winged keel fimbriate from the apex to below the middle; corolla-lobes obovate, 2"-3" long.
In bogs, Maryland to Florida and Louisiana. Widely distributed in tropical America. June-Aug.
Xyris elata Chapm. Fl. S. States 501. i860.
Scapes rather stout, 1°-4 1/2° tall, solitary or several together, 2-edged above. Leaves decidedly equi-tant, linear or nearly so, 8'-24' long; head oblong or nearly cylindric, 8"-12" long; scales suborbicular, numerous; lateral sepals 2"-2 1/2" long, the narrowly winged keel toothed above the middle; corolla-lobes about 2" long.
In sandy swamps near the coast, southeastern Virginia to Florida and Louisiana. July-Oct.
Xyris Congdoni Small; Britton, Man. Ed. 2, 1057. 1905.
Scapes relatively stout, smooth, flattened above, 1 1/3°-2 1/2° tall. Leaves over one-half as long as the scape, decidedly equitant, linear from a broad base which is commonly over 5" wide; head oval or nearly so, 6"-8" long; scales erose at the apex, less concave than those of X. flcxitosa; lateral sepals 3"-3 1/2" long, the broad keel erose-lacerate above the middle.
Xyris fimbriata Ell. Bot. S. C. & Ga. 1: 52. 1816.
Scapes rather stout, roughish, straight or somewhat twisted, strongly 2-edged above, 2°-4° high. Leaves flat, one-half as long as the scapes or more, 3"-6" wide; head oblong-cylindric, 1/2-1' long or sometimes globose-ovoid and about 1/2 in diameter; scales obovate, their margins entire or the apex lacerate; lateral sepals longer than the bracts, ex-serted, long-fringed on the winged keel above the middle.
In wet pine barrens, southern New Jersey to Florida and Mississippi, mostly near the coast. July-Sept.
Scapes stout, much spirally twisted, 1-edged below, or 2-edged at the summit, smooth or very nearly so, the base conspicuously bulbous-thickened and with the sheathing leaves sometimes 1' in diameter. Leaves narrowly linear from a broad shining nearly black base, rigid, rather shorter than the scapes, spirally twisted (very markedly so when old); head oblong or oblong-cylindric, acute or subacute, 1/2'-1' long; bracts oblong-obovate, minutely lacerate-serrulate at the apex or entire; lateral sepals linear, exserted, the winged keel fringed with rather short processes above the middle.
In dry pine barrens, southern New Jersey to Florida, west to Texas, mostly near the coast. May-Aug.