7 R. niiliacea Gray. Culm slender, triangular, very leafy below, 2f high, fistulous; lvs. rather rigid, flat, lance-linear, smooth, glaucous, 6 to 8' long, 3 to 4" wide; spikes obovate, all pedicellate, 3 to 5-flowered, forming diffuse, compound, axillary and terminal cymous panicles; setm 6, a little longer than the roundish obovate achenlum and very short tubercle. - Wet pine barrens, N. Car. to Fla. and La. (R. sparsa Vahl. Schœnus Lam.)
8 R. caduca Ell. Culm acutely triangular, 1 to 3f high; lvs. broadly linear, smooth, 2 to 3" wide; spikes ovate, large (4 to 5" long), pedicellate or sessile, in several rather close, erect, axillary and terminal panicles; glumes caducous, ovate, the outer broad; setm twice longer than the orbicular-ovate, rugous achenium; tubercle flattened, conical, a third as long as the achenium. - Wet soils, N. Car. to Fla.
9 R. schœnoides. Culm triangular, 2 to 3f high, leafy at base; lvs. linear, 2" wide, glabrous, not half the length of the culm; spikes very numerous, lance-ovate, small (2" long), sessile or nearly so, clustered, forming several axillary and terminal, pedunculate panicles; glumes fuscous, broad-ovate; setae twice as long as the obovate, flat, rugous achenium and small tubercle. Bogs, Ga., Fla. to La. (Seir-pus, Ell.)
10 R. patula Gray. Culm 3-angled, thick and stout at the base, 2f high; lvs. linear, short; spikes ovate, small (2" long), forming several spreading, loose-flowered corymbs, of which the terminal one is much the longest; setae scarcely exceeding the roundish, flattened, strongly rugous achenium and tubercle, the latter nearly half as long as the former. - Ga. and Fla., rare.
11 R. Elliottii Gray. Culm 3-angled, slender, 1 to 2f high; lvs. linear, flat, glabrous, serrulate on the margins, the cauline short; spikes ovate, sessile in fascicles forming 3 or 4 few-flowered, subsimple corymbs, borne on exserted peduncles; setae a little longer than the roundish-ovate, minutely rugous achenium; tubercle very short, flattened, conic. - Wet soils, Ga. and Fla. Jn, - Sept.
12 R. microcarpa Baldw. Culm slender, teretish, tufted, nearly naked; lvs. narrowly linear, setaceous at end, mostly radical; spikes turgid-ovate, dark brown, 1 to 2" long, loosely fascicled in several approximate, pedunculate corymbs; setae very fragile, scarcely equaling the minute, ovate, flat, rugous achenium. - Wet grounds, N. Car. to Fla.
13 R. punctata Ell. Culm slender, 3-angled, 1 to 2f high; lvs. lance-linear, acute, rough-edged; spikes ovate, chestnut brown, fascicled, in several pedunculate corymbs; setae a little longer than the achenium, which is ovate, compressed, and rugous-netted, with impressed dots in the furrows. - Marshes, Ga. and Fla.
14 R. alba Vahl. Culm triangular above, very slender, leafy, smooth, 10 - 16' high; lvs. linear-setaceous, channeled; corymbous fascicles pedunculate, both terminal and from the axils of the sheaths, with setaceous bracts; spikelets lanceolate, acute at each end, with crowded, lanceolate, whitish glumes; seeae 9 or 10, as long as the ach. and tubercle. - In wet, shady grounds; common. July - Sept.
15 R. Knieskernii Carey. Culms in tufts, 6 to 16' high, slender; lvs. mostly cauline, setaceous, linear, shorter; spikes small (1" long) in 4 or 5 dense fascicles, distant along the whole length of the culm; setae 6, downwardly hispidulous, as long as the minute, obovate achenium. - In bog iron soil, N. J. (Holton), rare. (R. distans? Nutt.)
16 R. capillacea Torn Culm 6 to 12' high, filiform, glabrous, triangular; lvs. setaceous, much shorter than the stem; spikes 1 to 3 to 6 (mostly in 1 terminal fascicle), oblong, each with a setaceous bract; glumes chestnut-colored, with scar-ious edges; bristles 6, much longer than the oblong, substipitate achenium; tubercle about half the length of the achenium. - Swamps, N. Y. (Sartwell), Penn. to Mich.
17 R. fusca Roem. & Schult. Culm 3-angled, about 2f high; lvs. setaceous-carin-ate; smooth; fascicles alternate, pedunculate; bract3 setaceous, longer than the ovoid spikes; glumes brown, ovate; ach. obovate, its pointed tubercle as long, both equaling the hispid setx. - Wet places, Mass. to N. J., rare.
18 R. gracilenta Gray. Culms 1 to 2f high, very slender or filiform, smooth; lvs. linear-setaceous, much shorter than the stem; corymbs small, fasciculate, the lateral on slender peduncles exserted from the sheaths; spikes ovoid; glumes ovate, acute, dark brown; bristles 6, a third longer than the roundish-ovoid acheni-um; tubercle flat, subulate, as long as the achenium. - Dry grounds, N. Y. to Fla.
19 R. filifolia Torr. (nee Kunth). Culm filiform, 6 to 12 to 18' high, lvs. filiform, or almost capillary, many, much shorter; spikes very small (1" long), in 2 or 3 small fascicles, the lateral pedunculate; setae 6, upwardly scabrous-hispid, as long as the roundish-ovate, lens-shaped, smooth achenium and the hispid-scabrous tubercle. - N. Car. to Fla. Its hispid tubercles distinguishes it from Nos. 17 and 18.
20 R. Baldwinii Gray. Culms slender, acutely 3-angled, 2 to 3f high; lvs. linear, acute, keeled, 2 ' wide, glaucous, not ciliate, spikes ovate, in a crowded, fasciculate, terminal corymb; seta. 12, upwardly hispidulous, as long as the smooth, roundish-ovate achenium; stam. 3. - Pine barrens, Ga.
21 R. dodecandra Baldw. Culm rigid, 3-angled, 1 to 3f high; lvs. rigid, coriaceous, keeled, rough-edged, broadly linear (2 to 4," wide), all nearly equaling the culm at first, at length the culm longer; spikes ovate (lance-ovate when young), 4" long, light chestnut color, pedicellate, in 4 to 6 pedunculate corymbs; setae 6 to 12, as long as the large (1 1/2" diam.), roundish, smooth achenium; stam. 10 to 12, much longer; tubercle broad, depressed. - Bogs, S. Ga., Fla. (R. megalocarpa and pyncocarpa Gray.)
22 R. glomerata Vahl. Culm slender, smooth, leafy, a foot or more high; lvs. flat, carinate, rough-edged; corymbed fascicles very remote, in pxirs, axillary and terminal; spikelets lanceolate; glumes keeled, mucronate. brown; ach. obovoid or cuneiform, very smooth as long as the tubercle; setae 6, rough, backwards. - In bogs, Can. to Fla. July, Aug.