6 T. carinata. Culm flattened, setaceous, 3 to 6' high, with a short, solitary setaceous leaf near the base; spike single, ovoid, lateral near the top of the culm; glumes green, 5 to 8, broad-ovate, veined acuminate; sty. 3-cleft; ach. short-triangular, grayish, half as long as the glume. - Near N. Orleans (Hale) (Isolepis, Hook. & Arn.).

12. PSILOCAR'YA, Torr. (Gr. naked, nut; no bristles.) Flowers . Glumes ∞, imbricated all round, all fertile; perigynium 0; stam. 2; filaments long, persistent; style 2-cleft, dilated or tuberculate at base; achenium biconvex, crowned with the persistent style. - Steins leafy. Spikes lateral and terminal, cymous.

1 P. scirpoides Torr. Culm slender, leafy, smooth, 3-sided, 5 - 9'high; lvs. linear, smooth, 3 - 5' by 1', cauline about 2; cymes terminal, and one from the sheath of each cauline leaf; spikes about 3" long, oblong-ovate, in small, loose clusters, 20 - 30 flowered; glumes chestnut-colored, thin ovate, acute; ach. tumid, dark brown, crowned with the long style, which is much dilated at base.' - Borders of ponds, Smithfleld, R. I. (Olney), Mass. (Greene), and Ark. (Hale).

2 P.rhynchosporoides Torr. Culm 8 to 14'high, leafy, smooth; lvs. linear, 2" broad, overtopping the culm; umbel few-rayed; spikes ovoid, 2 to 3" long, all pedunculate, 8 to 10-flowered; glumes roundish ovate, obtuse pale brown; ach. roundish, lenticular, strongly rugous; tubercle short, obtuse,. - Quincy, Fla. (Chapman).

13. DICHROM'ENA, Richard. (Gr. two, color.) Spikes flattened, collected into a terminal head; glumes imbricate on all sides, many abortive; perigynium none; stamens 3; styles 2-cleft; achenium lens-shaped, crowned with the broad, tuberculate base of the style. - Rhizome creeping. Culms leafy. Lvs. of the invol. usually whitened at the base.

1 D. leucocephala Mx. Culm triangular, 2 to 3f high; lvs. concave, narrow, shorter than the culm; invol. 6 to 8-leaved, the lvs. lanceolate, long-pointed, whitened below, spreading, 1 to 4' long; ach. truncate at the summit, transversely rugulous. - Bogs, Md. to Fla. and La. Known at a distance by its white involucre.

2 D. latifolia Baldw. Culm tereteish, stout, 9' to 2f high; lvs. broadly linear, very long, overtopping the culm; invol. 8 to 10-leaved, whitish, becoming dull red at the base; ach. roundish in outline (except the tubercle), roughened, dull, the tubercle broad, conical at top, base 2-horned. decurrent on the edges of the ach, with its horns. - Ponds in pine barrens, N. Car. to Fla.

14. RHYNCHOS'PORA, Vahl. (Gr. a beak, seed; from the character.) Flowers or , few in each spikelet; , glumes loosely imbricated, the lowest small and empty; perigynium of 0 to 12 bristles; stamens 3 to 12; style bifid; achenium lens-shaped or subglobous, crowned with a tubercle, the distinct, bulbous base of the style. St. leafy, 3-sided. Inflor. terminal and axillary. Setae hispid (under a strong magnifier).

1 R. plumosa Ell. Culm rigid, wiry, 8 to 2f high; lvs. rigid, involute, setaceous above, half as long as the culm; spikes lance-ovate, chestnut red, in a terminal fascicle, rarely a smaller axillary fascicle below on an exserted peduncle; glumes broad-ovate, acute; bristh (setae) 6, densely plumous, as long as the globular-ovoid, rugous achenium; tubercle short. - Dry pine barrens, N. Car. to Fla.

β. semiplumosa. Setae feathery half way up, naked and denticulate above. - Near N. Orleans (lngalls. R. semiplumosa Gray., Monog., Rhyn., p. 213).

2 R. oligantha Gray. Culm filiform, 8 to 12' high, with one or two filiform-setaceous lvs. about the same height; spikes 2 to 6, pedicellate, rarely solitary, lance-ovate, fuscous-red, lateral near the summit of the culm; glumes ovate, mu-cronate; setas 6, as long as the ach. and short tubercle, plumous below, hispid above. - N. Car. to Fla., in sandy bogs.

3 R. cynadsa Nutt. Culm 1 to 2f high, triangular, angles acute; radical lvs. linear, shorter than the stem, cauline rising above the stem; corymbs 3 to 4, the terminal largest; spikelets ovoid, in close fascicles of about 5; glumes broad-ovate, dark brown; bristles 6, 2/3 as long as the broad ovate, transversely ruguous achenium; tubercle depressed, much shorter than the achenium. - N. J. to La. Jl, Aug.

4 R. Torreyana Gray. Culm 2f high, teretish, slender, casspitous, striate; lvs. setaceous, the radical 6 to 10" long, cauline much shorter; corymbs few-flowered, the lateral, if any, on capillary pedurcles; spikes ovoid, pedicellate or sessile; glumes ovate, mucronate, brown; bristles 6, scarcely half as long as the oblong-obovate achenium; tubercle short, nearly as broad at base as the achenium. - N. J. Jl, Aug. (Holton.)

5 R. rariflora Ell. Culms tufted, 6 to 16' high, filiform, with much shorter, setaceous leaves; spikes lanceolate, fuscous, near 2" long, pedicellate, few in 2 or 3 loose, simple, corymbous panicles terminal and lateral; bracts capillary; glumes ovate, acute; setse about 6, nearly as long as the strongly rugous, roundish obo-vate achenium; tubercle very short. - S. Car. to Fla. and La., in bogs. Has the aspect of a Trichelostylis.

6 R. inexpansa Vahl. Culm slender, teretish, rather rigid, 18' to 3f high; lvs. narrowly linear, flat, smooth, half as long as the culm; spikes lanceolate, fuscous, about 3" long, 3 to 5-flowcred, forming several axillary and terminal, rather long, drooping panicles; setae nearly twice longer than the rugous, oblong, flattish ache-nium and short tubercle. - Wet soils, S. Car. to Fla, and La. (Schoenus Mx.)