[+][+] _Bristles 2--4, shorter than the achene, slender and fragile, or none._

14. E. tenuis, Schultes. _Culms almost capillary, erect_ from running rootstocks, _4-angular_ and flattish (1 high), the sides concave; _spikelet elliptical, acutish, 20--30-flowered_ (3" long); _scales ovate, obtuse_, chestnut-purple with a broad scarious margin and green keel; _achene obovate, roughish-wrinkled, crowned with a small depressed tubercle_, persistent after the fall of the scales; bristles as long as the achene or none.--N. Scotia to N. C., Minn., and Mo. June.

15. E. compressa, Sullivant. _Culms flat_, striate, tufted, erect (1--2 high); _spikelet ovate-oblong_, or at length lanceolate, _20--30-flowered_ (4--7" long); _scales lanceolate-ovate, acute_, dark purple with broad white pellucid margins and summit; _achene_ yellowish, _obovate-pear-shaped_, obtusely triangular, _wrinkled, crowned with a small conical_ and pointed _tubercle; bristles 1--4, very slender_, fragile, shorter than or equalling the achene (sometimes none or a single rudiment).--Wet places, N. Y. and Ont. to Minn. and Mo.

16. E. melanocarpa, Torr. _Culms flattened_, grooved, wiry, erect (9--18' high); _spikelet cylindrical-ovoid or oblong, thick_, obtuse, densely many-flowered (3--6" long); scales closely many-ranked, roundish-ovate, very obtuse, brownish with broad scarious margins; _achene smooth, obovate-top-shaped, obtusely triangular, the broad summit entirely covered like a lid by the flat depressed tubercle_, which is raised in the centre into a short abrupt triangular point; bristles often obsolete; achene soon blackish.--Wet sand, Ma.s.s. to Fla.

17. E. tricostata, Torr. _Culms flattish_ (1--2 high); _spikelet soon cylindrical_, densely many-flowered (6--9" long), thickish; scales ovate, very obtuse, rusty brown, with broad scarious margins; _achene obovate, with 3 prominent thickened angles, minutely rough-wrinkled, crowned with a short-conical acute tubercle_; bristles none.--N. J. to Fla.

18. E. Wolfii, Gray. Culms slender (1 high), from very small creeping rhizomes, _2-edged_; spikelet ovate-oblong, acute; scales ovate-oblong, obtuse, scarious, pale purple; achene pyriform, shining, _with 9 nearly equidistant obtuse ribs and transverse wrinkles between them; tubercle depressed, truncate_, more or less apiculate; bristles not seen.--Wet prairies, N. Iowa and S. Minn.

-- 4. _Spikelet more or less flattened, thicker than the slender or capillary culm, few--many-flowered; the thin membranaceous scales somewhat 2--3-ranked; style 3-cleft; bristles of the perianth 3--6, fragile or fugacious. Small or delicate species, differing from the last division chiefly in the flattish spikelets._

[*] _Tubercle contracted at its junction with the achene._

19. E. acicularis, R. Br. Culms finely capillary (2--8' long), _more or less 4-angular_; spikelet 3--9-flowered; scales ovate-oblong, rather obtuse (greenish with purple sides); achene obovate-oblong, _with 3-ribbed angles and 2--3 times as many smaller intermediate ribs_, also transversely striate, longer than the 3--4 very fugacious bristles; _tubercle conical-triangular_.--Muddy sh.o.r.es, across the continent.

(Eu., Asia.)

20. E. pygmae'a, Torr. Culms bristle like, flattened and grooved (1--2'

high); spikelet ovate, 3--8-flowered; scales ovate (greenish), the upper rather acute; _achene ovoid, acutely triangular, smooth and shining, tipped with a minute tubercle_; bristles mostly longer than the fruit, sometimes wanting.--Brackish marshes, from N. Brunswick to Fla.

[*][*] _Tubercle continuous with the nutlet and not contracted at base._

21. E. pauciflra, Link. Culms striate-angled, very slender (3--9'

high), scarcely tufted, on slender running rootstocks, with a short truncate sheath at base; scales of the ovate spikelet evidently 2-ranked, chestnut-brown, pointless, all flower-bearing, the two lower larger; bristles 3--6, about as long as the conspicuously beaked triangular achene. (Scirpus pauciflorus, _Lightfoot_.)--Wet places, N. Y. to N. Ill. and Minn., north and westward. (Eu., Asia.)

5. DICHRMENA, Richard. (Pl. 4.)

Spikelets aggregated in a terminal leafy-involucrate head, more or less compressed, few-flowered, all but 3 or 4 of the flowers usually imperfect or abortive. Scales imbricated somewhat in 2 ranks, more or less conduplicate or boat-shaped, keeled, white or whitish. Stamens 3.

Style 2-cleft. Perianth, bristles, etc., none. Achene lenticular, wrinkled transversely, crowned with the persistent and broad tubercled base of the style.--Culms leafy, from creeping perennial rootstocks; the leaves of the involucre mostly white at the base (whence the name, from d??, _double_, and ???a, _color_).

1. D. leucocephala, Michx. Culm triangular (1--2 high); leaves narrow; those of the involucre 4--7; achene truncate, not margined.--Damp pine-barrens, N. J. to Fla. Aug., Sept.

2. D. latiflia, Baldwin. (Pl. 4, fig. 1--5.) Culm stouter, nearly terete; leaves broadly linear, those of the involucre 8 or 9, tapering from base to apex; achene round-obovate, faintly wrinkled, the tubercle decurrent on its edges.--Low pine-barrens, Va. to Fla.

6. PSILOCaRYA, Torr. BALD-RUSH. (Pl. 4.)

Spikelets ovoid, terete, the numerous scales all alike and regularly imbricated, each with a perfect flower. Perianth (bristles) wholly wanting. Stamens mostly 2. Style 2-cleft, its base or the greater part of it enlarging and hardening to form the beak of the lenticular or tumid more or less wrinkled achene.--Annuals, with leafy culms, the spikelets in terminal and axillary cymes. (Name from ?????, _naked_, and ?a??a, _nut_.)

1. P. scirpodes, Torr. Annual (4--10' high), leafy; leaves flat; spikelets 20--30-flowered; scales oblong-ovate, acute, chestnut-colored; achene somewhat margined, beaked with a sword-shaped almost wholly persistent style. (Rhynchospora scirpoides, _Gray_.)--Inundated places, S. N. Eng.

7. FIMBRiSTYLIS, Vahl. (Pl. 3.)

Spikelets several--many-flowered, terete; scales all floriferous, regularly imbricated in several ranks. Perianth (bristles, etc.) none.

Stamens 1--3. Style 2--3-cleft, often with a dilated or tumid base, which is deciduous (except in n. 4) from the apex of the naked lenticular or triangular achene. Otherwise as in Scirpus.--Culms leafy at base. Spikelets in our species umbelled, and the involucre 2--3-leaved. (Name compounded of _fimbria_, a fringe, and _stylus_, style, which is fringed with hairs in the genuine species.)

[*] _Style 2-cleft, flattened and ciliate; achene lenticular; tubercle soon deciduous; spikelets many-flowered._

1. F. spadicea, Vahl, var. castanea, Gray. Culms (1--2 high) tufted from a _perennial root, rigid_, as are the _thread-form convolute-channelled leaves_, smooth; spikelets ovate-oblong becoming cylindrical, dark chestnut-color (2" thick); _stamens 2 or 3; achene very minutely striate and reticulated_.--Salt marshes along the coast, N. Y. and N. J. to Fla. July--Sept.--Scales lighter colored than in the tropical form.

2. F. laxa, Vahl. (Pl. 3, fig. 1--5.) Culms slender (2--12' high) from an _annual root, weak_, grooved and flattish; _leaves linear, flat, ciliate-denticulate, glaucous_, sometimes hairy; spikelets ovate, acute (3" long); _stamen 1; achene conspicuously 6--8-ribbed on each side, and with finer cross-lines_.--Low ground, Penn. to Fla., west to Ill.

and La. July--Sept.

[*][*] _Style 3-cleft and achene triangular; tubercle soon deciduous; spikelets smaller and fewer-flowered._

3. F. autumnalis, Roem. & Schult. (Pl. 3, fig. 6--9.) Annual (3--16'

high), in tufts; culms flat, slender, diffuse or erect; leaves flat, acute; umbel compound; spikelets oblong, acute (1--2" long), single or 2--3 in a cl.u.s.ter; scales ovate-lanceolate, mucronate; stamens 1--3.--Low grounds, Maine to Fla., west to Ill. and La.

[*][*][*] _Style 3-cleft, filiform and not ciliate; achene acutely triangular; tubercle more or less persistent._

4. F. capillaris, Gray. Low annual, densely tufted (3--9' high); culm and leaves nearly capillary, the latter short; umbel compound or panicled; spikelets (2" long) ovoid-oblong; stamens 2; achene minutely wrinkled, very obtuse.--Sandy fields, N. Eng. to Fla., west to Minn., Tex., and the Pacific.

F. VaHLII, Link (F. congesta, _Torr._), a diminutive southern species, with long filiform leaves, sessile capitate spikelets, narrow ac.u.minate scales, and the style 2-cleft and not ciliate, has been found in ballast-sand along the northern coast.

8. SCiRPUS, Tourn. BULRUSH or CLUB-RUSH. (Pl. 3.)

Spikelets several--many-flowered, solitary or in a terminal cl.u.s.ter which is subtended by a 1--several-leaved involucre (this when simple often appearing like a continuation of the culm), terete, the scales being regularly imbricated all round in many or several ranks, or rarely somewhat compressed and the fewer scales inclining to be 2-ranked.

Flowers to all the scales, or to all but one or two of the lowest, all perfect. Perianth of 3--6 mostly retrorsely barbed or ciliate bristles (not elongated), or sometimes wanting. Stamens mostly 3. Style 2--3-cleft, simple, not bulbous at base, wholly deciduous, or sometimes leaving a tip or point to the lenticular or triangular achene.--Culms sheathed at base; the sheaths usually leaf-bearing. Mostly perennials; flowering in summer. (The Latin name of the Bulrush.)

[*] _Spikelets solitary, few-flowered, small, often flattish; achene triangular, smooth._

[+] _Involucre a short awl-shaped bract; culms tufted (3--12' high), filiform._

1. S. caespitsus, L. _Culms terete_, wiry, densely sheathed at base, in compact turfy tufts; the upper sheath bearing a very _short awl-shaped leaf_; spikelet ovoid, rusty-color; involucral bract a rigid-pointed scale, resembling the lowest proper scale of the spikelet and scarcely surpa.s.sing it; _bristles 6, smooth_, longer than the abruptly short-pointed achene.--Coast of Maine, alpine summits of N. Eng., swamps of northern N. Y., N. Ill., Minn., and northward; also on Roan Mt., N. C. (Eu.)

2. S. Clintnii, Gray. _Culms acutely triangular_, almost bristle-like; sheaths at the base bearing a _very slender almost bristle-shaped leaf_ shorter (usually very much shorter) than the culm; involucral bract awl-shaped, mostly shorter than the chestnut-colored ovate spikelet, which has _pointless scales_; otherwise as the next.--Rather dry plains, N. Y. June.

3. S. planiflius, Muhl. _Culms triangular, leafy_ at base; _leaves linear, flat, as long as the culm_, and like it rough-edged; involucral bract a bristle-tipped scale usually overtopping the ovate or oblong chestnut-colored spikelet, the green midrib of the _scales extended into sharp points; bristles upwardly hairy_, as long as the pointless achene.--Dry or moist ground, N. Eng. to Del., west to western N. Y. and Penn.; W. Mo. (_B. F. Bush._).

[+][+] _One-leaved involucre more conspicuous, and as if continuing the culm._

4. S. subterminalis, Torr. Aquatic; culms (1--3 long, thickish-filiform) partly and the shorter filiform leaves wholly submersed, cellular; the filiform green bract 6--12" long, much surpa.s.sing the oblong spikelet; scales somewhat pointed; bristles 6, bearded downward, rather shorter than the abruptly-pointed achene.--Slow streams and ponds, N. Eng. to N. J., west to Mich. and N. Ind.--Var.

TERReSTRIS, Paine; less tall, with firmer stem and leaves, and fruiting spike more turgid. Growing chiefly emersed; Herkimer Co., N. Y.

[*][*] _Spikelets cl.u.s.tered (rarely only one), appearing lateral, the one-leaved involucre resembling and seeming to be a continuation of the naked culm._

[+] _Culm sharply triangular, stout, chiefly from running rootstocks; spikelets many-flowered, rusty brown, closely sessile in one cl.u.s.ter; sheaths at base more or less leaf-bearing._

5. S. pungens, Vahl. Running rootstocks long and stout; _culm sharply 3-angled_ throughout (1--4 high) with concave sides; _leaves 1--3, elongated_ (4--10' long), keeled and channelled; spikelets 1--6, capitate, ovoid, usually long, overtopped by the pointed involucral leaf; scales ovate, sparingly ciliate, 2-cleft at the apex and awn-pointed from between the acute lobes; _anthers tipped with an awl-shaped minutely fringed appendage; style 2-cleft_ (rarely 3-cleft); bristles 2--6, shorter than the obovate plano-convex and mucronate smooth achene.--Borders of salt and fresh ponds and streams, throughout N. Am. (Eu., S. Am.)

6. S. Torreyi, Olney. Rootstocks slender if any (so that the plant is readily pulled up from the mud); _culm 3-angled_, with concave sides, rather slender (2--4 high), _leafy at base; leaves 2 or 3, more than half the length of the culm_, triangular-channelled, slender; _spikelets 1--4, oblong or spindle-shaped, acute, distinct_, pale chestnut-color, long overtopped by the slender erect involucral leaf; scales ovate, smooth, entire, barely mucronate; _style 3-cleft; bristles longer than the unequally triangular-obovate very smooth long-pointed achene_.--Borders of ponds, brackish and fresh, N. Eng. to Penn., Mich., and Minn.

7. S. Olneyi, Gray. _Culm 3-wing-angled, with deeply excavated sides_, stout (2--7 high), the _upper sheath bearing a short triangular leaf or none_; spikelets 6--12, closely capitate, ovoid, obtuse, overtopped by the short involucral leaf; scales...o...b..cular, smooth, the inconspicuous mucronate point shorter than the scarious apex; _anthers with a very short and blunt minutely bearded tip; style 2-cleft_; bristles 6, scarcely equalling the narrowly obovate plano-convex and mucronate achene.--Salt marshes, S. New Eng. to Fla., west to the Pacific.