Part 77

4. Eleocharis. Spikelets solitary, terminating the culm. Stamens 3.

[++][++] Bristles always none; culm leafy.

5. Dichromena. Spikelets crowded into a leafy-involucrate head, laterally flattened, the scales more or less conduplicate and keeled. Many of the flowers imperfect or abortive.

6. Psilocarya. Spikelets in broad open cymes. Style almost wholly persistent.

7. Fimbristylis. Spikelets in an involucrate umbel. Culm leafy at base. Style usually wholly deciduous.

[+][+] Style not bulbous at base.

[++] Flowers without inner scales, but bristles generally present.

8. Scirpus. Spikelets solitary or clustered, or in a compound umbel, the stem often leafy at base and inflorescence involucrate. Barbed bristles 3--8 or none. Stamens mostly 3.

9. Eriophorum. As Scirpus, but the bristles naked, exserted and often silky in fruit. Stamens 1--3.

[++][++] Flower with one or more inner scales.

10. Fuirena. Scales of the spikelet awned below the apex. Flower surrounded by 3 stalked petal-like scales alternating with 3 bristles.

11. Hemicarpha. Flower with a single very minute hyaline scale next the axis of the spikelet; bristles none.

12. Lipocarpha. Flower enclosed by 2 inner scales, one next the axis, the other in front of the achene; bristles none.

Tribe II. RHYNCHOSPOREAE. Spikelets mostly 1--2-flowered, with 2--many of the lower scales empty.

13. Rhynchospora. Spikelets terete or flattish; scales convex, either loosely enwrapping or regularly imbricated. Achene crowned with a persistent tubercle or beak, and commonly surrounded by bristles.

14. Cladium. Spikelets terete, few-flowered, the scales, etc., as in the preceding. Achene destitute of tubercle. No bristles.

II. Flowers unisexual.

Tribe III. SCLERIEAE. Flowers monoecious; the staminate and pistillate in the same or in different clustered spikes. Achene naked, bony or crustaceous, supported on a hardened disk.

15. Sclerlia. Spikes few-flowered; lower scales empty. No bristles or inner scales.

Tribe IV. CARICEAE. Flowers monoecious in the same (androgynous) or in separate spikes or sometimes dioecious. Achene enclosed in a sac (_perigynium_).

16. Carex. Hypogynous bristle short and enclosed in the perigynium or none.

1. CYPERUS, Tourn. GALINGALE. (Pl. 1.)

Spikelets many--few-flowered, mostly flat, variously arranged, mostly in clusters or heads, which are commonly disposed in a simple or compound terminal umbel. Scales 2-ranked, conduplicate and keeled (their decurrent base below often forming margins or wings to the hollow of the joint of the axis next below), deciduous when old. Stamens 1--3. No bristles or inner scales. Style 2--3-cleft, deciduous. Achene lenticular or triangular, naked at the apex.--Culms mostly triangular, simple, leafy at base, and with one or more leaves at the summit, forming an involucre to the umbel or head. Peduncles or rays unequal, sheathed at base. All flowering in late summer or autumn. ([Greek: Ky/peiros], the ancient name.)

Sec. 1. PYCREUS. _Achene lenticular, the edge turned to the rhachis; spikelet flattened, many flowered; rhachis narrow, not winged. Annuals._

[*] _Umbel simple or capitate, rarely slightly compound._

1. C. flavescens, L. Culms 4--10' high, spikelets 5--8'' long; involucre 3-leaved, very unequal; spikelets becoming linear, obtuse, clustered on the 2--4 very short rays (peduncles); _scales obtuse, straw-yellow; stamens 3; achene shining, orbicular_, its superficial cells oblong.--Low grounds, N. Eng. to Mich., Ill., and southward. (Eu., etc.)

2. C. diandrus, Torr. (Pl. 1, fig. 1--4.) Spikelets lance-oblong (3--9''), scattered or clustered on the 2--5 very short or unequal rays; _scales rather obtuse, purple-brown_ on the margins or nearly all over; _stamens 2, or sometimes 3; achene dull, oblong-obovate_; otherwise much like the last.--Low grounds, common from the Atlantic to Minn., Ark., and N. Mex.--Var. CASTANEUS, Torr. Scales more firm and browner; with the type.

3. C. Nuttallii, Torr. Culms 4--12' high; spikelets lance-linear, acute and very flat (1/2--1' long), crowded on the few usually very short (or some of them distinct) rays; _scales oblong, yellowish-brown_, rather loose; _stamens 2; achene oblong-obovate, very blunt, dull_.--Mostly in salt or brackish marshes, along the coast from Mass. to the Gulf.

4. C. polystachyus, Rottb., var. leptostachyus, Boeckl. Culms very slender, 6--15' high; leaves and elongated involucre very narrow; spikelets few to many on the 4--8 rays, linear, acute, 2--9'' long; _scales thin, ovate, acute, closely imbricated, pale brown_; stamens 2; _achene linear-oblong or clavate, short-pointed, grayish and minutely pitted_. (C. microdontus, _Torr._)--Margins of ponds and streams, Va. to Fla. and Tex.

[*][*] _Umbel compound._

5. C. flavicomus, Vahl. Culm stout (1--3 deg. high); leaves of the involucre 3--5, very long; spikelets linear (4--9'' long), spiked and crowded on the whole length of the branches of the several-rayed umbel, spreading; _scales oval, very obtuse, yellowish and brownish, broadly scarious- (whitish-) margined; stamens 3; achene obovate, mucronate_, blackish.--Low grounds, Va. to Fla.

Sec. 2. CYPERUS proper. _Achene triangular; spikelets usually many-flowered, more or less flattened, with carinate scales, the rhachis marginless or nearly so (winged in n. 12)._

[*] _Stamen 1; spikelets short and small (11/2--5'' long) in globular heads, ovate or linear-oblong, many-flowered; achene oblong-obovate to linear._

[+] _Low annuals; involucre 2--3-leaved; heads few; scales pointed._

6. C. aristatus, Rottb. Dwarf (1--5' high); _spikelets chestnut-brown, oblong becoming linear_, 7--13-flowered, in 1--5 ovate heads (sessile and clustered, or short-peduncled); _scales nerved, tapering to a long recurved point_; achene oblong-obovate, obtuse. (C. inflexus, _Muhl._)--Sandy wet shores; common. Sweet-scented in drying.

7. C. acuminatus, Torr. Slender (3--12' high); _spikelets ovate, becoming oblong_, 16--30-flowered, _pale; scales obscurely 3-nerved, short-tipped_; achene oblong, pointed at both ends.--Low ground, Ill. and southwestward.

[+][+] _Tall perennial (1--4 deg. high); heads many, greenish; scales pointless._

8. C. calcaratus, Nees. Culm obtusely triangular; leaves and involucre very long, keeled; umbel compound, many-rayed; spikelets ovate (11/2'' long), in numerous small heads; achenes pale, linear, on a slender stipe; scales narrow, acutish, obscurely 3-nerved. (C. virens, _Gray_, in part; not _Michx._ C. Luzulae, var. umbellatus, _Britt._)--Wet places, Del. to Fla. and Tex.

[*][*] _Stamens 3 (2 in _C. fuscus_); spikelets clustered on the rays of a simple umbel (or in a single sessile head); scales mostly green or greenish and many-nerved, abruptly sharp-pointed; achene obovate, sharply triangular._

[+] _Low annuals._

9. C. Compressus, L. Culms 3--9' high, with a simple sessile or a few umbellate clusters of oblong to linear spikelets (15--30-flowered and 3--8'' long) with crowded strongly keeled and very acute pale scales.--Sterile fields along the coast, Md. to Fla. and Tex.; also adventive near Philadelphia.

C. FUSCUS, L. Of similar habit; spikelets much smaller (2--4'' long), the thin brown scales (greenish only on the keel) barely acutish and very faintly nerved.--Revere Beach, Mass. (_Young_); on ballast at Philadelphia. (Adv. from Eu.)

[+][+] _Perennial, propagating from hard clustered corms or bulb-like tubers._

10. C. Schweinitzii, Torr. _Culm rough on the angles (1--2 deg. high)_; umbel 4--8-rayed, rays very unequal, erect; _spikelets loosely or somewhat remotely 6--12-flowered, with convex many-nerved scales_; joints narrowly winged.--Dry sandy shores and ridges, western N. Y. and Penn. to Minn. and Kan.

11. C. filiculmis, Vahl. Culm slender, wiry, often reclined (8--15' high); _leaves linear_ (1/2--2'' wide) or filiform; _spikelets numerous and clustered in one sessile dense head, or in 1--7 additional looser heads on spreading rays_ of an irregular umbel; _joints of the axis naked; scales blunt_, greenish.--Dry sterile soil; common, especially southward.

12. C. Grayii, Torr. Culm thread-form, wiry (6--12' high); _leaves almost bristle-shaped_, channelled; _umbel simple, 4--6-rayed; spikes 5--10 in a loose head, spreading; joints of the axis winged; scales rather obtuse_, greenish-chestnut-color.--Barren sands, Plymouth, Mass., to N. J., near the coast.

Sec. 3. PAPYRUS. _Style 3-cleft; achene triangular; stamens 3; spikelets many-flowered, flattened, the carinate scales decurrent upon the rhachis as scarious wings; spikes in simple or compound umbels._

[*] _Wings of the rhachis soon separating to the base as a pair of free scales; annual._

13. C. erythrorhizos, Muhl. (Pl. 1, fig. 5--8.) Culm obtusely triangular (3'--3 deg. high); umbel many-rayed; involucre 4--5-leaved, very long; involucels bristle-form; spikelets very numerous, crowded in oblong or cylindrical nearly sessile heads or spikes, spreading horizontally, linear, flattish (3--6'' long), bright chestnut-colored; scales lanceolate, mucronulate.--Alluvial banks, L. I. to Penn., Mich., Minn., and southward; also adventive in N. Eng.

[*][*] _Wings of the rhachis persistently attached; perennial by slender running rootstocks._

[+] _Achene round-obovate; scales mucronate or acute, free or spreading._

14. C. Haspan, L. Culms sharply angled (1--11/2 deg. high); leaves linear, often reduced to membranous sheaths; _umbel spreading, the filiform rays mostly longer than the 2-leaved involucre_; spikelets narrowly linear; scales light reddish-brown, oblong, _mucronate, 3-nerved_.--Ponds and ditches, Va. to Fla. and Tex.

15. C. dentatus, Torr. (Pl. 1, fig. 9.) Culms slender (1 deg. high); leaves rigid and keeled; _umbel erect, shorter than the 3--4-leaved involucre_; scales reddish-brown, _with green keel_, ovate, _acute, 7-nerved_.--Sandy swamps, N. Eng. and northern N. Y. to S. C. and W. Va. Spikes often abortive and changed into leafy tufts.

[+][+] _Achene linear to oblong; scales appressed, pointless or nearly so._

[++] _Perennial by tuberiferous stolons._

16. C. rotundus, L. (NUT-GRASS.) Culm slender (1/2--11/2 deg. high), longer than the leaves; umbel simple or slightly compound, about equalling the involucre; the few rays each bearing 4--9 _dark chestnut-purple_ 12--40-flowered _acute spikelets_ (4--9'' long); _scales ovate, closely appressed, nerveless_ except on the keel.--Sandy fields, Va. to Fla. and Tex.; also adventive near Philadelphia and New York city. (Eu.)

17. C. esculentus, L. Culm (1--21/2 deg. high) equalling the leaves; umbel often compound, 4--7-rayed, much shorter than the long involucre; _spikelets numerous, light chestnut or straw-color, acutish_, 12--30-flowered (4--7'' long); _scales ovate or ovate-oblong narrowly scarious-margined, nerved_, the acutish _tips rather loose_; achene oblong-obovate. (C. phymatodes, _Muhl._)--Low grounds, along rivers, etc., N. Brunswick to Fla., west to Minn, and Tex.; spreading extensively by its small nut-like tubers and becoming a pest in cultivated grounds.

[++][++] _Perennial, propagating by corm-like tubers from the base; spikelets narrow, acuminate, often teretish; scales oblong-lanceolate; achene linear-oblong._

18. C. strigosus, L. Culm mostly stout (1--3 deg. high); most of the rays of the umbel elongated (1--5'), their sheaths 2-bristled; _spikelets 5--25-flowered_, spreading; scales several-nerved, much longer than the achene.--Damp or fertile soil, Canada to Fla., west to Minn., Tex., and the Pacific. Very variable in the number and length of the rays of the simple or compound umbel, and in the size of the spikelets (21/2--6 or even 12'' long), more or less densely crowded on the axis.

Sec. 4. DICLIDIUM. _Style 3-cleft; spikelets narrow, terete or nearly so, few--many-flowered, the scales closely appressed and the broad wings of the jointed rhachis enclosing the triangular achene._

19. C. speciosus, Vahl. Culm stout, _mostly low_ (5--20' high); _rays of the simple or compound umbel mostly all short and crowded; spikelets 10--20-flowered, yellowish-brown_ at maturity (3--7'' long), the short joints of its axis winged with very broad scaly margins which embrace the _ovate triangular achene; the scales ovate, obtusish, imbricately overlapping_. (C. Michauxianus, _Gray_, Manual; not _Schultes_.)--Low grounds and sandy banks, N. Eng. to Fla., west to Minn. and Tex.

20. C. Engelmanni, Steud. Resembles n. 19; but the _spikelets more slender_ and terete, _somewhat remotely 5--15-flowered_, the zigzag joints of the axis slender and narrowly winged, and the oblong or oval broadly scarious _scales proportionally shorter_, so as to expose a part of the axis of each joint, _the successive scales not reaching the base of the one above_ on the same side; achene oblong-linear, very small.--Low grounds, Mass. to Wisc. and southward.

Sec. 5. MARISCUS. _Spikelets 1--4-flowered, subterete, usually in dense heads; scales oppressed, several-nerved, the lower empty and often persistent after the fall of the rest of the spikelet; joints of the rhachis winged, enclosing the triangular achene. Perennial._

[*] _Spikelets slender and acuminate, more or less refracted in usually close umbelled spikes.--Connecting with Sec. 4._

21. C. Lancastriensis, Porter. Culm (1--2 deg. high) triangular; _leaves rather broadly linear_; umbel of 6--9 mostly elongated rays; _spikelets very numerous in short-oblong close heads_, soon reflexed, of 3--6 narrow scales, the upper and lower empty, twice the length of the linear-oblong achene, which is nearly 1'' long.--Rich soil, Penn. and N. J. to Ala.

22. C. retrofractus, Torr. Culm and leaves usually minutely downy and rough on the obtusish angles (1--3 deg. high); umbel many-rayed; _spikelets slender-awl-shaped_, very numerous in obovate or oblong heads terminating the elongated rays, _soon strongly reflexed, 1--2-flowered_ in the middle (3--5'' long); scales usually 4 or 5, the two lowest ovate and empty, the fertile lanceolate and pointed, the uppermost involute-awl-shaped; achene linear, 11/4'' long.--Sandy fields, N. J. to Fla. and Tex.

23. C. refractus, Engelm. Culm 1--2 deg. high; rays usually more or less elongated; spikelets very slender, in rather loose heads, divaricate or more or less reflexed, 2--4-flowered; achene linear, 11/4'' long.--N. J. to N. C. and Mo.

[*][*] _Spikelets very short, blunt, in densely compacted globose or cylindrical heads._

24. C. ovularis, Torr. Culm sharply triangular (6'--2 deg. high); umbel 1--6-rayed; _spikelets_ (50--100) in a _globular head, 3-flowered, oblong, blunt_ (11/2--2'' long); scales ovate, obtuse, a little longer than the ovate-oblong achene.--Sandy dry soil, southern N. Y. to Fla., west to Ill., Ark., and Tex.--Var. ROBUSTUS, Boeckl., is a form with large heads (4--8'' long), the spikelets 3--4-flowered. (C. Wolfii, _Wood_.)--Ill. to Ark., and southward.

25. C. Torreyi, Britton. Like the last, but the _heads cylindrical or oblong, spikelets usually 2-flowered_, and _achene linear-oblong_.--L. Island to Fla., west to Tex.

2. KYLLINGA, Rottboell. (Pl. 1.)

Spikelets of 3 or 4 two-ranked scales, 1--1{1/2}-flowered; the 2 lower scales minute and empty, as in Cyperus, Sec. 4, but style oftener 2-cleft and achene lenticular; spikes densely aggregated in solitary or triple sessile heads.--Culms leafy at base; involucre 3-leaved. (Named after _Peter Kylling_, a Danish botanist of the 17th century.)

1. K. pumila, Michx. Annual; culms 2--9' high; head globular or 3-lobed, whitish-green (about 4'' broad), spikelets strictly 1-flowered; upper scales ovate, pointed, rough on the keel; stamens and styles 2; leaves linear.--Low grounds, Ohio to Ill., south to Fla. and Tex. Aug.

3. DULICHIUM, Pers. (Pl. 1.)

Spikelets many- (6--10-) flowered, linear, flattened, sessile in 2 ranks on axillary solitary peduncles emerging from the sheaths of the leaves; scales 2-ranked, lanceolate, decurrent, forming flat wing-like margins on the joint below. Perianth of 6--9 downwardly barbed bristles. Stamens 3. Style 2-cleft above. Achene flattened, linear-oblong, beaked with the long persistent style.--A perennial herb, with a terete simple hollow culm (1--2 deg. high), jointed and leafy to the summit; leaves short and flat, linear, 3-ranked. (An alteration of _Dulcichinum_, an old name for a species of Cyperus.)

1. D. spathaceum, Pers.--Borders of ponds, N. Scotia to Fla., west to Minn. and Tex. July--Sept.

4. ELEOCHARIS, R. Br. SPIKE-RUSH. (Pl. 3.)

Spikelet single, terminating the naked culm, many--several-flowered. Scales imbricated all round in many (rarely in 2 or 3) ranks. Perianth of 3--12 (commonly 6) bristles, usually rough or barbed downward, rarely obsolete. Stamens 2--3. Style 2--3-cleft, its bulbous base persistent as a tubercle jointed upon the apex of the lenticular or triangular achene.--Leafless, chiefly perennial, with tufted culms sheathed at the base, from matted or creeping root-stocks; flowering in summer. (Name from [Greek: e(/los], _a marsh_, and [Greek: chai/ro] _to delight in_; being marsh plants.)

Sec. 1. _Spikelet terete, hardly if at all thicker than the spongy-cellular culm; scales firmly persistent; style mostly 3-cleft; bristles 6 (rarely 7), firm or rigid, mostly barbed downward, equalling or surpassing the triangular or lenticular achene._

[*] _Spikelet linear or lanceolate-awl-shaped, few-flowered; scales (only 3--9) few-ranked, convolute-clasping the long flattened joints of the axis, lanceolate, herbaceous (green) and several-nerved on the back, and with thin scarious margins._

1. E. Robbinsii, Oakes. _Flower-bearing culms exactly triangular_, rather stout, erect (8'--2 deg. high), also producing tufts of capillary abortive stems or fine leaves, which float in the water; sheath obliquely truncate; spikelet 4--10'' long; achene oblong-obovate, triangular, minutely reticulated, about half the length of the bristles, tipped with a flattened awl-shaped tubercle.--Shallow water, N. Eng. to Fla.

[*][*] _Spikelet cylindrical, many-flowered, 1--2' long; scales in several ranks, firm-coriaceous with scarious margin, pale, nerveless or faintly striate; culms large and stout (2--4 deg. high); basal sheaths often leaf-bearing._

2. E. equisetoides, Torr. _Culm terete, knotted as if jointed by many cross-partitions; achene smooth_ (the minute reticulation transversely linear-rectangular), with a conical-beaked tubercle.--Shallow water, R. I. to Fla., west to Mich. and Tex.

3. E. quadrangulata, R. Br. (Pl. 3, fig. 6--9.) _Culm continuous and sharply 4-angled; achene finely reticulated_, with a conical flattened distinct tubercle.--Shallow water, central N. Y. to Mich., and southward; rare.

Sec. 2. _Spikelet terete and turgid-ovate, much thicker than the very slender culm; scales thin-coriaceous or firm-membranaceous, persistent, ovate; style 3-cleft; bristles stout, barbed downward (or sometimes upward), as long as the striate and pitted-reticulated triangular achene and its tubercle; culms tufted from fibrous roots, 1--2 deg. high._

4. E. tuberculosa, R. Br. (Pl. 3, fig. 10.) _Culms flattish_, striate; spikelet 3--6'' long, many-flowered; _tubercle flattish-cap-shaped, as large as the body of the achene_.--Wet sandy soil, from Mass. along the coast to Fla.

5. E. tortilis, Schult. _Culms sharply triangular, capillary_, twisting when dry; spikelet 2--3'' long, few-flowered; _conical-beaked tubercle much smaller than the achene_. (E. simplex, _Torr._)--Eastern shore of Md. to Fla.

Sec. 3. _Spikelets terete, much thicker than the culm, many-flowered; scales imbricated in many or more than 3 ranks, thin-membranaceous or scarious, with a thicker midrib, usually brownish or purplish, sometimes deciduous._

[*] _Style 2-cleft (often 3-cleft in n. 7 and 10) and the smooth achene lenticular; culms slender or thread-form, terete or compressed._

[+] _Annuals; culms tufted, from fibrous roots._

6. E. capitata, R. Br. Culms terete, 1/4--8' high or more; _spikelets ovate to oblong_ (1--3'' long), obtuse, 15--40-flowered; _scales thickish_, round-ovate, _obtuse_, brown or brownish with green keel and paler margins; stamens 2; achene obovate, _black, about equalling the 6--8 bristles_, tipped with a flattened or saucer-shaped tubercle. (E. dispar, _E. J. Hill_.)--In sand or gravel near sloughs, Md. (_Canby_) to Fla. and Tex.; N. Ind. (_Hill_). (S. Am., etc.)

7. E. ovata, R. Br. Culms nearly terete, 8--14' high; _spikelet globose-ovoid to ovate-oblong, obtuse_, 1--6'' long (dull brown); _scales very obtuse, densely crowded in many ranks; style_ 3- (rarely 2-) _cleft_; achene obovate with narrow base, pale-brownish, shining, shorter than the 6--8 bristles, _broader than the short-deltoid, acute and flattened tubercle_. (E. obtusa, _Schult._)--Muddy places, N. Brunswick to Minn., south and westward. Variable as to the length of its bristles. A low form, with smaller and more narrowly obovate achenes, and the bristles very short or none, is E. diandra, _Wright_. A dwarf form occurs with very small and few-flowered heads. (Eu.)

8. E. Engelmanni, Steud. Like the last; spikelets usually narrowly cylindrical and acute or acutish, 2--8'' long; achene broad and truncate, the tubercle covering the summit; bristles not exceeding the achene. (E. obtusa, var. detonsa, _Gray_.)--Mass. to Penn. and Mo.

[+][+] _Perennials, with running rootstocks._

9. E. olivacea, Torr. (Pl. 2, fig. 1--5.) Culms flattish, grooved, diffusely tufted on slender matted rootstocks (2--4' high); _spikelet ovate, acutish, 20--30-flowered; scales ovate, obtuse_, rather loosely imbricated (purple with a green midrib and slightly scarious margins); achene obovate, dull, abruptly beaked with a narrow tubercle, shorter than the _6--8 bristles_.--Wet, sandy soil, Mass. to N. C., and western N. Y.

10. E. palsutris, R. Br. Culms nearly terete, striate, 1--5 deg. high; _spikelet oblong-lanceolate, pointed, many-flowered; scales ovate-oblong_, loosely imbricated, reddish-brown with a broad and translucent whitish margin and a greenish keel, the upper acutish, the lowest rounded and often enlarged; achene rather narrowly obovate, somewhat shining, crowned with a short ovate or ovate-triangular flattened tubercle, shorter than the _usually 4 bristles_.--Very common, either in water, when it is pretty stout and tall, or in wet grassy grounds, when it is slender and lower. (Eu., Asia.)--Var. GLAUCESCENS, Gray. Culms slender or filiform; tubercle narrower, acute, beak-like, sometimes half as long as the achene. With the type.--Var. CALVA, Gray. Bristles none; tubercle short, but narrower than in the type.--Var. VIGENS, L. H. Bailey. Culms very stout, rigid; achene more broadly obovoid. Lake Champlain and along the Great Lakes to Minn.

[*][*] _Achene triangular or turgid; style 3-cleft._

[+] _Bristles at least equalling the smooth achene, downwardly barbed, persistent._

11. E. rostellata, Torr. _Culms flattened and striate-grooved_, wiry, erect (1--21/2 deg. high), _the sterile ones reclining, rooting and proliferous_ from the apex (1--2 deg. high), the sheath transversely truncate; _spikelet spindle-shaped_, 12--20-flowered; scales ovate, obtuse (light-brown); achene obovate-triangular, narrowed into the confluent pyramidal tubercle, which is overtopped by the 4--6 bristles.--Marshes, N. Eng. to S. C., west to Mich. and Ky.

12. E. intermedia, Schultes. _Culms capillary, wiry_, striate-grooved, densely tufted from fibrous roots, _diffusely spreading or reclining_ (6--12' long); _spikelet oblong-ovate, acutish, loosely 10--20-flowered_ (2--3'' long); scales oblong, obtuse, green-keeled, the sides purplish-brown; achene obovoid with a narrowed base, beaked with a slender conical-awl-shaped distinct tubercle, which nearly equals the 6 bristles.--Wet slopes, Penn. to Iowa, north to Canada.