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..
Grass-like sedges, perennial by rootstocks. Culms mostly 3-angled, often strongly phyllopodic, or aphyllopodic. Leaves 3-ranked, the upper elongated or very short (bracts) and subtending the spikes of flowers, or wanting. Flowers monoecious or dioecious, solitary in the axils of bracts (scales). Spikes either wholly pistillate, wholly staminate, androgynous or gynaecandrous. Perianth none. Staminate flowers of 3 stamens, the filaments filiform.
Pistillate flowers of a single pistil with a style and 2 or 3 stigmas, surrounded by the perigynium, which completely encloses the achene or is rarely ruptured by it in ripening. Achene 3-angled, lenticular or plano-convex. Racheola occasionally developed.
Species over 1000, widely distributed, most abundant in the temperate zones. Besides the following about an equal number occur in western and southern North America. Specimens can only be satisfactorily determined when nearly or quite mature. Type species: Carex pulicaris L.
A. Spike one, androgynous; perigynia glabrous, not margined; leaves acicular, their sheaths
striate, conspicuously clothing base of stem; stigmas 2 or 3.
B. Spikes one to very numerous; if one, plant not as above.
I. ACHENES LENTICULAR AND STIGMAS 2; LATERAL SPIKES SESSILE; TERMINAL SPIKE PARTLY PISTILLATE, OR IF STAMINATE, THE LATERAL SPIKES SHORT OR HEADS DIOECIOUS. VlGNEA.
a. Spike one, androgynous, orbicular to short ovoid.
b. Spikes one to very numerous; if one, not as above.
+ Rootstocks long-creeping, the culms arising 1-few together.
Spikes several, densely aggregated into a globular ovoid head, appearing like one spike; perigynia
Spikes not as above; perigynia not membranaceous.
Spike one, staminate, pistillate or androgynous.
Spikes more than one.
Perigynia not thin or wing-margined, the beak obliquely cut, in age often bidentate.
Culms becoming decumbent and branching.
Culms not branching.
Perigynia thin or wing-margined, the beak bidentate.
++ Culms caespitose, but plants sometimes stoloniferous, or with slender rootstocks.
* Spikes always androgynous.
Perigynia strongly compressed, not whitish-green.
Perigynia 1 -2 1/2" long, the beak not exceeding the body.
Spikes usually ten or less, green or reddish-brown tinged; sheaths loose, or if tight not red-
dotted or transversely rugulose.
Perigynia plano-convex, yellowish; opaque part of leaf-sheath transversely rugulose, often
Perigynia thick, much rounded on outer, somewhat on inner surface, brownish; opaque
part of leaf-sheath red-dotted, not transversely rugulose.
Perigynia 2"-4l/2" long, spongy at base; beak much longer than body.
Perigynia scarcely compressed, nearly terete, whitish-green.
* Spikes gynaecandrous, rarely staminate or pistillate.
Perigynia ascending or appressed, the body not margined.
Perigynia 2" long or less, puncticulate.
Perigynia longer, not puncticulate.
Perigynia body with thin or winged margins.
Perigynia spongy at base, usually spreading at maturity, thin-margined.
Perigynia not spongy at base, not widely spreading at maturity, wing-margined. 16. Ovales.
2. ACHENES TRIANGULAR OR LENTICULAR; IF LENTICULAR, THE LOWER LATERAL SPIKES CONSPICUOUSLY PEDUNCLED OR WITH STAMINATE TERMINAL SPIKE AND ELONGATED LATERAL SPIKES. Eu-CAREX.
a. Scales bract-like; achenes strongly constricted at the base.
b. Scales not bract-like; achenes not strongly constricted at the base
+ Spike normally one, the perigynia reflexed, or rounded and beakless at the apex.
Perigynia rounded at apex, beakless, glabrous; scales persistent.
Perigynia beaked, strongly reflexed; scales soon deciduous.
++ Spikes one to many; when one, the perigynia neither reflexed nor rounded.
* Perigynia both coriaceous and shining, the beak obliquely cut.
** Perigynia not both coriaceous and shining.
! Spike one; perigynia triangular, glabrous, not flattened.
! ! Spikes one to many; when one, perigynia not as above.
0 Perigynia triangular, membranous, closely enveloping the achene, essentially nerveless, or 2-ribbed, pubescent or puberulent at least at base of beak, stipitate; bracts sheathless or nearly so.
Spikes normally one.
Spikes androgynous; leaf-blades filiform.
Spikes dioecious; leaf-blades not filiform.
Spikes normally two or more.
Perigynia obtusely triangular; foliage not pubescent.
Young achenes, lowest scales, and perigynia not as above.
Perigynia acutely triangular; foliage usually pubescent.
°°Perigynia not as above; or if so, bracts strongly sheathing.
§ Lowest bract strongly green-sheathing; perigynia beakless to beaked, entire, oblique or emarginate at apex; or long-beaked and apex hyaline, becoming bidentate, teeth weak; achenes triangular, or if rarely lenticular, the perigynia dull and subterete.
* Text contributed by Mr. Kenneth K. Mackenzie.
Spike normally solitary.
Spikes two or more.
(1) Neither perigynia nor scales blackish.
Bracts with obsolete or rudimentary blades.
Lower spikes nearly radical; scales abruptly cuspidate.
Lower spikes not radical; scales not abruptly cuspidate.
Leaf-blades flat; perigynia puberulent to pubescent.
Leaf-blades filiform; perigynia glabrous.
Bracts with well-developed blades.
Pistillate spikes short-oblong to linear, erect, or if drooping the spikes short and the perigynia acutely triangular; terminal spike staminate.
Achenes lenticular; styles two.
Achenes triangular; styles three.
Perigynia with few to many strong nerves or nerveless.
Perigynia tapering at base, triangular, closely enveloping the achene.
Rootstock not long-creeping.
Perigynia rounded at base, suborbicular in cross-section, loosely enveloping the
Perigynia finely many-striate.
Perigynia tapering at base, constricted at apex, obtusely triangular, closely
enveloping the achene.
Perigynia rounded at both ends, cross-section suborbicular.
Pistillate spikes elongated, linear to cylindric, slender-peduncled, the lower drooping.
Perigynia beakless or short-beaked; terminal spike gynaecandrous.
Perigynia conspicuously or strongly beaked.
Culms strongly reddish-tinged at base, aphyllopodic.
Leaves glabrous; spikes very slender.
Leaves pubescent; spikes dense.
Culms not strongly reddish-tinged at base, phyllopodic.
Spikes slender, few-flowered; perigynia 2" long or less, not inflated, the beak
not becoming bidentate.
Spikes dense, many-flowered; perigynia longer, more or less inflated; the beak
(2) Perigynia and scales strongly blackish.
§§ Lowest bract sheathless to strongly green-sheathing; if green-sheathing, achenes lenticular ana perigynia not dull and subterete, or perigynia with strongly bidentate non-hyaline apex and stiff teeth.
= Perigynia or foliage (at least the lower sheaths) pubescent; perigynia beakless, or the beak not strongly bidentate; achenes triangular.
Terminal spike gynaecandrous.
Terminal spike staminate.
= = Perigynia and foliage glabrous, or if pubescent, the perigynia strongly bidentate; achenes tnan-sular or lenticular.
Perigynia rough-papillose or granular, beakless; or if beaked, the orifice not bidentate; achenes triangular.
Perigynia beakless or very short-beaked.
Perigynia conspicuously beaked.
Perigynia glabrous or pubescent, neither papillose nor granular.
Perigynia beakless or very short-beaked; achenes triangular.
Terminal spike, if staminate, without rough-awned scales.
Terminal spike staminate, lateral ones drooping on slender peduncles, at least at maturity.
Perigynia glaucous, flattened; spikes not linear-cylindric.
Perigynia not glaucous, not flattened in our species; spikes narrow
Terminal spike gynaecandrous, or if staminate, the lateral ones strictly erect.
Scales not dark-tinged.
Terminal spike staminate; scales rough-awned.
Perigynia with strongly bidentate beak, or if not, the achenes lenticular.
Achenes lenticular; perigynia dull.
Scales obtuse to acuminate, not long-aristate; achenes not constricted
Scales broad, long-aristate or in some arctic species acute or obtuse; achenes strongly
constricted at the middle.
Achenes triangular, or if (rarely) lenticular, the perigynia not dull.
Perigynia coriaceous, little if any inflated, often pubescent; bracts sheathless. 54. Hirtae.
Perigynia membranous or papery, from little to much inflated, never pubescent (rarely hispidulous); or if slightly coriaceous the lower bract long-sheathing.
Perigynia little inflated, abruptly beaked, pistillate scales reddish or chestnut brown;
lower bract strongly sheathing.
Perigynia little to much inflated, pistillate scales not reddish brown or chestnut, or if somewhat so, lower bract not strongly sheathing.
Perigynia lanceolate or lance-subulate, tapering into the beak, many-nerved.
Perigynia-teeth reflexed; perigynia green, early deciduous.
Perigynia-teeth not reflexed; perigynia yellowish-green.
Perigynia broader, abruptly contracted into beak, usually strongly ribbed.
Perigynia less than 5" long.
Perigynium-body ovoid or globose, not truncately contracted.
Perigynia coarsely ribbed or nerveless.
Perigynia finely and closely ribbed.
Perigynia with an obovoid or obconic body truncately contracted into the
Perigynia 5" long or longer.
Nardinae. Represented by 1 species.
Capitatae. Represented by 1 species.
Incurvae. Represented by 1 species.
Dioicae. Represented by 1 species.
Chordorrhizeae. Represented by 1 species.
Heads not dioecious; styles short; perigynia short-beaked.
Leaves narrowly involute.
Leaves 1"-2" wide, flat above.
Heads normally dioecious; styles long; perigynia long-beaked.
Spikes numerous; head heavy.
Spikes few (3-8); head slender.
Sheaths tight, often thickened at mouth: inconspicuously if at all septate-nodulose.
Perigynia corky-thickened at base, usually widely radiating or reflexed at maturity.
Perigynia beak smooth; scales acuminate, deciduous; spikes mostly approximate.
Perigynia body broadly ovate, bi-convex.
Perigynia body lanceolate or ovate-lanceolate, plano-convex.
Perigynia beak minutely roughened; scales obtuse or acutish, persistent.
14. C. rosea.
Perigynia not corky-thickened at base, spreading or ascending.
Scales tinged with reddish-purple; perigynia more than 2" long.
Scales not tinged with reddish-purple; perigynia 2" or less long.
Head 7l/2"-18" long, the lower spikes distinct.
Perigynia spreading, 1 1/2" long; bracts not broadly dilated at base; scales about length
of and narrower than perigynia, short-awned.
Perigynia ascending, 2" long; bracts broadly dilated at base; scales (especially lower)
exceeding and as wide as perigynia, strongly awned.
Head 4"-10" long, the spikes densely capitate.
Scale body about length of broadly ovate perigynia.
Scale body much exceeded by perigynia.
Perigynia elliptic-ovate or narrower; leaves 1 1/4"-2" wide,
Perigynia orbicular-ovate; leaves 1/2"-i" wide.
Sheaths loose and membranous, easily breaking, conspicuously septate-nodulose.
Culms sharply triangular, not flattened or winged.
Perigynia dull, its beak 1/4-1/3 length of orbicular body.
Perigynia deep green, its beak 1/2 length of ovate body or more.
Bracts not developed; scales one half length of body of perigynia.
Some bracts developed; scales equalling body of perigynia or longer.
Leaves 1 1/2"-2" wide; spikes aggregated or approximate.
Leaves 2 1/4"-5" wide; lower spikes strongly separate.
Culms narrowly winged, more or less flattened.
Perigynia faintly nerved on outer face.
Perigynia strongly nerved on outer face.
Leaves exceeding culms; perigynia beak equalling body.
Culms exceeding leaves; perigynia beak shorter than body.
Perigynia ovate to suborbicular.
Perigynia lanceolate to ovate-lanceolate.
Leaves 1/2"- 1 1 /2 wide; perigynia tapering into beak, rounded or truncate at base.
Spikes approximate or little separate, the lower simple or nearly so; perigynia dark-brown,
rounded on inner face, i"-1 1/4" long.
Spikes strongly separate, the lower compound; perigynia light-brown, nearly flat on inner face,
1 1/4"-1 1/2" long.
Leaves 2"-4" wide; perigynia very abruptly short-beaked, tapering at base.
Perigynia 2"-2 1/2" long; beak 1-2 times length of body.
Perigynia 3"-3 1/2" long; beak 3-4 times length of body.
12. Tenellae. Represented by 1 species.
Lowest bract bristle-form, much prolonged, many times exceeding its 1-5-flowered spike; spikes
Lowest bract much shorter or none; spikes several-many-flowered, the upper approximate.
Spikes 2-4, subglobose, closely approximate, forming an ovate or suborbicular head; perigynia •
scarcely beaked; scales white-hyaline.
Spikes 1-many, the lower more or less strongly separate, the head elongate; perigynia short to
strongly beaked; scales darker.
Perigynia broadest near middle; beak short, smooth or moderately serrulate.
Perigynia beak smooth or very nearly so; scales very obtuse to acutish, strongly reddish-brown tinged; spikes closely approximate or in C. norvegica the lower remote.
Spikes 1 or more, approximate, the lower less than 2" wide.
Spike 1, rarely with a smaller one at base.
Terminal spike strongly clavate at base; culms rough at apex only.
Perigynia ovate, abruptly beaked.
Leaves flat, 1/2"-1 1/2" wide; culms strict, erect.
Leaves involute, 1/4"-3/4" wide; culms weak, slender.
Perigynia lanceolate, long-tapering.
Terminal spike little clavate; culms usually very rough.
Lower spikes widely separate, 2"-2 1/2" wide.
Perigynia beak serrulate, or if smooth the scales acutish to cuspidate and scarcely if at all reddish-brown tinged; lower spikes remote.
Glaucous; leaves \"-2" wide; spikes many-flowered, the scarcely beaked appressed-
ascending perigynia with emarginate or entire orifice.
Not glaucous; leaves 1/2"-1 1/4" wide; spikes fewer-flowered, the distinctly beaked,
loosely spreading perigynia with minutely.bidentate orifice.
Perigynia ovate, broadest near base, the beak conspicuous, strongly serrulate.
46. C. arcta.
Spikes oblong-ovoid; perigynia nerveless or nearly so, sharply margined above; achenes 1" long;
Spikes linear; perigynia noticeably or strongly nerved, little margined above; achenes 7/8" long or
less; scales brownish-tinged.
Spike one (rarely with a small additional one).
Spikes more than one.
Perigynia soon ruptured by elongating achene and appearing glume-like.
Perigynia not soon ruptured, remaining normal.
Perigynia broadest near base,the beak serrulate.
Perigynia beak 1/4-1/3 length of body, the teeth very short, the suture on inner side inconspicuous; scales very obtuse to acutish.
Leaves flat, 1/2"-1" wide, usually shorter than culm; perigynia little nerved.
Leaves usually involute, 1/4" wide, usually exceeding culm; perigynia strongly nerved.
Perigynia beak longer, strongly bidentate, the suture conspicuous; scales sharper.
Perigynia body lanceolate to broadly ovate, narrowed into beak more than half its
length; perigynia usually inconspicuously nerved on inner face.
Perigynia body suborbicular, abruptly contracted into beak less than half its length; perigynia conspicuously nerved on inner face.
Perigynia lightly nerved on both faces; scales acute to short acuminate; leaves
usually less than 1" wide; culms slender, sharply triangular.
Perigynia strongly nerved on both faces; scales acutish to acute; leaves 1"-2"
wide, the lower very short; culms stout, obtusely triangular.
Perigynia broadest near middle, the beak smooth.
Perigynia subulate, at least three times as long as wide, less than 3/4" wide, wing near base almost obsolete.
Bracts much elongated, many times exceeding head, leaf-like; perigynia 2 1/2" long, the beak 2-3
times length of body.
Bracts much shorter and reduced; perigynia 2 1/4" long or less.
Tips of perigynia equalling or scarcely exceeded by the obtuse or acute dark brown scales;
leaves 1 1/4"-2" wide; culms 20'-40' high.
Tips of perigynia conspicuously exceeding the acute or acuminate light brown scales; leaves
1/2"-1 1/2" wide; culms 5'-24' high.
. C. Crawfordii.
Perigynia lanceolate to reniform; wing near base narrow to very wide, but never almost obsolete.
A. Perigynia narrowly to broadly lanceolate, at least 2 1/2 times as long as broad; tips of perigynia prominently exceeding scales.
Spikes 2"-7 1/2" long; perigynia 3 1/4" long or less; achene short-oblong.
Leaves at most 1 1/2" wide, those of sterile shoots few, ascending.
Leaves broader, those of sterile shoots very numerous, widely spreading.
Tips of perigynia appressed or ascending; spikes 3 1/2"-6" long.
61. C. tribuloides.
Tips of perigynia widely spreading or recurved; spikes 2"-4" long.
Inflorescence dense, oblong; culm stiff, stoutish.
Inflorescence loose, elongate; culm weak, slender.
Spikes 7 1/2"-13" long; perigynia 3 1/2"-5" long; achenes linear-oblong.
B. Perigynia ovate-lanceolate or broader, at most twice as long as broad, or if narrower tips of perigynia equalled by scales.
a. Perigynia strongly exceeding scales or if nearly equalled by them much wider.
+ Perigynia narrowly to broadly ovate, 1 1/2"-2" long, nerveless or few-nerved on inner face, the tips not appressed.
Perigynia brownish; spikes closely aggregated, rounded at base.
65. C. Bebbii.
Perigynia green; spikes contiguous to widely separate, usually clavate at base.
Leaves 1" wide or less.
Leaves 1 1/4"-3" (averaging 2") wide.
++ Perigynia ovate to reniform, 2" or more long, or if shorter with closely appressed
Spikes closely aggregated, the scales dark brown or blackish.
Spikes approximate to widely separate, the scales lighter.
Perigynia spreading-ascending; spikes green or brownish.
Spikes approximate or scattered, the head stiff; scales obtuse or acutish.
Perigynia 2"-2 3/4" long, thickish, nerveless or obscurely nerved on inner face.
Perigynia 2 3/4"-3 3/4" long, very thin, prominently about
Spikes in a moniliform flexuous head; scales long-pointed.
Pengynia closely appressed, or if somewhat spreading-ascending, the spikes whitish or silvery green.
Spikes approximate, the head stiff; lateral spikes rounded or little clavate at base.
Perigynia ovate, tapering into beak half length of body or more.
Perigynia broader, abruptly contracted into beak about third length of body.
Scales long acuminate or aristate; perigynia more than 2" long and nearly
1 1/2" wide or more; achenes stipitate.
Scales obtuse or acutish; perigynia I 1/2"-2" long (rarely slightly more)
and 1 1/2" or less broad; achenes nearly sessile.
Spikes in a moniliform flexuous head; lateral spikes long clavate. 75. C. siiicea.
b. Scales very slightly shorter to slightly longer than perigynia and concealing them.
Scales strongly dark-tinged, narrowly hyaline-margined; head stiff, the spikes approximate,
Scales usually not dark-tinged, strongly hyaline margined; if dark-tinged not as above.
Inflorescence stiff, the spikes closely approximate.
Spikes elliptic, tapering at base; perigynia closely appressed; bracts scale-like.
Spikes suborbicular, rounded at base; perigynia loosely ascending; lower 1-2 bracts
Inflorescence not stiff, often flexuous and moniliform.
Perigynia nerveless on inner face or faintly nerved.
Perigynia lance-ovate, 2 1/4"-3 1/4" long, 1" wide or less; leaves about 1" wide.
Perigynia ovate, 2"-2 1/2" long, 1"-1 1/2" wide; leaves 1 1/2"-2"wide.
Pengynia strongly nerved on inner face.
Scales (except lowest) not leaf-like, not enveloping perigynia, green with hyaline margins.
Body of perigynia oblong; pistillate flowers usually 3-10.
Body of perigynia globose; pistillate flowers usually 2-3.
Scales leaf-like, half-enveloping perigynia, without conspicuous hyaline margins.
84. C. durifolia.
18. Polytrichoideae. Represented by 1 species.
Racheola absent or rudimentary, not conspicuously exserted.
Racheola present, conspicuously exserted.
20. Nitidae. Represented by 1 species.
21. Rupestres. Represented by 1 species.
22. Filifoliae. Represented by 1 species.
23. Scirpinae. Represented by 1 species.
24. Mitratae. Represented by 1 species.
None of the culms short and hidden among the bases of the leaves.
Aphyllopodic and not stoloniferous; lower sheaths but little fibrillose.
Phyllopodic and often long-stoloniferous.
Perigynia about equalling scales, 1 1/4" long or less.
Staminate spike stout; lower sheaths usually strongly fibrillose.
Long stoloniferous; staminate spike 6"-12" long.
Short stoloniferous; staminate spike 2"-6" long.
Staminate spike not over 1/2" thick; sheaths little fibrillose.
Perigynia twice length of scales, 1 1/2"-2" long.
Many of the culms short and hidden among the bases of the leaves.
Lower bract exceeding the culm, leaf-like.
Staminate spike 1"-3" long; perigynia 1 1/2" long, or less.
Staminate spike 3"-6" long; perigynia 2" long, or more.
Lower bract exceeded by the culm, scale-like.
Pistillate and staminate spikes contiguous; culms aphyllopodic.
Lower pistillate spikes widely separate; culms phyllopodic.
Perigynia 2" long or less, puberulent; leaves slender, light green, ascending, 1 1/2" wide
Perigynia longer, glabrous except the long beak; leaves stiff, deep green, spreading, wider.
Triquetrae. Represented by 1 species.
Pictae. Represented by 1 species.
Pedunculatae. Represented by 1 species.
Staminate spike 1 1/2 "-3" long; scales obtuse, one-half length of perigynia.
Staminate spike 6"-10" long; scales acute to acuminate, exceeding perigynia
30. Albae. Represented by 1 species.
Mature perigynia whitish, ellipsoid, not fleshy or translucent.
Mature perigynia orange or brownish, broader, fleshy, translucent.
110. C. aurea.
Perigynia beak none or very short, often bent.
Leaves 1" wide or less, involute or folded; leaves and perigynia very glaucous; bract sheaths
short; spikes approximate.
Leaves 1"-3" wide, flat; leaves green or bluish-green; bract sheaths long; spikes distant.
Perigynia turgid; peduncle of staminate spike smooth; leaves bluish-green.
Perigynia not turgid; peduncle of staminate spike rough; leaves green.
Culms phyllopoclic, not strongly purplish tinged at base; rootstocks very slender, deep-seated.
Fertile culm blades usually 6-10, 1 1/2"-3 1/2" wide; perigynia more than 1 1/2" long;
spikes oblong or linear-oblong.
Fertile culm blades usually 3-5, i"-1 3/4" wide; perigynia less than 1l/2" long; spikes
Culms aphyllopodic, purplish at base; plants loosely stoloniferous.
Perigynia beak straight, prominent, 1/4- 1/2 length of body.
Culms phyllopodic; lower sheaths not purplish; pistillate spikes 2-3, spreading
116. C. vaginala.
Culms aphyllopodic; lower sheaths purplish; pistillate spikes 1-2, erect.
Sheaths and base of culm strongly purplish; staminate scales purplish.
Leaf-blades of fertile culms rudimentary; perigynia 2 1/4" long or less.
Leaf-blades of fertile culms developed; perigynia 2 3/4" long or more.
Sheaths not purplish tinged, the base of culms but rarely so; staminate scales never purplish.
A. Perigynia acutely triangular, short tapering at base.
Leaf-blades very smooth (except edges), the larger 6" wide or more, those of fertile culm
much smaller than those of sterile; perigynia smooth.
Leaf-blades hispidulous on veins, 5" wide or less; those of fertile culm moderately smaller than those of sterile; perigynia minutely roughened.
Staminate spike sessile or nearly so; peduncles short, erect.
Staminate spike usually strongly peduncled; lower peduncles capillary.
Perigynia short-beaked; second bract and leaves usually exceeding culm; blades
1 1/4"-21/2" wide, erect.
Perigynia beakless or nearly so; second bract and leaves usually exceeded by culm;
blades 2"-4" wide, spreading.
B. Perigynia obtusely triangular, long tapering at base, smooth.
Pistillate scales very truncate; blades 7 1/2"-20" wide; culms very strongly flattened and wing-
Pistillate scales acuminate to strongly cuspidate; blades narrower.
Spikes elongated, 8-20-flowered, the lower normally on erect-stiff peduncles.
Perigynia obovoid; beak abruptly bent, minute; sterile shoots developing conspicuous culms.
Culms stout; sheaths loose, the margins crisped; staminate spike short-stalked or
Culms slender; sheaths rather tight, the margins little if at all crisped; staminate
spike long or rarely short-stalked.
Perigynia obovoid or fusiform with straight or oblique conspicuous beak; sterile shoots reduced to tufts of leaves.
Culms slightly wing-angled, stout, densely cespitose; basal leaves generally less than 1° long, their sides not parallel; perigynia appressed-ascending.
Culms scarcely wing-angled, slender, often loosely cespitose; basal leaves generally more than 1° long, their sides parallel; perigynia spreading-ascending.
Spikes short, 5-10-flowered, the lower on capillary spreading or drooping peduncles.
Culms tufted; bracts elongated, overtopping spikes; staminate spike short-stalked.
Basal leaves 2l/2"-8" wide; lower bract not extending beyond upper spikes; perigynia narrowly
Basal leaves 1 1/2"-4 1/2" wide; lower bract extending beyond upper spikes; perigynia elliptic
Rootstocks long-creeping; bracts short, rarely overtopping spikes; staminate spikes long-stalked.
Sheaths smooth; perigynia 1 3/4"-2" long.
Sheaths rough-pubescent; perigynia 2 1/4"-2 1/2" long.
Perigynia elliptic, 3/4" wide; leaves 2" wide or less; bract sheaths rough and peduncles very rough.
Culms 2 1/2' high or less, much exceeded by leaves; staminate spike nearly sessile.
Culms 6'-36' high, exceeding leaves or shorter; staminate spike long-stalked.
Perigynia oblong, 1" wide; leaves 1 1/2"- 3 1/2" wide; bract sheaths smooth and peduncles nearly so.
Leaves not glaucous; larger spikes less than 12-flowered; lower scales usually equalling perigynia.
Leaves 1"-2" wide, erect; spikes widely scattered, the lower nearly basal; perigynia little
Leaves 2"-3" wide, spreading; lower spikes not nearly basal; perigynia turgid.
Leaves glaucous; larger spikes more than 12-flowered; lower scales shorter than perigynia.
Perigynia 11 /2"-2" long, somewhat exceeding scales.
Perigynia 2 1/4"-3" long, 2-3 times exceeding scales.
Plant glabrous; perigynia 1 3/4" long or less.
Perigynia rounded at apex, beakless.
Perigynia sharp-pointed at apex, short-beaked.
Sheaths and often foliage pubescent.
Scales except lowest obtuse or acute; spikes all gynaecandrous.
Scales acuminate to cuspidate; lateral spikes pistillate.
Bracts strongly sheathing; leaves 1l/2"-2" wide.
Upper scales acuminate or short-cuspidate; perigynia 1 3/4"-2" long, less than 1" wide;
Upper scales sharply cuspidate; perigynia 2"-2 1/2" long, more than 1" wide; spikes linear-
oblong or oblong-cylindric.
Lower bract only strongly sheathing; leaves 1"-2" wide.
Perigynia nearly 1" wide, slightly inflated, strongly nerved; lateral spikes scarcely loosely
flowered at base.
Perigynia about 1/2" wide, obscurely nerved; lateral spikes alternately flowered at base.
Perigynia smooth or puberulent.
Scales tinged with reddish brown; perigynia firm, strongly several-nerved; upper sheaths
Scales hyaline with green midrib or somewhat reddish-brown tinged; perigynia membranous, lightly nerved; upper sheaths glabrous.
Perigynia sessile or subsessile; blades 1"-2 1/2" wide; scales obtuse to short-cuspidate.
Perigynia 3"-5" long, the beak subulate; scales white hyaline margined
Perigynia 2 1/4"-3 1/4" long, the beak less subulate; scales tawny tinged.
Perigynia strongly stipitate; blades 2 l/2"-5" wide; scales strongly cuspidate.
Perigynia tuberculate hispid.
39. Flexiles. Represented by 1 species.
40. Capillares. Represented by 1 species.
Beak of perigynia much shorter than body; culms not fibrillose at base.
Beak of perigynia longer than body; culms strongly fibrillose at base.
Perigynia rounded at base, its beak very short.
Perigynia strongly narrowed at base, its beak conspicuous, serrulate.
Perigynia densely pubescent.
Leaves exceeding culms; lowest bract setaceous, 1/4" wide; pistillate spikes oblong cylindric;
Culms exceeding leaves; lowest bract leaflet-like, 1/4"-1 1/2 wide; pistillate spikes linear-cylindric;
Perigynia glabrous, at least at maturity.
Perigynia much flattened, rounded at apex, lightly nerved.
Perigynia swollen, nearly orbicular in cross-section, pointed at apex, coarsely nerved.
Perigynia 1" long, brownish-green; scales not rough-cuspidate.
Perigynia longer, green; scales rough-cuspidate.
Perigynia beakless, lightly nerved.
Perigynia short-beaked, strongly nerved.
45. Trachychlaenae. Represented by 1 species.
46. Anomalae. Represented by 1 species.
Perigynia ovoid-elliptic, thick; pistillate scales broadly oval, obtuse or abruptly minutely pointed;
culms obtusely triangular.
Perigynia broader, much flattened; pistillate scales ovate, tapering at apex to long cuspidate; culms sharply triangular
Strongly stoloniferous; leaves involute, glaucous, 1 1/2" wide or less; scales little exceeding peri-
Tufted; leaves flat, not glaucous, wider; scales much exceeding perigyni;
48. Scitae. Represented by 1 species.
Scales not exceeding perigynia or but slightly so; sheaths not filamentose.
Perigynia not flattened and two-edged.
Perigynia 1 1/4" long or less, nerveless, the beak minutely bidentate, the style not prominent.
Perigynia longer, two-nerved; beak not bidentate, style prominent.
Perigynia flattened and two-edged.
Spikes all contiguous, sessile or short-peduncled, erect.
Lower spike strongly stalked, often drooping and distant.
Scales awned, noticeably exceeding perigynia; sheaths strongly filamentose,
50. Shortianae. Represented by 1 species.
Perigynia not compressed-triangular, obovoid; staminate spike one.
Perigynia strongly ribbed, squarrose, slightly glaucous; staminate scales tapering into short
awn; basal sheaths not fibrillose.
Perigynia obscurely nerved, ascending, very glaucous; staminate scales abruptly awned; basal
sheaths strongly fibrillose.
Perigynia compressed-triangular, ovoid; staminate spikes two or three.
Culms very strongly tufted, slender, very rough above; perigynia beak very short, not twisted.
Perigynia elliptic, longer than or little exceeded by scales.
Perigynia obovate or orbicular, shorter than scales.
Culms tufted and short stoloniferous, stout at base, smooth above; perigynia beak prominent,
twisted when dry.
Perigynia beak if present not bidentate.
Culms single or in small clumps, strongly stoloniferous; scales very dark with slender mid-vein; strict and generally low species.
Leaves with revolute margins; perigynia at most obscurely nerved
Leaves with involute margins; perigynia conspicuously nerved.
Culms densely cespitose, the stolons absent or not prominent; scales with broad light-colored center; tall slender species.
Leaves 1/2"-l 1/2" wide; staminate spike one; rootstocks not sending out long stolons.
Leaves broader; staminate spikes two or more; stolons long.
Perigynia beak markedly bidentate; perigynia strongly ribbed.
Pistillate spikes strictly erect, the upper sessile or nearly so; perigynia coriaceous.
Leaves 1 1/4" wide or less, the margins involute; lowest bract somewhat spathe-like; pistillate
spikes few-flowered; culms 7' or less high.
Leaves 1" - 3" wide, flat or with revolute margins; lowest bract not spathe-like; pistillate spikes many-flowered; culms usually taller.
Scales little longer than perigynia, pale reddish; pistillate spikes usually 4' long or less.
Scales much exceeding perigynia, dark purple, light brownish or chestnut; pistillate spikes
1 1/4-3' long.
Pistillate spikes peduncled, drooping, widely spreading or suberect.
Pistillate scales purplish brown; perigynia coriaceous.
Pistillate scales lighter colored; perigynia membranaceous.
Awnsof pistillate scales erect or appressed-ascending; perigynia not inflated; basal sheaths
little or not at all fibrillose.
Awns of pistillate scales spreading or loosely-ascending; perigynia generally somewhat
inflated; basal sheaths fibrillose.
Sheaths rough hispid; lower pistillate scales tapering into awn.
Sheaths smooth; lower pistillate scales abruptly contracted into awn.
Staminate scales not ciliate.
Perigynia beak much shorter than body, the teeth 1/2" long or less.
Perigynia glabrous to sparsely pubescent.
Leaves 3"-6" wide, flat.
Culms aphyllopodic, strongly purplish tinged and filamentose at base; mature peri-
gynia strongly nerved.
Culms phyllopodic, not purplish tinged or filamentose at base; mature perigynia im-
Leaves 1"-2" wide, becoming involute.
Perigynia densely or strongly pubescent.
Perigynia nerves obscured by dense pubescence, the teeth of beak short.
Perigynia beak with hyaline orifice at length somewhat bidentate; staminate spike
usually one, sessile or short-stalked.
Perigynia beak with non-hyaline, strongly bidentate orifice; staminate spikes long-stalked.
Leaves flat, more than 1" wide.
Leaves involute, 1" wide or less.
Perigynia nerves prominent, the teeth of beak prominent, slendei
Perigynia beak including teeth nearly as long as body, the teeth 3/4" long or more.
Perigynia glabrous or pubescent, ovoid, the teeth less than 1" long, erect or spreading; scales
acute to aristate.
Perigynia glabrous, lanceolate or ovoid-lanceolate, the teeth 1"-2" long, widely spreading;
C. other odes.
Staminate scales strongly ciliate.
Bracts long-sheathing, erect; pistillate spikes scattered.
Bracts except lower not long-sheathing, widely spreading; pistillate spikes, at least upper, approximate.
Leaves involute; perigynia ascending, not yellowish.
Leaves not involute; perigynia squarrose, yellowish.
Perigynia l"- 1 1/2" long, the beak scarcely half length of body.
Perigynia 2"-3 long, the beak about length of body.
Scales hidden; perigynia 2" long; beaks spreading or lower reflexed.
Scales conspicuous; perigynia 2l/2"-3" long, the beaks spreading in all directions.
56. Collinsiae. Represented by 1 species.
Leaves 1"-2" wide; scales acute or short acuminate.
Leaves 2"-8" wide; scales strongly awn-tipped.
1. Perigynia scarcely inflated; beak entire or emarginate; stigmas usually two; achenes lenticular.
Leaves strongly involute, 1/2"-I 1/2" wide; rootstocks creeping, the culms arising one-several together-.spikes sessile or short-peduncled: culms often somewhat filamentose at base.
Pistillate spikes linear- or oblong-cylindric, 2"-2 1/2" wide; perigynia loosely ascending; leaves
1" wide or less.
Pistillate spikes suborbicular to oblong, wider; perigynia appressed-ascending; leaves mostly
Leaves flat, wider; rootstocks not creeping, but plants freely stoloniferous; culms not filamen-
tose at base; spikes from nearly sessile to strongly peduncled.
2. Perigynia from little to much inflated; beak bidentate; stigmas normally three; achenes triangular.
A. Pistillate scales (except rarely lowest) not rough-awned.
a. Pistillate spikes oblong to cylindric, 15 to many-flowered.
Perigynia not reflexed; bracts not more than several times exceeding spikes.
Achenes not excavated on one side or but little so.
Beak of perigynia smooth.
Culms sharply triangular, rough above, scarcely spongy at base; perigynia ascending.
Perigynia 2"-2 1/2" long; culms often not filamentose at base.
Perigynia longer; culms markedly filamentose at base.
Perigynia lanceolate, tapering into beak; spikes loosely flowered at base.
Perigynia ovoid or globose-ovoid; spikes not loosely flowered. :
Pistillate spikes less than 4 1/2" wide; perigynia globose-ovoid, abruptly con-
tracted into beak.
Pistillate spikes 4 1/2"-7 1/2" wide; perigynia ovoid, contracted into beak.
Culms obtusely triangular, usually smooth above, often thick and spongy at base; perigynia often spreading, abruptly contracted into beak.
Leaves very narrow, involute.
Leaves broad, flat.
Spikes 1 1/4' long or less; perigynia strongly dark tinged, very membranous; culms
1° high or less.
Spikes much longer; perigynia little tinged, less membranous; culms much higher.
Beak of perigynia rough.
Achenes deeply excavated on one side.
Lower perigynia reflexed; bracts many times exceeding spikes.
b. Pistillate spikes globose or short-oblong, 5- to 15-flowered.
B. Pistillate scales rough-awned.
Spikes cylindric, 7"-9" thick; perigynia contracted into beak.
Spikes narrowly cylindric, 4"-6" thick; perigynia abruptly contracted into beak.
Perigynia suborbicular in cross-section, more or less inflated.
Spikes linear-cylindric; staminate scales scarcely awned.
Spikes oblong or oblong-cylindric; staminate scales with short rough awns.
Perigynia obtusely triangular, scarcely inflated, closely enveloping achene.
Perigynia teeth erect, l/2" long; body of beak 1/2" long.
Perigynia teeth recurved or spreading, 3/4"-1" long; body of beak 3/4"-1" long.
Scales exceeding perigynia; terminal spike small, normally staminate.
Scales much shorter than perigynia; terminal spike gynaecandrous.
Scales acuminate or awned; spikes oval.
Scales obtusish; spikes oblong-cylindric.
Pistillate spikes globose or subglobose; style straight.
Scales usually strongly awned (varying to obtuse in few-flowered northern plants); pistillate
spikes 1-12-flowered; leaves 1 1/4"-3 1/2" wide, the sheath prolonged.
Scales usually obtuse, varying to slightly cuspidate; pistillate spikes 6-30-flowered; leaves
2 1/2"-4 1/2" wide, the sheath not prolonged.
Pistillate spikes oblong or cylindric; style abruptly bent.
Perigynia ascending, the beak less than twice length of body.
Culms arising singly from elongated rootstocks; leaves 1"-2l/2" wide.
Culms cespitose; kaves 2"-5" wide.
Achenes longer than thick, the angles not prominently knobbed.
Achenes not longer than thick, the angles prominently knobbed.
Perigynia spreading at right angles, the beak 2-3 times length of body
2. C. eieantea.