CYPERACEAE

ANDROPOGON L

PL 2:788. 1891 P. praemorsa (Nees) Hack

18. CYPERACEAE

Aquatic or terrestrial herbs {Scleria secans a scandent vine), usually tufted, rhizomatous or stoloniferous, with 3-sided stems. Leaves mostly crowded and basal with a closed sheath; blades simple, entire or sharply serrulate;

venation parallel; stipules lacking. Flowers bisexual or unisexual (monoecious or andromonoecious), in bracteate spikelets, the spikelets solitary or variously compound (often umbellate); perianth reduced to several scales or bristles; stamens 1-3, free, hypogynous; anthers 2-celled, basifixed, dehiscing longitudinally, often having a pro- duced connective; ovary 1, superior, 1-locular, 2- or 3- carpellate, with basal placentation; ovule 1, anatropous;

style simple, 2- or 3-branched (depending on the number of carpels). Fruits achenes, sometimes in utricles, with albumen.

Easily mistaken for Gramineae (17), but distinguished by having solid, three-sided stems and three-ranked leaves with usually closed sheaths and basifixed anthers.

KEY TO THE TAXA OF CYPERACEAE

Inflorescences simple and unbranched or if compound the heads ± sessile:

Spikelets solitary, not subtended by leafy bracts; plants usually aquatic Eleocharis Spikelets numerous, in dense heads subtended by leafy bracts; plants rarely aquatic:

Spikelets ovate, flattened Cyperus luzulae (L.) Retz.

Spikelets not ovate and flattened:

Blades usually more than 5 mm wide; heads usually more than 1.5 cm diam Rhynchospora cephalotes (L.) Vahl Blades less than 5 mm wide; heads usually less than 1 cm diam:

Bracts subtending inflorescence usually white, at least at base; spikelets few, 5-10 mm long Rhynchospora nervosa (Vahl) Boeck.

Bracts subtending inflorescence always green (sometimes only 1 or 2); spikelets numer- ous, less than 4 mm long:

Spikelets usually ca 3 mm long; scales smooth on keel, blunt at apex with a tiny mucro Cyperus sesquiflorus (Torr.) Mattf. & Kuek.

Spikelets 1.5-2 mm long; scales spinulose-scabrous on keel, subacute at apex with a short cusp:

Plants perennial, the rhizomes elongate, creeping ... Cyperus brevifolius 'Rottb.) Hassk.

Plants annual, rhizomes lacking Cyperus densicaespitosus Mattf. & Kuek.

Inflorescences compound, the heads not sessile:

Spikelets very numerous, in dense, ± globose heads, the heads few, mostly more than 6 mm diam, radiating on short or long rays at apex of stem:

Heads whitish, borne on very short rays usually less than 1 cm long, the heads lacking leaflike bracts at base; spikelets markedly flattened with numerous scales easily disarticulating;

plants not aquatic Cyperus luzulae (L.) Retz.

Heads greenish, on rays more than 2 cm long, subtended by short leaflike bracts; spikelets not markedly flattened, the scales few, not disarticulating; plants aquatic , Scirpus cuhensis Kunth Spikelets not in dense globose heads radiating from a central point, or if in dense globose heads,

the heads less than 6 mm diam:

Achenes white, often shiny, exposed at maturity, ± globose:

Leaves less than 2 mm wide; plants slender annuals; achenes conspicuously transversely

^"^8°^^ Rhynchospora micrantha Vahl Leaves more than 2 mm wide; plants perennials; achenes not transversely rugose:

Achenes clustered in small glomerules at apex of slender rays Calyptrocarya glomerulata (Brongn.) Urban Achenes solitary, not borne in clusters on slender rays Scleria Achenes not as above (if exposed at maturity, not white and shiny):

Spikelets, at least in part, solitary on conspicuous peduncles, terete:

Blades less than 4 mm wide; peduncles glabrous Fimhristylis dichotoma (L.) Vahl Blades more than 1 cm wide; peduncles scabrid Hypolytrum schraderianum Nees Spikelets sessile, never solitary on conspicuous peduncles, terete or not, or if spikelets borne

solitary, then not terete:

Plants not aquatic (except sometimes C. odoratus); blades less than 1.5 cm wide Cyperus (in part) Plants usually aquatic; blades more than 1.5 cm wide (except Cladium with very stiff,

spinulose margins):

Spikelets in racemes, at least some racemes on long rays subtended by a whorl of long, leaflike bracts Cyperus giganteus Vahl Spikelets in umbels or corymbs, not borne on long rays subtended by leaflike bracts:

Leaf blades usually 5- or more-veined; scales of spikelet pubescent Fuirena umbellata Rottb.

Leaf blades with only 1 prominent vein; scales of spikelet glabrous or pubescent only on keel:

Bracts subtending uhimate clusters of spikes usually acute at apex, the awns, if present, very short; achenes lacking a tubercle at apex; leaves very stiff, the margins very coarsely spinulose-serrate Cladium jamaicense Crantz Bracts subtending ultimate clusters of spikes long caudate-acuminate, the awns

equaling or longer than remainder of bract; achenes having a cone-shaped tubercle at apex; leaves not very stiff', the margins not coarsely spinulose- serrate Rhynchospora corymbosa (L.) Britt.

Flowers are probably all wind pollinated except for Rhynchospora nervosa (Leppik, 1955; Baker, 1963), whose pollination is discussed in the systematic treatment. Other species that need to be investigated for possible insect pollination, because they occur deep in the forest where they cannot rely on wind, are Cyperus simplex, Hypo- lytrum schraderianum, and Calyptrocarya glomerulata.

Some taxa, such as Calyptrocarya and Scleria, with shiny white or colored achenes, are well suited for bird dispersal. Adapted also for dispersal by shore birds and by water are the following principally aquatic genera:

Eleocharis, Scirpus, Fuirena, and some species of Cyperus.

Taxa occurring on mud flats, such as Cyperus, may have seeds dispersed on the feet of birds. Most members of the family have very small diaspores, which could be eaten easily by small birds. Ducks and otiier shore birds are very important in the dispersal of aquatic Cyperaceae (Ridley, 1930). The seeds of many species occurring in clearings are probably spilled and scattered by the me- chanical action of passing animals. Van der Pijl (1968)

said that some Cyperaceae seeds are wind dispersed.

About 70 genera and over 3,500 species; widespread, but particularly numerous in high latitudes, usually in wet places.

CALYPTROCARYA Nees

Calyptrocarya glomerulata (Brongn.) Urban, Symb.

Ant. 2:169. 1900

Small perennial, to ca 60 cm tall. Leaves linear, longer than culms, 2-9 mm wide, 3-veined, prominently folded along midrib, glabrous but with minutely scabrid mar- gins. Spikelets minute, in small globular heads less than 4 mm diam on rays of compound or simple axillary corymbs; rays to ca 1.5 cm long; pistillate spikelets termi- nal, minutely puberulent, bearing 1 flower; style bifid;

staminate spikelets lateral, bearing 1-4 flowers; stamen 1.

Achenes ovoid, weakly compressed, apiculate, whitish, puberulent, ca 1.3 mm long. Croat 15249.

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CYPERACEAE/CYPERUS

153

Uncommon; known from a few areas along trails in the forest, collected from Zetek and Balboa trails. Seen fertile April through July.

Mexico to Brazil. In Panama, known from tropical moist forest in the Canal Zone, Bocas del Toro, and Panama, from premontane moist forest in Panama, from premontane wet forest in Panama (Cerro Jefe) and Colon, and from tropical wet forest in Colon.

CLADIUM P.Browne

Cladium jamaicense Crantz, Inst. Rei Herb. 1:362.

1766 Saw grass

Coarse perennial, 1.5-3 m tall; culms ± terete, leafy throughout. Blades to 70 cm long or more, 4-12 mm wide, stiff, the margins and medial rib on lower surface very strongly spinulose-serrulate. Panicles diffuse, to ca 15 cm long, arising from alternate leaf axils; spikelets in clusters of 2-5, terete, ovoid, acute, 4-5 mm long, brown, the uppermost flower perfect; perianth lacking;

stamens 2; middle scales of spikelet sometimes with staminate flowers. Achenes ovoid, gradually tapered to a blunt apex, ca 3 mm long, dull, reddish-brown; tubercle lacking.

Reported by Standley to be "common in shallow water at the lake." I have seen no collections, but the plant could be there. Flowers in April and May. The fruits mature during July and August.

This species might be confused with Rhynchospora

corymbosa, which grows in the same places and has a similar habit; it is possible that Standley confused the two species. Cladium can be most easily distinguished from Rhynchospora corymbosa by its much coarser leaf margins, its fruits lacking a cone-shaped tubercle at the apex, and its inflorescence lacking antrorsely barbed, attenuate bracteoles.

Throughout tropical and subtropical America. In Panama, known from tropical moist forest on the Atlantic slope in the Canal Zone and from tropical wet forest in Colon (Portobelo).

CYPERUS L.

The styles of Cyperus may be cleft two or three times, usually corresponding to whether the achenes are two- sided (lenticular) or three-sided.

Cyperus brevifolius (Rottb.) Endl. ex Hassk., Catal.

Hort. Bogor. 24. 1884 Kyllingia brevifolia Rottb.

Very similar to Cyperus densicaespitosus, except perennial, the rhizomes usually elongate, and the spikelets slightly smaller. Croat 12011.

Occasional, in the Laboratory Clearing. Seasonality uncertain; probably flowers and fruits throughout the year. It has been seen fertile from January to September.

The habit of growth is noteworthy. Since the plant is perennial and develops elongate rhizomes, a whole series

KEY TO THE SPECIES OF CYPERUS Spikelets clustered in dense, ± globose heads:

Heads borne on short rays C. luzulae (L.) Retz.

Heads sessile:

Scales of spikelets smooth; the headlike spikes often cylindrical, usually 3 in number C. sesquiflorus (Torr.) Mattf. & Kuek.

Scales of spikelets spinulose-scabrous on keel; the headlike spikes round or ellipsoid, fre- quently solitary:

Plants annual, caespitose, lacking elongate rhizomes C. densicaespitosus Mattf. & Kuek.

Plants perennial, the rhizome elongate, creeping C. brevifolius (Rottb.) Hassk.

Spikelets in open, diffuse inflorescences:

Ultimate clusters of spikelets forming simple umbels:

Umbels on rays usually less than 5 cm long; culms long, weak, and flexuous, with most leaves reduced to sheaths; plants growing in swamps C. haspan L.

Umbels on rays usually 10-20 cm long; culms not weak and flexuous, erect, the leaves not reduced to sheaths; plants not growing in swamps:

Inflorescences simple; spikelets 1-3 at apex of long, unbranched rays, the rays longer than culms C. simplex H.B.K.

Inflorescences compound; spikelets several on compound rays, the rays much shorter than culms ". C. dijfusus Vahl Ultimate clusters of spikelets racemose:

Spikelets purple to black C. rotundus L.

Spikelets green to brown:

Culms terete, naked; plants aquatic, usually 1.5-2 m tall C. giganteus Vahl Culms ± trigonous, leafy at least at base; plants usually terrestrial and less than 1 m tall:

Spikelets usually more than 1 cm long, sparse along rachis, decurrent, the scale bases becoming corky, the rachilla breaking into 1-fruited joints; inflorescences usually compound C. odoratus L.

Spikelets less than 1 cm long, very dense on rachis (usually contiguous), the rachilla wings not becoming corky; inflorescences simple C. tenuis Sw.

of plants may be produced in succession. The species thus tends to be more locally gregarious than is C. densi- caespitosus, which it very closely resembles, except for being somewhat more robust and having creeping rhi- zomes. Reportedly the most common species of Cyperus in Panama, growing in all but the drier areas of the west.

Southern United States to Argentina. In Panama, known from tropical moist forest on both slopes of the Canal Zone and in Bocas del Toro, from premontane wet forest in Chiriqui and Code, from tropical wet forest in Colon, and from lower montane wet forest in Chiriqui.

Cyperus densicaespitosus Mattf. & Kuek., Pflanzenr.

IV.20(Heft 10I):597. 1936 Kyllingia pumila Michx.

Small annual, 4-30(40) cm tall; culms very slender.

Leaves linear, usually shorter than culms, 1-3 mm wide.

Bracts subtending inflorescence 3-9 cm long, 2-4 mm wide; heads globose to ovoid, terminal, usually solitary (to 3), sessile, 4-6 mm long; spikelets 1.5-2 mm long;

scales membranaceous, pale, keeled, the apex subacute with a short cusp, the keel spinulose-scabrous; stamens 1 or 2; style bifid. Achenes lenticular, elliptic, pale, 1-1.5 mm long. Croat 5910.

Occasional, in the Laboratory Clearing. Flowering and fruiting throughout the year, especially in the dry season.

Easily confused with C. sesquiflorus. Plants tend to be taller, more slender, and more widely spaced than those of C. sesquiflorus, and have spikes tending to be greenish rather than whitish.

Widely distributed in the United States from New York to Ohio and south to Argentina; Africa. In Panama, known from tropical moist forest in the Canal Zone, Panama, and Darien, from premontane moist forest in the Canal Zone, and from lower montane wet forest in Chiriqui.

Cyperus difiFusus Vahl, Enum. PL 2:321. 1806 Perennial, 30-60 cm tall; culms slender. Leaves linear, 4-12 mm wide, the underside of midrib and the margins scabrid. Inflorescences subtended by several, long, leaflike bracts, compound; spikelets both at base of inflorescence and on long, spreading rays, the ultimate clusters forming simple umbels, greenish, 10-24-flowered, 5-15(20) mm long; scales green only on keel, with a narrow, incurved tip. Achenes obovate to globose, brown, trigonous with concave sides, smooth, 1-1.5 mm long. Croat 6912.

Abundant in clearings, especially near the laboratory.

Apparently flowers throughout the year.

Throughout warmer regions of Western and Eastern hemispheres. In Panama, widespread and ecologically variable; known from tropical moist forest all along the Atlantic slope as well as in Chiriqui, Herrera, Panama, and Darien, from tropical dry forest in Panama (Taboga Island), from premontane moist forest in the Canal Zone and Panama, from premontane wet forest in Chiriqui, Code, Panama, and Darien, from tropical wet forest in Panama and Darien, and from lower montane wet forest in Chiriqui.

Cyperus giganteus Vahl, Enum. PI. 2:364. 1806 Stout aquatic perennial, 1-2(2.5) m tall; culms terete.

Leaves reduced to basal sheaths. Bracts subtending inflo- rescence leaflike, 10-40 cm long, 0.5-2 cm wide, the margins and the underside of midrib scabrous; inflores- cences large, compound; spikes elongate, lax, on spreading rays; spikelets 3-10 mm long, slender, cylindrical, 8-14- flowered; scales straw-colored, green on keel. Achenes minute, 1 mm long, trigonous with 1 face concave, pale yellow or white. Croat 6168.

Forming dense stands in a few places along the shore, especially in quiet coves. Flowers in the rainy season, with the fruits persisting into the dry season.

Mexico to Argentina. In Panama, known from tropical moist forest in the Canal Zone, Bocas del Toro, and Panama, from premontane wet forest in Bocas del Toro, and from tropical wet forest in Colon.

Cyperus haspan L., Sp. PI. 45. 1753

Slender, glabrous perennial, mostly 50 cm to more than 1 m tall; culms mostly slender, glabrous. Leaves mostly short or reduced to sheaths, sometimes with longer basal leaves usually to 3 mm wide. Bracts subtending inflores- cence 2, usually shorter than inflorescence; inflorescences usually compound with several spikelets at apex of simple or branched, umbellate rays; spikelets 5-10(15) mm long, bearing many flowers, flattened, brownish; scales 1.2-1.7 mm long, obtuse and minutely apiculate at apex. Achenes usually white, ca 0.5 mm long, obovoid to ellipsoid, trigo- nous, with a rough granular surface. Croat 13241.

Infrequent, in swamps at the edge of the lake in some areas of the south shore. Flowers and fruits throughout the year, perhaps principally in the rainy season.

Warmer regions of Western and Eastern hemispheres.

In Panama, ecologically variable; known from tropical moist forest in the Canal Zone, Veraguas, and Panama, from tropical dry forest in Code, from premontane moist forest in Panama, from premontane wet forest in Chiriqui, Panama, and Code, from tropical wet forest in Col6n and Panama, and from lower montane wet forest in Chiriqui.

Cyperus luzulae (L.) Retz., Obs. Bot. 4:11. 1786 Perennial, 0.5-1 m tall. Leaves linear, 3-7 mm wide, glabrous or the margins and the underside of midrib scabrous. Bracts subtending inflorescence leaflike, to 30 cm long; spikelets in dense globose heads about 1 cm diam, mostly on short rays, numerous, ovate, flattened, 2-5 mm long, bearing up to 10 or more flowers; scales whitish, membranaceous, boat-shaped, easily disarticulat- ing; stamen 1. Achenes oblong, 1 mm long, trigonous, smooth, light brown. Croat 5810.

Common in the Laboratory Clearing. Flowers and fruits throughout the year.

Throughout tropical America. In Panama, known from tropical moist forest all along the Atlantic slope as well as in Veraguas, Los Santos, Herrera, Panama, and Darien;

known also from premontane moist forest in the Canal

Zone and Panama, from premontane wet forest in Chi- riqui, Code, Panama, and Darien, and from tropical wet forest in Code (Atlantic slope) and Colon.

Cyperus odoratus L., Sp. PL 46. 1753 C. ferax L.

Annual, usually (10) 50-100 cm tall. Leaves linear, (1.5)5-14 mm wide. Bracts subtending inflorescence large and leaflike, mostly 15-50 cm long; inflorescences compound (rarely simple), the racemes sessile or on short to long rays (to 20 cm long); spikelets linear, subterete, mostly 7-22 mm long, brownish at maturity; scales 2-3 mm long, striate, ± divergent in age; rachilla strongly winged, the wings becoming corky in age, the spikelets breaking up into single segments. Achenes oblong, 1.5-2.7 mm long, weakly trigonous, dark brown, densely papil- lose. Croat 9563, 13239.

An occasional weed of clearings and marshes. Flowers throughout most of the year.

Well-developed or fruiting specimens are not confused with any other species. Depauperate epiphytic plants on floating logs in the lake may be only 10-25 cm tall and with leaves 1.5-2.5 mm wide. These specimens have a simple inflorescence, but may be distinguished from C.

tenuis by having corky rachilla wings.

Tropics and subtropics throughout the world. In Panama, known principally from tropical moist forest in the Canal Zone, Bocas del Toro, San Bias, Los Santos, Panama, and Darien; known also from tropical dry forest in Code, from premontane moist forest in Panama, from premontane wet forest in Veraguas and Panama, from tropical wet forest in Colon, and from lower montane wet forest in Chiriqui.

Cyperus rotundus L., Sp. PL 45. 1753 Nut grass. Purple nutsedge, Junco

Slender perennial, 10-60 cm tall. Leaves linear, 2-6 mm wide, usually much shorter than culms. Bracts subtending inflorescence leaflike, short, 1-5 cm long; spikes several, lax, on rays to 6 cm long or very short; spikelets linear, 1-3 cm long, bearing 12-30 flowers; scales purplish to black, keeled, obtuse, Achenes ca 1.5 mm long, obovate- ellipsoid, dark, bluntly trigonous. Kenoyer 152, Shattuck 357.

Not seen recently, but to be expected in clearings.

Often abundant elsewhere in open areas of the Canal Zone, especially along railroad tracks. Flowers in the rainy season.

Throughout warmer regions of the world. In Panama, known principally from tropical moist forest in the Canal Zone, Bocas del Toro, Panama, and Darien; known also from premontane dry forest in Los Santos and from premontane moist forest in the Canal Zone and Panama.

Cyperus sesquiflorus (Torr.) Mattf. & Kuek., Pflanzenr.

IV.20(Heft 101):591. 1936 Kyllingia odorata Vahl

Small caespitose perennial, 5-40 cm tall; culms very slender. Leaves linear, shorter or slightly longer than

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CYPERACEAE/CYPERUS

155

culms, 2-3 mm wide. Bracts subtending inflorescence linear, leaflike, 3-8 cm long; spikes 1-3, terminal, head- like, ovoid to cylindroid, sessile and confluent, 5-12 mm long, the terminal spike tending to be cylindrical, the lateral ones usually ovoid; spikelets 3-3.5 mm long;

scales opaque, keeled, the apex blunt with a tiny mucro, the keel smooth; style bifid. Achenes lenticular. Croat 6458.

A weedy sedge locally common in the Laboratory Clearing. May be found in flower and fruit throughout most of the year.

The spikes are usually whitish, compared to the green- ish color of C. densicaespitosus.

Widespread distribution from southern United States to Uruguay; West Indies; tropical areas of Africa and Asia. In Panama, known from tropical moist forest in the Canal Zone and Darien, from premontane moist forest in Panama, and from lower montane wet forest in Chiriqui.

Cyperus simplex H.B.K., Nov. Gen. & Sp. 1:207. 1816 Small perennial, 5-35 cm tall; culms slender, glabrous.

Leaves linear, 3-6 mm wide, purplish at ground level.

Bracts subtending inflorescences leaflike, to 30 cm long;

inflorescences simple, with 1-3 sessile spikelets at apex of a ray 10-20 cm long; spikelets 5-15 (20) mm long, many- flowered, compressed; scales with a green keel, acuminate;

stamen 1. Achenes subglobose, trigonous, ca 1 mm long, brownish, densely papillose, roughened. Croat 15157.

Frequent in the forest. Flowers and fruits principally in the rainy season (April to October).

Southern Mexico to Bolivia and Brazil. In Panama, known from tropical moist forest in the Canal Zone, Panama, and Darien and from premontane moist, pre- montane wet, and tropical wet forests in Panama.

See Fig. 52.

Cyperus tenuis Sw., Prodr. Veg. Ind. Occ. 20. 1788 C. caracasanus Kunth

Perennial, the culms 15-60 cm tall, the underground part purplish. Leaves mostly basal, linear, to 4(5.5) mm wide.

Bracts subtending inflorescence long and leaflike; inflo- rescences of 5-15, simple, loosely cylindrical or flattened spikes; spikes sessile or on short rays, less than 7 cm long including rays; spikelets 5-7(10) mm long, subterete, 3-8-flowered; scales having green median stripe, the margin broad and thin. Achenes subcylindric-trigonous, slightly curved, beaked at both ends, brownish, minutely papillose, 1.5-1.8 mm long. Croat 11866.

Very abundant during part of the year in the Labora- tory Clearing. May be found in flower throughout the year.

Mexico to Brazil; West Indies; tropical Africa. In Panama, known from tropical moist forest in the Canal Zone, San Bias, Panama, and Darien, from tropical dry forest in Panama (Taboga Island), from premontane wet forest in Chiriqui and Code, and from lower montane wet forest in Chiriqui.

See Fig. 53.