578 CLX. CYPERACEiE. Carex. 



one- veri^^ ovate, convex above, very smooth, nerved, bifid, scabrous on the 

 mar'/n, smne diverging, a little shorter than the ovate and mucronate glume ; 

 St. 12-^18' high.— In fields, not very common, readily distmguished Irom tlie 

 three preceding and following. 



12. C. CHORDORRHiZA. 



Spikekts 3—5, aggregated into a head, ovate, sessile ; perig. ovate, acumi- 

 nate subrostrate, convex above, equaling the broad, ovate and acute glume , 

 St branching towards the base and sending out roots at the joints ; spikes rarely 

 bearing only stamens,— Marshes, New York ; common, Sartweil. Michigan, 

 Cooky. 



13. C. Prairea. Dew. 



Spike below branched ; spikelels ovate, sessile, 5—7 on a branch ; perig 

 ovate-lanceolate, convex both sides, scabrous on the margin, slightly bifid, 

 equaling the ovate-lanceolate glume; st. 2— 3f high, leafy towards the base.- 

 Abundant in the prairies'of Michigan, and sparingly found m N.England and 

 N. Y. Resembles C. paniculata. L., which has a much broader ovate glume, 

 shorter than the perigynium and is far more paniculate, and for which this has 

 been taken. 



14. C. TERETIDSCULA. Good. 



Spikekts ovate, acute, sessile, decompound, brownish, lower one bracteate ; 

 perio- ovate, acute, convex and gibbous, scabrous on the edge, spreading, lon- 

 ger "than the ovate and acute glume; fr. brown; st. 18—36' high, leafy towards 

 the root. — Wet places, common, in tuits. 



15. C. DEcoMPOsiTA. Muhl. 



Spike decompound or paniculate; spikekts very many, ovate, alternate ; 

 perig. ovate, convex on both sides, triangular, acutish or short-rostrate, short, 

 brownish, glabrous, about equal to the ovate and acuminate, whitish glume ; 

 s^. 18—30' high. — Found in swamps, Michigan, and in Yates Co., N. York, 

 Sa7-iweU. 



16. C. PANICULATA. 



Spike paniculate, often J* 9, long and spreading; spikelets ovate, sessile, 

 6—18 on a branch below, short bracteate ; perig. ovate, acute, gibbous, nerved, 

 2-toothed, brownish or tawny, 2-toothcd, serrulate on the margin, a little 

 shorter than the broad-ovate, short-acute glume ; st. 2f high.— Found in North- 

 ern America, and hardly known in the United States. 

 1>. Perigynia radiating. 



17. C. ROSEA. Schk. 



Spikekts 3—5, subremote, sessile, alternate, stellate, even before maturity, 

 .lowest long bracteate ; perig. oblong-lanceolate, 5 — 12, convex above, scabrous 

 on the margin, 2-toothed, very diverging or even reflexed, twice as long as the 

 ovate-obtuse glume; st. 8 — 16' high. 



0. radiata. Dew. Spikelets distant, about 3-flowered, with setaceous bracts ; 

 perig. oblong, acute ; st. 4 — B' high, flaccid or lax, setaceous, with very narrow 

 leaves. — Common in pastures and moist woods ; the variety is about woods, or 

 open places in woods. 



18. C. RETROFLEXA. Muhl. 



Spikekts about 4, ovate, alternate, subapproximate, sessile, bracteate and 

 stellate in maturity; ]xrig. ovate, acutish, 2-toothed, subscabrous or smooth on 

 the margin, reflexed andspreading, about equal to the ovale and acute glume ; 

 St. about a foot high. — Readily di.slinguished from the preceding. Woods and 

 pastures, not abundant. 



19. C. sTiPATA. Muhl. 



Spike often decompound ; spikekts oblong, aggregated, numerous, bracte- 

 ate ; perig. ovate-lanceolate, round at the base, plano-convex, nerved, bifid, sub- 

 scabrous on the margin, diverging, twice longer than the ovate-lanceolate 

 glume ; st. thick, acutely triquetrous, concave on the sides. — Wet places and 

 marshes, abundant. 



20. C. ALOPECoiDA. Tuckerman. (C. cephalophora, /?. maxima. Dew.) 

 Spike compound, rather loose ; spikekts 8 — 10, aggregated into an oblong 



