578 CLX. CYPERACE^E. CAUEX. 



one ; perig. ovate, convex above, very smooth, nerved, bifid, scabrous on the 

 margin, some diverging, a little shorter than the ovate and mucronate glume ; 

 st. 12 18' high. In fields, not very common, readily distinguished from the 

 three preceding and following. 



12. C. CHORDORRHlZA. 



Spikelets 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, Sartwdl. Michigan, 

 Cooky. 



13. C. PRAIREA. Dew. 



Spike below branched ; spikelets 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 in N. England and 

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

 shorter than the perigynium and is i'ar more paniculate, and for which this has 

 been taken. 



14. C. TERETIUSCULA. God. 



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

 perig. 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 

 '.he root. Wet places, common, in tufts. 



15. C. DECOMPOSITA. Muhl. 



Spike decompound or paniculate ; spikelets 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; 

 rf. 18 30' high. Found in swamps, Michigan, and in Yates Co., N. York, 

 Sarltcett. 



16. C. PANICULATA. 



Spike paniculate, often ^ 9> ' on S an ^ spreading; spikelets ovate, sessile, 

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

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

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

 ern America, and hardly known in the United States. 

 "b. Perigynia radiating. 



17. C. ROSEA. Schk. 



Spikelets 3 5, subremote, sessile, alternate, stellate, even before maturiiy, 

 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. 



/?. radiata. Dew. Spikekts distant, about 3- flowered, with setaceous bracts; 

 perig. oblong, acute ; st. 4 8' 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. Mllhl. 



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

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

 the margin, reflexed and spreading, about equal to the ovate and acute glume; 

 st. about a foot high. Readily distinguished from the preceding. Woods and 

 pastures, not abundant. 



19. C. STIPATA. Muhl. 



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

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

 scabrous on the margin, diverging, twice longer 4han the ovate-lanceoluu 

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

 marshes, abundant. 



20. C. ALOPEColDA. Tnckerman. (C. cephalophora, 0. maxima. Dew.) 

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



