AREX. CLX. CYPERACEJE. 579 



head, bracteate, sessile ; pcmg. ovate, plano-convex, scarcely nerved, acumi- 

 nate, serrulate on the edge, bifid, subrostrate, a little longer than the ovate and 

 acuminate glume ; st. triquetrous, scabrous on the edges. Moist woods, Penn. 

 and N. York, SartioeU. 



21. C. CEPHALOIDEA. Dew. 



Spikelets 4 6, ovate, aggregated closely, sessile and bracteate; perig. 

 ovate, obtusish, bifid, scabrous on the margin, plano-convex, very diverging in 

 maturity, about twice as long as the short, ovate, obtusish glume. Dry fields 

 not abundant, but common over New England and New York. In hedges it 

 is often four feet long, and subrostrate, leafy towards the base. 



22. C. SPARGANOlDES. Muhl. 



Spikelets 7 10, ovate, rather distant, bracteate, sessile; perig. ovate, 

 acute, compressed, diverging, acuminate, 2-toothed, scabrous on the margin, 

 nearly twice the length of the ovate, acute, or mucronate glume ; st. about 2f 

 high, with long, striate leaves. 



/?. ramea. Dew. has one branch or more at the base, with several spikelets in 

 the place of the lower spikelet, and is the C. divulsa of Pursh. About culti- 

 vated and moist fields, common. N 



23. C. MURICATA. 



Spikelets about 5, ovate, sessile, approximate, bracteate, lower ones some- 

 times remotish; perig. ovate-lanceolate, plano-convex, 2-toothed, horizontal, 

 scabrous on the margin, sometimes longer than the ovate-lanceolate glume. 

 Fields near Boston, B. D. Greene, and. common in Arctic America ; Charles- 

 town, Mass., M. A. Curtis. 



c. Perigynia few. 



24. C. DISPERMA. Dew. 



Spikelets 34, erect, subapproximate, lowest bracteate ; perig. ovate, 

 obtuse, about two, nerved, plano-convex, short-beaked, glabrous, twice longer 

 than the ovate, acute, submucronate glume ; st. slender, 6 18' high, with nar- 

 row and linear leaves. Perigynia 1 2, sometimes 3. Wet woods, N. Eng- 

 land, N. York, Michigan and Wisconsin Territory. 



3. Androgynous ; stamens at the base of the spikelets. 

 d. Perigynia radiating: 



25. C. STELLULATA. Good. 



Spikelels 4 6, ovate, remotish, sessile ; perig. broad ovate, contracted into 

 a short beak, compressed, slightly bifid, scabrous on the edge, diverging and 

 reflexed, a little longer than the ovate, obtusish glume ; st. erect, stiff, leafy 

 below, 8 24' high. Common in wet places over the Northern States. 



26. C. sciRpolDEs. Schk. 



Spikelets about 4, ovate, approximate, sessile, obtuse, lowest bracteate ; 

 perig. ovate, cordate, compressed, lanceolate or rostrate, scabrous on the margin, 

 diverging or horizontal, longer than the ovate-lanceolate, acute glume - K st. 

 6 16' high, leafy towards the base. Wet places in the country. The more 

 lanceolate fruit and glume, and more flexible stem, separate it from the pre- 

 ceding. C. scirpoides has the stamens chiefly below the upper spikelet. 



27. C. CURTA. Good. 



Spikelets 4 7, ovate-oblong, upper subapproximate, lower often remote ; 

 perig. round-ovate,, acutish, obtusish, diverging, convexo-concave, 2-toothed, 

 slightly scabrous, longer than the ovate, white, hyaline glume ; st. 1 2f high, 

 usually light green, with silvery or hoary spikelets. Moist places over the 

 country. 



28. C. SPHJEROSTACHYA. Dew. (C. canescens, 0. sphaerostachya. Tuck.} 

 Spikelets 3 4, ovate, roundish, remote, sessile, few fruited, 2 6 ; perig. 



ovate- lanceolate or roundish, rostrate, longer than the ovate and hyaline, white 

 glume ; st. 1 2f high, slender, flaccid, subrostrate, and with the leaves, green. 

 Common in N. England and N. York, in wet places. 

 e . Ovate-lanceolate spikelefs ; few-fruited. 



29. C. DEWEYANA. Schk. 



Spikelets about 3, sessile, ovate-lanceolate, alternate, subremote, highest 

 49* 



