Cauex. CLX. CYPERACEiE. 579 



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

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

 acuminatL" gluuie; .sV. triquetrous, scabrous on the edges. — Moist woods, Penn. 

 and N. York, SartwcU. 



21. C. CKPHALOIDEA. DcW. 



Spikclcts 4 — G, ovate, aggregated closely, sessile and bracteate; pcri^. 

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

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

 not al)unilant, but common over New England and New York. In hedges it 

 is ollen lour feet long, and subrostrate, leaiy towards the base. 



2-2. C. SPARGANolDES. Muhl. 



Spikclcts 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. 



/?. ramca. Dew. has one branch or more at the base, with several spikeletsin 

 the place of the loM'er spikelet, and is the C. divuba of Pursh. — About culti- 

 vated and moist fields, common. 



23. C. MURICATA. 



Spikclcts 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, D. D. Greciic, and common in Arctic America ; Charles- 

 town, Mass., 31. A. Curtis. 



c> Perigynia feio. 



24. C. DispERMA. Dew. 



Spikclcts 3 — 4, erect, subapproximate, lowest bracteate ; perig. ovate, 

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

 than the ovate, acute, submucronate glume; 5^. 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 iJie spikelets. 

 d. Perigynia radiating. 



25. C. STELLULATA. Good. 



Spikelets 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. sciRPoiDEs. 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 ; 5/. 

 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 silver}- or hoary spikelets. — Moist places over the 

 countr)^ 



28. C. sphjErostachya. Dew. (C. canescens, (i. sphaerostachya. Thuk.) 

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



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

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

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

 e. Ovate-lanceolate spikelets; feio-fruited. 



29. C. Deweyana. Schk. 



Spikcht^ about 3, sessile, ovate-lanceolate, alternate, subremote, highest 

 49* 



