Oedeb 156.— CTPEBA.OEA 761 



fields, not very common, readily distinguished from the three preceding and fol- 

 lowing. 



13 C. stenopIi;p'Ua Wahl. Spikes 3 to 5, aggregated into aroundish head; perig. 

 ovate, roundish-ventricotis, subplano-convex, 'vsined, scabrous or serrulate on the 

 margin, bidentate, about equaling the ovate, acmte glume ; culm 3 to 6' high, smooth, 

 with long, narrow leaves. — 111. to Nebraska and.Brit. Am. 



14 C. chordorrhiza L. Spikeleis 3 — 5, aggregated into a head, ovate, sessile ; 

 perig. ovate, acuminate, 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, N. T., common (Sartwell), Mich. 

 (Cooley.) 



15 C. Leaven-V76rt]iil Dew. Spikelets 4 to 6, smaM, ovate, sessile, bracteate, 

 aggregated into an ohlong head, the lower sometimes separated a little ; perig. 

 ovate, broad, short, convex above, dbrvptly shozt-beaked, slightly bifid, glabrous, 

 scabrous on tlie edge, scarcely twice longer than the short, ovate, acute glume; 

 culm rarely If high, slender, leafy towards the base ; Ivs. narrow, flat ; whole 

 plant pale green. — Ky. (Short) to Ala. (Wood), Fla. (Chapman) and La. (Leaven- 

 worth.) 



16 C. cephaloidea Dew. Spikelets i — 6, ovate, aggregated closely, sessile and 

 bracteate; perig. ovate, ohtusish; bifid, scabrous ou the margin, plano-convex, 

 very diverging in maturity, about twice as long ag the short, ovate, obtusish glwme. 

 ^— Dry fields, not abundant, but common over New England and New Tori* In 

 hedges it is often four feet long, and subrostrate, leafy towards the base. (C. 

 sparganoides, /3. Carey.) 



17 C. mtiricata L. Spi/tefete about 5, ovate, sessile, approximate, bracteate, lower 

 ones sometimes remotish ; perig. ovate-lanceolate, plano-convex, 2-toothed, hori- 

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

 Fields near Boston (Green, Curtis), and common in Arc. Am. 



18 C. sparganioides Mulil. Spikelets 1 — 10, ovate, rather distant, bracteat^, 

 sessile ; perig. ovale, 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. 



p. RAMEA Dew, has one branch or more at the base, with several spikelets in 

 the place of the lower spikelet, and is the 0. divulsa of Pursh. — About culti- 

 vated and moist fields, common. 



19 C. rosea Schk. Spikelets 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 thepvate-oltuse glume; st. 8 — 16' high. 



p. EADIATA Dow. Spikelets distant, about 3-flowered, with setaceous bracts ; 

 perig. oblong, acute ; st. 4 — 8' high, flaccid or lax, setaceous, with very nar- 

 row leaves.- — Common in pastures and moist woods ; the variety is about 

 woods, or open places in woods. 



20 C. retroflexa iluhl. Spikelets about 4, ovate, alternate, subapproximate, 

 sessile, bracteate and stellate in maturity ; perig. ovate, acutish, 2-toothed, sub- 

 scabrous or smooth on the margin, reflexed and spreading, about equal to the ovate 

 and acute glume; ct. about a foot high. — Eeadily distinguished from the preced- 

 ing. "Woods and pastures, not abundant. . (0. rosea, /J. Tonm.) 



21 C. disp^rma Dew. Spikelets 3 or 4, erect, subapproximate, lowest bracte- 

 ate ; perig. 1 or 2, rarely 3, ovate, obtuse, nerved, plano-convex, short-beaked, 

 glabrous, twice longer than the ovate, acute, submucronate glume ; st. slender, 5 

 to 12' high, flexile, in tufts of several, with narrow and Imear leaves. — ^Wet 

 woods, N. Eng. to "Wis. (C. tenella, Carey, Boott., not of Ehrh.).— The species is 

 common in N. Eur., but had never been recognized in this country, when de- 

 scribed, 1824. 



22 C. vTilpinoidea Mx. Spikelets ovate-oblong, obtuse; spike decompound, 

 bracteate, conglomerate ; perig. ovate, acuminate, densely imbricate, bifid, tripli- 

 nerved, diverging, n little shorter than the ovate-cuspidate glume; sL obtusety 

 triangular, round and leafy towards the bas.";. — Common in fields. (0. multiflora 

 Muhl.) 



