580 CYPERACE^E. (SEDGE FAMILY.) 



firm, scarcely at all scarious ; style 3-cleft ; achene smaller, broadly obovate. 

 In a single locality in Delaware Co., Penn. ; probably introduced from S. 

 Europe. 



- -v- Culm triangular, tall and stout, from slender running rootstocks ; spikelets 

 many-flower ed t loosely umbellate or corymbed, involuceiiate-bracted . 



8. S. Cnbyi, Gray. Culm (3 - 5 high) 3-angled, usually sharply so 

 above, obtusely below, the sheath at base extended into a long slender trian- 

 gular and channelled leaf (2-4 long) ; involucral leaf similar (4-8' long), 

 continuing the culm ; spikelets oblong (4 - 6" long), single or sometimes pro- 

 lif erously 2 or 3 together, nodding on the apex of the 5-9 long filiform and 

 flattened peduncles or rays of the dichotomous umbel-like corymb, or the cen- 

 tral one nearly sessile ; scales loosely imbricated, oblong-ovate, acute, pale, 

 thin and scarious, with a greenish nerved back ; bristles 6, firm, furnished 

 above with spreading hairs rather than barbs, equalling the slender abrupt 

 beak of the obovate-triangular shining achene (l$" long). In a pond near 

 Salisbury, Md. 



H- H- *- Culm terete, very tall and stout, from a deep running root stock, leafless 

 or very nearly so; spikelets numerous, clustered in a one-sided compound 

 umbel-like panicle longer than the involucral leaf; involucellate bracts small, 

 scale-like and rusty-scarious ; scales of the spikelets rusty or chestnut-brown, 

 scarious, the midrib extended into a mucronate point. 



9. S. lacustris, L. (GREAT BULRUSH.) Culm 3 - 9 high, - V thick 

 at base ; spikelets ovate-oblong (3 - 4" long) ; scales mostly a little downy on 

 the back and ciliate ; style 2-cleft ; achene pale and dull, obovate with a nar- 

 rowed base, plano-convex, mucronate-pointed, usually overtopped by the 4-6 

 slender downwardly barbed bristles. (S. validus, Vahl.) Common every- 

 where in still fresh water. (Eu., Asia, etc.) 



- - - - Culms slender from an annual root, terete, plano-convex or obtusely tri- 

 angular, naked ; the sheaths rarely bearing a short leaf; spikelets few or 

 several in a sessile cluster, sometimes solitary, much overtopped by the invo- 

 lucral leaf; bristles often few or wanting. 



10. S. debilis, Pursh. (PI. 3, fig. 1 -5.) Culms obtusely triangular, with 

 ?*omewhat hollowed sides, 1-2 high, yellowish-green, shining ; spikelets 3 - 

 12, capitate, ovate-oblong, obtuse (3-4" long), chestnut-brown; involucral 

 leaf often horizontal at maturity; scales roundish; stamens 3; style 2-3* 

 cleft ; bristles 6, stout, downwardly barbed, equalling or two surpassing the ob 

 ovate turgidly plano-convex (or bluntly 3-sided) abruptly mucronate-pointed 

 smoothish achene. Swamps, Mass, to S. C., Minn, and Neb. Aug., Sept. 



11. S. Smithii, Gray. Culms terete, slender, 3-12' high, often leaf- 

 bearing from the upper sheath, dull green as are the 1-3 oblong-ovate acute 

 spikelets ; involucral leaf always erect ; scales oblong-oval ; style 2-cleft ; 

 bristles 1 or 2 minute rudiments or none; achene somewhat lenticular, smooth, 

 deciduous with the scales. Wet shores, Delaware Bay to L. Ontario, Mich., 

 N. Ind., and 111. July. 



12. S. SUpinus, L., var. Hllii, Gray. Culms filiform, 5-12' high; 

 upper sheath rarely distinctly leaf-bearing ; spikelets 1 - 7 in a sessile or some- 

 times geminiitely proliferous cluster, ovate-oblong becoming cylindrical, green 



