580 CYPERACEiE. (SEDGE FAMILY.) 



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

 la a single locality m JJelaware Co., Peun. ; probably introduced from S. 

 Europe. 



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

 many-flowered, loosely umbellate or corymbed, involucellate-bracted. 



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

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

 gular aud channelled leaf (2-4 long) ; iuvolucral leaf similar (4- 8' loug), 

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

 liferously 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-triaugular shining acheue (1^" long). iu a pond near 

 Salisbury, Md. 



-t- - -i- Culm terete, very tall and stout, from a deep running rootstock, leafless 

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

 umbel-like panicle longer than the involucral leaf; inoolucellate 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, |-l' thick 

 at base; spikelets ovate-obloug (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, mucrouate-poiiited, usually overtopped by the 4-6 

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

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



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

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

 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 

 wmewhat 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- 

 *left; bristles 6, stout, downwardly barbed, equalling or two surpassing the ob- 

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

 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 ; iuvolucral 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., aud 111. July. 



12. S. supinus, L., var. Hallii, Gray. Culms Jit i form, 5-12' high; 

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

 times geminately proliferous cluster, ovate-oblong becoming cylindrical, greeu 



