520 CYPERACE^E. (SEDGE FAMILY.) 



smooth, orbicular, 2-cleft, mucronatc ; anthers obtuse ; style 2-clcft ; nut round- 

 obovate, planoconvex, as long as the 6 hispid bristles. Brackish marshes, West 

 Florida, and northward. June - Sept. Culms 2 - 4 high. Leaves 2' - 4' long. 

 Spikes 2" long. 



H <- Spikes umbelled. 



5. S. lacustris, L. Culm tall (3 -8 high), terete, leafless, or the radical 

 sheaths leafy-pointed ; involucre 1-leaved, pungent, shorter than the decompound 

 umbel ; spikes ovate or oblong, mostly clustered ; scales ovate, emarginate, rough- 

 awned, ciliate on the margins, pubescent on the back and green keel ; style 2-cleft ; 

 nut obovate, pointed, plano-convex, shorter than the 3-6 strongly hispid bristles. 

 (S. validus, Vahl.) Varies, with the broader keeled and fimbriate bristles rather 

 shorter than the round-obovate nut. Fresh or brackish marshes and ponds, 

 Florida, and northward. July -Sept. 



6. S. leptolepis. Culms 3-angled, leafy at the base (2 - 3 high) ; leaves 

 long, sharply keeled, triangular-compressed near the obtuse curved apex, the 

 immersed ones flat and pellucid; involucre slender (7' long), leaf-like, with 

 shorter ones at the divisions of the compound umbel ; spikes single, oblong or 

 cylindrical, many-flowered, acute ; scales light brown, lanceolate-oblong, acute, 

 smooth, membranaceous, mucronate, and, like the three obtuse anthers, finely 

 spotted ; style 3-parted ; nut whitish, 3-angled, ohlong-obovate, long-pointed, 

 shorter than the 5 slender and minutely denticulate bristles. (S. maritimus, var. 

 cylindricus, Torr.?) Lakes and ponds, Middle Florida, and westward. Dr. 

 Hale. September. 



2. Culms jointed, leafy throughout: umbel terminal: involucre 2 -several-leaved, 



spreading. 

 * Bristles hispid downward. 



7. S. maritimus, L. Culm sharply 3-angled, rough above ; leaves longer 

 than the culm, keeled ; umbel simple, 1 3-rayed, bearing single or 2 - 3 spikes 

 in a cluster, or the spikes all clustered and sessile ; involucre 2 - 4-leaved, much 

 longer than the umbel ; spikes large, ovate or oblong-ovate, dull brown ; scales 

 thin, ovate, pubescent, tipped with a spreading awn ; nut round-obovate, plano- 

 convex or lenticular, smooth and shining, twice the length of the 4 weak bristles. 

 Saline marshes, Florida, and northward. Aug. and Sept. Culms 2 - 3 

 high. Spikes 6" - 10" long, 4" in diameter. 



8. S. polyphyllus, Vahl. Culm obtuse-angled, smooth ; leaves long, 

 rough on the margins ; umbel decompound, spreading ; spikes small, 3 - 8 in a 

 cluster, ovate, yellowish-brown ; scales ovate, mucronate, keeled ; bristles 6, 

 slender, hispid near the summit, mostly tortuous, 2-3 times as long as the pale 

 compressed-3-angled pointed nut. (S. exaltatus, Pursh.) Shady swamps, 

 North Carolina, and northward. July. Culm 2 -5 high. Spikes 1" long. 



9. S. divaricatus, Ell. Culm round-angled, many-jointed; leaves flat, 

 broadly linear ; umbel large, widely spreading or drooping, decompound, longer 

 than the 3-leaved involucre ; spikes all single, oblong-linear, scattered ; scales 

 ovate, obtuse, 3-nerved, brown on the sides ; bristles hair-like, rather roughened 

 than hispid, crisped at the summit, longer than the obovate pointed equal-sided 



