CYPERACEiE. (.SEDGE FAMILY.) 509 



on the back, thrice the length of the linear-oblong dull nut ; rhizoma creeping, 

 bearing tuber-like buds ; culms stout. (3° - 5° high), tumid at the sheathed base. 



— Marshes near the coast, Florida to South Carolina. Aug. - Sept. 1J. — 

 Flowers mostly abortive. 



* * Calms 3-angled, knoiless : involucre leafy : nut obovate. 



17. C. Haspan, L. Umbel many-rayed, decompound, spreading, the fili- 

 form rays mostly longer than the 2-leavcd involucre; spikelets small (4" -5" 

 long), 3-5 in a cluster, linear, acute, 20 - 40-flowered ; scales light reddish- 

 brown, very small, oblong, mucronate, 3-nerved, free at the apex ; nut white, 

 round-obovate, granular-roughened ; culms tender, sharply angled ; leaves lin- 

 ear, smooth, shorter than the culms (1°- 1^°), often reduced to membranaceous 

 sheaths. (C. gracilis, Muhl. C. leptos, Schultes.) — Ponds and ditches, Flor- 

 ida to North Carolina, and westward. July - Sept. 



18. C. dentatus, Torr. Umbel compound, erect, 4- 7-rayed, shorter than 

 the 3-4-lcaved involucre; spikelets 3-5 in a cluster (3" - 7" long), ovate -ob- 

 long, obtuse, flat, 1 2 - 30-flowercd ; scales ovate, acute, compressed, 7 -nerved on 

 the green keel, membranaceous on the reddish brown sides, spreading at the 

 apex ; nut minute, round-obovate, whitish ; rhizoma creeping, bearing tubers ; 

 culms slender (1° high), obtuse-angled, longer than the rigid keeled leaves. — 

 Sandy swamps and banks, South Carolina, Torrcy, and northward. Sept. 1J. 



— Rays l'-2' long. 



19. C. Leeontii, Torr. Umbel compound, erect, 6-12-rayed, shorter 

 than the 3-leaved involucre ; spikelets commonly three in a cluster, oblong or 

 linear-oblong, obtuse, flat, 30- 70 -flowered (£'- l'long) ; scales closely imbri- 

 cated, ovate, obtuse, compressed, yellowish, faintly 7-nerved, appressed at the 

 apex ; nut minute, round-obovate, blackish ; culms rigid, obtuse-angled, as long 

 as the rigid leaves. — Low sandy places along the coast, East and West Florida. 

 July -Sept. y. — Rhizoma creeping Culms 6'- 12' high. Rays 2' -6' long. 

 Rachis with very short joints. Whole plant pale straw-color. 



4. Glomerati. Umb4 simple or compound: spikelets many -flowered, compressed, 

 numerous in a cluster \ forming more or less dense heads at the summit of the com- 

 mon and partial rays: rachis wingless: stamen solitary. 



* Umbel compound : spikelets ovate or oblong, flat : scales 3-nei'ved, concave on the 

 back, acute : nut minute, lanceolate or oblong. 



20 C. vireilS, Michx. Umbel spreading, compound, many-rayed; invo- 

 lucre 4-6-leaved, many times longer than the umbel; spikelets (4'' -6" long, 

 and about 20 in a cluster) oblong, 30 -40-flowered, pale green ; scales oblong- 

 lanceolate, straight; nut lanceolate, acute at each end; culms stout (2° -4° 

 high), rough-angled above; leaves broad, elongated, reticulated, rough on the 

 margins. Miry places, Florida to North Carolina. July- Sept. 1J. — Plant 

 pale green. Rays 3' -4' long. Spikelets turning yellowish. 



21 C. vegetus, Willd. Umbel often decompound, many-rayed, widely 

 spreading , involucre 4-Ieaved, many times longer than the umbel ; spikelets 

 short (l£"-2" long), ovate, 10- 15-flowcred, very numerous in the heads ; scales 



.43* 



