CYPERACE.E. (sedge FAMILY.) 509 



on the back, tlirice the length of the linear-ohlong dull nut ; rhizoma creeping, 

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



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



Flowers mostly abortive. 



* * Calms 3-angled, knotless: involucre leafy : nut ohovate. 



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

 form rays mostly longer than the 2-leaved 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, JI/hW. C. leptos, Schultes.) — Ponds and ditches, Flor- 

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



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

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

 long, obtuse, flat, 12-30-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), ol)tuse-angled, longer than the rigid keeled leaves. — 

 Sandy swamps and banks. South Carolina, Torrey, and northward, Sept. 1|. 

 — Rays l'-2' long. 



19. C. Lecontii, 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- 7()-flowered (J'- I'long); scales closely imbri- 

 cated, ovate, obtuse, compressed, yellowish, faintly 7-nei-ved, 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: 7 achis wingless : stamen solitary. 



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

 back, acute . nut minute, lanceolate or oblong. 



20 C. virens, 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 tiie 

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

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



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

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

 short (lJ"-2" long), ovate, 10- 15-flowered, very numerous in the heads ; scales 



43* 



