508 CYPERACEJ2. (SEDGE FAMILY.) 



* * Spilcelets compressed, somewhat ^.-ranked, mostly few and scattered on the com- 

 mon rachis : perennials, with creeping tuber-bearing rootstocks : Jlowers mostly 

 abortive. 



12. C. repens, Ell. Umbel mostly simple, erect, 5- 6-raycd, shorter than 

 the 3-5-lcavcd involucre; spikelets linear, spreading, 12- 24-flowered, the 

 lower ones often clustered; scales oblong, obtuse or short mucronate, com- 

 pressed-keeled, thin-margined, spreading at the apex, yellowish brown ; nut ob- 

 long, triquetrous, acute. Sandy soil near the coast, Florida, and northward. 

 July - Sept. Culms 1- l high, acute-angled, longer than the erect smooth 

 leaves. Rays 2' -4' long. Spikelets 6" - 8" long. Whole plant yellowish. 



13. C. lutescens, Torr. & Hook. Umbel simple, large, 5-7-rayed, short- 

 er than the 3 - 5-leaved involucre ; spikelets horizontal, flat, linear, 30 - 40-flow- 

 ered, the lowest 2 - 3 in a cluster ; scales light brown, oblong-lanceolate, acute, 

 rounded on the back, slightly spreading at maturity ; nut obovate-oblong ; culms 

 stout (2 - 3 high), acute-angled, shorter than the broadly linear leaves. Key 

 West. Nov. Leaves 3" - 6" wide, very smooth. Rays 4' - 8' long. Spike- 

 lets 1' long, l" wide, serrate, the lower ones with a bristly involucel. 



14. C. rotundus, L. Umbel simple or compound, 3-8-rayed, mostly 

 longer than the 3-leaved involucre ; spikes composed of 3 - 9 scattered linear 

 flat 20 - 30-flowered spikelets ; scales oblong, obtuse, appressed, 7-nerved on the 

 green keel, the membranaceous sides dark chestnut ; nut obovate ; culms smooth, 

 slender, longer than the broadly linear crowded spreading rough leaves. (C. 

 Hydra, Michx.) Sandy soil, along the coast, Florida to North Carolina. Aug. 

 and Sept. Culm 9' -18' high. Rays slender, 2' -4' long. Spikelets '-!' 

 long. 



2. SPARSIFLORI. Umbel compound : spikelets compressed, many -flowered, scattered 

 in loose spikes at the filiform summit of the rays: scales thin, 5-ncrved, separate ; 

 joints of the rachis slightly margined: stamens 2. 



15. C. Iria, L. Umbel 6- 8-rayed, erect, shorter than the 3 - 4-leaved in- 

 volucre; spikelets erect-spreading, oblong-linear, 12 -24-flowered ; scales spread- 

 ing, nearly orbicular, obtuse or emarginate, short-mucronate, 5-nerved on the 

 green keel, the thin whitish sides minutely pitted; nut oblong-obovate, abruptly 

 pointed; style very short; culms (1 high) slender, acute-angled, longer than 

 the smooth narrow leaves. Santee Canal, South Carolina, Ravenel. Probably 

 introduced from Eastern Asia. 



3. PALMATI. Umbel compound or decompound, diffuse: spikelets 2-ranked, com- 

 pressed, many-flowered, 3-10 in a cluster at the summit oj the general and par- 

 tial rays : scales closely imbricated, 3 1-nerved, decurrent on the rachis : sta- 

 mens 3. 



* Culms terete, knotted, leafless : involucre very short : nut oblong. 



16. C. articulatus, L. Umbel compound, many-rayed, spreading or re- 

 curved ; involucre of three bract-like pungent leaves; spikelets long (/-l^' 

 long), linear, spreading, 30 - 40-flowered ; scales whitish, oblong, obtuse, 7-nerved 



