508 cyperacejE. (sedge family.) 



* * Spikelets compressed, somewhat 2-ranJceil, mostly few and scattered on the com- 

 mon rachis : perennials, with creeping tuber-bearing rootstocks : flowers mostlij 

 abortive. 



12. C. repens, Ell. Umbel mostly simple, ereot, 5 - e-raycd, shorter than 

 the 3 - S-leaved involucre ; spikelets linear, spreading, 1 2 - 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° - ]^° high, acute-angled, longer than the erect smooth 

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



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

 er than the 3 - 5-lcaved 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. Kays 4' - 8' long. Spike- 

 lets 1' long, 1 J" 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. Eays slender, 2' -4' long. Spikelets J'-l' 

 long. 



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

 in loose spikes at thefllifl)rm summit of the rays : scales thin, 5-nerved, 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 cmarginate, short-mucronate, 5-nerved on the 

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

 pointed; style very short; culms (I*' high) slender, aeute-angled, longer than 

 the smooth narrow leaves. — Santee Canal, South Carolina, Ravenet. Probablj 

 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 of the general and par. 

 tial rays: scales dosdij imbricated, 3-7-nercfd, 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 (^'-1^' 

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



