556 ORDER CXLI. CYPEEACEJE. 



linear-lanceolale, compressed, 10 — 11-flowered. Scales keeled, obovate. 

 Stamens 2. — Georgia. 



4. C. FLAVic'oMis, (Mich.) Stem obtusely angled. Leaves linear- 

 lanceolate, slightly serrulate near the summit. Umbels compound ; 

 involucre long ; spikes expanding, 10 — 12-flowered. — U- May — Sept. 

 Rich soils. 1 — 2 feet. 



§ 2. Sti/le trijid ; achenium triangular. 



(1.) Spikes onany-Jlowered, compressed ; stamen I. 



5 C. vege'tus, (Willd.) Stem slender, nearly terete. Leaves linear- 

 lanceolate, channeled, finely serrulate near the summit. Flowers in 

 compound umbels; spikelets in globose heads; involucre 4-leaved. 

 Glumes ovate. — It. June — Sept. Ponds and ditches. 2 — 3 feet. 



6. C. vi'rexs, (Mich.) Stem triquetrous. Leaves lineai--laneeolate, 

 2 — 3 feet long. Uinbels compound ; spikelets in compact heads, many- 

 flowered ; involucre long, i^/oit'crs monandrous. — IX- May — October. 

 Rich swamps. Common. 



(2.) Spikes many-fowered, compressed ; stamens B. 



7. C. coMPREs'sus, (L.) Stem triquetrous, naked. Leaves linear- 

 lanceolate. Flowers in compound umbels ; spikelets many-flowered, 

 nearly capitate. Glumes acuminate, with white margins. — If. Aug. 

 — Sept. Sandy pastures. 3 — 8 inches. 



8. C. autumna'lis. (Vahl.) (C. harpan, L. ; C. gracilis, Muhl.) Stem 

 nearly terete. Spikes slender, terminal, digitate, usually by threes ; 

 involucre 2-leaved, as long as the umbel. Glumes purple. — If. July 

 — Aug. On margins of ponds. 



9. C. articula'tus, (L.) Stem erect, jointed, clothed at the base with 

 3 sheath-like leaves. Flowers in compound umbels ; spikelets many- 

 flowered. Glumes dotted with red ; two or three of the lowest sterile. 

 — If. June — Aug. Wet places. 3 — 6 feet. 



10. C. hy'dra, (Mich.) {C. rotundus, L.) Stem obtusely angled. 

 Leaves radical, recurved. U)nhels simple and compound ; spikelets 

 linear; involucre 2 — 3-leaved. — If. Througli the summer. Sea-coast. 

 3 — 8 inches. 



11. C. re'pexs, (Ell.) {O. phyma.todes,^l\\\\\.) Stem 3-angled, with 

 the sides concave. Leaves glabrous, recurved. Umbels usually simple; 

 involucre 3 — 4-leaved ; spikes crowded. — If. July — Sept. In fields. 

 12—18 inches. 



(3.) Spikes few-jlowered. 



12. C. briz.e'us. Culm triangular, leafy at the base. L^eaves longer 

 than the culm, rigid. Umbel compound, crowded; involucre 3-leaved, 

 long; spikes 12 — 14-flowered, compressed ; scales elliptic, short, mucro- 

 nate, concave, 9 — 10-nerved, purple. — Geo. and Car. Grows in swamps. 



13. C. STRiGo'sus, (L.) Stem 3-angled. Leaves long, minutely ser- 

 rate. Spikes oblong ; spikelets subulate ; involucre longer than the 

 umbel. — If. Aug. — Oct. Wet places. 2 — 3 fett. 



