570 cypERACEjE. (SEDGE FAMILY.) 



2. CYPERUS proper. Achene triangular ; spikelets usually many-flowered, 

 more or less flattened, with car mate scales, the rhachis marginless or nearly 

 so (winged in n. 12). 



* Stamen 1 ; spikelets short and small (1^-5" /OH//) in globular heads, ovate or 



linear-oblong, many-flowered ; achene obiong-obovate to linear. 



*-Loiv annuals; involucre 2-3-Ieaved ; heads Jew ; scales pointed. 



6. C. aristatUS, Kottb. Dwarf (1-5' high); spikelets chestnut-brown, 

 oblong becoming linear, 1 - 13-flowered, iu 1-5 ovate heads (sessile and clus- 

 tered, or short-peduiicled) ; scales nerved, tapering to a long recurved point ; 

 acliene obiong-obovate, obtuse. (C. iuflexus, Muhl.) Sandy wet shores; 

 common. Sweet-scented iu drying. 



7. C. acuminatus, Torr. Slender (3-12' high); spikelets ovate, be- 

 coming oblong, 16-30-flowered, pale; scales obscurely 3-nerved, short-tipped; 

 acheue oblong, pointed at both ends. Low ground, 111. and south west ward. 



H--I- Tall perennial (1 -4 high) ; heads many, greenish ; scales pointless. 



8. C. calcaratus, Nees. Culm obtusely triangular; leaves and involucre 

 very long, keeled; umbel compound, many-rayed; spikelets ovate (!" long), 

 in numerous small heads* achenes pale, linear, on a slender stipe ; scales nar- 

 row, acutish, obscurely 3-uerved. (C. vireus, Gran, in part; not Miclix. C. 

 Luzultc, var. umbellatus, Britt.) Wet places, Dei. to Fla. and Tex. 



* * Stamens 3 (2 in C. fuscus) ; spikelets clustered on the rays of a simple umbel 



(or in a single sessile head) ; scales mostly green or greenish and many-nerved, 

 abruptly sharp-pointed ; achene. obovate, sharply triangular. 



i Loir annuals. 



9. C. COmpressus, L. Culms 3-9' high, with a simple sessile or a few 

 umbellate clusters of oblong to linear spikelets ( 1 5 - 30-flowered and 3-8" 

 long) with crowded stronglv keeled and very acute pale scales. Sterile fields 

 along the coast, Md. to Fla. and Tex. ; also adventive near Philadelphia. 



C. FUSCUS, L. Of similar habit; spikelets much smaller (2-4" long), 

 the thin brown scales (greenish only on the keel) barely acutish and very 

 faintly nerved. Revere Beach, Mass. ( Young) ; on ballast at Philadelphia. 

 (Adv. from Eu.) 



>- -<- Perennial, propagating from hard clustered conns or bulb-like tubers. 



10. C. Schweinitzii, Torr. Culm rough on the angles (1 -2 high) ; um- 

 bel 4 - 8-rayed, rays very unequal, erect ; spikelets loosely or somewhat remotely 

 6 - \2-flowered, with convex many-nerved scales ; joints narrowly winged. Dry 

 sandy shores and ridges, western N. Y. and Penn. to Minn, and Kan. 



11. C. filiciilmis, Vahl. Culm slender, wiry, often reclined (8-15' 

 high); leaves linear (i-2" wide) or filiform ; spikelets numerous and clustered 

 in one sessile dense head, or in 1-7 additional looser heads on spreading rays of 

 an irregular umbel; joints of the axis naked; scales blunt, greenish. Dry 

 sterile soil ; common, especially southward. 



12. C. Grayii, Torr. Culm thread-form, wiry (6-12' high) ; leaves al- 

 most bristle-shaped, channelled ; itmhel simple, 4-6-rayed ; spikes 5-10 in a 

 loose head, spreading ; joints of the axis winged; scales rather obtuse, greeuish- 

 chestuut-color. Barren sands, Plymouth, Mass., to N. J., near the coast. 



