570 CYPERACKit:. (sedge family.) 



§2. CYPERUS proper. Achene triangular ; spikelets usually man jj-flowered, 

 more or less flattened, with cannate scales, the I'hachis marginless or nearly 

 so (winged in n. 12). 



* Stamen 1 ; spikelets short and small (l^- 5" long) in globidar heads, ovate or 



linear-oblong, many-flowered ; achene oblong -obov ate to linear. 

 ^ Low annuals ; involucre 2- 3-leaved ; heads few; scales pointed. 



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

 oblong becoming /mear, 7 - 13-flo\vered, iu 1-5 ovate heads (sessile and clus- 

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

 achene obloug-obovate, obtuse. (C. inflexus, Muhl.) — Sandy wet shores ; 

 common. Sweet scented in dry ing. 



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

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

 achene oblong, pointed at both ends. — Low ground, 111. and south westward. 



•t--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 (H" long), 

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

 row, acutish, obscurely 3-nervea. (C. vireus. Gran, in part; not Michx. C. 

 Luzulae, 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-Low annuals. 



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

 umbellate clusters of oblong to linear spikelets (15-30-flowered and 3-8" 

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

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



C. Fijscus, 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.) 



-I- -(- 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, ivith convex many-nerved scales ; joints narrowly winged. — Dry 

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



11. C. filiculmis, 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 rai/s of 

 an irregular nmhel; 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 brisde-shaped, d\a.nnel\ed ; umbel simple, A-Q,-rayed; spikes 5-10 in a 

 loose head, spreading ; joints of the axis ivinged ; scales rather obtuse, greenish- 

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



