North American Cyperacea. 275 



28. Cyperus virens, Michx. 



Culm acutely triangular; umbel compound ; involucre many- 

 leaved, very long; involucels nearly equalling the partial rays; 

 spikelets ovate and ovate-lanceolate, much compressed, col- 

 lected in dense globose heads, 12 — 20-flowered ; rachis naked ; 

 scales oblong-lanceolate, acute ; stamen 1 ; nut oblong, trique- 

 trous, acute at each end. 



C. virens, Michx. ! fl. 1. p. 28 ; Pursh, fl. 1. p. 52 ; Muhl. ! gram. p. 

 24; EUiott, sk. 1. p. 66; VaJil, enum. 2. p. 353; Rce7n. S^- Schult, syst. 

 2. p. 210; Spreng. syst. 1. 226. 



C. glomeratus, Walt. fl. Car. p. 70? 



Culm 2 — 5 feet high, thick and firm, very acutely triquetrous, tlie 

 angles sharply serrulate near the summit. Leaves nearly as long as 

 the culm, 4 — 5 lines wide, rough on the edges and keel, the sides 

 folded together. Umbel with 5 — 7 very unequal rays ; partial rays 

 pearly an inch long, each bearing a dense head of about 20 spikelets. 

 Ochrece bifid. Involucre 6 — 8 times as long as the umbel ; involucels 

 foliaceous, about as long as the partial umbels. Spikelets varying from 

 ovate to lanceolate, rather obtuse, 3 — 5 lines long, and a line and a half 

 broad. Scales carinate, greenish. Interior scales entirely wanting- 

 Stamen always solitary. Style 3-cleft. Nut acute at each end, dull 

 yellow. 



Hab. In swamps: confined to the Southern States. Wil- 

 mington, North Carolina, Mr.Curtis! ; South Carolina, jEZ/io«.'; 

 Georgia, Muhlenberg! ; Middle Florida, Dr. Chapmati! ; New 

 Orleans, Dr. Ingalls! 



29. Cyperus vegetus, WiUd.7 



Culm obtusely triangular, smooth on the angles; umbel com- 

 pound ; involucre 4-leaved ; involucels bracteiform, shorter 

 than the partial rays ; spikelets ovate, much compressed, col- 

 lected in dense globose heads, 9 — 16-flowered ; rachis naked ; 

 scales oblong, acute, somewhat incurved ; stamen 1 ; nut lan- 

 ceolate, attenuated to a long point, tumid at the base. 



