266 North American Cyperacea. 
C. Hydra, Michx. ! fl. 1. p. 27 ; Vahl, enum. 2. p. 344, PursJi, ft. I. 
p. 52; Elliott! sk. 1. p. 68; Kunth, syn. 1. p. 140; Rcem. S^- Sclmlt. 
syst. 2. p. 201 ; Spreng. ! syst. 1. p. 224. 
C. rotundus, Mulil.! gram. p. 17. 
Rhizoma creeping extensively, its branches ending in small tubers. 
Culm 6 — 12 inches high, smooth, triquetrous. Leaves about two lines 
wide, shorter than the culm, often recurved, somewhat glaucous. Umbel 
usually 4-rayed ; the rays 2 — 3 inches long, erect or only a little spread- 
ing. Involucre 2 — 3-leaved ; the leaves often shorter than the umbel, 
rarely exceeding it in length. Ochres truncate, pointless. Spikelets 
nearly an inch long, alternate along the upper part of the rays. Scales 
closely imbricated, bright chesnut and shining, without nerves, slightly 
mucronate. Interior scales narrow, adnate, hyaline. Stamens 3. Style 
3-cleft about Imlf-way down. Ripe fruit not seen. 
Hab. Sandy fields, and in sand-drifts near the sea ; Virgi-' 
nia to Florida. Virginia, Carolina and Florida, Michaux ; 
Wilmington, N. Carolina, Mr. C^irtis ! ; sea shore of S. Caro- 
lina, Ellioii!; St. Mary's, Georgia, Dr. Bacon! ; Florida, Dr. 
Baldwin!; x\rkansas, Nuttall ; Mexico, Hnmboldt; Bahia, 
Brazil, Di: Baldwin!; Guadaloupe, Dr.Madiana! 
Obs. This species is nearly allied to C. rotvndus, L,irm. 
and also to C. Iicxastachyus, Rotfb. In the Southern States, it 
is very troublesome to planters on account of its rapid multipli- 
cation by means of its creeping rhizomas and tubers. See 
Elliott. 
19. CyPERUS DTSSITIFLORUS. 
Culms filiform, cespitose, tumid at the base; leaves very 
narrow ; umbel simple 3 — 4-rayed ; involucre 3-leaved ; spike- 
lets lanceolate, compressed, very acute, 5 — 7-flowered, re- 
motely and somewhat distichously inserted along the common 
rachis ; scales appressed, oblong-lanceolate, acute ; inner scales 
conspicuous; nut obovate-oblong, flattened on the back. 
Rhizoma short and thick. Culm 1—2 feet high, the base somewhat 
swollen, and of a reddish colour. Leaves mostly radical, narrow. Rays 
