278 North Amerlcaji Cyperaeed. 



scarious on the margin, yellowish on the sides; the keel grefen. Slamins 

 3. Style deeply three-parted. Nut nearly as long as the scale, light 

 brown. 



Hab. Lake of the Isles, North-West Territory, Dr. 

 Houghton ! 



Obs. Resembles the spreading species in the disposition 

 and structure of the spikelets, its large nut, and deeply 3-parted 

 style ; but the umbel is nearly sessile, the glumes much broader, 

 and scarcely mucronate. 



tttt Spikelets subtercte or angular, 2 — ^-jlowered, forming 

 dense ovate or globose heads at the summit of the rays ; the 

 two lowest scales commonly sterile. 



32. Cyperus ovularis. 



Culm acutely triangular ; umbel of 1 — 6 rays j involucre 

 3— ^4-leaVed ; heads globose, compact ; spikelets 2 — -4-flower- 

 ed, (only two of the florets fertile) radiated ; rachis winged ; 

 scales ovate, rather obtuse, the two lowest short and empty ;• 

 nut obovate, triangular^ 



Mariscus ovularis, Vahl, enum. 2. p. 374; Pursh, fl. 1. p. 58; Torr.! 

 1. p.58(excl. syn. Ell); Beck! Bot. p. 429; Gray ! Gram. Sf Cyp. 

 part 1. no. 76; Darlingt.! fl. Cest. ed. 2. p. 16; Ram. Sf Scliult. syst. 

 1. p. 244. 



Kyllingia ovularis, Michx.! fl. 1. p. 29; Pers. syn. 1. p. 57. 



Scirpus echinatus, Linn.fl. Zeyl. 38?; Muhl.! gram. p. 40. 



Cyperus floribus capitatus, &c. Gron. fl. Virg. 12. 



GrAMen Cyperoides Americanum, &c. PluTc. aim. 179. to 91. f. 4. 



Rhizoma short, tuberous. Culm 1 — 2 feet high, slender, smooth on the 

 angles. Leaves all radical, shorter than the culm, 2 — 3 lines wide. 

 Rays of the umbel simple, 1 — 2 inches long, sometimes contracted, so 

 that the heads appear to be almost sessile. Ochrete obtuse. Involucre 

 many times longer than the umbel. Heads about half an inch in dia- 

 meter, exactly globose, composed of 50 — 100 spikelets which radiate in 

 every direction from the common rachis. Spikelets commonly about 3- 

 flowered, short and thick, rather quadrangular than terete. Scales ap- 



