GENUS 2. 



SEDGE FAMILY. 



309 



34. Cyperus filiculmis Vahl. Slender Cyperus. Fig. 754, 



Cyperus filiculmis Vahl, Enum. 2: 328. 1806. 



C. filiculmis macilentits Fernald, Rhodora 8: 128. 1906. 



C. macilcntus Bicknell, Bull. Torr. Club 35: 478. 1908. 



Perennial by hard oblong corms, culm smooth, slen- 

 der or almost filiform, ascending or reclined, 6'-i8' 

 long, usually longer than the rough-margined leaves. 

 Leaves i"-2" wide, keeled, those of the involucre, or 

 some of them, much exceeding the inflorescence; 

 spikelets densely clustered in 1-7 globose heads, linear, 

 acute, 4-1 1 -flowered, subterete or compressed, ii"-6" 

 long, i" wide or less; rachis wingless; scales ovate, 

 acute or obtuse, pale green, strongly 7-n-nerved, 

 appressed ; stamens 3 ; style 3-cleft ; achene oblong or 

 obovoid, 3-angled, obtuse, apiculate, dull gray, two- 

 thirds as long as the scale, about twice as long as thick. 



In dry fields and on hills, Maine to Ontario, Minnesota, 

 Florida. Kansas, Texas and Mexico. June-Aug. In its 

 northern range the spikelets are fewer-flowered than in 

 the south. 



35- Cyperus cayennensis (Lam.) Brittoru 

 Cayenne Cyperus. Fig. 755. 



Kyllingia cayennensis Lam. 111. i: 149. 1791. 

 Mariscus flavus Vahl, Enum. 2 : 374. 1806. 

 C. flavus Boeckl. Linnaea 26: 384. 1869-70. 



C. cayennensis Britton, Bull. Dept. Agric. Jam. 5 : 

 Suppl. i, 8. 1907. 



Perennial by short rootstocks; culms trigonous, 

 smooth, 2 high or less. Leaves flat, 2"-^" wide, 

 the basal ones often as long as the culm, the largest 

 one of the involucre sometimes half as long; spike- 

 lets 2\" long or less, yellowish, turgid, spicate, the 

 spikes oblong, mostly sessile in a terminal cluster, 

 5"-^?" long, obtuse; scales ovate, striate, the lowest 

 persistent; style 3-cleft; achene trigonous, oblong- 

 obovoid, about half as long as the scale. 



Waste grounds, Camden, N. J., Philadelphia, Penna., 

 and in the southern states. Adventive from tropical 

 America. 



36. Cyperus Grayi Torr. Gray's Cyperus. 

 Fig. 756. 



Cyperus Grayi Torr. Ann. Lye. N. Y. 3 : 268. 1836. 



Perennial by thick hard oblong or ovoid corms, 

 culms tufted, ascending or reclined, stiff, smooth, very 

 slender, 6'-2o' long. Leaves shorter than the culm, 

 bright green, i" wide or less, those of the involucre 

 4-8, the longer somewhat exceeding the umbel; umbel 

 4-io-rayed, simple, the longer rays 3'-4' long; sheaths 

 of the rays truncate or nearly so; spikelets 2$"-$" 

 long, loosely capitate, compressed, linear, rigid, spread- 

 ing; scales green, ovate, obtuse or subacute, strongly 

 I3-i5-nerved. rather widely spreading when old; joints 

 of the rachis broadly winged; stamens 3; style 3-cleft; 

 achene oblong or oblong-obovoid, obtuse, apiculate. 

 about two-thirds as long as the scale. 



Tn sands of the sea shore and in pine barrens, New 

 Hampshire to Florida. July-Sept. 



