Genus 2. 



SEDGE FAMILY. 



3°3 



16. Cyperus fuscus L. Brown Cyperus. 

 Fig. 736. 

 Cyperus fuscus L. Sp. PI. 46. 1753. 



Annual, culms slender, tufted, 6-15' high, longer 

 than or equalled by the leaves. Leaves rather dark 

 green, about 1" wide, those of the involucre 4-6, 

 the longer much exceeding the inflorescence; umbel 

 several-rayed, somewhat compound, the rays short; 

 spikelets linear, z"-y" long, less than 1" wide, many- 

 flowered, acute; scales ovate, subacute, becoming 

 dark brown or remaining greenish on the keel, faintly 

 about 3-nerved on the back, separating from the nar- 

 rowly winged rachis as they mature; stamens 2 or 3; 

 style 3-cleft; achene sharply 3-angled, oblong, pointed 

 at each end, nearly as long as the scale. 



Waste grounds and in ballast, eastern Massachusetts to 

 New Jersey and Maryland. Adventive from Europe. 

 July-Sept. 



17. Cyperus Haspan L. Sheathed Cyperus. Fig. 737. 



Cyperus Haspan L. Sp. PI. 45. 1753. 



Perennial by short rootstocks (sometimes an- 

 nual?), roots fibrous, culms slender, weak, tufted, 

 i°-3° high. Lower leaves reduced to membranous 

 acuminate sheaths, those of the involucre about 2, 

 usually less than 1" wide, commonly little exceed- 

 ing or shorter than the inflorescence; umbel several- 

 rayed, simple or compound, the longer rays i'-2' 

 long; spikelets few, capitate, linear, acute, many- 

 flowered, 3"-6" long, about i" wide; scales oblong 

 or oblong-lanceolate, reddish-brown, acute, mucron- 

 ulate, keeled, 3-nerved ; rachis narrowly winged ; 

 stamens 3; style 3-cleft, scarcely exserted; achene 

 3-angled, broadly obovoid, obtuse, nearly white, very 

 much shorter than the scale. 



In swamps, Virginia to Florida and Texas, mostly 

 near the coast. Also in tropical America and in the 

 warmer parts of Europe, Asia and Australia. A long 

 basal leaf is rarely developed. July-Sept. 



18. Cyperus dentatus Torr. Toothed Cyperus. Fig. 738. 



Cyperus dentatus Torr. Fl. U. S. 1 : 61. 1824. 

 C. dentatus ctenostachys Fernald, Rhodora 8 : 126. 



1906. 



Perennial by scaly rootstocks which sometimes bear 

 small tubers, culms rather stiff, 8-20' tall, longer than 

 or equalled by the leaves. Leaves keeled, i"-a" wide, 

 those of the involucre 3-4, one or two of them usually 

 exceeding the inflorescence ; umbel several-rayed, some- 

 what compound; longer rays 1/-3' long; spikelets linear, 

 very flat, many-flowered, mostly blunt, s"-io" long, 

 nearly 2" wide; scales light reddish-brown, ovate- 

 lanceolate, thin, keeled, 5-7-nerved, mucronate, separat- 

 ing from the rachis when mature, their tips spreading, 

 causing the spikelet to appear toothed ; stamens 3 ; style 

 3-cleft, the branches exserted; achene 3-angled, obtuse, 

 mucronate, light brown, much shorter than the scale. 



In sandy swamps and on shores, Maine to northern New 

 York, West Virginia and South Carolina. Scales often 

 modified into tufts of small leaves. Aug.-Oct. 



