GENUS 2. 



SEDGE FAMILY. 



35 



22. Cyperus erythrorhizos Muhl. Red-rooted Cyperus. Fig. 742. 



Cyperus erythrorhizos Muhl. Gram. 20. 1817. 



Annual, culms tufted, stout or slender, 3'-2 tall. 

 Leaves ii"-4" wide, rough-margined, the lower 

 longer than or equalling the culm, those of the in- 

 volucre 3-7, some of them 3-5 times as long as the 

 inflorescence; umbel mostly compound, several-rayed^; 

 spikelets linear, subacute, 3"-io" long, less than i" 

 wide, compressed, many-flowered, clustered in oblong, 

 nearly or quite sessile spikes; scales bright chestnut 

 brown, oblong-lanceolate, mucronulate, appressed, 

 separating from the rachis at maturity, the mem- 

 branous wings of the rachis separating as a pair of 

 hyaline interior scales; stamens 3; style 3-cleft; 

 achene sharply 3-angled, oblong, pointed at both ends, 

 pale, one-half as long as the scale. 



In wet soil, especially along streams, southern Ontario 

 to Massachusetts, Florida, Minnesota, Kansas, Texas and 

 California. Aug.-Oct. 



23. Cyperus Halei Torr. Hale's Cyperus. 

 Fig- 743- 



C. Halei Torr. ; Britton, Bull. Torr. Club 13 : 213. 1886. 



Annual, culm stout, 2-3 tall, about equalled by 

 the leaves. Leaves 3"-4" wide, very rough-margined, 

 those of the involucre 5-8, much elongated ; umbel 

 compound, several-rayed ; spikes cylindric, sessile or 

 very nearly so, exceedingly dense, \'-\' long; spike- 

 lets very numerous, linear, i$"-2$" long, i" wide, 

 spreading; scales brown, keeled, indistinctly 5-nerved, 

 oblong, mucronulate, separating from the rachis at 

 maturity, the wings of the rachis separating as a 

 pair of hyaline scales, as in the preceding species ; 

 stamens 3; style 3-cleft; achene 3-angled, minute. 



In swamps, southern Missouri to Tennessee, Louisiana 

 and Florida. July-Sept. 



24. Cyperus speciosus Vahl. Michaux's 

 Cyperus. Fig. 744. 



Cyperus speciosus Vahl, Enum. 2: 364. 1806. 

 C. Michauxianns Schult. Mant. 2: 123. 1824. 



Annual, culms usually tufted, i'-2 tall, 

 reddish toward the base. Leaves rough-mar- 

 gined, \\"-2.\" wide, shorter than or equalling 

 the culm, the midvein prominent; leaves of 

 the involucre much exceeding the umbel ; um- 

 bel compound or nearly simple, 3~7-rayed, the 

 primary rays \'-k' long; involucels narrow; 

 spikelets subterete, very narrowly linear, 

 loosely or densely clustered, 4"-i2" long, less 

 than i" thick, io-30-flowered, falling away 

 from the axis at maturity ; scales dull brown 

 or reddish, thin, densely imbricated, ovate, ob- 

 tuse or acute, faintly 3~5-nerved on the back ; 

 rachis-wings broad, cfasping the achene, per- 

 sistent ; stamens 3 ; style 3-cleft, slightly ex- 

 serted ; achene pale, 3-angled, about one- 

 half as long as the scale. 



In marshes, Massachusetts to Ohio and South 

 Dakota, south to Florida, Kansas, Texas and Cali- 

 fornia. July-Sept. Sometimes flowering when i' 

 high ; variable in the overlapping of the scales. 



