170 CYPERACEAE 



of them 3-5 times as long as the inflorescence : umbel mostly compound : spikelets linear, 

 rather acute, 6-25 mm. long, less than 2 mm. wide, compressed, many-flowered, crowded 

 in oblong, nearly or quite sessile spikes : scales bright chestnut-brown, oblong-lanceolate, 

 mucronulate, loose : stigmas 3 : achene sharply 3-angled, oblong, about 1 mm. long, pointed 

 at both ends, pale, \ as long as the scale. 



In wet soil, southern Ontario to Massachusetts, Nebraska, Kansas, Florida, Texas and California. 

 Summer and fall. 



40. Cypems digitetus Roxb. Annual, yellowish green. Leaves sometimes over- 

 topping the scape ; blades 4-15 mm. wide, sometimes with rough margins and nerved be- 

 neath : scapes commonly solitary, 3-12 dm. tall, 3-angled, smooth : bracts of the involucre 

 6-10, the longer ones surpassing the umbel : umbel compound, of 5-8 more or less elon- 

 gated rays, and one or more spikes sessile in the involucre : spikes about 1 cm. thick : 

 spikelets laxly disposed, linear-subulate, 6-10 mm. long, chestnut-colored, 10-15-flowered, 

 numerous : scales broadly oblong, about 2 mm. long, closely appressed, abruptly pointed 

 or cuspidate, with pale hyaline margins : achenes 3-angled, fully 1 mm. long, elliptic or 

 oblong, pale brown. [C. erythrorhizos var. erectus Britton.] 



In low grounds or swamps, Texas and Mexico. Spring to fall. 



41. Cyperus Halei Torr. Annual. Leaf-blades 6-8 mm. wide, very rough-mar- 

 gined : scapes stout, 6-10 dm. tall, about equalled by the leaves : bracts of the involucre 

 5-8, much elongated : umbel compound, several-rayed : spikes cylindric, sessile or very 

 nearly so, exceedingly dense, 1-2.5 cm. long: spikelets very numerous, linear, 3-5 mm. 

 long, 1 mm. wide, spreading : scales brown, keeled, indistinctly 5-nerved, oblong, mucronu- 

 late : stigmas 3 : achene 3-angled, about 1 mm. long. 



In swamps, south Missouri to Tennessee, Louisiana and Florida. Summer and fall. 



42. Cyperus Floridinus Britton. Perennial, bright green. Leaves mostly reduced 

 to a few basal scales and several filiform blades : scapes tufted, erect or reclining, 1-7 dm. 

 long, filiform or wiry : bracts of the involucre 2, one about as long as the inflorescence, the 

 other longer: umbel capitate, sessile: spikelets linear-subulate, 6-10 mm. long, crowded, 

 chestnut brown : scales broadly oblong, fully 2 mm. long, blunt, closely imbricated, ribbed 

 on the back, very firm : achenes 3-angled, oblong or nearly so, about 1.5 mm. long, dark 

 brown, dull. 



In sand, southern Florida and the West Indies. Spring to fall. 



43. Cyperus Engelmarmii Steud. Annual. Leaves elongated ; blades 4-6 mm. 

 wide, flaccid, roughish on the margins : scapes slender, 15-75 cm. tall : bracts of the in- 

 volucre 4-6, the longer exceeding the umbel : umbel often compound, the spikelets often 

 densely crowded, very commonly linear, subterete, 1-2.5 cm. long, 5-15-flowered : rachis 

 narrowly winged : scales greenish brown, oblong, obtuse, thin, faintly 3-5-nerved on the 

 back, distant, the successive ones on each side of the spikelet separated by a space of about 

 their length : stigmas 3 : achene linear-oblong, 3-angled, as long as the scale, about 2 

 mm. long. 



In wet soil, Massachusetts to southern Ontario, Wisconsin, New Jersey and Missouri. Summer 

 and fall. 



44. Cyperus speciosus Vahl. Annual. Leaf-blades rough-margined, 3-5 mm. wide, 

 the midvein prominent : scapes usually tufted, 10-40 cm. tall, reddish toward the base : 

 bracts of the involucre much exceeding the umbel : umbel 3-7-rayed, the primary rays 

 2-15 cm. long: involucels narrow : spikes dull brown : spikelets subterete, very narrowly 

 linear, 8-25 mm. long, less than 2 mm. thick, 10-30-flowered, falling away from the axis 

 at maturity : scales dull brown, thin, not tightly appressed, ovate, obtuse, faintly 3-5- 

 nerved on the back : rachis-wings broad, clasping the achene, persistent : stigmas 3, 

 slightly exserted : achene obovoid. barely 1.5 mm. long, pale, 3-angled, about \ as long as 

 the scale. 



In marshes, eastern Massachusetts and Rhode Island to Ohio, Minnesota, Florida, Texas and Cali- 

 fornia. Summer and fall. A variety with reddish spreading or slightly recurved scales, is C. speciosus 

 ferruffintscens (Boeckl.) Britton ; its range is from Missouri to Texas and New Mexico. Another variety 

 with about the same range, C. speciosus pdrvits (Boeckl.) Britton, has scapes 2-7 cm. high, a very simple 

 umbel and generally a single cluster of short spikelets. 



45. Cyperus ferax Vahl. Annual, closely related to the next preceding species, but 

 with smooth-margined, shorter and broader leaf-blades : bracts of the involucre sometimes 

 but little exceeding the inflorescence : umbel often compact, the rays mostly short : spikes 

 yellowish or grayish brown : spikelets linear, subterete, 10-20-flowered, 16-25 mm. long, 

 about 2 mm. thick : scales ovate-oblong, appressed, imbricated, obtuse, rather firm, green 

 and 7-9-nerved on the back, yellowish on the sides : stigmas 3 : rachis broadly winged : 

 achene 3-angled, narrowly obovoid, obtuse, about 1-1.5 mm. long. 



In wet soil, Missouri to California, and widely distributed in tropical America. Summer and fall. 



