CYPEKACEAE 171 



46. Cyperus Egg^rsii Boeckl. Annual, pale or bright green. Leaves commonly 

 overtopping the scape, rough-margined: scapes. 3-9 dm. tall, smooth : bracts of the 

 involucre mostly 5, somewhat broader than the leaf-blades, much surpassing the umbel : 

 umbel of 2-4 rays 1-3 cm. long, compound : spikes several to many : spikelets greenish 

 brown, 4-7 mm. long, very brittle : scales blunt, less than 2 mm. long : achenes oblong, 

 fuUv 1 mm. long, abruptly pointed at the apex, pinched at the base, straight, brown. 



In low grounds, southern Texas. Also in tropical America. Spring to fall. 



47. Cyperus oxycarioidea Britton. Annual, bright green. Leaves mostly over- 

 topped by the scapes ; blades 3-8 mm. wide, roughish on the margins: scapes 5-12 dm. 

 tall, 3-angled, smooth : bracts of the involucre usually 5, several much longer than the 

 umbel, spreading : umbel capitate, the spikes congested into a dense terminal cluster : spike- 

 lets linear-subulate, numerous, light green-brown, 6-10 mm. long, brittle, 8-12-flowered, 

 densely crowded : scales oval-oblong, about 2 mm. long, blunt, delicately ribbed, closely 

 imbricated : achenes 3-angled, oblong-obovold, 1.5 mm. long, pale brown, slightly curved. 



In sandy swamps, southern Texas and Central America. Spring to fall. 



48. Cyperus Martindalei Britton. Perenial, bright green. Leaves overtopped by 

 the scape ; blades filiform by the revolute margins, smooth : scapes tufted, erect, 2-7 dm. 

 tall, 3-angled, smooth : bracts of the involucre 3-5, slender like the leaf-blades, several 

 much elongated : umbel capitate, or with 1-3 slender rays : spikes globular, 1-2 cm. in 

 diameter : spikelets linear or linear-subulate, 6-10 mm. long, yellowish green, densely 

 crowded : scales broadly oblong, 2-2.5 mm. long, prominently ribbed, often becoming 

 eroded at the apex, spreading at maturity : achenes 3-angled, oblong, 2 mm. long or nearly 

 so, brown, dull. 



In sand, Georgia to Florida and Louisiana. Spring to fall. 



49. Cyperus setigerus Torr. & Hook. Perennial, bright green. Leaves over- 

 topped by the scape ; blades 4-10 mm. wide, rough at least on the margins : scapes erect, 

 6-12 dm. tall, smooth : bracts of the involucre 3-5, with scabrous margins, the longer ones 

 much surpassing the umbels, spreading : umbels of usually 6-9 slender smooth or scabrous 

 rays, and one or more spikes sessile in the involucre : spikelets linear, 1-2.5 cm. long, 

 chestnut-brown, rather numerous : scales lanceolate, 3-4 mm. long, acute, rather closely 

 imbricated, ribbed on the back : achenes 3-angled, oblong-prismatic, 1.5 mm. long, pinched 

 at the apex. 



In low grounds, Texas and New Mexico. Spring to fall. 



50. Cyperus strigosus L. Perennial by basal tuber-like cornis. Leaves rough-mar- 

 gined, 4-6 mm. wide : scapes rather stout, 3-9 dm. tall : the longer bracts of the involucre 

 much exceeding the umbel : umbel several-rayed, some of the primary rays often 10-15 cm. 

 long, their sheaths terminating in two bristles : involucels setaceous : heads oblong or ovoid : 

 spikelets fiat, linear, 8-19 mm. long, 2 mm. wide or less, 7-15-flowered : scales straw- 

 colored, oblong-lanceolate, subacute, strongly several-nerved, appressed : stigmas 3 : achenes 

 linear-oblong, 3-angled, about 2 mm. long, acute, about ^ as long as the scale. 



In moist meadows, swamps or along streams, Maine to Ontario, Minnesota, Nebraska, Florida and 

 Texas. Summer and fall.— Several varieties have been described : C. strh/osus robustior Kunth, has a 

 compound umbel and large spikelets 16-25 mm. long with 10-25 flowers: it occurs with the type; C. 

 strir/osus capitdtus Boeckl., lias the umbel simple or nearly simple, and the spikelets 8-14 mm. long, 

 densely crowded in subglobose heads ; its range is like that of the type ; C. strif/osus compositus Britton, 

 has a compound umbel and spikelets 8-13 mm. long, with only 4 or 5 flowers ; it ranges from New York 

 to Iowa and Alabama. C. strigosus gmcilis Britton. is very slender, with leaves overtopped by the scape, 

 umbel of 1-3 short rays, bearing few linear spreading spikelets ; it is confined to Arkansas and Texas ; 

 and C. strigosus elongdtiis (Torr. ) Britton, has much elongated rays bearing single capitate clusters, North 

 Carolina and Texas. 



51. Cyperus stenolepis Torr. Perennial, bright green. Leaves overtopped by the 

 scapes ; blades 8-16 mm. wide, very rough on the margins, pale beneath : scapes erect, 5-12 

 dm. tall, smooth, 3-angled : bracts of the involucre 3-6, the longer ones much surpassing 

 the umbel, spreading : umbel simple or compound, of 6-9 rays of various lengths and one or 

 more spikes sessile in the involucre : spikelets numerous, linear, 15-20 mm. long, bright 

 straw-colored, 5-12-flowered : scales linear or linear-lanceolate, 4-5 mm. long, prominently 

 ribbed and deciduous at maturity, loose and somewhat spreading : achenes 3-angled, ob- 

 long-prismatic, about 2 mm. long, brown, abruptly pointed at the apex, pinched at the 

 base. 



In swamps or low grounds. North Carolina to Florida and Texas. Summer and fall. 



52. Cyperus refractus Engelm. ^Perennial by tuber-like corms. Leaf-blades 5-8 

 mm. wide, rough-margined, elongated : scapes stout, smooth, 3-9 dm. tall : umbel 6-13- 

 rayed, usually compound, the longer rays sometimes 20 cm. long, their sheaths terminating 

 in 1 or 2 short teeth : involucels setaceous : raylets filiform : spikelets very narrowly linear, 

 loosely spicate, acute, 1-2 cm. long, 1 mm. thick, 3-6-flowered, the upper spreading, the 

 lower reflexed : scales yellowish green, oblong-lanceolate, obtuse, closely appressed, 9-11- 



