CYPERACEAE 171 
46. Cyperus Eggérsii 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, 
fully 1 mm. long, abruptly pointed at the apex, pinched at the base, straight, brown. 
Inlow grounds, southern Texas. Alsoin tropical America. Spring to fall. 
47. Cyperus oxycarioides 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-obovoid, 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 
crowdedg; 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 strigdsus L. Perennial by basal tuber-like corms. 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 flat, 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 3 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. strigosus robüstior Kunth, has à 
compound umbel and large spikelets 16-25 mm. long with 10-25 flowers; it occurs with the type; C. 
strigosus capitàtus Boeckl., has the umbel simple or nearly simple, and the spikelets 8-14 mm. long, 
densely erowded in subglobose heads ; its range is like that of the type; C. strigosus compósitus 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 grácilis 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 elongátus (Torr.) Britton, has much elongated rays bearing single capitate clusters, North 
Carolina and Texas. 
51. Cyperus stenólepis 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-prismatie, about 2 mm. long, brown, abruptly pointed at the apex, pinched at the 
ase. 
In swamps or low grounds, North Carolina to Florida and Texas. Summer and fall. 
52. Cyperus refráctus 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 lor2 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- 
