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, 3 as long as the scale. 
In wet soil. southern Ontario to Massachusetts, Nebraska, Kansas, Florida, Texas and California. 
Summer and fall. 
40. Cyperus digitatus 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 Hàlei 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 Floridànus 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 Engelmannii 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 
j ini length : stigmas 3: achene linear-oblong, 3-angled, # as long as the scale, about 2 
mm. long. 
TT B wet soil, Massachusetts to southern Ontario, Wisconsin, New Jersey and Missouri. Summer 
44. Cyperus speciósus 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, 
Hi ges exserted : achene obovoid, barely 1.5 mm. long, pale, 3-angled, about 3 as long as 
e 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 
Jerruginéscens (Boeck].) Britton ; its range is from Missouri to Texas and New Mexico. Another variety 
with about the same range, C. speciosus pàrvus (Boeckl.) Britton, has scapes 2-7 cm, high, a very simple 
umbel and generally a single cluster of short spikelets. 
,.45. Cyperus férax 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 : urabel 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. 
