CYPERACEAE 173 
finely ribbed, closely imbricated : achenes 3-angled, oblong-prismatic, nearly 2 mm. long, 
abruptly pointed. 
In sand, Florida to Texas. Spring to fall. 
60. Cyperus Lancastriénsis Porter. Perennial by ovoid or oblong corms.  Leaf- 
blades 4-6 mm. wide: scapes slender, smooth, mostly longer than the leaves, 3-8 dm. tall : 
bracts of the involucre 4-7, the longer much exceeding the inflorescence : umbel simple, 
5-9-rayed, the longer rays 5-10 cm. long, their sheaths nearly truncate: spikes oval, ob- 
tuse, 1-2.5 cm. long: spikelets densely clustered, 8-10 mm. long, linear, nearly terete, 
2—4-flowered, the lower reflexed, the middle ones spreading, all separating from the axis at 
maturity : scales green, strongly several-nerved, the flowering ones lanceolate, subacute : 
stigmas 3: achenes linear, obtuse, 2.5-3 mm. long, apiculate, 2-3 times as long as thick, 4 
as long as the scale. 
In dry fields, New Jersey and Pennsylvania to Virginia and Alabama. Summer and fall. 
61. Cyperus uniflórus Torr. & Hook. Perennial, bright green. Leaves overtopped 
by the scape; blades 2-4 mm. wide, smooth: scapes often tufted, slender, 1-7 dm. tall, 
smooth : bracts of the involucre 4-7, the longer ones surpassing the umbel : umbel simple, 
of 3-6 slender rays and one or more spikes sessile in the involucre: spikes oval or ovoid, 
1.5-2 em. long: spikelets spreading in all directions, usually curved, subulate, 8-12 mm. 
long, gray-green, attenuate, never densely crowded : scales various, narrow, lower merely 
acute, upper more or less awn-tipped, closely imbricated: achenes 3-angled, oblong or 
slightly broadest above the middle, 2.5 mm. long, brown. 
In sandy swamps or low grounds, Arkansas and the Indian Territory to Texas, New Mexico and 
Mexico. Spring to fall. 7 
62. Cyperus subuniflòrus Britton. Similar to the next preceding species in habit, 
but more slender and smaller throughout. Umbels with fewer rays: spikes globular or 
ovoid-globose, 6-10 mm. long: spikelets more or less spreading, 3-5 mm. long, without 
conspicuous subulate tips, little if at all curved : achenes 3-angled, oblong, about 2 mm. 
long, abruptly pointed. 
In dry soil, the Indian Territory, Texas and Mexico. Spring to fall. 
63. Cyperus tetrágonus Ell. Perennial, bright green. Leaves mostly overtopped 
by the scape ; blades 4-10 mm. broad, smooth or nearly so: scape often solitary, erect, 3-8 
dm. tall, smooth: bracts of the involucre 8-10, the longer ones surpassing the umbel, as- 
cending, spreading : umbel mostly compound, of 6-12 slender erect or ascending rays and 
one or more spikes sessile in the involucre : spikelets linear-oblong, plump, 4-6 mm. long, 
acute, chestnut-colored, 4-6-flowered, spreading or the lower reflexed : scales oblong, fully 
3 mm. long, 9-11-nerved, closely imbricated : achenes oblong or elliptic, 3-angled, 2 mm. 
long, chestnut-colored, dull. 
In sandy soil, near the coast, North Carolina to Florida and Texas. Spring to fall. 
64. Cyperus flàvus (Vahl) Nees. Perennial, bright green. Leaves overtopped by 
the scape ; blades 2-6 mm. wide, smooth: scapes often tufted, 1-6 dm. tall, smooth : bracts 
of the involucre mostly 4—6, the longer ones surpassing the umbel: umbel capitate, of 3-6 
sessile cylindric spikes, 1-2 cm. long, or occasionally with 2-3 short rays: spikelets 
densely crowded, 3-5 mm. long, spreading, chestnut-colored: scales ovate to oblong, 2-2.5 
mm. long, finely ribbed, often eroded at the apex, closely imbricated : achenes 3-angled, 
broadly elliptic to obovoid-elliptic, about 2 mm. long, brown, dull. 
In sand, Texas and tropical America. Spring to fall. 
65. Cyperus fuliginéus Chapm. Perennial, deep green. Leaves overtopped by the 
scape ; sheaths blackish ; blades revolute, about as slender as the scape, smooth : scapes 
tufted, filiform, 1-4 dm. tall, smooth: bracts of the involucre 2, one much shorter than 
the other: spikelets crowded in a head about 1 cm. in diameter, linear-oblong, 4-7 mm. 
long, dark brown, 8-12-flowered, often apparently lateral: scales oval or ovate, barely 2 
mm. long, mucronulate, several-ribbed : achenes 3-angled, oblong-obovoid, barely 1.5 mm. 
long, dark brown, dull. 
Insand, Key West, Florida. Spring to winter. 
.. 66. Cyperus filicálmis Vahl. Perennial by hard oblong corms. Leaf-blades 2-4 mm. 
wide, keeled : scape smooth, slender, or almost filiform, ascending or reclined, 1.5-4.5 dm. 
long, usually longer than the rough-margined leaves: spikelets densely clustered in 1-7 
globose heads, linear, acute, 5-11-flowered, subterete or compressed, 5-12 mm. long, 2 mm. 
wide or less: scales ovate, acute or obtuse, pale green, strongly 7-11-nerved, appressed : 
stigmas 3 : achenes oblong or obovoid, fully 2 mm. long, 3-angled, obtuse, apiculate, dull 
gray, 3 as long as the scale, about twice as long as thick. 
In dry fields and on hills, New Hampshire to Ontario, Minnesota, Nebraska, Florida, Kansas, 
Texas and northern Mexico. Spring and summer. 
