166 CYPERACEAE 
25-flowered : scales silvery green, 1.5 mm. long, 3-toothed at the apex, the middle tooth 
longest and acuminate, thus forming a sharp mucro, with broad scarious margins: achenes 
about 0.5 mm. long, obovoid, truncate at the top, barely } as long as the scale. 
In sandy soil, Florida and Alabama. Common in the tropics. Summer. 
11. Cyperus flavicomus Michx. Annual. Leaves 4-6 mm. wide: scapes 3-10 dm. 
tall: bracts of the involucre 3-8, the longer ones much exceeding the inflorescence : um- 
bels few-several-rayed, often compound ; primary rays 1-6 cm. long: spikelets numerous, 
usually densely clustered, linear, acute, 8-20 cm. long, 2-3 mm. wide, flat, many-flowered, 
spreading : scales oblong, obtuse, thin, dull yellowish brown : stigmas 2, little exserted : 
achenes obovoid, lenticular, black, mucronate, not shining, nearly as long as the scales and 
often persistent on the rachis after these have fallen away. 
In wet or moist sandy soil, Virginia to Florida and Louisiana. Summer and fall. 
12. Cyperus Hochstétteri Nees. Annual, bright green. Leaves mostly 2 or 3; 
blades 2-4 mm. wide, smooth like the scape: scapes tufted, relatively stout, 1.5-6 dm. 
tall, mostly overtopping the leaves: bracts of the involucre 3-5, all, or only the longer ones 
surpassing the umbel, longer ones 10-20 em. long: umbel with 2-5 rays, 1-10 cm. long 
and one or more spikes sessile in the involucre: spikelets linear or linear-lanceolate, 1-4 
em. long, 12-54-flowered : scales broadly ovate, deep chestnut color, 2 mm. long, rather 
blunt: achenes lenticular, obliquely obovoid-orbicular, 1.5 mm. long, about à as long as 
the scale, apiculate, deep brown. 
In low grounds, Louisiana, Texas and New Mexico. Also in the tropics. Spring to fall. 
13. Cyperus laevigàtus L. Perennial, light green, resembling species of Scirpus. 
Leaves reduced to several colored scales at the base of the scape, the upper ones sometimes 
prolonged into short blades: scapes tufted from horizontal rootstocks, 0.5-4 dm. tall, 
smooth: spikelets few, usually 3-6 in a head at the top of the scape, subtended by the 
single conspicuous erect involucral bract, oblong-ovate to linear, 6-15 mm. long, rather 
obtuse, mostly 16-30-flowered : scales deltoid-ovate, blunt, nearly 2 mm. long, deep chest- 
nut-brown and lustrous or merely variegated with chestnut, deciduous at maturity : achenes 
1.5 mm. to nearly 2 mm. long, elliptic or obovoid-elliptic, minutely pointed. 
In sandy soil, South Carolina and California. Also cireumtropical. Spring to fall. 
14. Cyperus Careyi Britton. Annual, pale green. Leaves several; blades 1-1.5 
mm. wide, keeled: scapes tufted, slender, less than 1 dm. tall, surpassed by some of the 
leaves, densely leafy at the base : bracts of the involucre usually 3, surpassing the umbel, 
2-8 cm. long: umbel capitate, about 1 cm. broad, sessile: spikelets crowded, numerous, 
oblong or ovate-oblong, 3~4 mm. long: scales silvery or whitish, about 2 mm. long, broadly 
ovate, abruptly pointed, delicately ribbed : stigmas 2: achene lenticular, oblong. 
In sand, middle Florida. Summer. 
15. Cyperus infléxus Muhl. Annual, fragrant in drying. Leaf-blades 2 mm. wide 
or less : scapes slender or almost filiform, tufted, about equalled by the leaves: bracts of 
the involucre 2-3, exceeding the umbel: umbel sessile, capitate, or 1-3-rayed : spikelets 
linear-oblong, 6-10-flowered, 4-6 mm. long: scales light brown, lanceolate, rather firm, 
strongly several-nerved, each tapering into a long, recurved awn: stigmas 3: achene 3- 
angled, narrowly obovoid, 1 mm. long, obtuse, mucronulate, brown, dull. 
In wet, sandy soil, Vermont to the Northwest Territory, Oregon, Florida, Texas, California and 
Mexico. Summer. 
16. Cyperus squarrósus L. Annual, bright green, licorice-scented. Leaves few; 
blades mostly 1 mm. wide or narrower, curved, revolute: scapes tufted, 2-15 cm. tall, 
slender, overtopped by some of the leaves: bracts of the involucre usually 3 or 4, surpass- 
ing the umbel, rarely 10 cm. long: umbel of 2-5 rays with one or more spikes sessile in 
the involucre, or sometimes all the spikes collected in a head : spikelets linear, 5-10 mm. 
long, few in a spike, many-flowered: scales light chestnut-colored, nearly 2 mm. long, the 
recurved spreading awn-like tip nearly as long as the body: achenes 3-angled, broadly obo- 
void, 0.5 mm. long, brown, minutely apiculate. 
SA HS vd Bom Georgia and Florida to Texas and California. Alsoin the West Indies and tropics 
__ 17. Cyperus compréssus L. Annual. Leaves light green; blades about 2 mm. 
wide: scapes slender, erect or reclining, smooth, 7-25 cm. long: bracts of the involucre 
2-3, the longer exceeding the spikelets: umbel capitate or with 2—3 short rays: spikelets 
narrowly lanceolate, acute, 8-20 mm. long, 3-4 mm. wide, very flat, many-flowered : scales 
light green with a yellow band on each side, ovate, acuminate, firm, keeled, several-nerved : 
er im 3: achene sharply 3-angled, obovoid, obtuse, dull brown, about 3 as long as the 
scale. 
In fields, Maryland to Florida, Missouri and Texas. Also in tropical America and the Old World. 
Summer and fall. 
