166 CYPEKACEAE 



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 i as long as the scale. 

 In sandy soil, Florida and Alabama. Common in the tropics. Summer. 



11. Cyperus flavlcomus 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 f e\v -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 Hochst6tteii 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 cm. 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 

 cm. 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 h 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 laevigatus 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 inflexus 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 squarrosus 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 1 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. 



In sandy soil, Georgia and Florida to Texas and California. Also in the West Indies and tropics 

 of the Old World. 



17. Cyperus compressus L. Annual. Leaves light green; blades about 2 ram. 

 wide : scapes slender, erect or reclining, smootli, 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 : 

 stigmas 3: achene sharply 3-angled, obovoid, obtuse, dull brown, about ^ as long as the 

 scale. 



In fields, Maryland to Florida, Missouri and Texas. Also in tropical America and the Old World. 

 Summer and fall. 



