40 CYPEKACEAE. 



appressed, twice as long as the achene: stigmas 2: aehenes orbicular or orbicular- 

 obovoid, black, obtuse, shining. — Common, in low grounds. — Sum. and fall. 



2. C. diandrus Torr. Annual. Leaves deep-green : scapes tufted, slender, 5-40 

 cm. tall: spikelets 8-18 mm. long, linear-oblong, acute, flat, many-flowered: 

 scales short, green or brown, or with brown margins, obtuse, 1-nerved, thin, dull: 

 stigmas 2, much exserted: aehenes lenticular, oblong, dull. — Eather rare, in 

 swampy places. • — • Sum. and fall. 



3. C. rivularis Kunth. Similar to the next preceding species: scapes slender, 

 tufted: spikelets linear or linear-oblong, acutish, 8-20 mm. long: scales dark- 

 green or brown, or with brown margins, appressed, thick, shining, obtuse: 

 stigmas 2, scarcely exserted: aehenes oblong or oblong-obovoid, lenticular, dull, 

 — M. S. Eather common, in low grounds. — Limestones, schists. — Sum. and fall. 



4. C. inflexus Muhl. Annual, fragrant in drying. Leaves bright-green: scapes 

 slender or almost filiform, tufted: umbel sessile, capitate or 1-3-rayed: spikelets 

 linear-oblong, 6-10-flowered, 4-6 mm. long: scales light-brown, lanceolate, 

 several-nerved, each tapering into a long, recurved awn: stigmas 3: achene 3- 

 angled, narrowly obovoid, mucronate, brown. — Susquehanna valley. Eather 

 rare, in wet sandy soil. — Schists. 



5. C. dentatus Torr. Perennial. Leaves light-green: scapes 2-5 dm. tall: 

 umbel somewhat compound: spikelets few, light reddish-brown, linear, very flat, 

 many-flowered, mostly blunt, 10-20 mm. long, nearly 4 mm. wide: scales thin, 

 keeled, 5-7-nerved, mucronate: ffchene 3-angled, obovoid, less than 1 mm. long, 

 mucronate, light-brown, much shorter than the scale. — Susquehanna valley. 

 Eather common, in sand, on the river shore and low islands. — Sum. 



6. C. esculentus L. Perennial. Leaves light-green : scapes 3-8 dm. tall : umbel 

 4-10-rayed, often compound: spikelets numerous in loose spikes, straw-color or 

 yellowish-brown, flat, spreading, 1-2.5 cm. long, about 3 mm. wide, many- 

 flowered: scales rather acute, 3-5-nerved: achene obovoid, fully 1 mm. long, 

 obtuse, 3-angled. — Common in moist fields; a troublesome weed in places. — 

 Sum. 



7. C. strigosus L. Perennial. Leaf-blades rough-margined, 4-6 mm. wide: 

 scapes rather stout, 3-9 dm. tall: umbel several-rayed, some of the primary rays 

 often 10-15 cm. long, their sheaths terminating in two bristles: spikes oblong 

 or ovoid: spikelets flat, linear, 8-19 mm. long, 2 mm. wide or less, 7-15-flowered: 

 scales straw-colored, strongly several-nerved, appressed: aehenes linear-oblong, 

 3-angled, about 2 mm. long, acute, about J as long as the scale. — Common, in 

 swamps and waste places. — Sum. 



8. C. refractus Engelm. Perennial. Leaf-blades 5-8 mm. wide, rough-mar- 

 gined: scapes stout, smooth, 3-9 dm. tall: umbel 6-13-rayed, usually compound, 

 the longer rays sometimes 20 cm. long, their sheaths terminating in 1 or 2 short 

 teeth: spikes lax: spikelets very narrowly linear, loosely spicate, acute, 1-2 cm. 

 long, 1 mm. thick, 3-6-flowered, the upper spreading, the lower refiexed : scales 

 yellowish-green, closely appressed, Q'-ll-nerved: aehenes linear, about 3 mm. 

 long, obtuse and apiculate, about 5 times as long as thick, and i as long as the 

 scale. — Susquehanna valley. Eather rare, on dry banks. — Sum. 



9. C. ovularis (Michx.) Torr. Perennial. Leaf -blades smooth: scape usually 

 strict, smooth, 2-8 dm. tall, longer than the leaves: umbel simple, few-rayed: 

 spikes globose, 8-14 mm. in diameter, very dense, the spikelets radiating in all 

 directions: spikelets 4-7 mm. long, usually 3-flowered: scales green, several- 

 nerved: aehenes linear-oblong, 3-angled, about 1.5 mm. long, 1-3 times as long 

 as thick. — S. Eather rare, in old fields and on dry banks. — Schists. — Sum. 



10. C. lancastriensis Porter. Perennial. Leaf -blades 1 cm. wide or less: 

 scapes slender, smooth, 3-8 dm. tall : umbel 5-9-rayed : spikes oval, obtuse, 1-2.5 

 cm. long: spikelets densely clustered, 8-10 mm. long, linear, nearly terete, 2-6- 



