145. Cyperaceae 301 



3. Inflorescence usually simple; stigmas 1-2 mm long; ditches; 



Cook, Du Page, McHenry, and Winnebago counties 



S. annricanum Nutt. 



2. Pistillate heads usually supra-axillary; leaves 3-7 mm wide; 

 ditches and ponds, not common; Cook Co., /. A. Steyermark 



40920: Union Co., G. Dillard & S. Abncy in 1959 



S. chlorocarpum Rydb. 



145. Cyperaceae J. St. Hil. — Sedge Family 



1. Spikelets all alike; flowers of the spikelet, or at least one of them, perfect. 

 2. Glumes of the spikelet 2-ranked: spikelets flattened or subterete. 



3. Perianth bristles none; spikelets in umbellate clusters; stems mostly 

 triangular 1. Cyperus 



3. Perianth of 6-9 bristles; inflorescence axillary; stem terete, hollow; 



achenes beaked 2. Dulichium 



2. Glumes spirally imbricated. 



4. Spikelets with several to many perfect flowers. 



5. Base of the style swollen, persistent as a tubercle on the achene. 



6. Spikelet solitary; bristles usually present; stems leafless 



3. Eleocharis 



6. Spikelets several; bristles none; leaves filiform, the sheaths 



pubescent 4. Bulbostylis 



5. Base of style deciduous, sometimes enlarged. 



7. Flowers with a perianth of 3 stalked sepals, or of 1 or 2 hyaline 



glumes. 



8. Bristles 3; bracteoles 5. Fuirena 



8. Bristles 0; bracteoles 1-2. 



9. Flowers with a single minute inner scale (bracteole) 



6. Hemic arpha 



9. Flowers with 2 con\olute inner scales 7. Lipocarpha 



7. Flowers without a perianth. 



10. Style swollen at the base; bristles none 8. Fimbristylis 



10. Style not at all or only slightly thickened at base; bristles 

 usually present. 



11. Bristles few (0-8), short, not long and silky 9. Scirpus 



11. Bristles numerous, long, slender, silky 10. Eriophorum 



4. Spikelets 1- to 4-flowered, polygamous. 



12. Base of the style persistent as a tubercle on the achene; perianth 



bristles usually present; style 2-cleft or entire 



1 1. Rhynchospora 



12. Style wholly deciduous; bristles 0; style 3-cleft 12. Cladium 



1 . Spikelets usually unisexual ; plants monoecious, or rarely dioecious. 



13. Achenes white, bony, globose, usually supported on a disk, not enclosed 



in a sac (perigynium) ; pistillate spikes 1-flowered 13. Scleria 



13. Achenes not bony, enclosed in a perigynium 14. Carex 



1. Cyperus L.* 



1. Achenes lenticular; stigmas 2. 



* Revised by R. H. Mohlenbrock. 



