92 PUBLIC HEALTH BULLETIN NO. 286 



7. Achene gray, reddish, or black, abruptly acuminate 6. S. validus. 



7. Achene nearly white, narrowed to short tip 7. *S. californicus. 



8. Spikelets crowded into 1-several globose 8. S. cubensis. 

 heads. 



8. Spikelets not crowded into globose heads 9. 



9. Perianth-bristles downwardly barbed or wanting 10. 



9. Perianth-bristles smooth or occasionally with a few 13. 

 ascending hairs. 



10. Perianth-bristles wanting 9. S. georgianus. 



10. Perianth-bristles present 11. 



11. Perianth-bristles twice as long as the achene 10. S. polyphyllus. 



1 1 . Perianth-bristles not exceeding achene in length 12. 



12. Spikelets 3-8 in each head; scales obtuse; II. S. sylvaticus. 

 lower leaf -sheaths red-tinged; perianth- 

 bristles barbed to base. 

 12. Spikelets 8-20 in each head; scales acute; 12. S. atrovirens. 

 lower leaf -sheaths green; perianth-bristles 

 not barbed near base. 

 13. Perianth-bristles at maturity scarcely if at all exceed- 14. 



ing the scales. 

 13. Perianth-bristles at maturity greatly exceeding scales 13, S. eriophorum. 

 making spikelet appear wooly. 

 14. Perianth-bristles about equalling achene; 15. 



scales acute. 

 14. Perianth-bristles about twice as long as 14. S. lineatus. 

 achene; scales mucronate. 

 15. Spikelets 1 mm. thick; achene not papillose; inflores- 15. S. divaricatus. 



cence terminal only. 

 15. Spikelets 2-3 mm. thick; achenes papillose; inflores- 16. S.fontinalis. 

 cence terminal and lateral. 



1. S. subterminalis Torr. — Probably occurs in western part of our 

 range, not noted by the writers. 



2. S. debilis Pursh — Swamps mostly in the northern parts of our 

 territory. 



3. S. americanus Pers.. Three-square Bulrush — Should occur over 

 all of our territory, uncommon except along the coast, noted in 

 marshes in the Everglades of Florida. 



4. S. olneyi A. Gray — Supposed to occur in our territory from 

 Florida north but not observed by the writers. Probably will be found 

 along the coast. 



5. S. etuberculatus (Steud.) Kuntze — Mostly Coastal Plain, in 

 acid limesinks in Georgia and South Carolina, not frequent, ranges 

 from Florida north and west to beyond the limits of our territory. 



6. S. validusY&hl. Great Bulrush — Range covers all of our territory, 

 observed mostly along the coast, but occurs in hard waters inland. 



7. S. californicus (C. A. Meyer) Britton — Similar in appearance to 

 the preceding, occurs in the southernmost part of our territory from 

 Florida westward, common in marshes along some parts of the Gulf of 

 Mexico. 



