96 PUBLIC HEALTH BULLETIN NO. 286 



25. Inflorescence with many spikelets, more or less nodd- 23. R. perplexa. 



ing; tubercle confluent with achene body. 

 25. Inflorescence with few spikelets; tubercle with a ring- 24. R. globularis. 

 like base, sharply differentiated from achene body. 



26. Achene constricted at base to a stipe 25. R.stipiiata. 



26. Achene not stipitate 27. 



27. Clusters of spikelets on erect or ascending stalks 28. 



27. Clusters of spikelets with divaricate stalks. 26. R.miliacea. 



28. Tubercle not setose 29. 



28. Tubercle setose 31. 



29. Perianth-bristles about as long as achene but shorter 30. 



than tubercle. 

 29. Perianth-bristles as long as achene and tubercle 27. R.schoenoides. 



30. Tubercle blunt, achene orbicular 28. R. rrdcrocarpa. 



30. Tubercle sharp-pointed, achene ellipsoidal 20. R.decurrens. 



31. Perianth-bristles not longer than achene and tubercle. _ 30. R.patula. 

 31. Perianth-bristles longer than achene and tubercle 32. 



32. Achene broadly obovoid or orbicular obovold- 31. R.caduca. 



32. Achene narrowly obovoid 32. R, mixta. 



1. R. tracyi Britton — Coastal Plain pineland ponds and swamps, 

 Florida to Georgia and Mississippi. 



2. R. corniculata (Lam.) A. Gray — Mostly on the Coastal Plain 

 over most of our territory. A variety, interior Fernald, is found in the 

 western part of our range. 



3. R. wucrostachya Torr. — Found in a variety of aquatic situations, 

 range includes all of our territory. 



4. R. inundata (Oakes) Fernald — Coastal Plain, probably most 

 common in the eastern part of our territory. 



5. R. careyana Fernald — Coastal Plain, recorded in the literature 

 only from Florida. The- senior author has collected it also in South 

 Georgia. 



6. R. intermixta C. Wright — Piueland ponds and swamps in the 

 southern part of our territory, Florida westward along the Gulf to 

 beyond the limits of our territory. 



7. R. chapmanii M. A. Cm-tis — Coastal Plain in acid situations, 

 Florida to North Carolina and Louisiana. 



8. R. glomerata (L.) Vahl — As used here, includes R. capitellata 

 (Michx.) Vahl and R. lepiocarpa (Chapm.) Small. Ranges over all of 

 our territory, conunon mostly in acid situations especially in the 

 Coastal Plain. 



9. R. chalarocephala Fernald & Gale — Recently described species, 

 acid ponds, Virginia south to South Carolina. May prove to have a 

 wider distribution. 



10. R. cephalantha A. Gray — Acid ponds and swamps, Coastal Plain, 

 over most of our territory. 



11. .R. microcephala Britton — Similar species, distribution very like 

 that of the preceding. 



