A GUIDE AND KEY TO AQUATIC PLANTS 105 



5. Sepal wing narrow, narrower than the sepal body 3. X. amhigua. 



5. Sepal wing broad, broader than the sepal body 4. X. stricta. 



6. Keel or wing cross-toothed or incised 7. 



6. Keel or wing lacerate 9. 



7. Spike ovoid, oval or globular, 5-15 mm. long at 8. 



maturity; scales in relatively few series. 

 7. Spikes oblong to conic-oblong, 16-23 mm. long at 5. X. elata. 

 maturity; scales in many series. 



8. Bracts loosely imbricate in few series, decid- 6. X. caroliniana. 



uous. 

 8. Bracts closely imbricate in several series, 7. X. jupacai. 

 persistent. 

 9. Lateral sepals crested from about the middle or just 10. 



below it to the apex, the crest erect or nearly so. 

 9. Lateral sepals crested from the base to the apex, the 8. X. iridifolia. 

 crest spreading or partially recurved. 



10. Spike acute; lateral sepals with the wing nar- 9. X. difformis. 

 row or obsolete near the base; leaves and 

 scape smooth. 

 10. Spike obtuse; lateral sepals with the wing 10. X. serotina. 

 broad to the base; leaves and scape rough- 

 margined. 

 11. Leaves numerous, blades mostly 1-2 mm. wide at 11. A', elliottii. 



maturity. 

 11. Leaves few; blades mostly 5-10 mm. wide at maturity— 12. 



12. Crest of the lateral sepals of very short erect 12. X. smalliana. 



segments; upper part of scape smooth. 

 12. Crest of the lateral sepals of very long spread- 13. X. fimbriata. 

 ing segments; upper part of scape rough. 



1. X. haldwiniana R. & S. St. Marys-grass — Coastal Plain pine- 

 land ponds, Florida to North Carolina and westward to beyond our 

 boundary. 



2. X. torta J. E. Smith— Of more northern distribution, various 

 provinces, Georgia north and west. 



3. X. amhigua Beyr. — Swamps in the Coastal Plain, Florida to 

 North Carolina and westward along the Gulf to beyond the limit of 

 our territory. 



4. X. stricta Chapm. — More southernly in its distribution. Found 

 around pineland pools. Coastal Plain, Florida to Mississippi along the 

 Gulf of Mexico. 



5. X. elata Chapm. — Florida northward and westward to the limits 

 of our range in Coastal Plain swamps and ponds. 



6. X. caroliniana Walt. Yellow-eyed Grass — Shallow ponds and 

 swamps, often very acid, Coastal Plain, Florida north and west to the 

 limits of our territory. 



7. X. jupacai Rich. — Distribution very similar to the preceding. 

 Called X. communis Kunth in many manuals. 



8. X. iridifolia Chapm. — Shallow ponds, Florida to Georgia and 

 westward mostly in the Coastal Plain. 



